Image processing device, method, and program

Abstract

To provide an image processing device that improves image quality in edge portions of an object.SOLUTION: As a result of processing by dot arrangement means, in a first edge pixel of a first edge portion of an object, a ratio of dots arranged in a second region is smaller than a ratio of dots arranged in a first region. In a second edge pixel of a second edge portion different from the first edge portion of the object, the ratio of dots arranged in the first region is smaller than the ratio of dots arranged in the second region.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image processing device, method, and program. [Background technology]

[0002] In a recording device that records color materials on a recording medium, a technique for detecting edges of an image and changing the recording process to improve the sharpness of recorded characters and lines (hereinafter referred to as edge processing) is generally known. Patent Document 1 discloses a technique for changing the recording dots inside edge pixels in an inkjet recording device to reduce deterioration of image quality caused by bleeding of the recorded ink on the recording medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-52872 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need to improve image quality at the edges of objects.

[0005] An object of the present invention is to provide an image processing device, method, and program that can further improve image quality at the edge portions of objects. [Means for solving the problem]

[0006] In order to solve the above problem, the image processing device of the present invention comprises a recording means capable of recording dots at a resolution higher than the resolution of image data, a quantization means that performs a quantization process based on image data including an object, and a dot arrangement means that performs a process of arranging dots in pixels using a dot arrangement pattern corresponding to the quantization value obtained by the quantization process, wherein the recording means has a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object, and as a result of the processing by the dot arrangement means, the ratio at which dots are arranged in the second region at first edge pixels of a first edge portion of the object is smaller than the ratio at which dots are arranged in the first region, and the ratio at which dots are arranged in the first region at second edge pixels of a second edge portion different from the first edge portion of the object is smaller than the ratio at which dots are arranged in the second region. Effect of the Invention

[0007] According to the present invention, the image quality at the edge portion of an object can be further improved. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating a configuration of a recording apparatus. [Diagram 2] FIG. 1 is a diagram showing a configuration including an image processing device. [Diagram 3] 13 is a flowchart showing a process of an image processing unit. [Figure 4] FIG. 13 is a diagram for explaining edge pattern detection. [Diagram 5] FIG. 13 is a diagram for explaining pattern matching. [Figure 6] 13 is a flowchart showing a process of an image processing unit. [Figure 7] 13 is a flowchart showing a process of an image processing unit. [Figure 8] FIG. 11 is a diagram for explaining an index expansion process. [Figure 9] FIG. 2 is a diagram showing a configuration of a recording head. [Figure 10] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 11] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 12] 13 is a flowchart showing a process of an image processing unit. [Figure 13] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 14] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 15] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 16] 13 is a flowchart showing a process of an image processing unit. [Figure 17] 13 is a flowchart showing a process of an image processing unit. [Figure 18] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 19] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 20] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 21] FIG. 11 is a diagram for explaining an index expansion process. [Figure 22] FIG. 11 is a diagram for explaining an index expansion process. [Diagram 23] FIG. 11 is a diagram for explaining an index expansion process. [Figure 24] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Diagram 25] FIG. 11 is a diagram for explaining an index expansion process. [Figure 26] 13 is a flowchart showing a process of an image processing unit. [Figure 27] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 28] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Figure 29] 13 is a flowchart showing a process of an image processing unit. [Diagram 30] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Diagram 31] 13 is a flowchart showing a process of an image processing unit. [Diagram 32] 5A to 5C are diagrams for explaining data on which each process has been executed by the image processing unit; [Diagram 33] FIG. 1 is a diagram showing a configuration including an image processing device. [Diagram 34] 13 is a flowchart showing a process of an image processing unit. [Diagram 35] FIG. 2 is a diagram for explaining a configuration of an image processing unit. [Diagram 36] FIG. 2 is a diagram for explaining a configuration of an image processing unit. [Figure 37] FIG. 2 is a diagram for explaining a configuration of an image processing unit. [Figure 38] FIG. 13 is a diagram showing an edge pixel group. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] [First embodiment] <Structure of the recording device> The structure of the recording device in this embodiment will be described below with reference to FIG. 1. FIG. 1 is a perspective view showing an outline of a recording unit in a recording device 2 (hereinafter also simply referred to as a recording device). A recording medium P (hereinafter also simply referred to as a recording medium) fed to the recording unit is conveyed in the -Y direction (sub-scanning direction) by a nip between a conveying roller 101 arranged on a conveying path and a pinch roller 102 driven by the conveying roller 101 as the conveying roller 101 rotates. A platen 103 is provided at a recording position facing a surface (nozzle surface) on which nozzles are formed of a recording head H of an inkjet recording method, and supports the back surface of the recording medium P from below to maintain a constant distance between the front surface of the recording medium P and the nozzle surface of the recording head H. The recording medium P in the area where recording has been performed on the platen 103 is conveyed in the -Y direction as the discharge roller 105 rotates while being nipped by a discharge roller 105 and a spur 106 driven by the discharge roller 105, and is discharged to a paper discharge tray 107.

[0011] The print head H is detachably mounted on the carriage 108 with its nozzle surface facing the platen 103 or the print medium. The carriage 108 is reciprocated in the X direction, which is the main scanning direction, along two guide rails 109 and 110 by the driving force of a carriage motor (not shown), and during the movement, the print head H executes a discharge operation according to a discharge signal. The ±X direction in which the carriage 108 moves is a direction perpendicular to the -Y direction in which the print medium is transported, and is called the main scanning direction. In contrast, the -Y direction in which the print medium is transported is called the sub-scanning direction. An image is formed stepwise on the print medium P by alternately repeating the main scanning (movement accompanied by discharge) of the carriage 108 and print head H and the transport of the print medium (sub-scanning). The above is the content of the structure of the print device in this embodiment.

[0012] <Recording head structure> The structure of the print head in this embodiment will be described below with reference to FIG. 9. FIGS. 9(a) to 9(c) are schematic diagrams of the print head H used in this embodiment as viewed from the top of the printing apparatus. The print head H has print chips 1105 and 1106, each of which receives a print signal from the printing apparatus body via a contact pad (not shown), and is supplied with power required to drive the print head. As shown in FIG. 9(a), the print chip 1105 is provided with a nozzle row 1101 (hereinafter also referred to as a black nozzle row) in which a plurality of nozzles for ejecting black ink are arranged in the Y direction. Similarly, the print chip 1106 is provided with a nozzle row 1102 for ejecting cyan ink, a nozzle row 1103 for ejecting magenta ink, and a nozzle row 1104 for ejecting yellow ink.

[0013] FIG. 9B is an enlarged view of the black nozzle row 1101. FIG. 9C is an enlarged view of one of the three nozzle rows, i.e., the nozzle rows 1102, 1103, and 1104, i.e., the cyan, magenta, and yellow nozzle rows. This enlarged view is common to all color inks. On both sides of the ink liquid chambers 1107 and 1110, nozzles 1108 and 1111 that eject ink are arranged. Directly below (on the +Z direction side) each nozzle are ejection heaters 1109 and 1112. When a voltage is applied to both heaters 1109 and 1112, they generate heat to generate bubbles, causing ink to be ejected from each nozzle. The nozzle 1108 has 832 nozzles, and the nozzle 1111 has 768 nozzles. The nozzle 1108 ejects black ink, and is arranged in an Ev row and an Od row arranged in the Y direction at a pitch of 600 dpi. The Ev row is shifted by half a pitch in the -Y direction from the Od row. By performing a print scan using the black nozzle row 1101 configured in this way, it is possible to print on the print medium at a print density of 1200 dpi. The cyan nozzle row 1102, magenta nozzle row 1103, and yellow nozzle row 1104 have the same configuration as the black nozzle row 1101.

[0014] The print head H of the present embodiment has a configuration including a print chip having a black nozzle row, and a print chip having a cyan nozzle row, a magenta nozzle row, and a yellow nozzle row, but is not limited to this configuration. Specifically, the black nozzle row, the cyan nozzle row, the magenta nozzle row, and the yellow nozzle row may all be mounted on one chip. Alternatively, a print head mounting a print chip having a black nozzle row and a print head mounting a print chip having a cyan nozzle row, a magenta nozzle row, and a yellow nozzle row may be separate. Alternatively, the black nozzle row, the cyan nozzle row, the magenta nozzle row, and the yellow nozzle row may each be mounted on a separate print head. In addition, the print head H of the present embodiment is a so-called bubble jet type that ejects ink by applying a voltage to a heater to generate heat, but is not limited to this configuration. Specifically, the print head may be configured to eject ink using an electrostatic actuator or a piezoelectric element. The above is the content of the structure of the print head in the present embodiment.

[0015] FIG. 2(a) is a diagram showing an example of the configuration of a printing system including an image forming apparatus 10 equipped with a recording device 2. FIG. 2(a) shows a cloud print system in which a terminal apparatus 11, a cloud print server 12, and an image forming apparatus 10 are connected via a network 13. The cloud print server 12 is a server apparatus that provides a cloud print service. That is, in the configuration of FIG. 2(a), the image forming apparatus 10 is a cloud print-compatible printer. The network 13 is a wired network, a wireless network, or a network including both. The network 13 may be, for example, the Internet, a WAN, or a VPN environment. However, the printing system is not limited to the cloud print system. For example, the network 13 may be configured as an in-house LAN, or the terminal apparatus 11 and the image forming apparatus 10 may be configured to be directly connected without the network 13. FIG. 2(a) shows one each of the terminal apparatus 11 and the image forming apparatus 10, but there may be a plurality of the terminal apparatus 11 and the image forming apparatus 10. The cloud print server 12 may also be a server system configured of a plurality of information processing apparatuses. Furthermore, the printing system may be a cloud print system in which a plurality of cloud print services cooperate with each other.

[0016] The terminal device 11 is an information processing device such as a PC, tablet, or smartphone, and has a cloud printer driver for the cloud print service installed. A user can run any application software on the terminal device 11. For example, a print job and print data are generated via the cloud printer driver based on image data generated on a print application. The print job and print data are transmitted to an image forming device 10 registered in the cloud print service via a cloud print server 12. The image forming device 10 is a device that prints on a recording medium such as paper, and prints an image on the recording medium based on the received print data.

[0017] <Control system configuration> The configuration of the control system in this embodiment will be described below with reference to FIG. 2(b). FIG. 2(b) is a schematic diagram of the image processing device 100. In this embodiment, the image processing device 100 will be described as being included in the image forming device 10. However, the image processing device 100 may be configured as a device connected to the image forming device 10 including the printer 2 and the scanner 202. For example, the image processing device 100 may be configured inside the host computer 201. In that case, the image processing device 100 may not include the printhead control unit 213 and the scanner IF control unit 205.

[0018] The host computer 201 is an information processing device that creates print jobs consisting of input image data and recording condition information required for recording, and corresponds to the terminal device 11 in Fig. 2(a), for example. The recording condition information is information such as the type and size of recording paper, and recording quality.

[0019] The scanner 202 is a scanner device connected to the image processing device 100, and optically reads an original placed on a scanner table, generates analog data, and converts the data into digital data via an AD converter. Scanning by the scanner 202 is executed by sending a scan job from the host computer 201 to the image processing device 100, but is not limited to this. It may also be replaced by a dedicated UI device connected to the image processing device 100 or the scanner 202.

[0020] The ROM 206 is a readable memory that stores a program for controlling the image processing device 100. The CPU 203 controls the image processing device 100 by executing the program stored in the ROM 206. The host IF control unit 204 communicates with the host computer 201, receives print jobs, and stores them in the RAM 207. The RAM 207 is a readable and writable memory that is used as an execution area for programs and a storage area for data.

[0021] The image processing unit 208 generates nozzle data broken down into printable nozzle units from the input image data stored in the RAM 207 in accordance with the printing conditions included in the print job. The generated nozzle data is stored in the RAM 207. The image processing unit 208 is internally configured to include a decoder unit 209, a scan image correction unit 216, an image analysis unit 210, a color separation / quantization unit 211, and a nozzle separation processing unit 212.

[0022] The printhead control unit 213 generates print data based on the nozzle data stored in the RAM 207, and controls the printhead H in the printer 2. The shared bus 215 is connected to each of the processing units, the CPU 203, the host IF control unit 204, the scanner IF control unit 205, the ROM 206, the RAM 207, and the image processing unit 208. The connected units can communicate with each other via the shared bus 215. The above is the configuration of the control system in this embodiment.

[0023] <Overall flow> The flow of edge processing according to this embodiment will be described below. Fig. 3(a) is a flow diagram showing the processing performed by the image processing unit 208 in this embodiment. In this embodiment, the input image data can be converted into nozzle data by the processing in Fig. 3(a).

[0024] In S301, the image processing unit 208 acquires input image data from the RAM 207. In S302, the decoder unit 209 performs a decoding process on the acquired input image data. There are various storage formats for the input image data, and a compression format such as JPEG is generally used to reduce the amount of communication between the host computer 201 and the image processing device 100. If the storage format is JPEG, the decoder unit 209 decodes the JPEG and converts it into a bitmap format (an information format in which an image is recorded as a continuous value of pixel values). When the host computer 201 communicates with the image processing device 100 via a dedicated driver or the like, a dedicated storage format may be handled. If a dedicated storage format that is convenient for both the driver and the image processing device 100 is available, the decoder unit 209 can convert to the dedicated storage format. For example, it is also possible to apply a storage format with a different compression rate between an area where information needs to be stored with fine accuracy and an area where it is not, according to the characteristics of the inkjet recording device. If emphasis is placed on image quality rather than on reducing the amount of communication, the input image data may be in bitmap format, in which case the decoder unit 209 may simply output the bitmap format as the conversion result.

[0025] In S303, the image analysis unit 210 performs image analysis using the bitmap image resulting from the decoding. In this embodiment, the image is analyzed to estimate whether the target pixel is an edge of a pixel formed with paper white or a different ink from the target pixel based on the characteristics of the image. It also estimates whether the target pixel is at the edge of the shape formed by the pixel group in the direction of up, down, left, or right.

[0026] 3B shows an internal processing flow of the image analysis process performed in S303. In S401, the image analysis unit 210 converts the bitmap image, which is the decoded result, into a luminance value. For example, if the bitmap image data is information of three channels of RGB, it is converted into one channel of luminance Y. Note that, if the image data transmitted from the user to the application is already expressed in luminance, S401 does not need to be performed.

[0027] In S402, the image analysis unit 210 converts the luminance Y data into binary data for edge detection. In the present embodiment, as an example, the data is converted into binary data (Bin) according to the following conditional formula (1) using threshold data Th that is provided in advance in accordance with the recording modes provided in the printer. The following binary data generation formula is an example, and the design of the inequality condition and the form of the formula are not limited to this.

[0028] IF Y > Th : Bin = 0 else : Bin = 1 (1) In this embodiment, image analysis is performed using an index called luminance. In an inkjet recording device, the gradation using black ink in color separation is limited. This is because the black ink has a large change in paper surface density for each drop with respect to the white paper, and the use of black ink in large quantities from a light gradation is likely to cause a deterioration in image quality in terms of graininess. For this reason, it is easier to determine the ink generation position of black ink based on the luminance information of the input image compared to other color inks. By setting the above threshold data Th to an appropriate value, it is possible to set a luminance value corresponding to the gradation at which a predetermined amount or more of black ink after ink separation begins to be applied for the luminance information. In this embodiment, it is possible to control the number and arrangement of black ink dots, and the number and arrangement of dots of other color inks adjacent to black ink, and the use of luminance values ​​is in line with this control. However, this embodiment is not limited to this. For example, color separation may be performed in advance for this analysis process to accurately grasp the pixels where black ink occurs as a predetermined color component. If color separation is performed in advance, it is possible to grasp the pixels where not only black ink but also cyan, magenta, and yellow ink occurs and the ejection amount, making it possible to perform a more detailed analysis. There may be cases where the input image data contains information that is useful for analysis, such as the input image data being in CMYK format rather than RGB format. If the ejection amounts of cyan, magenta, and yellow inks are known, it may be possible to make a judgment such as assuming that a small ejection amount is the same as paper white and analyzing the black ink occurring in an area on the paper surface that is equivalent to paper white. In this embodiment, such judgments are expressed by threshold data Th. The threshold data Th may be updated successively based on the degree of wear of each nozzle of the nozzle rows 1101 to 1104 of the print head in the printing apparatus.

[0029] In S403, the image analysis unit 210 performs edge pattern detection using the binary data.

[0030] 4(a) and (b) show examples of pattern information for edge pattern detection. There are two types of pattern information: "for generating pattern matching data" and "for generating edge pattern detection results." For the pattern matching data generation information, a bit AND process is performed on each pixel of the rectangular area of ​​binary data obtained in S402. The pattern matching data obtained as a result of the bit AND process is in a form in which only information necessary for detecting an edge pattern in the rectangular area is extracted. The edge pattern detection result generation information is information for performing pattern matching processing on the pattern matching data. If a perfect match is found as a result of the pattern matching processing, the rectangular area is determined to be a specified edge pattern. The determination result is linked to the central pixel in the rectangular area.

[0031] FIG. 4(a) shows pattern information for determining that the target pixel is "the left and right ends of a 1-dot vertical line." The pattern matching data generation information is set to a value so that edge pattern detection is performed on 3×3 pixels including the target pixel. A pixel assigned with "0" in the pattern matching data generation information is considered to be a pixel that is not considered in pattern matching, regardless of how the binary data is formed. Next, the edge pattern detection result generation information corresponds to the above-mentioned predetermined edge pattern, and in this example, it is a pattern in which only the central row and vertical three pixels in the 3×3 pixels are set to 1. This information is equivalent to determining whether the central row and vertical three pixels are low-luminance and the other six pixels are high-luminance. If the pattern matching data completely matches this pattern, it can be seen that at least the left and right sides have high-luminance characteristics = paper white or low-density color ink, and the target pixel and the upper and lower sides have low-luminance characteristics = black ink.

[0032] Figure 4(b) shows pattern information for determining that the target pixel is not only "the left or right end of a 1dot vertical line" but also "part of a 1dot1space." "1dot1space" refers to a pattern in which multiple 1dot vertical lines are arranged at 1dot intervals. By expanding the range of the pattern matching data generation information to 7x3 pixels, it is possible to include information about the surroundings of the 1dot line to which the target pixel belongs in the determination.

[0033] Figure 4(c) shows the results of sequentially performing pattern matching on binary data using Figures 4(a) and (b). When the pattern matching data generation information and edge pattern detection result generation information in Figure 4(a) are applied to the target binary data, the judgment result is "match." When the pattern matching data generation information and edge pattern detection result generation information in Figure 4(b) are applied, the judgment result is "mismatch." Based on the detection results of the two patterns, it can be seen that the target binary data "is the left or right end of a 1-dot vertical line" and "is not part of a 1-dot 1-space."

[0034] Based on the above method, it is possible to detect various edge patterns. In this embodiment, the target of pattern matching is 7×7 pixels, but this is only one example. For example, if it is sufficient to be able to detect the patterns in FIG. 4(a)(b), the target of pattern matching is 7×3 pixels. On the other hand, if it is desired to individually detect line shapes of 4 dots or more, 7×7 pixels is not sufficient, and a wider area may be set as the target. By expanding the target, more work memory for holding the binary data to be compared and work memory for holding the pattern matching information are required. The work memory corresponds to the RAM 207. When the image analysis unit 210 is a dedicated circuit, if it is desired to process multiple pixels by parallel clk for pattern matching, the number of processing registers and processing circuits will also increase. In addition, since the pattern matching information needs to be held in the ROM 206 of the image processing device 100 in advance, the capacity of the ROM 206 is also required. When checking edge patterns in detail and in a variety of ways, a lot of pattern matching information must be held, so it is necessary to design in consideration of such memory capacity and the increase in analysis time due to the increase in the number of comparisons. The determination that "0" in the pattern matching data generation information = "not considered in pattern matching" contributes to reducing memory capacity and the number of comparisons. As another configuration for reducing memory capacity, as shown in FIG. 5, pattern matching of different variations can be performed by processing such as rotation and phase shift. In the upper part of FIG. 5, the pattern matching information shown in FIG. 4(a) is rotated 90 degrees, and the processed pattern information can be used to determine that "it is the upper or lower end of a 1-dot horizontal line." In the lower part of FIG. 5, the pattern information shown in FIG. 4(a) is shifted horizontally by one pixel, and the processed pattern matching information can be used to determine that "it is an adjacent pixel of a 1-dot vertical line." In FIG. 5, the pattern matching information is processed to increase the variation, but the binary data side can also be processed to increase the variation.

[0035] As shown in Fig. 4(c), it is also effective to narrow down the judgment results by sequentially applying multiple pattern matching information, or to obtain information that could not be obtained from individual pattern matching information. For example, in Fig. 4(c), when the pattern in Fig. 4(a) is "matched", it is not necessary to perform the judgment on the 2-dot line or more that was prepared in advance. Also, by applying only the pattern matching information that judges more detailed information on the 1-dot line, as shown in Fig. 4(b), it is possible to reduce the number of comparisons. Also, by applying Fig. 4(a) and (b), it is possible to know that the target binary data is "the left and right ends of a 1-dot vertical line" and "not part of a 1-dot 1-space". By deriving this information from the results of both Fig. 4(a) and (b) rather than preparing individual pattern matching information that can be obtained, it is effective in reducing memory capacity.

[0036] As described above, this embodiment can determine whether a pixel requires special processing such as thinning out dots or changing the arrangement of dots. This processing is just one example, and an example in which there are more restrictions on the memory and speed of the image processing device 100 will be described later in another embodiment.

[0037] The result of the image analysis process in S303 is output in an information format suitable for processing in the subsequent steps. For example, the result of the determination can be expressed as a 3-bit multi-value such as non-detection (not applicable to any detection pattern) = 0, upper end detection = 1, lower end detection = 2, left end detection = 3, right end detection = 4, adjacent to some end = 5. Alternatively, each bit within 5 bits can be expressed as non-detection = 00000, upper end detection = 00001, lower end detection = 00010, left end detection = 00100, right end detection = 01000, adjacent to some end = 10000. The former has a small amount of data and can be transmitted to the next process. The latter has the advantage of being able to use bit processing in the next process, thereby reducing the processing load. Here, it is described that five pieces of information are transmitted to the subsequent steps, but as explained in the explanation in S303 that "pattern matching information can be expressed in various ways," it is also possible to detect and transmit more information than the control information required in the subsequent processing steps.

[0038] 6 and 7(a) show examples of the internal processing flow of the color separation quantization process performed in S304 and the nozzle separation process performed in S305, respectively. As a premise for the following explanation, it is assumed that the bitmap image resulting from the decoding in S302 has 8-bit 256-level luminance values ​​for each pixel arranged at 600 dpi for R (red), G (green) and B (blue). In addition, in the end information detected in S303, the upper end (first end) is defined as the pixel on the side where Bin changes from 1 to 0 in the -Y direction, the lower end (second end) is defined as the pixel on the +Y direction, the right end (fourth end) is defined as the pixel on the +X direction, and the left end (third end) is defined as the pixel on the -X direction where Bin changes from 1 to 0 and Bin=1. The nozzles of each color in the print head H are arranged at 1200 dpi in the Y direction per color, so that each pixel is printed using the nozzles in the consecutive Ev row (hereinafter referred to as Ev nozzles) and Od row (hereinafter referred to as Od nozzles). Here, the nozzles located on the upper end side of each pixel are defined as upstream nozzles, and the nozzles located on the lower end side of each pixel are defined as downstream nozzles. In this embodiment, the upstream nozzles correspond to the Ev nozzles, and the downstream nozzles correspond to the Od nozzles. That is, in this embodiment, the print resolution is twice as high in the Y direction as the resolution of the image data for which edge pattern detection is performed.

[0039] In the color correction process of S801, the color separation and quantization unit 211 converts the RGB data of each pixel into R'G'B' data expressed in a color space specific to the recording device. A specific conversion method may be, for example, by referring to a lookup table stored in advance in memory.

[0040] In S802, the color separation and quantization unit 211 performs color separation processing on the R'G'B' data. Specifically, by referring to a lookup table stored in advance in memory, the luminance value R'G'B' of each pixel is converted into 8-bit 256-level density value CMYK corresponding to the ink color used by the recording device. Furthermore, the color separation and quantization unit 211 duplicates the density value data of one or more colors of CMYK to generate a total of two identical data. For simplicity, the following will show an example of generating black data K1 and K2. Note that K1 and K2 are applied to the Ev nozzle and Od nozzle of the black nozzle row 1101, respectively, by processing described later.

[0041] In S803 to 805, the color separation and quantization unit 211 performs separate gradation correction processes based on whether the pixel to be processed is the second end or not, using the density value K1 and the result determined in S303. Furthermore, in S806 to 808, the color separation and quantization unit 211 performs separate gradation correction processes based on whether the pixel to be processed is the first end or not, using the density value K2 and the result determined in S303. The gradation correction process is a correction for making the input density value and the optical density expressed by the recording medium P have a linear relationship. This correction process converts the 8-bit 256-level density values ​​K1 and K2 into density values ​​K1'K2' also of 8 bits and 256 levels. If the pixel is detected to be the second end in S303, the density value K1 is converted to K1'=0 in S805, and if not, it is converted to K1' in the first gradation correction process in S804. On the other hand, if the pixel is detected to be the first end in S303, the density value K2 is converted to K2'=0 in S808, and if not, it is converted to K2' in the first gradation correction process in S807. Figures 7(b) and (c) are diagrams showing examples of settings for the first gradation correction process, where In corresponds to the density values ​​K1 and K2, and Out corresponds to the density values ​​K1' and K2'. For simplicity, this explanation shows an example in which In and Out have a linear relationship.

[0042] In S809, the color separation and quantization unit 211 performs a predetermined quantization process on the density value K1' to convert it into quantized data (quantized values) of 4-bit 3 values ​​of "0000", "0001", and "0010". In this example, it is expressed as three values ​​of low density, medium density, and high density. Furthermore, in S810 to S812, the color separation and quantization unit 211 uses the result of the determination in S303 to set a value to the most significant bit based on whether the pixel to be processed is the first end or not, and outputs 4-bit quantized data K1''. Specifically, if the pixel is detected to be the first end, the most significant bit is set to 1 in S812, and if not, the most significant bit is set to 0 in S811. Similarly, in S813, the color separation and quantization unit 211 performs a predetermined quantization process on the density value K2' to convert it into quantized data of 4-bit 3 values ​​of "0000", "0001", and "0010". In this example, it is expressed as three values ​​of low density, medium density, and high density. Furthermore, in S814 to S816, the decomposition quantization unit 211 uses the result of the determination in S303 to set a value to the most significant bit based on whether or not the pixel to be processed is the second end portion, and outputs 4-bit quantized data K2". Specifically, if it is detected to be the second end portion, the most significant bit is set to 1 in S816, and if not, the most significant bit is set to 0 in S815.

[0043] In S305, the nozzle resolution processing unit 212 performs index expansion processing on the quantized data K1'' and K2'' output in S304. In the index expansion processing of this embodiment, a prepared index pattern is used to convert the 600 x 600 dpi quantized data K1'' and K2'' into 600 dpi x 600 dpi binary nozzle data K1p, K2p. The quantized data K1'' is converted into nozzle data K1p in a first index expansion processing in S817 of FIG. 7(a), and the quantized data K2'' is converted into nozzle data K2p in a second index expansion processing in S818. In other words, an index pattern is a dot arrangement pattern for arranging dots in pixels.

[0044] 8(a) to 8(d) are diagrams showing examples of dot arrangement patterns and reference index patterns used in the index expansion process. FIG. 8(a) is a diagram showing dot arrangement patterns in the first index expansion process. When quantized data K1'' of one pixel of 600 dpi x 600 dpi indicates "0000" or "1000", dots are not arranged in the corresponding pixel. When quantized data K1'' indicates "0001", pattern A in which dots are arranged and pattern B in which dots are not arranged are prepared. When quantized data K1'' indicates "0010", "1001", or "1010", dots are always arranged in the corresponding pixel. FIG. 8(b) is a diagram showing dot arrangement patterns in the second index expansion process. When quantized data K2'' of one pixel of 600 dpi x 600 dpi indicates "0001", pattern A in which dots are not arranged and pattern B in which dots are arranged are prepared. When the quantized data K2'' indicates "0000", "1000", "0010", "1001", or "1010", the process is the same as the first index expansion process. FIG. 8C is a diagram showing an example of a reference index pattern. In this embodiment, different index patterns are used in the first index expansion process in S817 and the second index expansion process in S818, but both are created based on the reference index pattern in FIG. 8C. In the reference index pattern, each square corresponds to a one-pixel area of ​​600 dpi x 600 dpi, and it is determined whether dots are arranged in pattern A or pattern B in each pixel. The nozzle resolution processing unit 212 generates nozzle data K1p for each pixel after the first index expansion process as data for the Ev nozzle of the black nozzle row 1101 corresponding to each pixel, and stores the data in the RAM 207. Furthermore, the nozzle resolution processing unit 212 generates nozzle data K2p for each pixel after the second index expansion processing as data for the Od nozzle of the black nozzle row 1101 corresponding to each pixel, and stores this in the RAM 207. Figure 8(d) shows binary data of 600 dpi in the X direction and 1200 dpi in the Y direction after the index expansion processing, and the positional relationship between this data and the nozzles of the black nozzle row 1101 when the quantized data of each pixel is all uniformly "0001" (medium density).As shown in the figure, of the Y direction data, 0th, 2nd, 4th,... dots are formed by the Ev nozzles, and 1st, 3rd, 5th,... dots are formed by the Od nozzles. As a result, for each pixel of the 600 dpi x 600 dpi input image data, printing or non-printing is set for each nozzle in the black nozzle row 1101, and printing or non-printing is set for 600 dpi x 1200 dpi. This concludes the edge processing flow according to this embodiment.

[0045] <Modifications of Color Separation and Quantization Unit and Nozzle Separation Processing Unit> In realizing this embodiment, the processing of the color separation and quantization unit 211 and the nozzle separation processing unit 212 is not limited to the examples shown in FIGS.

[0046] For example, the setting example of the index expansion process shown in FIG. 8(a)(b) is a so-called 1-bit index pattern in which the dot arrangement pattern and nozzle data are equivalent to the dot arrangement information, but is not limited to this example. For example, for a dot arrangement pattern of one pixel, a pixel on which a dot is not arranged may be expressed as "00", and a pixel on which a dot is arranged may be expressed as "01" if the most significant bit of the quantized data is "0", and "10" if the most significant bit of the quantized data is "1". Furthermore, the nozzle resolution processing unit 212 may multiply the nozzle data K1p, K2p generated based on the dot arrangement pattern by a mask pattern to generate nozzle data K1p', K2p' equivalent to the dot arrangement condition. Here, the mask pattern is a pattern that expresses one pixel stored in the ROM 206 or the RAM 207 in 2 bits. For example, if the nozzle data K1p is "00", any mask pattern can be set as K1p'=0 to obtain the same dot arrangement condition as in this embodiment. Furthermore, when the nozzle data K1p is "01", the mask pattern is "01" and "11", and when K1p is "10", the mask pattern is "10" and "11" and K1p'=1 is set, and a predetermined mask pattern is applied to achieve the same dot arrangement conditions as in this embodiment. The nozzle data K2p is also the same as K1p.

[0047] Further, in FIG. 6, an example is shown in which the density value K1 referred to by the Ev nozzle and the density value K2 referred to by the Od nozzle are processed separately, but the processing shown in FIG. 16(a) to FIG. 16(c) may also be used.

[0048] 16(a) and (b) are diagrams showing a modified example of FIG. 6. S2201 is the same as S801, so the explanation will be omitted. In S2202, the color separation and quantization unit 211 performs color separation processing on the R'G'B' data and converts it into density values ​​CMYK. The conversion method is the same as S802. However, unlike S802, the density value data is not copied. For simplicity, an example of processing black data K will be shown below.

[0049] In S2203, the color separation and quantization unit 211 performs tone correction processing on the density value K to convert it into a density value K'. The method of tone correction processing is the same as in S804 or S807, and therefore description thereof will be omitted.

[0050] In S2204, the color separation and quantization unit 211 performs a predetermined quantization process on the density value K' to convert it into 4-bit 3-value quantized data of "0000", "0001", and "0010". Furthermore, in S2205 to S2209, the color separation and quantization unit 211 uses the result determined in S303 to set a value to the most significant 2 bits based on the end information of the pixel to be processed, and outputs 4-bit quantized data K''. If the pixel is detected to be the first end, the most significant 2 bits = 01 in S2209, and if the pixel is detected to be the second end rather than the first end, the most significant 2 bits = 10 in S2208. If neither the first end nor the second end is detected, the most significant 2 bits = 00 in S2207.

[0051] In S2210, the nozzle resolution processing unit 212 performs index expansion processing on the quantized data K'' output in S304. In the index expansion processing in this example, a prepared index pattern is used to convert the 600 x 600 dpi quantized data K'' into binary nozzle data K1p, K2p of 600 dpi x 600 dpi.

[0052] FIG. 16(c) is a diagram showing an example of a dot arrangement pattern used in the index expansion process. The dot arrangement pattern in FIG. 16(c) is one in which 600 dpi x 1200 dpi arrangement information is linked above and below. When the quantized data K'' indicates "0000", "0100", or "1000", dots are not arranged above or below the corresponding pixel. When the quantized data K'' indicates "0001", pattern A for arranging dots on the upper side and pattern B for arranging dots on the lower side are prepared. When the quantized data K'' indicates "0010", dots are always arranged above and below the corresponding pixel. When the quantized data K'' indicates "0101" or "0110", dots are always arranged above the corresponding pixel, and dots are never arranged below. When the quantized data K'' indicates "1001" or "1010", dots are always arranged below the corresponding pixel, and dots are never arranged above. The reference index pattern is the same as that in FIG. 8(c). The nozzle resolution processing unit 212 then generates the upper data of the top and bottom arrangement information for each pixel as nozzle data K1p as data for the Ev nozzle in the black nozzle row 1101 corresponding to each pixel and stores this in RAM 207. Furthermore, the nozzle resolution processing unit 212 generates the lower data of the composite nozzle data Kp for each pixel as nozzle data K2p as data for the Od nozzle in the black nozzle row 1101 corresponding to each pixel and stores this in RAM 207.

[0053] According to the above flow, the data printed by each nozzle becomes the same as the flow shown in Fig. 6 to Fig. 8, and the same effect can be obtained. Specifically, for example, in the case of "0110" indicating the upper end, a dot is never placed below the corresponding pixel, and in the case of "1010" indicating the lower end, a dot is never placed above the corresponding pixel. The above is the content related to the modified example of the color separation quantization unit and nozzle separation processing unit according to this embodiment.

[0054] <Processing when nozzles are shifted> In this embodiment, an example is shown in which the upstream nozzle of each pixel is the Ev nozzle and the downstream nozzle is the Od nozzle, but this is only one example. For example, in order to correct a physical positional deviation in the Y direction that may occur between the black nozzle row 1101 and the nozzle rows 1102 to 1104 of other colors, the black nozzle may be shifted in the Y direction by 1200 dpi x odd number with respect to the input image and printed. In this case, the Ev and Od of the nozzles to be used may be interchanged. In S305, the nozzle resolution processing unit 212 generates the nozzle data K1p as data for the Od nozzle of the black nozzle row 1101 and generates K2p as data for the Ev nozzle of the black nozzle row 1101, thereby obtaining the same effect. The above is the content related to the process when shifting the nozzle to be used according to this embodiment.

[0055] <Processing other than the black nozzle row> In this embodiment, the processing from S803 onwards has been described for black data only, but in S802, density value data other than black data, i.e. cyan, magenta and yellow data, are also output. These may be processed in the same way as black data. Alternatively, a different process from that for black data may be used, as shown below.

[0056] 12 shows an example of the internal processing flow of the color separation quantization processing performed in S304 and the nozzle separation processing performed in S305 for cyan, magenta, and yellow. S4701 and S4702 are the same as S801 and S802. Also, S4703 and S4704 are the same as S804 and S809, so their explanation will be omitted.

[0057] In S4705, the color separation and quantization unit 211 uses the result determined in S303 and outputs 4-bit quantized data C'', M'', Y'' based on which end the pixel to be processed is adjacent to. The end here is, for example, the first end or the second end. Specifically, if it is detected that the pixel is adjacent to which end, the most significant bit of the quantized data is set to 1 in S4707, and if not, the most significant bit of the quantized data is set to 0 in S4706.

[0058] In S4708, the nozzle resolution processing unit 212 performs index expansion processing on each of the quantized data C'', M'', and Y'' output in S304. In the index expansion processing in this example, a prepared index pattern is used to convert the 600 dpi x 600 dpi quantized data C'', M'', and Y'' into 600 dpi x 600 dpi binary nozzle data C1p, C2p, M1p, M2p, Y1p, and Y2p.

[0059] 12(c) and (d) are diagrams showing examples of dot arrangement patterns used in index expansion processing, where FIG. 12(c) is an arrangement pattern for Y'', and FIG. 12(d) is an arrangement pattern for C'' and M''. The dot arrangement patterns in FIG. 12(c) and (d) are such that 600 dpi x 1200 dpi arrangement information is linked vertically. When quantized data C'', M'', and Y'' respectively indicate "0000" and "1000", dots of the corresponding color are not arranged on either the top or bottom of the corresponding pixel. When quantized data C'', M'', and Y'' respectively indicate "0001", pattern A is prepared in which dots of the corresponding color are arranged on the top, and pattern B is prepared in which dots of the corresponding color are arranged on the bottom. When quantized data C'', M'', and Y'' respectively indicate "0010", dots of the corresponding color are arranged on either the top or bottom of the corresponding pixel. For quantized data C'', M'', and Y'', dots of the corresponding color are arranged on either the top or bottom of the corresponding pixel even when "1010" is indicated. On the other hand, when the quantized data Y'' indicates "1010", a pattern A in which dots of the color are arranged on the upper side and a pattern B in which dots of the color are arranged on the lower side are prepared. The reference index pattern is the same as that in FIG. 8(c). Then, the nozzle resolution processing unit 212 generates the upper data of the upper and lower arrangement information of the cyan dots of each pixel as nozzle data C1p as data for the Ev nozzle of the cyan nozzle row 1102 corresponding to each pixel, and stores it in the RAM 207. Furthermore, the nozzle resolution processing unit 212 generates the lower data of the upper and lower arrangement information of the cyan dots of each pixel as nozzle data C2p as data for the Od nozzle of the cyan nozzle row 1102 corresponding to each pixel, and stores it in the RAM 207. The same is true for magenta and yellow. As described above, for cyan and magenta, the dots are arranged in the same way regardless of whether the pixel is adjacent to any edge, so dot thinning is not performed. On the other hand, for yellow, if the pixel is adjacent to any edge, dot thinning is performed. Here, it has been explained that dots are thinned out when yellow is adjacent to any edge, but this is not limited to yellow, and thinning may also be performed on cyan and magenta dots when they are adjacent to any edge.This concludes the explanation of the processing for the nozzles other than the black nozzle row. Note that this explanation is common to all embodiments of the present invention.

[0060] <Horizontal line edge processing> An example of edge processing using this embodiment will be described below with reference to the flow shown in FIGS. 3 to 8, with reference to FIGS. 10 and 11. FIG. 10(a) is a diagram showing an input image used in this description, in which a horizontal line is arranged as an image object. Here, the horizontal line is an image that extends uniformly in a direction intersecting with the arrangement direction of the nozzles of the print head H. FIG. 10(a) shows a line in which pixels are arranged at 600 dpi, each pixel has 8 bit 256 gradations for R, G, and B, and each pixel has a luminance value of 0, that is, a so-called black pixel, and has a pixel width of 4 pixels in the Y direction, which is the arrangement direction of the nozzles.

[0061] An input image is first acquired by the image processing unit 208 in S301, and then decoded by the decoder unit 209 in S302. For simplicity, the image after the decoding process is assumed to be the same as that shown in FIG. 10(a). In S303, the image analysis unit 210 detects which end each pixel corresponds to from the decoded image. FIG. 10(b) is a diagram showing luminance Y data after luminance conversion in S401. FIG. 10(c) is a diagram showing binary data obtained by binarizing the luminance Y data with Th=50 in S402. FIG. 10(d) is a diagram showing the result of determining edges for the above binary data. Here, "0" in FIG. 10(d) indicates non-detection, "1" indicates the upper end, and "2" indicates the lower end.

[0062] Next, in S304, the image decoded in S302 is subjected to color separation quantization processing by the color separation quantization unit 211 based on the edge end detection result in S303. FIG. 10(e) is a diagram showing density values ​​K1 and K2 after color separation processing in S802. FIG. 10(f) is a diagram showing density value K1' after gradation correction processing in S803 to S805, and is an example in which the second end is determined to be the lower end in S803. Therefore, the pixel with "2" in FIG. 10(d), that is, the lower end pixel, has a density value of 0. FIG. 10(g) is a diagram showing density value K2' after gradation correction processing in S806 to S808, and is an example in which the first end is determined to be the upper end in S806. Therefore, the pixel with "1" in FIG. 10(d), that is, the upper end pixel, has a density value of 0. FIG. 11(a) shows quantized data K1'' after S809 to S812, and FIG. 11(b) shows quantized data K2'' after S813 to 816. Here, in both S809 and S813, an example is shown in which a density value of 128 is quantized as "0001" and a density value of 255 is quantized as "0010". The definitions of the first end and the second end in S810 and S814 are the same as those in S803 and S806. Therefore, as shown in FIG. 11(a), among the pixels with K1'=255 in FIG. 10(f), the pixels with "1" in FIG. 10(d), i.e., the upper end pixels, have quantized data of "1010", and the other pixels have quantized data of "0010". On the other hand, as shown in FIG. 11(b), among the pixels where K2'=255 in FIG. 10(g), the pixels that are "2" in FIG. 10(d), i.e., the pixels at the bottom, have quantized data of "1010", and the other pixels have quantized data of "0010".

[0063] Next, in S305, the image quantized in S304 is index-expanded by the nozzle resolution processor 212. Figures 11(c) and 11(d) are diagrams showing nozzle data K1p and nozzle data K2p after index expansion processing in S817 and S818. Figure 11(e) is a diagram showing dot arrangement when the print head H prints at 600 dpi x 1200 dpi based on the nozzle data K1p and nozzle data K2p. Comparing Figures 10(a), (d) and 11(e), it can be seen that among the pixels with a luminance value of 0 in Figure 10(a), pixels that are not at the top or bottom in Figure 10(d) have dots arranged in each of the 600 dpi x 1200 dpi regions in Figure 11(e). And among the pixels with a brightness value of 0 in Fig. 10(a), those determined to be at the top in Fig. 10(d) have dots placed only by the upstream nozzle, i.e., the Ev nozzle, in Fig. 11(e).Furthermore, among the pixels with a brightness value of 0 in Fig. 10(a), those determined to be at the bottom in Fig. 10(d) have dots placed only by the downstream nozzle, i.e., the Od nozzle, in Fig. 11(e).

[0064] As described above, in this embodiment, in an apparatus configuration capable of recording dots at a higher resolution in the Y direction than the image data for edge detection, the upper end pixel and the lower end pixel are detected as edge pixels on the object side of two opposing sides (one side and the other side) of the edge portion of the object in the image data. Then, by determining whether the edge pixel is an upper end pixel or a lower end pixel and changing the arrangement of the dots, dots in the area closer to the inside of the object (hereinafter also referred to as the non-end side) are thinned out, and dots in the area closer to the end of the object (hereinafter also referred to as the end side) are not thinned out. In other words, the ratio of dots formed on the non-end side is smaller than the ratio of dots formed on the end side, and the magnitude relationship between the ratios is equal between the edge pixels at the upper end and the edge pixels at the lower end. This arrangement of dots can reduce image quality degradation due to bleeding of the recorded ink on the recording medium. Furthermore, since edge detection can be performed with image data with a lower resolution than the apparatus configuration, i.e., the resolution in the nozzle arrangement direction of the recording head H, it is possible to reduce the load of image processing.

[0065] [Second embodiment] <Edge processing for widths of 2 pixels or less> The second embodiment will be described below with respect to the differences from the first embodiment. In the first embodiment, the processing in the case of a horizontal line having a width of four pixels as an object of the input image was described. FIG. 13(a) is a diagram showing a horizontal line (hereinafter referred to as a 2dоt horizontal line) in which pixels are arranged at 600 dpi, each pixel has 8 bit 256 gradations for R, G, and B, and each pixel has a luminance value of 0, that is, a so-called black pixel, has a width of two pixels in the Y direction. FIG. 13(b) shows the edge detection result when the processing of the first embodiment is applied to the 2dоt horizontal line. As shown in the figure, the pixel indicating the upper end "1" and the pixel indicating the lower end "2" are adjacent to each other in the Y direction. FIG. 13(c) is a diagram showing the dot arrangement after processing is performed based on the edge detection result and index development is performed in S305. As shown in the figure, the thinned-out areas are adjacent to each other in the Y direction. In this case, the thinned-out areas are easily visible, and there is a risk of a visual mismatch occurring between the input image and the recorded image. In this embodiment, the flow of edge processing for the 2dot horizontal line shown in Fig. 13(a) will be described. Note that steps S301 to S302 are the same as those in the first embodiment, so the description will be omitted.

[0066] In the image analysis process performed in S303, the image analysis unit 210 detects a 2dot horizontal line during edge detection in S403. As a result of the detection, the upper edge pixel is output as "1" as in the first embodiment, while the lower edge pixel is output as "0" as a non-detected pixel. The lower edge pixel is output as "0" only when there is only a 2dot horizontal line. In other words, when a horizontal line having a width of 3 pixels or more is detected, it is output as "2" as in the first embodiment. FIG. 13(d) is a diagram showing the edge detection result of S303 in this embodiment. The subsequent steps S304 to S305 are the same as in the first embodiment, so a description thereof will be omitted.

[0067] FIG. 13(e) is a diagram showing the dot arrangement of a 2dоt horizontal line when printing is performed after index expansion processing in S305 of this embodiment. As shown in the figure, the upper pixels have the same edge detection result as the upper end pixels in the first embodiment, so dots are thinned out in the same way as in the first embodiment. On the other hand, the lower pixels are not detected as edge pixels, so they are processed in the same way as pixels not detected as edge pixels in the first embodiment, and dots are not thinned out. As described above, by changing the edge determination of the lower end pixels only for 2dоt horizontal lines, thinning areas are no longer adjacent in the Y direction, and the possibility of a visual mismatch between the input image and the printed image can be reduced.

[0068] In this embodiment, the lower pixel is treated as not detected in S403, but this is merely an example. For example, the upper end pixel of the detected 2dot horizontal line may be treated as not detected and output as "0", and the lower end pixel may be output as "2" as in the first embodiment. Even in this case, the thinning areas are not adjacent to each other in the Y direction, and the same effect can be obtained.

[0069] In addition, for horizontal lines with a width of 1 pixel (hereinafter referred to as 1dot horizontal lines), the number of dots on the recording medium is halved when processing is performed in the same manner as in the first embodiment. Even in this case, the change in density due to thinning is easily visible, and there is a risk of a visual mismatch between the input image and the recorded image. In order to reduce the possibility of this mismatch occurring, a 1dot horizontal line may be detected during edge detection in S403, and the pixel may be output as non-detected "0" and not thinned out in subsequent processing. For the same reason, a vertical line with a width of 1 pixel (1dot vertical line) and a pixel surrounded by pixels with Bin=0 on the top, bottom, left and right may also be output as non-detected in 403 and not thinned out in subsequent processing.

[0070] [Third embodiment] <Edge processing of solid images> The third embodiment will be described below with respect to the differences from the first and second embodiments. In the first embodiment, the processing in the case of a horizontal line having a width of four pixels as an object of the input image was described. FIG. 14(a) is a diagram showing an input image in which pixels are arranged at 600 dpi, each pixel has 8 bit 256 gradations for R, G, and B, and each pixel has a luminance value of 0, i.e., a so-called black pixel, and has an object including a left edge pixel and a right edge pixel. Hereinafter, the above rectangular image is referred to as a solid image. FIG. 14(b) is a diagram showing a dot arrangement after the above solid image is subjected to the same processing as the first embodiment and index development processing is performed in S305. As shown in the figure, a portion of the dots is not thinned out at the left edge pixel and the right edge pixel. In order to reduce image quality deterioration due to bleeding of the printed ink on the printing medium at the left and right edges of the printed image, it is preferable to thin out the dots at the left edge pixel and the right edge pixel. In this embodiment, the flow of edge processing of the solid image shown in FIG. 14(a) will be described. Note that, since S301 to S302 are similar to those in the first embodiment, the description thereof will be omitted.

[0071] In the image analysis process performed in S303, the image analysis unit 210 outputs the upper edge pixel as "1" in the same manner as in the first embodiment, and also outputs the left edge pixel as "1" in the edge detection in S403. Furthermore, the image analysis unit 210 outputs the right edge pixel as "2" in the same manner as in the first embodiment, and also outputs the lower edge pixel as "2". FIG. 14(c) is a diagram showing the edge detection result in S303 of this embodiment. In this embodiment, the lower left pixel, which is the left edge and the lower edge, is set to "1", and the upper right pixel, which is the right edge and the upper edge, is set to "2", but this is merely an example and other settings may be used. The subsequent steps S304 to S305 are the same as in the first embodiment.

[0072] 14D is a diagram showing the dot arrangement of a solid image when printing is performed after index expansion processing by the nozzle decomposition processing unit 212 in S305 of this embodiment. As shown in the figure, the left edge pixel has a dot arrangement similar to that of the top edge pixel, and the right edge pixel has a dot arrangement similar to that of the bottom edge pixel. In other words, it can be seen that dots are also thinned out for the left edge pixel and the right edge pixel.

[0073] As described above, in this embodiment, in addition to the upper and lower edge pixels, which are edge pixels on two opposing sides of an object, the left and right edge pixels are detected and determined. Then, by changing the dot arrangement according to the determination result, the dots on the left and right edges are thinned out, making it possible to reduce the above-mentioned image quality degradation in those areas.

[0074] In this embodiment, the outputs of the left edge pixel and the right edge pixel in S403 are "1" and "2", respectively, but this is merely an example and other combinations are also possible. Even if the outputs are "1" "1", "2" "1", "2" "2", the dots of the left edge pixel and the right edge pixel are thinned out, so the same effect can be obtained.

[0075] In this embodiment, the outputs of the left edge pixel and the right edge pixel in S403 are "1" and "2", respectively, but the outputs may be "3" and "4" so as to be distinguishable separately. Then, in S806 and S810, the first edge is judged as to whether "1" or "3" is detected, and in S803 and S814, the second edge is judged as to whether "2" or "4" is detected. This can provide the same effect.

[0076] On the other hand, for vertical lines with a width of two pixels (hereinafter referred to as 2dоt vertical lines), the number of dots on the print medium is halved when processing is performed in the same manner as in this embodiment. As in the second embodiment, in this case, the change in density due to thinning is easily visible, and there is a risk of a visual mismatch between the input image and the printed image. To reduce the possibility of this mismatch occurring, as with the 2dоt horizontal lines in the second embodiment, 2dоt vertical lines may be detected during edge detection in S403, and the left edge pixel or right edge pixel may be output as non-detected "0", so that dots are not thinned out in subsequent processing.

[0077] [Fourth embodiment] <Edge processing of solid images with medium density> The fourth embodiment will be described below with respect to the differences from the first to third embodiments. In the first to third embodiments, the processing for the case where the luminance values ​​of an object in an input image are so-called black pixels, that is, R, G, and B are all 0, has been described. Naturally, this is not limited to black pixels. Below, as shown in FIG. 14(e), an example of edge processing of a solid image with intermediate density will be described using an example where the luminance values ​​of an object are all 128 for R, G, and B. Note that the processing itself of S301 to S305 is the same as that of the third embodiment, and therefore a description thereof will be omitted.

[0078] FIG. 14(f) is a diagram showing luminance Y data after luminance conversion in S401 by the image analysis unit 210. FIG. 14(g) is a diagram showing binary data obtained by binarizing the luminance Y data at Th=50 in S402. FIG. 14(h) is a diagram showing the results of edge detection on the binary data. As shown in the diagram, even though the input image has a medium density, it can be seen that the edge ends are detected with the upper and left edge pixels being "1" and the lower and right edge pixels being "2". This is because the luminance-converted image is binarized at Th=50 and edge detection is performed using this image.

[0079] FIG. 15(a) shows the density value K1' after the gradation correction process in S803 to S805 by the color separation and quantization unit 211. As shown in the figure, the pixels indicated as "2" in FIG. 14(h), i.e., the pixels at the bottom and right ends, have a density value of 0, and the pixels of the other objects have been converted to a value of 128 according to the gradation correction process shown in FIG. 7(b) and (c). FIG. 15(b) shows the density value K2' after the gradation correction process in S806 to S808. As shown in the figure, the pixels indicated as "1" in FIG. 14(h), i.e., the pixels at the top and left ends, have a density value of 0, and the pixels of the other objects have been converted to a value of 128 according to the gradation correction process shown in FIG. 7(b) and (c). FIG. 15(c) shows the quantized data K1'' quantized by the color separation and quantization unit 211 under the conditions described in the first embodiment in S809 and then passed through S810 to S812. FIG. 15(d) is a diagram showing quantized data K2'' that has been quantized by the color separation and quantization unit 211 under the conditions described in the first embodiment in S813 and then passed through S814 to S816. As shown in FIG. 15(c), among the pixels with K1'=128 in FIG. 15(a), the quantized data of the pixels that are "1" in FIG. 14(h), i.e., the upper end pixel and the left end pixel, is "1001", and the other pixels are "0001". On the other hand, as shown in FIG. 15(d), among the pixels with K2'=128 in FIG. 15(b), the quantized data of the pixels that are "2" in FIG. 14(h), i.e., the lower end pixel and the right end pixel, is "1001", and the other pixels are "0001".

[0080] 15(e) and (f) are diagrams showing nozzle data K1p and nozzle data K2p after index expansion processing by the nozzle resolution processing unit 212 in S817 and S818. FIG. 15(g) is a diagram showing a dot arrangement when the print head H prints at 600 dpi x 1200 dpi based on the nozzle data K1p and nozzle data K2p. As shown in the diagram, pixels where the quantized data K1'' and K2'' are both "0001", i.e., pixels that are not determined to be at the end, have different dot arrangements in 600 dpi x 600 dpi, as in FIG. 8(d). On the other hand, for the pixels at the top and left ends, dots are uniformly arranged only on the upstream nozzles, i.e., the Ev nozzles. Furthermore, for the pixels at the bottom and right ends, dots are uniformly arranged only on the downstream nozzles, i.e., the Od nozzles. That is, the dot arrangement of the pixels at the end is the same as the dot arrangement of the third embodiment shown in FIG. 14(d). This is because, as shown in FIGS. 8(a) and 8(b), the same arrangement is set for the quantized data "1001" and "1010".

[0081] As described above, in this embodiment, even for objects of intermediate density, the edge pixels of the object are detected and determined to be the upper end pixel, lower end pixel, left end pixel, or right end pixel, and the arrangement of dots is changed accordingly. This makes it possible to uniformly arrange dots on edge pixels and improve the sharpness of the edges. Furthermore, for the upper and lower edges, by arranging dots only on the edge side of the edge pixels, it is possible to reduce deterioration of image quality due to bleeding of the recorded ink on the recording medium.

[0082] [Fifth embodiment] <Modification of dot arrangement of edge pixels using tone correction processing> The fifth embodiment will be described below with respect to the differences from the first to fourth embodiments. In the first to fourth embodiments, when thinning out or changing the arrangement of dots of edge pixels, an example of arrangement in which dots are uniformly arranged on the end side of the pixel and dots are not placed on the non-end side is described. However, this example is only one example, and the optimal dot arrangement of edge pixels may differ depending on the configuration of the recording device and the degree of bleeding of the recorded ink on the recording medium. For example, an arrangement in which dots are added to the non-end side of edge pixels or an arrangement in which dots on the end side of edge pixels are thinned out may be preferable. In this embodiment, an example of edge processing that realizes the above arrangement by applying the tone correction process performed by the color separation and quantization unit 211 will be described. In the example described below, S301 to S303 are all the same as in the first embodiment, so the explanation will be omitted.

[0083] FIG. 17 shows an example of an internal processing flow of the color separation and quantization processing performed by the color separation and quantization unit 211 in S304 in this embodiment. S2401 and S2402 are the same as S801 and S802, respectively, and therefore the description will be omitted. In S2403 to S2407, the color separation and quantization unit 211 converts the density value K1 to a density value K1' by performing separate gradation correction processing using the result determined in S303. Specifically, if the pixel is the second end in S303, it is converted to K1' by the third gradation correction processing in S2407, and if it is not the second end but the first end, it is converted to K1' by the second gradation correction processing in S2406. If it is neither the second end nor the first end, it is converted to K1' by the first gradation correction processing in S2405. On the other hand, in S2408 to S2412, the color separation and quantization unit 211 converts the density value K2 to a density value K2' by performing separate gradation correction processes using the results determined in S303. Specifically, if the pixel is the first end in S303, it is converted to K2' by the third gradation correction process in S2412, and if it is not the first end but the second end, it is converted to K2' by the second gradation correction process in S2411. If it is neither the first end nor the second end, it is converted to K2' by the first gradation correction process in S2410. The first gradation correction process in this embodiment is the same as that described in the first embodiment. The second gradation correction process is a correction of the gradation value for controlling the number of dots on the end side of the edge pixel, and the third gradation correction process is a correction of the gradation value for controlling the number of dots on the non-end side of the edge pixel. These will be described in detail later. In S2413, the color separation and quantization unit 211 performs the same quantization process as in S809 on the density value K1', converting it into 4-bit 3-value quantized data. Furthermore, in S2414 to S2416, the color separation and quantization unit 211 uses the result of the determination in S303, sets a value to the most significant bit of the quantized data based on the end information of the pixel to be processed, and outputs 4-bit quantized data K1". Specifically, if the pixel is detected to be the first end or the second end, the most significant bit is set to 1 in S2416, and if not, the most significant bit of the quantized data is set to 0 in S2415.Similarly, in S2417, the color separation and quantization unit 211 performs the same quantization process as in S812 on the density value K2', converting it into 4-bit 3-value quantized data. Furthermore, in S2418 to S2420, the color separation and quantization unit 211 uses the result determined in S303, sets a value to the most significant bit of the quantized data based on edge information of the pixel to be processed, and outputs 4-bit quantized data K2". Specific processing details are the same as in S2414 to S2416. Next, in S305, the image quantized in S304 is subjected to index expansion processing by the nozzle separation processing unit 212, but since the processing details are the same as in the first embodiment, a description thereof will be omitted.

[0084] Below, a specific processing example is shown in which, as in the third embodiment, the first end is the top end or the left end, the second end is the bottom end or the right end, and the input image is as shown in Figure 14(a).

[0085] FIG. 18(a) shows an example of setting the second gradation correction process and the third gradation correction process to realize an arrangement in which dots are added to the non-end side of edge pixels. In this example, the dot arrangement on the end side of edge pixels is the same as in the first to fourth embodiments, so the second gradation correction process is equal to the first gradation correction process. On the other hand, in the third gradation correction process, Out=0 when In≦128, Out is gradually increased when In>128, and Out=32 when In=255. FIGS. 18(b) and (c) show density values ​​K1' and K2' to which this setting value is applied. FIGS. 19(a) and (b) show quantized data K1'' obtained by performing S2413 to S2416 on density value K1', and quantized data K2'' obtained by performing S2417 to S2420 on density value K2', respectively. FIG. 19(c) shows a dot arrangement when printing is performed after index expansion processing in S305. As shown in these figures, since the density value K1 of the right-most pixel and the bottom-most pixel is "32", a part of the quantized data of the pixel may be "1001" probabilistically, and a dot is placed downstream of the pixel accordingly. On the other hand, since the density value K2 of the left-most pixel and the top-most pixel is "32", a part of the quantized data of the pixel may be "1001" probabilistically, and a dot is placed upstream of the pixel accordingly. In other words, a dot can be added to the non-end side of the top-most pixel and the bottom-most pixel. In this description, the maximum value of the third gradation correction process is "32", but it is not limited to this value. For example, if it is more preferable to add dots to the non-end side of the edge pixel, a value larger than "32" may be used, and if it is more preferable to reduce dots, a value smaller than "32" may be used.

[0086] FIG. 20(a) shows an example of the settings of the second tone correction process and the third tone correction process for realizing an arrangement in which dots on the end side of edge pixels are thinned out. In this example, the dot arrangement on the non-end side of edge pixels is the same as in the first to fourth embodiments, so the third tone correction process sets Out=0 regardless of the value of In. On the other hand, the second tone correction process sets the relationship between In and Out to be the same as that of the first tone correction process in the area where Out≦96, and sets Out=96 in the other areas. FIG. 20(b) and (c) respectively show density values ​​K1' and K2' to which this setting value is applied. And FIG. 19(d) and (e) respectively show quantized data K1'' obtained by performing S2413 to S2416 on density value K1', and quantized data K2'' obtained by performing S2417 to S2420 on density value K2'. FIG. 19(f) shows the dot arrangement when printing is performed after index expansion in S305. As shown in these figures, the density value K1 of the leftmost pixel and the topmost pixel is "96", so part of the quantized data of the pixel may be "0000" with probability, and the dots on the upstream side of the pixel are thinned out accordingly. On the other hand, the density value K2 of the rightmost pixel and the bottommost pixel is "96", so part of the quantized data of the pixel may be "0000" with probability, and the dots on the downstream side of the pixel are thinned out accordingly. In other words, an arrangement in which dots on the edge side of the topmost pixel and the bottommost pixel are thinned out can be realized. In this explanation, the maximum value of the second gradation correction process is "96", but it is not limited to this value. For example, if it is preferable to add more dots to the edge pixel, the value may be greater than "96", and if it is preferable to reduce the dots, the value may be less than "96".

[0087] As described above, in this embodiment, it is detected and determined whether the edge pixel of the object is the upper edge pixel, the lower edge pixel, the left edge pixel, or the right edge pixel, and the gradation correction process is changed accordingly. As a result, it is possible to control the ratio of dots formed in the outer and inner regions while keeping the ratio of dots formed on the non-edge side smaller than the ratio of dots formed on the edge side, as in the first to fourth embodiments.

[0088] [Sixth embodiment] <Modification of dot arrangement of edge pixels using index expansion processing> The sixth embodiment will be described below with respect to the differences from the first to fifth embodiments. In the fifth embodiment, an example of tone correction processing performed by the color separation and quantization unit 211 has been described as a configuration for realizing an arrangement in which dots are added to the non-end side of edge pixels, or an arrangement in which dots on the end side of edge pixels are thinned out. The above arrangement can also be realized by index expansion processing performed by the nozzle separation processing unit 212. In this embodiment, an example of the edge processing will be described. In the example described below, S301 to S303 are all the same as in the third embodiment, so their explanations will be omitted. In addition, S304 is the same as in FIG. 16 described as a modified example of the first embodiment, so their explanations will be omitted. In addition, the input image is the image shown in FIG. 14(a) as in the third embodiment. In addition, in the same manner as in the third embodiment, the first end is the upper end or the left end, and the second end is the lower end or the right end.

[0089] 21(a) to (c) are diagrams showing examples of settings for the third index expansion process performed by the nozzle decomposition processing unit 212 in S305, which are diagrams showing examples of settings for realizing an arrangement in which dots are added to the non-end side of edge pixels. FIG. 21(a) is a diagram showing an example of a dot arrangement pattern. When the quantized data K'' indicates "0000", "0100", or "1000", dots are not arranged on either the top or bottom of the corresponding pixel. When the quantized data K'' indicates "0001", patterns A and C for arranging dots on the top side and patterns B and D for arranging dots on the bottom side are prepared. When the quantized data K'' indicates "0010", dots are always arranged on both the top and bottom of the corresponding pixel. When the quantized data K'' indicates "0101", dots are always arranged on the top side of the corresponding pixel, and dots are never arranged on the bottom side. When the quantized data K'' indicates "0110", dots are always arranged on the top side of the corresponding pixel. And only pattern D arranges dots on the bottom side as well. When the quantized data K'' indicates "1001", dots are always placed below the corresponding pixel, and dots are never placed above it. When the quantized data K'' indicates "1010", dots are always placed below the corresponding pixel. And, only for pattern D, dots are placed above it. Furthermore, the nozzle decomposition processing unit 212 uses two types of reference index patterns according to the quantized data. Specifically, when the quantized data K'' is "0000", "0001", "0010", "0100", or "1000", the first reference index pattern is used, and otherwise the second reference index pattern is used. FIG. 21(b) is a diagram showing the first reference index pattern, and FIG. 21(c) is a diagram showing the second reference index pattern. FIG. 21(d) shows a diagram of dot arrangement when this setting value is applied. As shown in these figures, in the leftmost pixel and the topmost pixel, dots are also placed downstream of the pixel that indicates "D" in the second reference index pattern. Similarly, in the rightmost pixel and the bottommost pixel, dots are also placed upstream. In other words, an arrangement can be realized in which dots are added to the non-end sides of the upper and lower edge pixels.

[0090] FIG. 22(a) is a diagram showing a setting example of the third index development process performed by the nozzle resolution processing unit 212 in S305, which is a setting example for realizing an arrangement in which dots on the end side of edge pixels are thinned out. FIG. 22(a) is a diagram showing an example of a dot arrangement pattern. When the quantized data K'' indicates "0000", "0100", "1000", "0001", or "0010", it is the same as FIG. 21(a). When the quantized data K'' indicates "0101" or "0110", patterns A, B, and C in which dots are arranged only on the upper side of the corresponding pixel, and pattern D in which dots are not arranged are prepared. When the quantized data K'' indicates "1001" or "1010", patterns A, B, and C in which dots are arranged only on the lower side of the corresponding pixel, and pattern D in which dots are not arranged are prepared. Furthermore, the nozzle resolution processing unit 212 uses two types of reference index patterns according to the quantized data. The relationship between the quantized data K'' and the reference index pattern used is the same as in Figure 21(a), and the first and second reference index patterns are the same as in Figures 21(b) and (c), respectively. Figure 22(b) shows the dot arrangement when this setting value is applied. As shown in these figures, for the leftmost and topmost pixels, dots on the upstream side of the pixels showing "D" in the second reference index pattern are thinned out. Similarly, for the rightmost and bottommost pixels, dots on the downstream side are thinned out. In other words, an arrangement can be achieved in which dots on the edge sides of the topmost and bottommost pixels are thinned out.

[0091] As described above, in this embodiment, it is detected and discriminated whether the edge pixel of the object is an upper-end pixel, a lower-end pixel, a left-end pixel, or a right-end pixel, and the index expansion process is changed. As a result, as in the first to fourth embodiments, the ratio of forming dots on the non-edge side remains smaller than the ratio of forming dots on the edge side, and furthermore, it becomes possible to control the ratios of forming dots on the non-edge side and the edge side respectively. Note that, in this embodiment, an example using four types of dot arrangement patterns A to D is shown, but the present invention is not limited to this setting. By defining more dot arrangement patterns and preparing reference index patterns corresponding thereto, it is also possible to further control the amount of dots applied to the non-edge side of the upper and lower pixels, or the amount of dots thinned out on the edge side. In addition, in this embodiment, an example in which only the reference index pattern of the edge pixel is changed is shown, but the present invention is not limited to this setting. Even when a common reference index pattern is used for the edge pixels and the non-edge pixels, it is possible to apply dots to the non-edge side of the upper and lower pixels, or to thin out the dots on the edge side.

[0092] [Seventh Embodiment] [Edge Processing in the Case of Recording with High Resolution in the X Direction] Hereinafter, the seventh embodiment will be described with respect to the differences from the first to sixth embodiments. In the first to sixth embodiments, the edge processing in a device configuration for recording dots with high resolution in the Y direction, that is, the arrangement direction of the nozzles of each color, is described with respect to the image data for edge detection. In this embodiment, the flow of edge processing in a device configuration for recording dots with high resolution in the X direction, that is, the main scanning direction of the recording head H, will be described.

[0093] As a first flow of this embodiment, an example in which a maximum of two dots are arranged in a 600 dpi x 600 dpi pixel, regardless of whether it is an edge pixel or not, will be described. S301 to S304 are the same as in the third embodiment, and therefore description thereof will be omitted. In S305, the nozzle resolution processing unit 212 performs index expansion processing on the quantized data K1'' and K2'' output in S304. In the index expansion processing of this embodiment, a prepared index pattern is used to convert the 600 dpi x 600 dpi quantized data K1'' and K2'' into nozzle data K1p and K2p in which 1200 dpi x 600 dpi data is linked in the left-right direction. The quantized data K1'' is converted into nozzle data K1p in a first index expansion processing in S817, and the quantized data K2'' is converted into nozzle data K2p in a second index expansion processing in S818.

[0094] 23(a) and (b) are diagrams showing examples of dot arrangement patterns in the first index expansion process and the second index expansion process, respectively. In the first index expansion process, when the quantized data K1'' indicates "0000" or "1000", dots are not arranged on either the left or right side of the corresponding pixel. When the quantized data K1'' indicates "0001", pattern A is prepared in which dots are arranged on the left side, and pattern B is prepared in which dots are not arranged on either the left or right side. When the quantized data K1'' indicates "0010", "1001", or "1010", dots are always arranged only on the left side. In the second index expansion process, when the quantized data K2'' indicates "0000" or "1000", dots are not arranged on either the left or right side of the corresponding pixel. When the quantized data K2'' indicates "0001", pattern A is prepared in which dots are not arranged on either the left or right side, and pattern B is prepared in which dots are arranged on the left side. When the quantized data K2'' indicates "0010", "1001", or "1010", dots are always arranged only on the right side. The reference index pattern is the same as that in FIG. 8(c). The nozzle resolution processing unit 212 generates the nozzle data K1p as data for the Ev nozzle of the black nozzle row 1101 corresponding to each pixel, and stores it in the RAM 307. Furthermore, the nozzle data K2p is generated as data for the Od nozzle of the black nozzle row 1101 corresponding to each pixel, and stores it in the RAM 307. When the head control unit 213 generates the print data 214 from the nozzle data K1p and K2p to control the print head H, if the main scanning direction of the print head H is the +X direction, the head control unit 213 generates the K1p and K2p in the order from the left data to the right data. On the other hand, if the main scanning direction of the print head H is the -X direction, the head control unit 213 generates the K1p and K2p in the order from the right data to the left data.

[0095] FIG. 23(c) to FIG. 24(f) are diagrams showing a processing example of the first flow. Note that the first end in S304 is the left end, and the second end is the right end. FIG. 23(c) is a diagram showing an input image having a vertical line as an object. Here, the vertical line is an image that extends uniformly in the arrangement direction of the nozzles of the print head H. FIG. 23(c) shows a line in which pixels are arranged at 600 dpi, each pixel has 8 bit 256 gradations for R, G, and B, and each pixel has a luminance value of 0, that is, a so-called black pixel, has a width of 4 pixels in the X direction. FIG. 23(d) is a diagram showing the result of edge detection of the input image by the image analysis unit 210 in S303. As shown in the figure, the left end pixel is "1" and the right end pixel is "2" as in the third embodiment. FIG. 24(a) shows the density value K1' after the gradation correction processing by the color separation and quantization unit 211 in S803 to S805. As shown in the figure, the pixel marked with "2" in FIG. 23(d), i.e., the pixel at the right end, has a density value of 0. FIG. 24(b) shows density value K2' after gradation correction processing in S806 to S808. As shown in the figure, the pixel marked with "1" in FIG. 23(d), i.e., the pixel at the left end, has a density value of 0. FIG. 24(c) is a diagram showing quantized data K1'' that has been quantized by the color separation and quantization unit 211 in S809 under the conditions described in the first embodiment and then passed through S810 to S812. FIG. 24(d) is a diagram showing quantized data K2'' that has been quantized by the color separation and quantization unit 211 in S813 under the conditions described in the first embodiment and then passed through S814 to S816. As shown in Fig. 24(c), among the pixels where K1'=255 in Fig. 24(a), the pixels where it is "1" in Fig. 23(d), i.e., the left edge pixels, have quantized data of "1010", and the other pixels have quantized data of "0010". On the other hand, as shown in Fig. 24(d), among the pixels where K2'=255 in Fig. 24(b), the pixels where it is "2" in Fig. 23(d), i.e., the right edge pixels, have quantized data of "1010", and the other pixels have quantized data of "0010". The quantized data K1" and K2" are converted to nozzle data K1p and K2p based on the index patterns shown in Figs. 23(a) and (b).Fig. 24(e) is a diagram showing the dot arrangement when the printhead H prints at 1200 dpi x 1200 dpi based on the nozzle data K1p and nozzle data K2p. As shown in the figure, among the pixels with a brightness value of 0 in Fig. 23(c), pixels that are determined to be neither the left end nor the right end in Fig. 23(d) have dots arranged on both the left and right sides of 1200 dpi x 1200 dpi. On the other hand, pixels that are determined to be the left end in Fig. 23(d) have dots arranged only on the left side in Fig. 24(e), and pixels that are determined to be the right end in Fig. 23(d) have dots arranged only on the right side in Fig. 24(e). That is, dots on the non-end side of the pixels are thinned out for both the left end and the right end.

[0096] From the above, even in a device configuration that records dots at a higher resolution in the X direction than the input image data, it is possible to realize an arrangement in which dots on the non-end side of edge pixels are thinned out by determining whether the pixel is a left end pixel or a right end pixel and changing the arrangement of dots accordingly. FIG. 25(a) shows the arrangement of dots when the input image is the solid image shown in FIG. 14(a), the first end in S304 is the upper end or the left end, and the second end is the lower end or the right end. As shown in the figure, in addition to the dots on the non-end side being thinned out at the left end and the right end, similar to FIG. 24(e)(f), the dots on the non-end side are also thinned out at the upper end and the lower end. That is, this embodiment can realize an arrangement in which dots on the non-end side are thinned out at any end pixel.

[0097] In this embodiment, the image resolution for edge detection is 600 dpi x 600 dpi, and the dot arrangement when printing is performed at 1200 dpi x 1200 dpi is shown. However, the resolution in the Y direction may be the same as the resolution for edge detection and the resolution for printing. As a specific example, FIG. 24(f) shows a case where the Ev column and the Od column are not arranged with a half pitch (1200 dpi) shift in the print head H. FIG. 24(f) shows the dot arrangement when the vertical line in FIG. 23(c) is used as the input image in that case. As shown in the figure, at the left end and right end, dots on the non-end side are thinned out as in FIG. 24(e), and it can be seen that the same effect can be obtained.

[0098] <Edge processing when placing 4 dots on a 600dpi x 600dpi pixel> Next, as a second flow of this embodiment, an example of arranging a maximum of four dots in a pixel of 600 dpi x 600 dpi will be described. Since S301 to S302 are the same as those in the third embodiment, the description will be omitted.

[0099] In the image analysis process performed in S303, the image analysis unit 210 outputs the top edge pixel as "1", the bottom edge pixel as "2", the left edge pixel as "3", and the right edge pixel as "4" when detecting edges in S403.

[0100] FIG. 26 shows an example of an internal processing flow of the color separation and quantization processing performed by the color separation and quantization unit 211 in S304 in this embodiment. S3601 to S3608 are the same as S801 to S808, respectively. In S3609, the color separation and quantization unit 211 performs the same quantization processing as S809 on the density value K1', converting it into 4-bit 3-value quantized data. Furthermore, in S3610 to S3616, the color separation and quantization unit 211 uses the result determined in S303, sets a value to the most significant 2 bits based on the edge information of the pixel to be processed, and outputs 4-bit quantized data K1''. Specifically, if the pixel is detected as the first edge, the most significant 2 bits = 01 in S3616; if the pixel is detected as the third edge, the most significant 2 bits = 10 in S3615; and if the pixel is detected as the fourth edge, the most significant 2 bits = 11 in S3614. If the pixel is not the first end, the third end, or the fourth end, the upper 2 bits are set to 00 in S3613. Similarly, in S3617, the color separation and quantization unit 211 performs the same quantization process as in S813 on the density value K2', converting it into 4-bit ternary quantized data. Furthermore, in S3618 to S3624, the color separation and quantization unit 211 uses the result determined in S303 to set a value to the upper 2 bits based on the end information of the pixel to be processed, and outputs 4-bit quantized data K2''. Specifically, if the pixel is detected to be the second end, the upper 2 bits are set to 01 in S3624; if the pixel is detected to be the third end, the upper 2 bits are set to 10 in S3623; and if the pixel is detected to be the fourth end, the upper 2 bits are set to 11 in S3622. If the pixel is not the second end, the third end, or the fourth end, the upper 2 bits are set to 00 in S3621.

[0101] Next, in S305, the image quantized in S304 is index-expanded by the nozzle resolution processor 212. The process flow is the same as that of the first flow. FIG. 25(b) and (c) are diagrams showing examples of dot arrangement patterns in the first index expansion process and the second index expansion process in this flow, respectively. In the first index expansion process, when the quantized data K1″ indicates “0000”, “0100”, “1000”, or “1100”, dots are not arranged on either side of the pixel. When the quantized data K1″ indicates “0001”, “1001”, or “1010”, dots are arranged on the left side of the pixel. When the quantized data K1″ indicates “0010”, “0101”, or “0110”, dots are arranged on both sides of the pixel. When the quantized data K1″ indicates “1101”, “1110”, dots are arranged on the right side of the pixel. In the second index expansion process, if the quantized data K2'' indicates "0001", a dot is placed to the right of the corresponding pixel. In other cases, it is the same as the first index expansion process. The subsequent processing for the nozzle data K1p and K2p generated by the above settings is the same as in the first flow, so a description will be omitted.

[0102] 27(a) to (f) are diagrams showing a processing example of the second flow when the input image is the solid image shown in FIG. 14(a). In this processing example, the first end is the upper end, the second end is the lower end, the third end is the left end, and the fourth end is the right end. FIG. 27(a) is a diagram showing the result of edge detection of the input image by the image analysis unit 210 in S303. As shown in the figure, the upper end pixel is "1", the lower end pixel is "2", the left end pixel is "3", and the right end pixel is "4". FIG. 27(b) shows the density value K1' after the gradation correction processing in S3603 to S3605 by the color separation and quantization unit 211. As shown in the figure, the pixel with "2" in FIG. 27(a), i.e., the lower end pixel, has a density value of 0. FIG. 27(c) shows the density value K2' after the gradation correction processing in S3606 to S3608. As shown in the figure, the pixels that are "1" in FIG. 27(a), i.e., the upper end pixels, have a density value of 0. FIG. 27(d) is a diagram showing quantized data K1" that has been quantized by the color separation and quantization unit 211 in S3609 under the conditions described in the first embodiment and then passed through S3610 to S3616. FIG. 27(e) is a diagram showing quantized data K2" that has been quantized by the color separation and quantization unit 211 in S3617 under the conditions described in the first embodiment and then passed through S3618 to S3624. As shown in FIG. 27(d), of the pixels with K1'=255 in FIG. 27(b), the pixels that are "1" in FIG. 27(a), i.e., the upper end pixels, have quantized data of "0110". Similarly, the pixel with "3" in FIG. 27(a), i.e., the left edge pixel, has quantized data of "1010", and the pixel with "4" in FIG. 27(a), i.e., the right edge pixel, has quantized data of "1110". The pixel with "0" in FIG. 27(a), i.e., the pixel that is not at either edge, has quantized data of "0010". On the other hand, as shown in FIG. 27(e), among the pixels with K2'=255 in FIG. 27(c), the pixel with "2" in FIG. 27(a), i.e., the bottom edge pixel, has quantized data of "0110". The pixels with "3", "4", and "0" in FIG. 27(a) are the same as K1''.The quantized data K1'' and K2'' are converted into nozzle data K1p and K2p based on the index patterns shown in Figs. 25(b) and (c). Fig. 27(f) is a diagram showing the dot arrangement when the printhead H prints at 1200 dpi x 1200 dpi based on the nozzle data K1p and nozzle data K2p. As shown in the figure, among the pixels with a luminance value of 0 in Fig. 14(a), pixels that are determined to be neither the upper end, lower end, left end, nor right end in Fig. 27(a) have dots arranged in the entire 1200 dpi x 1200 dpi area. On the other hand, pixels that are determined to be the upper end in Fig. 27(a) have dots arranged only on the upper side in Fig. 27(f), and pixels that are determined to be the lower end in Fig. 27(a) have dots arranged only on the lower side in Fig. 27(f). Furthermore, pixels determined to be the left end in Fig. 27(a) have dots placed only on the left side in Fig. 27(f), and pixels determined to be the right end in Fig. 27(a) have dots placed only on the right side in Fig. 27(f). In other words, this flow realizes an arrangement in which dots on the non-end side are thinned out for all end pixels.

[0103] In FIG. 27(f), a blank area A is generated in the upper left pixel, upper right pixel, lower left pixel, and lower right pixel in units of 1200 dpi×1200 dpi. It is possible to avoid the blank area A by changing the edge pattern output in S403 and the processes of S3610, S3616, S3618, and S3624. Specifically, first, in S403, the image analysis unit 210 outputs the upper left pixel, which is the left end and upper end, as "5", the lower left pixel, which is the left end and lower end, as "6", the upper right pixel, which is the right end and upper end, as "7", and the lower right pixel, which is the right end and lower end, as "8". FIG. 28(d) is a diagram showing the output result. Then, in S3610, when the color separation and quantization unit 211 detects the upper left "5" and the upper right "7" in addition to the upper end "1", it sets the upper 2 bits of the quantization data K1'' to 01 in S3616. Furthermore, in S3618, if the color separation and quantization unit 211 detects a "6" at the bottom left and an "8" at the bottom right in addition to the "2" at the bottom end, it sets the most significant 2 bits of the quantized data K2" to 01 in S3624. Figures 28(a) and (b) show the quantized data K1" and K2" at this time. This changes the quantized data for the upper left pixel, lower left pixel, upper right pixel, and lower right pixel, and changes the dot arrangement selected in S305. Figure 28(c) is a diagram showing the dot arrangement by this process, and it can be seen that the occurrence of blank area A has been avoided.

[0104] As described above, in this embodiment, in an apparatus configuration capable of recording dots at a higher resolution in the X direction than the image data for edge detection, it is detected and determined whether the edge pixel of the object is an upper end pixel, a lower end pixel, a left end pixel, or a right end pixel, and the arrangement of dots is changed accordingly. As a result, in the X direction, the ratio of dots formed on the non-end side is smaller than the ratio of dots formed on the end side, and the relationship of the magnitude of the ratio is equal between the edge pixel region consisting of the left end pixel and the edge pixel region consisting of the right end pixel. Furthermore, in an apparatus configuration capable of recording dots at a higher resolution in the Y direction, the edge pixel region consisting of the upper end pixel and the edge pixel region consisting of the lower end pixel are also arranged with the same characteristics. This arrangement of dots can reduce image quality degradation due to bleeding of the recorded ink on the recording medium. Furthermore, since edge detection can be performed with image data with a lower resolution than the apparatus configuration, i.e., the resolution in the nozzle arrangement direction and the main scanning direction of the recording head H, it is possible to reduce the load of image processing.

[0105] In this embodiment, an example of processing has been described in which the luminance values ​​of an object in an input image are so-called black pixels, with R, G, and B all being 0, but it is of course not limited to black pixels. As in the description of the fourth embodiment, even in the case of an input image of medium density, if the quantized data is of a density consisting of "XX01" or "XX10" (XX is other than 00), the dot arrangement of edge pixels will be the same as in the case of black pixels. In other words, even in the case of medium density, the sharpness of the edge can be improved, and deterioration of image quality due to bleeding of the recorded ink on the recording medium can be reduced.

[0106] In this embodiment, an example of an arrangement in which dots are uniformly arranged on the end side of edge pixels and dots are not placed on the non-end side has been described. However, this is only one example, and the optimal dot arrangement for edge pixels may differ depending on the configuration of the recording device and the degree of bleeding of the recorded ink on the recording medium. Therefore, as in the explanation of the fifth and sixth embodiments, the settings of the gradation correction process and the index expansion process may be changed to an arrangement in which dots are added to the non-end side of edge pixels, or an arrangement in which dots are thinned out on the end side of edge pixels.

[0107] [Eighth embodiment] <Edge processing to realize a dot arrangement that thins out edge pixels on the edge side> The eighth embodiment will be described below with respect to the differences from the first to seventh embodiments. In the first to seventh embodiments, an example of edge processing in which dots on the non-end side of edge pixels are mainly thinned out has been described. However, depending on the characteristics required for an image recorded on a recording medium, it may be preferable to not thin out dots on the non-end side. When it is required to narrow the image width of a recorded image, it may be more preferable to thin out dots on the end side of edge pixels and uniformly arrange them on the non-end side. For example, when a character or symbol includes a portion in which horizontal and vertical lines are finely arranged, it is possible to more effectively prevent line thickening in such a portion by thinning out dots on the end side of edge pixels and uniformly arranging them on the non-end side. In this embodiment, an example of edge processing that realizes such an arrangement will be described.

[0108] First, an example of printing with high resolution in the Y direction for input image data is shown, similarly to the first to sixth embodiments. As for the flow of edge processing, S301 to S303 and S305 are all similar to the third embodiment, and therefore the description is omitted. FIG. 29 shows an example of the internal processing flow of the color separation quantization processing carried out in S304. Here, the difference between FIG. 29 and FIG. 6 is that the edge information detected in S4103, S4106, S4110, and S4114 is replaced with that in S803, S806, S810, and S814. That is, the arrangement of dots of edge pixels in this embodiment is only the arrangement of the upstream nozzles and the downstream nozzles (Ev nozzles and Od nozzles) replaced with respect to the arrangements in the first to fourth embodiments. As an example, FIG. 30(a) shows the dot arrangement of this embodiment when the input image data is the solid image shown in FIG. 14(a). The definitions of the first and second ends in this example are the same as those in the explanation of the third embodiment. As shown in the figure, except for the pixel indicated by B, the upper edge pixel has a dot arranged only on the downstream side, and the lower edge pixel has a dot arranged only on the upstream side. If it is preferable to arrange a dot on the non-end side for the pixel indicated by B, this can be realized by changing the edge pattern output in S403. Specifically, in S403, the image analysis unit 210 outputs the lower left pixel as "2" like the lower edge pixel, and the upper right pixel as "1" like the upper edge pixel. FIG. 30(b) is a diagram showing the output result. As a result, for the lower left pixel and the upper right pixel, the nozzles that print are switched between the Ev nozzle and the Od nozzle compared to FIG. 29. FIG. 30(c) is a diagram showing the arrangement of dots.

[0109] Next, a processing example will be shown when arranging 4 dots in a pixel of 600 dpi x 600 dpi in the case of printing with high resolution in the X direction for input image data as in the seventh embodiment. As for the flow of edge processing, S301 to S303 and S305 are all similar to the second flow of the seventh embodiment, so the description will be omitted. FIG. 31 shows an example of the internal processing flow of the color separation quantization processing performed in S304. Here, the differences between FIG. 31 and FIG. 26 are S4403, S4406, S4410 to 4412, S4418 to 4420, and S803, S806, S810 to 812, and S818 to 820. Specifically, the first end and the second end are interchanged, and the third end and the fourth end are interchanged for the detected ends. That is, in the arrangement of dots of edge pixels in this embodiment, the arrangement of the upstream nozzles and downstream nozzles (Ev nozzles and Od nozzles) is swapped with respect to the arrangement of the seventh embodiment shown in FIG. 27(f), and the arrangement of the left and right sides is swapped. As an example, FIG. 32(a) shows the dot arrangement of this embodiment when the input image data is the solid image shown in FIG. 14(a). The definitions of the first to fourth ends in this embodiment are the same as those explained in the seventh embodiment. As shown in the figure, except for the pixel indicated by C, dots are arranged only on the downstream side for the upper edge pixel and only on the upstream side for the lower edge pixel, dots are arranged only on the right side for the left edge pixel, and dots are arranged only on the left side for the right edge pixel. If it is preferable not to arrange dots on the end side of the pixel indicated by C, this can be achieved by changing the edge pattern output in S403 and the processes of S4403 and S4406. First, in S403, the image analysis unit 210 outputs the edge information shown in Fig. 28(d) in the same manner as described in the avoidance of blank area A in the seventh embodiment. Then, in S4403, if the color separation and quantization unit 211 detects the upper left edge pixel "5" and the upper right edge pixel "7" in addition to the upper edge pixel "1", it sets the density value K1'=0 in S4405. Furthermore, in S4406, if the color separation and quantization unit 211 detects the lower left edge pixel "6" and the lower right edge pixel "8" in addition to the lower edge pixel "2", it sets the density value K2'=0 in S4408.FIG. 32(b) and (c) are diagrams showing the subsequent quantized data K1'' and K2'', and FIG. 32(d) is a diagram showing the arrangement of dots by this process. As a result of this process, the upper left and upper right edge pixels have quantized data K1''="0000" and no dots are placed on the edge sides, and the lower left and lower right edge pixels have quantized data K2''="0000" and no dots are placed on the edge sides. In other words, for the pixel indicated by C, no dots are placed on the edge sides.

[0110] As described above, in this embodiment, in an apparatus configuration capable of recording dots at a higher resolution than the image data for which edge detection is performed, it detects and determines whether the edge pixel of an object is an upper end pixel, a lower end pixel, a left end pixel, or a right end pixel, and changes the arrangement of dots accordingly. This makes it possible to realize a dot arrangement in which dots are formed only on the non-end side of each end pixel. In other words, it is possible to realize an arrangement that is suitable for narrowing the image width of a recorded image.

[0111] In this embodiment, the input image is described as a solid image, but the input image is not limited to this example. As in the other embodiments, the operation of this embodiment can also be applied to horizontal and vertical lines.

[0112] In this embodiment, an example in which the upper end pixel, the lower end pixel, the left end pixel, and the right end pixel are all thinned out has been described, but this is not limited to the example depending on the characteristics required for the image. For example, if it is desired to output the image width of the recorded image wider than in this embodiment and narrower than in the first to seventh embodiments, it is preferable to thin out one of the upper end pixel and the lower end pixel, and one of the right end pixel and the left end pixel. In that case, it can be realized by setting the output of either the upper end pixel or the lower end pixel to 0 and the output of either the right end pixel or the left end pixel to 0 in the edge pattern output in S403.

[0113] In this embodiment, the processing is described for the case where the luminance values ​​of the object in the input image are so-called black pixels, where R, G, and B are all 0, but it is not limited to black pixels. As in the fourth and seventh embodiments, even if the input image is of medium density, if the quantized data is of a density composed of "XX01" or "XX10" (XX is other than 00), the dot arrangement of the edge pixels will be the same as in the case of black pixels. In other words, even if the input image is of medium density, an arrangement suitable for narrowing the image width of the printed image can be realized.

[0114] In this embodiment, the image analysis process in S303 is similar between this embodiment and the third to seventh embodiments, and an example is shown in which the edge information detected in the color separation quantization process in S304 is changed. However, this process is not limited to this. For example, the parameters of the edge information detected in S304, "1", "2", "3", and "4", may all be the same as those in the third to seventh embodiments, and the edge determination output of the image analysis process in S303 may be changed. As a specific setting example, when arranging two dots in a 600 dpi x 600 dpi pixel, the image analysis unit 210 may output the upper edge pixel and the left edge pixel as "2" in S303, and the lower edge pixel and the right edge pixel as "1". Also, when arranging four dots in a 600 dpi x 600 dpi pixel, the image analysis unit 210 may output the upper edge pixel as "2", the lower edge pixel as "1", the left edge pixel as "4", and the right edge pixel as "3" in S303. Even with such settings, it is possible to obtain a dot arrangement similar to that of this embodiment.

[0115] [Ninth embodiment] <Effective use of main unit resources> The ninth embodiment will be described below with respect to the differences from the first to eighth embodiments. In the first embodiment, image analysis is performed using pattern matching information. The image analysis is performed by the image analysis unit 210, and the analysis result is transmitted to the color separation and quantization unit 211.

[0116] Productivity (printing speed) is an important indicator for office documents printed on inkjet printers, and if the analysis process and the correction process are slower than the required speed, the print head may stop, causing deterioration of image quality. In order to ensure that the analysis process and correction process do not fall behind the required speed, it is effective to make the process a "dedicated circuit". By specializing the circuit logic for a limited purpose like ASIC, it is possible to control it so that there is no extra calculation cost or memory access compared to a CPU, and it is also possible to design the circuit wiring so that data processing can be done with low delay. Therefore, it is common to improve the processing speed compared to a CPU by using a dedicated circuit, and it is also used in the printing and scanning processes of inkjet printers. On the other hand, dedicated circuits take a long time to design once the circuit is decided, and the function cannot be changed after it is made into a circuit. There are semi-dedicated circuit forms with functional flexibility such as FPGA (Field Programmable Gate Array), but in exchange for gaining flexibility, it is necessary to load many wiring switches. Due to the constraints on the circuit size that can be installed in an image processing device, the function may be limited as in the case of ASIC. Considering the time it would take to incorporate new dedicated circuits, there was a problem that responsiveness to market launches would be compromised.

[0117] In this embodiment, a configuration is described in which dot thinning and arrangement control are achieved using dedicated circuits installed in the recording and scanning processes of an inkjet printer. This not only allows for quick response to the market, but also reduces the circuit scale (production costs) by not implementing special processes in dedicated circuits.

[0118] Fig. 33(a) shows an example of an assumed environment for the image processing device in this embodiment. Here, differences from Fig. 2 will be mainly explained. In Fig. 33(a), the image analysis unit 210 does not exist. Each processing unit of the image processing unit 208 is connected to a shared bus 215, and information is transmitted between each processing unit only via the shared bus.

[0119] In a recording process when this embodiment is not implemented, the image processing unit 208 uses dedicated circuits in the order of the decoder unit 209, color separation quantization unit 211, and nozzle separation processing unit 212. In a copy process, the image processing unit 208 uses dedicated circuits in the order of the scan image correction unit 216, color separation quantization unit 211, and nozzle separation processing unit 212. In a scan process, the image processing unit 208 uses a dedicated circuit for the scan image correction unit 216. Note that in copy and scan processes, images may be compressed once for convenience of data transfer, in which case the decoder unit 209 may also be used.

[0120] In this embodiment, a method of performing image analysis using the same dedicated circuit as that used in the scan image correction process originally performed by the scan image correction unit 216 will be described.

[0121] FIG. 33(b) shows a schematic diagram of a processing block of a dedicated circuit included in the scan image correction unit 216. The scan image correction unit 216 acquires data from the RAM 207 via the DMAC 5001. DMAC is an abbreviation for Direct Memory Access Controller, and the scan image correction unit 216 can execute memory access without instructions from the CPU. The presence of the DMAC allows data transfer faster than the CPU without considering the CPU processing load. The data received by the scan image correction unit 216 includes image data acquired from the scanner 202 and processing data (e.g., LookUpTable data, etc.) to be stored in the SRAM contained in the processing units from the DMAC 5001 to the LUT3D 5005. The scan image correction unit 216 includes four processing units. The LUT3D 5002 is a lookup table that outputs RGB three-dimensional output features for RGB three-dimensional input features. Since the scan image is color space information dependent on the scanner device when acquired from the scanner 202, it is converted to standard color space information by the LUT3D 5002. The LUT1D5003 is a lookup table that outputs 1-dimensional output features of RGB for each 1-dimensional input feature of RGB. Here, the density adjustment of the acquired scanned image is performed based on a UI instruction from the user. Next, the FLT5004 is a 5×5 filter for the 3-dimensional input feature of RGB. The data resolution of the scanned image acquired from the scanner 202 is determined based on the scanning resolution of the scanner and the arrangement resolution of the sensor, but the reading accuracy of the sensor is not accurate, so the scanned image appears blurred. The FLT5004 improves the blur by providing a filter coefficient that sharpens the blurred image. The LUT3D5005 is a lookup table that outputs 3-dimensional output features of RGB for each 3-dimensional input feature of RGB. A black crushing and white blowing process is performed in which the darkest part of the pixel value acquired from the scanned image is crushed to black (0, 0, 0) and the brightest part is blown to white (255, 255, 255).

[0122] 33(b) is an extraction of the minimum necessary functions in the scan image correction unit 216, and other functions may be included. For example, individual circuits for scanner shading correction and color misalignment correction may be installed.

[0123] As shown in Fig. 33(c), the individual dedicated circuit of the scan image correction unit 216 explained in Fig. 33(b) is used for the purpose of use in this embodiment. Each process will be explained in detail.

[0124] Fig. 34(a) shows a flowchart of the analysis process in this embodiment. This flowchart is an example of a method for realizing the process of Fig. 3(b), which describes the details of the image analysis process 303 in the first embodiment, with a different configuration.

[0125] In S5201, the bitmap image resulting from the decoding is converted into a luminance value using the LUT3D 5002 in the scan image correction unit 216. FIG. 34(b)(c) shows an example of information of a lookup table contained in the SRAM in the LUT3D. FIG. 34(b) shows table information when used in scan image correction. An example of a conversion table from the device color space at the time of acquisition from the scanner 202 to the sRGB color space, which is a standard color space, is shown. On the other hand, FIG. 34(c) shows table information when luminance conversion in this embodiment is performed. An example of a conversion table from input information RGB of the bitmap image resulting from the decoding to luminance Y is shown. For the purpose of explaining this embodiment, the same luminance value information is designed for each of the three dimensions of the output here, but it can be freely designed within the design constraints of the lookup table (for example, the number of grids, the internal interpolation method, etc.).

[0126] In S5202, the information converted to luminance is binarized using the LUT1D 5003 in the scan image correction unit 216. In the first embodiment, binarization was performed from equation (1) using a previously acquired threshold value Th, but in this embodiment, it is performed using a lookup table. Figures 35(a) and (b) show an example of lookup table information contained in the SRAM in the LUT1D. Figure 35(a) shows table information used in scan image correction. This is table information for deriving desired density correction from each of RGB information in the standard color space. Meanwhile, Figure 35(b) shows an example of a conversion table when binarization is performed in this embodiment. In the case of a circuit specification in which interpolation occurs between grids in the lookup table, it is necessary to design so that the binary information in the design value does not become ternary or more due to the interpolation.

[0127] In S5203, edge element detection is performed from the binarized information using the FLT5004 in the scan image correction unit 216. Figures 35(c) and 35(d) show an example of filter coefficient information stored in the SRAM in the FLT. Figure 35(c) shows filter coefficient information when used in scan image correction. The coefficient value is larger toward the center, and the filter end can be designed to have a negative strength. In addition, a desired filter result can be obtained by performing shift processing or offset processing on the filter design result. In addition, a process of clipping a result less than 0 to 0 is also included from the processing result. In scan image correction, the same filter coefficient is applied to each channel of RGB. When filter processing is applied to an isolated point, etc., the point may disappear or spread, so that an isolated point detection process may be performed in advance. On the other hand, Figure 35(d) shows the design of filter coefficients when edge element detection is performed in this embodiment. In this embodiment, as an example, it is assumed that the filter coefficient on the left of Figure 35(d) is applied to one channel, and the filter coefficient on the right of Figure 35(d) is applied to another channel. After filter processing, the offset is +48. The filter application results in FIG. 35(d) correspond to the extraction of "edge elements."

[0128] An example of filter application is shown in FIG. 37. Since FIG. 35(d) shows an example in which the 3×3 region of the filter coefficient is effective, FIG. 37 focuses on the 3×3 region of binary data to explain the application example. FIG. 37 shows the filter application results when the characteristics of the 3×3 region of binary data are different for two fixed filters. FIG. 37(a) shows an example in which the target pixel is an edge pixel at the top edge. When the two filters in FIG. 35(d) are applied, the application results are "48" and "32". FIG. 37(b) shows an example in which the target pixel is an edge pixel at the top right. When the two filters in FIG. 35(d) are applied, the application results are "16" and "32". In this way, it can be seen that the edge pixel at the top edge and the edge pixel at the top right can be determined from the difference in the filter results in FIG. 35(d). FIG. 37(c) shows an example in which the target pixel is an edge pixel at the right edge. When the two filters in FIG. 35(d) are applied, the application results are "16" and "48". It can be seen that the edge pixel at the right end and the edge pixel at the top right can be determined from the difference in the filter results in FIG. 35(d). FIG. 37(d) is an example in which the target pixel is an edge pixel of a 1-dot line. When the two filters in FIG. 35(d) are applied, the application results are "16" and "16". In this way, it can be seen that the edge pixel at the right end and the edge pixel of a 1-dot line can be determined from the difference in the filter results in FIG. 35(d). In this way, it can be said that the application results of the two filters are element information that can be determined by combining the application results, although it is difficult to determine the edge shape of the target pixel by itself. Instead of verifying the pattern matching information to be obtained by individual patterns as in the first embodiment, elements can be extracted without deviating from the functional specifications of FLT5004 in the scan image correction. Note that since the scan image correction unit 216 is premised on handling RGB information, three filter coefficients can be used to detect edge elements for luminance information. Two filters are used here, but three filter coefficients may be used as long as it does not change the existing circuit configuration. In that case, it is possible to design a filter that can estimate the edge shape in more detail. Also, although the description was based on the assumption that the filter coefficients of the FLT5004 are 5 × 5, it can also be said that the coefficient amount can be adjusted as long as it is within the range that does not change the existing circuit configuration.In this embodiment, the design was performed using only a 3 × 3 region out of the assumed 5 × 5, but more detailed judgment can be performed with 5 × 5. If FLT5004 is capable of designing 7 × 7, edge element detection may also be performed by filtering over a wider area.

[0129] In S5204, edge pattern matching is performed using the LUT3D 5005 in the scan image correction unit 216 from the information after applying the filter. FIG. 36 shows an example of lookup table information contained in the SRAM in the LUT3D. FIG. 36(a) shows table information when used in scan image correction. For black crush and white blowout, the table is designed so that the gradation near the input value of 0 approaches 0 and the gradation near 255 approaches 255. FIG. 36(b) shows an example of a table when edge pattern matching is performed in this embodiment. In this table, the table is designed as an example with non-detection=0, upper detection=1, lower detection=2, right detection=3, left detection=4, and adjacent to edge=5.

[0130] The viewpoints considered in designing the lookup table are explained with reference to FIG. 36(c). The binary data was converted into edge elements by FLT5004. The information of the edge pixel at the right end is obtained as "16" when the filter coefficient on the left of FIG. 35(d) is applied, and as "48" when the filter coefficient on the right of FIG. 35(d) is applied. In LUT3D5005, the pixel value after lookup table processing can be output as 3 by setting the output signal of the part corresponding to the grid of Rch=16 and Gch=48 to "3". When the grid intervals of the FLT5004 result and the LUT3D5005 are not aligned, this can be handled by designing to output all adjacent grids with the same value so as to sandwich the result of FLT5004. In this embodiment, the configuration is adopted in which all the results of edge pattern matching are consolidated into the R channel, but the output destination may be any channel, or the results may be distributed and generated for each RGB channel.

[0131] In this embodiment, three filters and a lookup table having three input dimensions are used as an example, but the number of filters and the number of dimensions of the lookup table are not limited to this. For example, even if the number of filters is one and the setting value on the left of Fig. 35(d) is applied, it is possible to distinguish whether the target pixel is an edge pixel at the top edge, or an edge pixel at the upper right or right edge from the application results of each of Figs. 37(a), (b), and (c). If the lookup table can input a number of dimensions greater than the number of filters, pattern matching is possible as explained above.

[0132] If one filter and a one-dimensional lookup table can determine X types of edges, then two filters and a two-dimensional lookup table can determine X x X types of edges. M filters and an N-dimensional lookup table can determine Min(M,N) powers of X edge types. If an attempt is made to determine the same number of edge types as two filters and two lookup tables using only filters, four filters will be required. If an attempt is made to determine the same number of edge types as three filters and three lookup tables using only filters, eight filters will be required.

[0133] Therefore, by combining multiple filters and multidimensional lookup tables as in this embodiment, it becomes possible to efficiently determine multiple types of edges with a smaller circuit scale. In comparison with the case where it is realized using filters only, the effect becomes greater as X (the number of edge types to be determined) in the above example increases.

[0134] By increasing the number of filters and the number of dimensions of the lookup table, the number of detectable patterns can become more diverse. The circuit resources used for scan image correction generally have one to three filters.

[0135] In this way, by using the dedicated circuit provided in the scan image correction unit 216, it is possible to generate the same detection result as in the first embodiment. Here, when the multi-values ​​that are the generated edge pattern matching results are transferred to the ink decomposition and quantization unit 211 via the RAM 207, only the R channel can be transferred. As a result, the bandwidth can be saved more than when all the RGB channels are transferred via the shared bus 215. When the image processing device 100 performs copy processing, the RGB three channels are transferred to the scan image correction unit 216 for both input and output, so the transfer bandwidth in this embodiment can be made smaller than the required bandwidth for copy processing. Therefore, in terms of bandwidth, it is possible to meet the required performance without improving the circuit performance of the printer. In addition, when performing recording processing via the host computer 201, if there is an existing mechanism for transferring one channel of attribute information in addition to the RGB channels, a configuration for transferring only the R channel can reduce new design work on the data flow.

[0136] In order to achieve the required speed for the image analysis configuration in the first embodiment, a dedicated analysis circuit is required, which requires cost and time to develop and produce a new circuit. This embodiment makes it possible to realize dot thinning and placement control by utilizing the configuration of an existing image processing device. This reduces the cost of producing new circuits. Since image quality improvements can be immediately introduced to the market, user satisfaction is improved, and since feedback from users can be received quickly, requirements for element development can be discovered early.

[0137] The scan image correction in this embodiment is used not only in the copy use case but also in the scan use case. The image acquired by the scanner 202 is corrected by the scan image correction unit 216 and then transferred to the host computer 201 or a memory card connected to the image processing device 100. In this embodiment, a configuration is described in which the existing circuit used in the scan process and copy process is used for image analysis. On the other hand, since the existing circuit is assumed to be used for the scan image correction, a "circuit contention" problem may occur in which the same circuit is used at the same time when the scan process, copy process, and recording process are executed in parallel. Therefore, measures such as making the product specifications exclusive in the use case or implementing the circuit in a time-sharing manner can be considered. In the latter case, although it is not exclusive in the use case, it can be said that the processing time tends to be longer because the circuit resources are shared in small time units.

[0138] In this embodiment, the outline of the scan image correction process is shown, but this is only one example. If there is another function that has already been implemented as a dedicated circuit for scan image correction, it can also be used for image analysis processing. It is also possible to use other existing circuits existing in the image processing device 100. As described above, when using an existing circuit used in a use case, special control is involved such that the existing circuit is used for image analysis and other processing in a time-division manner. Note that the realization circuits and design values ​​described in this embodiment are only one example, and are not limited to these.

[0139] (Other embodiments) In the above-mentioned embodiments, the image processing device is described as a serial type, but is not limited to this as long as the characteristics and configuration are similar. A line type recording head may be used, or a configuration in which serial types are arranged vertically may be used. Furthermore, in the above-mentioned embodiments, the image processing device is described as an inkjet printer, but is not limited to this as long as the characteristics and configuration are similar. For example, the image processing device may be a laser printer using toner, or a copier.

[0140] Furthermore, in the above-mentioned embodiments, the bitmap data area and the like are described as areas in the RAM, but this is not limited to this as long as it is a rewritable storage device. For example, a HDD or eMMC (Embedded Multi Media Card) may be provided in addition to the RAM, and the entire data area may be located in the storage area of ​​the HDD or eMMC, or a part of the data area may be located therein.

[0141] Furthermore, in each of the above-mentioned embodiments, the density value data is quantized and converted to three values, but the present invention is not limited to this, as long as the characteristics and configuration are similar. Conversion to two values ​​or four or more values ​​is also possible. Furthermore, in each of the above-mentioned embodiments, the print head is described on the assumption that it has an Ev nozzle and an Od nozzle, but the present invention is not limited to this, as long as the characteristics and configuration are similar. In the above-mentioned embodiments, when printing is performed at a higher resolution in the Y direction than the image data for edge detection, each of the above-mentioned embodiments is applicable, as long as the nozzles are arranged at a higher resolution than the image data for edge detection.

[0142] Furthermore, in each of the above-described embodiments, image processing including edge processing has been described as being performed within the image forming apparatus 10, but this is not limited as long as the characteristics and configuration are similar. Specifically, a part or all of the image processing including edge processing may be performed by a device outside the image forming apparatus 10, and subsequent processing may be performed within the image forming apparatus 10 in response to the processing results.

[0143] Furthermore, in the above-mentioned embodiments, the width of the edge pixel is described as one pixel, but this is not limited as long as the characteristics and configuration are similar. An end pixel and one or more adjacent pixels on the non-end side (inside) of the end pixel may be collectively defined as an end pixel group, and the image analysis unit 210 may detect the upper end pixel group, the lower end pixel group, the left end pixel group, and the right end pixel group in S303, and thin out the dots in the subsequent processing. Figures 38(a) and (b) are diagrams showing an example of an end pixel group. End pixel groups 3801 and 3811 represent the left end pixel group, end pixel groups 3802 and 3812 represent the upper end pixel group, end pixel groups 3803 and 3813 represent the lower end pixel group, and end pixel groups 3804 and 3814 represent the right end pixel group. In this way, by applying the operation of each embodiment as an end pixel group, line thickening can be more effectively reduced.

[0144] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0145] The disclosure of the present embodiment includes the following image processing device, method, and program. (Item 1) a recording means capable of recording dots at a resolution higher than the resolution of the image data; quantization means for performing quantization processing based on image data including an object; a dot arrangement means for performing processing to arrange dots in pixels using a dot arrangement pattern corresponding to the quantized value obtained by the quantization processing; Equipped with the recording means includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; As a result of the processing by the dot arrangement means, in a first edge pixel of a first edge portion of the object, a ratio at which dots are arranged in the second region is smaller than a ratio at which dots are arranged in the first region, and in a second edge pixel of a second edge portion different from the first edge portion of the object, a ratio at which dots are arranged in the first region is smaller than a ratio at which dots are arranged in the second region. 13. An image processing device comprising: (Item 2) The image processing device according to item 1, characterized in that the quantization means performs the quantization process so as to make a quantization value different between a first edge pixel in a first edge portion of the object and a second edge pixel in a second edge portion different from the first edge portion, for each of the image data corresponding to the first recording means and the image data corresponding to the second recording means. (Item 3) the quantization means makes a quantization value assigned to the first edge pixel for image data corresponding to the first recording means different from a quantization value assigned to the first edge pixel for image data corresponding to the second recording means; a quantization value to be assigned to the second edge pixel for image data corresponding to the first recording means is made different from a quantization value to be assigned to the second edge pixel for image data corresponding to the second recording means; 3. The image processing device according to item 2, (Item 4) the quantization means assigning a first quantization value to the first edge pixels and a second quantization value to the second edge pixels for the image data corresponding to the first recording means; For image data corresponding to the second recording means, the second quantization value is assigned to the first edge pixel, and the first quantization value is assigned to the second edge pixel. 4. The image processing device according to item 3, (Item 5) 4. The image processing device according to any one of items 1 to 3, wherein dots are uniformly arranged in the first area in the first edge portion. (Item 6) 6. The image processing device according to item 5, wherein in the first edge portion, no dots are placed in the second region. (Item 7) 7. The image processing device according to item 5 or 6, wherein dots are uniformly arranged in the second region in the second edge portion. (Item 8) 8. The image processing device according to item 7, wherein in the second edge portion, no dots are placed in the first region. (Item 9) 2. The image processing device according to item 1, further comprising a change unit for changing the gradation values ​​of the first edge pixels and the second edge pixels. (Item 10) 10. The image processing device according to item 9, wherein when the gradation value is changed by the change means, in the first edge portion, no dots are placed in a portion of the first region. (Item 11) 10. The image processing device according to item 9, wherein, when the gradation value is changed by the change means, a dot is arranged in a part of the second region in the first edge portion. (Item 12) 10. The image processing device according to item 9, wherein when the gradation value is changed by the change means, in the second edge portion, no dots are placed in a portion of the second region. (Item 13) 10. The image processing device according to item 9, wherein, when the gradation value is changed by the change means, a dot is arranged in a part of the first area in the second edge portion. (Item 14) 2. The image processing device according to item 1, wherein the dot arrangement pattern is determined so that no dots are arranged in the first edge portion in a portion of the first region. (Item 15) 2. The image processing device according to item 1, wherein the dot arrangement pattern is determined so that dots are arranged in a portion of the second region in the first edge portion. (Item 16) 2. The image processing device according to item 1, wherein the dot arrangement pattern is determined so that no dots are arranged in the second edge portion in a portion of the second region. (Item 17) 2. The image processing device according to item 1, wherein the dot arrangement pattern is determined so that dots are arranged in a portion of the first region in the second edge portion. (Item 18) 18. The image processing device according to any one of items 1 to 17, wherein the first edge portion and the second edge portion are one side and another side different from the one side of the object. (Item 19) 19. The image processing device according to any one of items 1 to 18, wherein the object is an object having a predetermined pixel width. (Item 20) 20. The image processing device according to item 19, wherein the object is a line. (Item 21) 20. The image processing apparatus according to item 19, wherein the object is a solid. (Item 22) 22. The image processing device according to any one of items 19 to 21, characterized in that, when the object is an object that does not have the specified pixel width, the quantization means sets the quantization value of at least one of the first edge pixel and the second edge pixel to the quantization value of pixels in a portion that is not an edge portion of the object. (Item 23) 23. The image processing device according to any one of items 1 to 22, further comprising a detection unit for detecting the first edge pixel and the second edge pixel from the image data. (Item 24) 24. The image processing device according to item 23, wherein the detection means detects the first edge pixels and the second edge pixels by using pattern matching. (Item 25) 25. The image processing device according to item 24, wherein the detection by the detection means is performed by a configuration for correcting a scanned image. (Item 26) A color separation unit performs color separation processing based on the image data, the quantization process by the quantization means and the process by the dot arrangement means are performed on the predetermined color that has been subjected to the color separation process; 26. The image processing device according to any one of items 1 to 25, (Item 27) 27. The image processing device according to item 26, wherein the predetermined color is black. (Item 28) 28. The image processing device according to any one of items 1 to 27, wherein the object is an object of medium density. (Item 29) 29. The image processing device of any one of items 1 to 28, characterized in that a first nozzle row provided in the first recording means is configured to be shifted by half a pitch in the nozzle arrangement direction with respect to a second nozzle row provided in the second recording means, the first region corresponds to the first nozzle row, and the second region corresponds to the second region. (Item 30) 30. The image processing device according to claim 29, wherein the first region and the second region are positioned side by side in an arrangement direction of a first nozzle row provided in the first recording means and a second nozzle row provided in the second recording means. (Item 31) 30. The image processing device described in item 29, characterized in that the first region and the second region are positioned side by side in a direction perpendicular to the arrangement direction of the first nozzle row provided in the first recording means and the second nozzle row provided in the second recording means. (Item 32) the recording means is capable of recording dots in a third region and a fourth region of each pixel of the object; The third region and the fourth region are positioned side by side in the arrangement direction, the third region is positioned side by side with the first region in a direction perpendicular to the arrangement direction, and the fourth region is positioned side by side with the second region in a direction perpendicular to the arrangement direction, as a result of the processing by the dot arrangement means, in the first edge pixel of the first edge portion, a ratio at which dots are arranged in the second region and the fourth region is smaller than a ratio at which dots are arranged in the first region and the third region, and in the second edge pixel of the second edge portion, a ratio at which dots are arranged in the first region and the third region is smaller than a ratio at which dots are arranged in the second region and the fourth region; as a result of the processing by the dot arrangement means, in a third edge pixel of a third edge portion different from the first edge portion and the second edge portion, a ratio at which dots are arranged in the third region and the fourth region is smaller than a ratio at which dots are arranged in the first region and the second region, and in a fourth edge pixel of a fourth edge portion different from the first edge portion, the second edge portion, and the third edge portion, a ratio at which dots are arranged in the first region and the second region is smaller than a ratio at which dots are arranged in the third region and the fourth region. 30. The image processing device according to item 29, characterized in that (Item 33) 33. The image processing device according to any one of items 1 to 32, characterized in that as a result of the processing by the dot arrangement means, in each of the first edge portion and the second edge portion, the ratio of dots arranged closer to the inside of the object is smaller than the ratio of dots arranged closer to the edge of the object. (Item 34) 33. The image processing device according to any one of items 1 to 32, characterized in that as a result of the processing by the dot placement means, in each of the first edge portion and the second edge portion, the ratio of dots placed near the edge of the object is smaller than the ratio of dots placed near the inside of the object. (Item 35) 1. A method executed in an image processing device having a recording means capable of recording dots at a resolution higher than the resolution of image data, comprising: A quantization step of performing a quantization process based on image data including an object; a dot arrangement process for performing a process of arranging dots in pixels using a dot arrangement pattern corresponding to the quantized value obtained by the quantization process; having the recording means includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; As a result of the processing in the dot arrangement step, in a first edge pixel of a first edge portion of the object, a ratio at which dots are arranged in the second region is smaller than a ratio at which dots are arranged in the first region, and in a second edge pixel of a second edge portion different from the first edge portion of the object, a ratio at which dots are arranged in the first region is smaller than a ratio at which dots are arranged in the second region. A method comprising: (Item 36) On the computer, A quantization step of performing a quantization process based on image data including an object; a dot arrangement process for performing a process of arranging dots in pixels using a dot arrangement pattern corresponding to the quantized value obtained by the quantization process; A program for executing the recording means capable of recording dots at a resolution higher than the resolution of the image data includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; As a result of the processing in the dot arrangement step, in a first edge pixel of a first edge portion of the object, a ratio at which dots are arranged in the second region is smaller than a ratio at which dots are arranged in the first region, and in a second edge pixel of a second edge portion different from the first edge portion of the object, a ratio at which dots are arranged in the first region is smaller than a ratio at which dots are arranged in the second region. A program characterized by: (Item 37) An acquisition means for acquiring image data including an object; a detection means for detecting, from the image data acquired by the acquisition means, first edge pixels of a first edge portion of the object and second edge pixels of a second edge portion different from the first edge portion; a recording means capable of recording dots at a resolution higher than the resolution of the image data acquired by the acquisition means; Equipped with the recording means includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; the detection means detects the first edge pixel and the second edge pixel by pattern matching using a filter and a lookup table; each of the first edge pixel and the second edge pixel is detected in at least one of a nozzle arrangement direction of the recording means and a scanning direction of the recording means which is different from the nozzle arrangement direction; 13. An image processing device comprising:

[0146] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0147] 10 Image forming apparatus: 100 Image processing apparatus: 203 CPU: 208 Image processing section: 209 Decoder section: 210 Image analysis section: 211 Color separation and quantization section: 212 Nozzle separation section: 216 Scan image correction section

Claims

1. a recording means capable of recording dots at a resolution higher than the resolution of the image data; quantization means for performing quantization processing based on image data including an object; a dot arrangement means for performing processing to arrange dots in pixels using a dot arrangement pattern corresponding to the quantized value obtained by the quantization processing; Equipped with the recording means includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; As a result of the processing by the dot arrangement means, in a first edge pixel of a first edge portion of the object, a ratio at which dots are arranged in the second region is smaller than a ratio at which dots are arranged in the first region, and in a second edge pixel of a second edge portion different from the first edge portion of the object, a ratio at which dots are arranged in the first region is smaller than a ratio at which dots are arranged in the second region.

13. An image processing device comprising:

2. The image processing device according to claim 1, characterized in that the quantization means performs the quantization processing so as to make the quantization values ​​different between a first edge pixel in a first edge portion of the object and a second edge pixel in a second edge portion different from the first edge portion, for each of the image data corresponding to the first recording means and the image data corresponding to the second recording means.

3. the quantization means makes a quantization value assigned to the first edge pixel for the image data corresponding to the first recording means different from a quantization value assigned to the first edge pixel for the image data corresponding to the second recording means; a quantization value to be assigned to the second edge pixel for image data corresponding to the first recording means is made different from a quantization value to be assigned to the second edge pixel for image data corresponding to the second recording means; 3. The image processing device according to claim 2.

4. the quantization means assigning a first quantization value to the first edge pixels and a second quantization value to the second edge pixels for the image data corresponding to the first recording means; For image data corresponding to the second recording means, the second quantization value is assigned to the first edge pixel, and the first quantization value is assigned to the second edge pixel.

4. The image processing device according to claim 3.

5. The image processing apparatus according to claim 1 , wherein dots are uniformly arranged in the first area in the first edge portion.

6. The image processing device according to claim 5 , wherein in the first edge portion, no dots are arranged in the second region.

7. The image processing apparatus according to claim 5 , wherein dots are uniformly arranged in the second region in the second edge portion.

8. The image processing apparatus according to claim 7 , wherein no dots are arranged in the first region in the second edge portion.

9. 2. The image processing apparatus according to claim 1, further comprising a change unit for changing the gradation values ​​of the first edge pixels and the second edge pixels.

10. 10. The image processing apparatus according to claim 9, wherein, when the gradation value is changed by the change means, no dots are arranged in a portion of the first area in the first edge portion.

11. 10. The image processing apparatus according to claim 9, wherein, when the gradation value is changed by the change means, a dot is arranged in a part of the second region in the first edge portion.

12. 10. The image processing apparatus according to claim 9, wherein, when the gradation value is changed by the change means, no dots are arranged in a portion of the second area in the second edge portion.

13. 10. The image processing apparatus according to claim 9, wherein, when the gradation value is changed by the change means, a dot is arranged in a part of the first area in the second edge portion.

14. 2 . The image processing apparatus according to claim 1 , wherein the dot arrangement pattern is determined so that no dots are arranged in a portion of the first area in the first edge portion.

15. 2 . The image processing device according to claim 1 , wherein the dot arrangement pattern is determined so that dots are arranged in a portion of the second region in the first edge portion.

16. 2 . The image processing device according to claim 1 , wherein the dot arrangement pattern is determined so that no dots are arranged in a portion of the second region in the second edge portion.

17. 2 . The image processing apparatus according to claim 1 , wherein the dot arrangement pattern is determined so that dots are arranged in a portion of the first area in the second edge portion.

18. The image processing apparatus according to claim 1 , wherein the first edge portion and the second edge portion are one side and another side different from the one side of the object.

19. 2. The image processing apparatus according to claim 1, wherein the object has a predetermined pixel width.

20. The image processing apparatus according to claim 19 , wherein the object is a line.

21. 20. The image processing apparatus according to claim 19, wherein the object is a solid.

22. 20. The image processing device according to claim 19, wherein, when the object does not have the specified pixel width, the quantization means sets the quantization value of at least one of the first edge pixel and the second edge pixel to the quantization value of pixels in a portion of the object that is not an edge portion.

23. 2. The image processing apparatus according to claim 1, further comprising a detection unit for detecting the first edge pixel and the second edge pixel from the image data.

24. 24. The image processing apparatus according to claim 23, wherein the detection means detects the first edge pixels and the second edge pixels by using pattern matching.

25. 25. The image processing apparatus according to claim 24, wherein the detection by the detection means is performed by a configuration for correcting a scanned image.

26. A color separation unit that performs color separation processing based on the image data, the quantization process by the quantization means and the process by the dot arrangement means are performed on the predetermined color that has been subjected to the color separation process; 2. The image processing device according to claim 1,

27. 27. The image processing apparatus according to claim 26, wherein the predetermined color is black.

28. 2. The image processing apparatus according to claim 1, wherein the object is an object of intermediate density.

29. 2. The image processing device according to claim 1, wherein a first nozzle row provided in the first recording means is shifted by half a pitch in the nozzle arrangement direction with respect to a second nozzle row provided in the second recording means, the first region corresponds to the first nozzle row, and the second region corresponds to the second region.

30. 30. The image processing apparatus according to claim 29, wherein the first region and the second region are positioned side by side in an arrangement direction of a first nozzle array provided in the first recording means and a second nozzle array provided in the second recording means.

31. 30. The image processing device according to claim 29, wherein the first region and the second region are positioned side by side in a direction perpendicular to an arrangement direction of the first nozzle row provided in the first recording means and the second nozzle row provided in the second recording means.

32. the recording means is capable of recording dots in a third region and a fourth region of each pixel of the object; the third region and the fourth region are positioned side by side in the arrangement direction, the third region is positioned side by side with the first region in a direction perpendicular to the arrangement direction, and the fourth region is positioned side by side with the second region in a direction perpendicular to the arrangement direction, as a result of the processing by the dot arrangement means, in the first edge pixel of the first edge portion, a ratio at which dots are arranged in the second region and the fourth region is smaller than a ratio at which dots are arranged in the first region and the third region, and in the second edge pixel of the second edge portion, a ratio at which dots are arranged in the first region and the third region is smaller than a ratio at which dots are arranged in the second region and the fourth region; as a result of the processing by the dot arrangement means, in a third edge pixel of a third edge portion different from the first edge portion and the second edge portion, a ratio at which dots are arranged in the third region and the fourth region is smaller than a ratio at which dots are arranged in the first region and the second region, and in a fourth edge pixel of a fourth edge portion different from the first edge portion, the second edge portion, and the third edge portion, a ratio at which dots are arranged in the first region and the second region is smaller than a ratio at which dots are arranged in the third region and the fourth region.

30. The image processing apparatus according to claim 29,

33. 2. The image processing device according to claim 1, characterized in that as a result of the processing by the dot placement means, the ratio of dots placed closer to the inside of the object in each of the first edge portion and the second edge portion is smaller than the ratio of dots placed closer to the edge of the object.

34. 2. The image processing device according to claim 1, characterized in that as a result of the processing by the dot placement means, the ratio of dots placed near the ends of the object in each of the first edge portion and the second edge portion is smaller than the ratio of dots placed near the inside of the object.

35. 1. A method executed in an image processing device having a recording means capable of recording dots at a resolution higher than the resolution of image data, comprising: A quantization step of performing a quantization process based on image data including an object; a dot arrangement process for performing a process of arranging dots in pixels using a dot arrangement pattern corresponding to the quantized value obtained by the quantization process; having the recording means includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; As a result of the processing in the dot arrangement step, in a first edge pixel of a first edge portion of the object, a ratio at which dots are arranged in the second region is smaller than a ratio at which dots are arranged in the first region, and in a second edge pixel of a second edge portion different from the first edge portion of the object, a ratio at which dots are arranged in the first region is smaller than a ratio at which dots are arranged in the second region. A method comprising:

36. On the computer, A quantization step of performing a quantization process based on image data including an object; a dot arrangement process for performing a process of arranging dots in pixels using a dot arrangement pattern corresponding to the quantized value obtained by the quantization process; A program for executing the recording means capable of recording dots at a resolution higher than the resolution of the image data includes a first recording means capable of recording dots in a first area of ​​each pixel of the object, and a second recording means capable of recording dots in a second area of ​​each pixel of the object; As a result of the processing in the dot arrangement step, in a first edge pixel of a first edge portion of the object, a ratio at which dots are arranged in the second region is smaller than a ratio at which dots are arranged in the first region, and in a second edge pixel of a second edge portion different from the first edge portion of the object, a ratio at which dots are arranged in the first region is smaller than a ratio at which dots are arranged in the second region. A program characterized by:

37. An acquisition means for acquiring image data including an object; a detection means for detecting, from the image data acquired by the acquisition means, first edge pixels of a first edge portion of the object and second edge pixels of a second edge portion different from the first edge portion; a recording means capable of recording dots at a resolution higher than the resolution of the image data acquired by the acquisition means; Equipped with the recording means includes a first recording means capable of recording dots in a first region of each pixel of the object, and a second recording means capable of recording dots in a second region of each pixel of the object; the detection means detects the first edge pixel and the second edge pixel by pattern matching using a filter and a lookup table; each of the first edge pixels and the second edge pixels is detected in at least one of a nozzle arrangement direction of the recording means and a scanning direction of the recording means which is different from the nozzle arrangement direction; 13. An image processing device comprising:

Images