Image processing apparatus, image forming apparatus, and program

Abstract

To provide an image processing apparatus, an image forming apparatus, and a program that can prevent the occurrence of white patches occurring near an edge portion of an image on a color background.SOLUTION: In an image forming apparatus, a controller comprises: an edge detection unit that detects pixels of an edge portion of an image in image data; an image on a color background determination unit that determines whether each of pixels in the image data is a pixel of an image portion of an image on a white background, a pixel of the background portion of an image on a color background, or a pixel other than the pixels; an edge on a white background correction unit that performs correction to prevent the occurrence of white patches by using a first setting value for a pixel value of the detected pixel of the edge portion, the pixel determined to be the image portion of the image on the white background; and an edge on a color background correction unit that performs correction to prevent the occurrence of white patches by using a second setting value different from the first setting value for a pixel value of the detected pixel of the edge portion, the pixel determined to be the background portion of the image on the color background.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image processing apparatus, an image forming apparatus, and a program.

Background Art

[0002] There is known a technique for appropriately reducing the toner consumption while avoiding a decrease in readability of images such as characters, thin lines, figures, or symbols in image data to be printed. In an electrophotographic process, a phenomenon called an edge effect occurs in which the amount of toner adhesion increases at the edge portion of an image during printing. This is caused by the concentration of the lines of electric force of the electrostatic latent image at the edge portion, resulting in the concentration of toner there. Further, there is a technique called low CPP (Cost Per Paper) edge processing that aims to maintain the appearance and reduce the printing cost by reducing the consumption of toner that has been excessively adhered to the edge portion of characters or thin lines.

[0003] As a technique for improving readability by adjusting the amount of toner adhesion at the edge portion, there is disclosed a technique in which different density correction processes are performed on the pixels at the edge portion of the image data and the pixels other than the edge portion, so that the printed content can be sufficiently read while suppressing the toner consumption other than the edge portion of the image (for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the technique of Patent Document 1 has a problem that it can only adjust the amount of toner adhesion at the edge portion of an image such as characters on a white background, and cannot suppress the whiteout that occurs in an image such as characters on a colored background.

[0005] The present invention has been made in view of the above, and an object thereof is to provide an image processing apparatus, an image forming apparatus, and a program that can suppress the occurrence of whiteout that occurs in the vicinity of the edge portion of an image on a colored background. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the present invention includes a detection unit that detects pixels in the edge portion of an image in image data, a determination unit that determines whether each pixel in the image data is a pixel in the image portion of a white background image, a pixel in the background portion of a color background image, or any other pixel, and a first set value that determines the pixel value of the pixel that is an edge portion detected by the detection unit and determined by the determination unit to be an image portion of the white background image. In the aforementioned image portion A first correction unit performs correction to suppress the occurrence of whiteouts, and a second setting value different from the first setting value is applied to the pixel value of the pixel of the edge portion detected by the detection unit and determined by the determination unit to be the background portion of the color ground image. In the aforementioned background portion It is characterized by comprising a second correction unit that performs correction to suppress the occurrence of white spots. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the occurrence of white spots that occur near the edges of images on a color background. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of the overall configuration of an information processing system according to the embodiment. [Figure 2] Figure 2 shows an example of the hardware configuration of an image forming apparatus according to an embodiment. [Figure 3] Figure 3 shows an example of the configuration of a functional block of the controller of the image forming apparatus according to the embodiment. [Figure 4] Figure 4 shows an example of the print state of colored and white background text when the amount of toner adhering to the edges is not corrected. [Figure 5] Figure 5 shows an example of the printed state when the amount of toner adhering to the edges of colored background characters and white background characters is corrected separately in the image forming apparatus according to the embodiment. [Figure 6] Figure 6 is a flowchart showing an example of the image processing flow of the image forming apparatus according to the embodiment. [Figure 7] Figure 7 is a flowchart showing an example of the color ground pixel determination process in the image forming apparatus according to the embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the image processing apparatus, image forming apparatus, and program according to the present invention will be described in detail below with reference to the drawings. Furthermore, the present invention is not limited by the following embodiments, and the components in the following embodiments include those that are easily conceivable by those skilled in the art, substantially identical, and so-called equivalents. Moreover, various omissions, substitutions, modifications, and combinations of components can be made without departing from the spirit of the following embodiments.

[0010] Computer software refers to programs related to the operation of a computer, and other information used for computer processing that is similar to a program (hereinafter, computer software is referred to as "software"). Application software is a general term for software used to perform specific tasks, within the classification of software. On the other hand, an operating system (OS) is software that controls the computer and enables application software and other programs to utilize computer resources. The operating system performs basic computer management and control, such as input / output control, management of hardware such as memory and hard disks, and process management. Application software operates by utilizing the functions provided by the operating system. A program is a set of instructions for a computer, combined to produce a specific result. Something similar to a program is something that cannot be called a program because it is not a direct instruction to the computer, but has similar properties to a program in that it defines the processing of the computer. For example, a data structure (the logical structure of data, represented by the interrelationships between data elements) falls under the category of something similar to a program.

[0011] (Overall configuration of the information processing system) Figure 1 is a diagram showing an example of the overall configuration of the information processing system according to this embodiment. The overall configuration of the information processing system 1 according to this embodiment will be described with reference to Figure 1.

[0012] As shown in Figure 1, the information processing system 1 includes an image forming apparatus 10 and a PC (Personal Computer) 20. Each of these devices is capable of data communication via network 2. Network 2 is a network composed of at least one of the following: a LAN (Local Area Network), a VPN (Virtual Private Network), or the Internet.

[0013] The image forming apparatus 10 is a printer, a copier, a digital multifunction peripheral, or the like that can reproduce halftones. In the present embodiment, as shown in FIG. 1, the image forming apparatus 10 will be described as being a MFP (Multifunction Peripheral). Here, the MFP is an image forming apparatus having at least two functions among a copying function, a printer function, a scanner function, and a fax function. The image forming apparatus 10 is an example of an image processing apparatus. Note that the image processing apparatus may be a DFE (Digital Front End) of a commercial printing machine or the like.

[0014] The PC 20 is an information processing apparatus that transmits image data to be printed to the image forming apparatus 10 via the network 2.

[0015] Note that, in the configuration of the information processing system 1 shown in FIG. 1, the image forming apparatus 10 and the PC 20 are each included as one unit, but the present invention is not limited to this, and at least one of them may be plural.

[0016] (Hardware Configuration of Image Forming Apparatus) FIG. 2 is a diagram showing an example of the hardware configuration of the image forming apparatus according to the embodiment. The hardware configuration of the image forming apparatus 10 according to the present embodiment will be described while referring to FIG. 2.

[0017] As shown in FIG. 2, the image forming apparatus 10 has a configuration in which a controller 500, an operation display unit 510, an FCU (Facsimile Control Unit) 520, a plotter 531, and a scanner 532 are connected by a PCI (Peripheral Component Interface) bus.

[0018] The controller 500 is a device that controls the entire image forming apparatus 10, performs drawing, communication, and controls inputs from the operation display unit 510.

[0019] The operation display unit 510 is, for example, a touch panel or the like, which is a device that accepts inputs to the controller 500 (input function) and displays the state of the image forming apparatus 10 and the like (display function), and is directly connected to an ASIC (Application Specific Integrated Circuit) 506 described later.

[0020] The FCU 520 is a device that realizes a facsimile function and is connected to the ASIC 506, for example, by a PCI bus.

[0021] The plotter 531 is a device that realizes a printing function and is connected to the ASIC 506, for example, by a PCI bus. The scanner 532 is a function that realizes a scanner function and is connected to the ASIC 506, for example, by a PCI bus.

[0022] The controller 500 includes a CPU (Central Processing Unit) 501, a system memory (MEM-P) 502, a north bridge (NB) 503, a south bridge (SB) 504a, a network I / F 504b, a USB (Universal Serial Bus) I / F 504c, a Centronics I / F 504d, a sensor I / F 504e, an ASIC 506, a local memory (MEM-C) 507, and an auxiliary storage device 508.

[0023] The CPU 501 is an arithmetic unit that performs overall control of the image forming apparatus 10, is connected to a chipset including the system memory 502, the north bridge 503, and the south bridge 504a, and is connected to other devices via this chipset.

[0024] System memory 502 is a memory used for storing programs and data, for expanding programs and data, and for drawing printer data, etc., and has ROM (Read Only Memory) and RAM (Random Access Memory). Of these, ROM is a read-only memory used for storing programs and data, and RAM is a writable and readable memory used for expanding programs and data, and for drawing printer data, etc.

[0025] The northbridge 503 is a bridge for connecting the CPU 501, system memory 502, southbridge 504a, and AGP (Accelerated Graphics Port) bus 505, and includes a memory controller that controls reading and writing to system memory 502, as well as a PCI master and an AGP target.

[0026] The Southbridge 504a is a bridge that connects the Northbridge 503 to PCI devices and peripheral devices. The Southbridge 504a is connected to the Northbridge 503 via the PCI bus, to which the Network I / F 504b, USB I / F 504c, Centronics I / F 504d, and Sensor I / F 504e are connected.

[0027] The AGP bus 505 is a bus interface for graphics accelerator cards proposed to accelerate graphics processing. The AGP bus 505 speeds up graphics accelerator cards by providing high-throughput direct access to system memory 502.

[0028] The ASIC506 is an integrated circuit (IC) for image processing applications that has hardware elements for image processing, and acts as a bridge connecting the AGP bus 505, PCI bus, auxiliary storage device 508, and local memory 507, respectively. The ASIC506 consists of a PCI target and an AGP master, an arbiter (ARB) which is the core of the ASIC506, a memory controller that controls the local memory 507, multiple DMACs (Direct Memory Access Controllers) that perform image data rotation etc. using hardware logic, and a PCI unit that performs data transfer via the PCI bus between the plotter 531 and scanner 532. For example, the FCU 520, plotter 531, and scanner 532 are connected to the ASIC506 via the PCI bus.

[0029] Local memory 507 is memory used as a copy image buffer and a code buffer.

[0030] The auxiliary storage device 508 is a storage device such as an HDD (Hard Disk Drive), SSD (Solid State Drive), SD (Secure Digital) card, or flash memory, and is used for storing image data, programs, font data, and forms.

[0031] Note that the hardware configuration of the image forming apparatus 10 shown in Figure 2 is just one example, and it is not necessary to have all of the components, nor is it necessary to have other components. For example, the image forming apparatus 10 may be equipped with an ADF (Automatic Document Feeder), etc.

[0032] (Configuration and operation of the functional blocks of the image forming apparatus controller) Figure 3 shows an example of the configuration of the functional block of the controller of the image forming apparatus according to this embodiment. Figure 4 shows an example of the printed state of colored background characters and white background characters when the amount of toner adhesion at the edges is not corrected. Figure 5 shows an example of the printed state when the amount of toner adhesion at the edges of colored background characters and white background characters is corrected separately in the image forming apparatus according to this embodiment. Referring to Figures 3 to 5, the configuration and operation of the functional block of the controller 500 of the image forming apparatus 10 according to this embodiment will be described.

[0033] As shown in Figure 3, the controller 500 of the image forming apparatus 10 includes an acquisition unit 101, an edge detection unit 102 (detection unit), a color ground image determination unit 103 (determination unit), a white ground edge correction unit 104 (first correction unit), and a color ground edge correction unit 105 (second correction unit).

[0034] The acquisition unit 101 is a functional unit that acquires image data (input image) to be processed. For example, the acquisition unit 101 acquires image data from the PC 20 via network 2 and network I / F 504b.

[0035] The edge detection unit 102 is a functional unit that performs a filter operation on each pixel of the image data acquired by the acquisition unit 101 to detect the edge portions of images such as characters, thin lines, shapes, or symbols in the image data. In other words, the edge detection unit 102 detects the pixels that constitute the edge portions of images such as characters, thin lines, shapes, or symbols in each pixel of the image data. For example, the edge detection unit 102 detects the first to fourth dots of an edge using 9x9 pattern matching. In the following explanation, the image for which edges are detected by the edge detection unit 102 will be described as "characters," but as mentioned above, it is not limited to characters and may be images such as thin lines, shapes, or symbols.

[0036] The colored ground image determination unit 103 is a functional unit that performs a filter operation on each pixel of the image data acquired by the acquisition unit 101 to determine whether the characters in the image data are white background characters, colored background characters (i.e., white background characters), or something else, based on the difference in brightness between the character portion and the background portion. Specifically, the colored ground image determination unit 103 performs a filter operation on each pixel to determine whether the pixel is a pixel in the character portion (an example of the image portion) of white background characters (an example of a white background image), a pixel in the background portion of colored ground characters (an example of a colored ground image), or some other pixel. In this case, if the colored ground image determination unit 103 determines that the pixel to be determined is "something else", the correction processing by the subsequent white background edge correction unit 104 and colored ground edge correction unit 105 is not performed on that pixel.

[0037] Here, Figure 4(a) shows an example of colored background text (colored background text with white gaps), and Figure 4(b) shows an example of white background text. In Figure 4(a), the colored background text has not undergone the correction processing by the colored background edge correction unit 105 described later, so it shows a state where white gaps occur on the background side of the edge portion of the colored background text due to the edge effect. In Figure 4(b), the white background text has not undergone the correction processing by the white background edge correction unit 104 described later, so it shows a state where white gaps occur on the character side of the edge portion of the white background text due to the edge effect.

[0038] Furthermore, the color background image determination unit 103 may determine whether the characters in the image data are halftone characters (an example of a halftone image) based on the distance to the edge obtained by a filter operation of size such as 13x13 for each pixel of the image data, and a smoothing filter process applied to the image data. This allows for the extraction of color background characters even when the background is halftone.

[0039] The white background edge correction unit 104 is a functional unit that corrects the pixel values ​​of pixels that are edge portions detected by the edge detection unit 102 and that have been determined by the color background image determination unit 103 to be character portions of white background characters, using a predetermined set value (first set value) to suppress the occurrence of white gaps. In this case, the amount of toner deposited is reduced according to the pixel values ​​corrected by the white background edge correction unit 104. For example, the white background edge correction unit 104 corrects the pixel values ​​of pixels from the 1st to the 4th dot from the edge detected by the edge detection unit 102. As shown in Figure 5(b), the correction by the white background edge correction unit 104 can suppress the occurrence of white gaps in the character portions of the edge portions of white background characters. The image data corrected by the white background edge correction unit 104 is output to the plotter 531 as print data. The image data corrected by the white background edge correction unit 104 may be further processed by other image processing before being output to the plotter 531 as print data.

[0040] The color ground edge correction unit 105 is a functional unit that corrects the pixel values ​​of pixels in the edge portion detected by the edge detection unit 102 and determined by the color ground image determination unit 103 to be the background portion of the color ground characters, using a setting value (second setting value) different from the setting value used by the white ground edge correction unit 104, in order to suppress the occurrence of white gaps. In this case, the amount of toner deposited is reduced according to the pixel value corrected by the color ground edge correction unit 105. The color ground edge correction unit 105 may also perform the correction using the above-mentioned alternative setting value corresponding to at least one of the brightness difference, color difference, or hue change amount between the character portion and the background portion of the color ground characters. For example, the color ground edge correction unit 105 corrects the pixel values ​​of the 1st to 4th dots from the edge detected by the edge detection unit 102. By correcting with the color ground edge correction unit 105, the occurrence of white gaps in the background portion of the edge portion of the color ground characters can be suppressed, as shown in Figure 5(a). The image data corrected by the color ground edge correction unit 105 is output to the plotter 531 as print data. Alternatively, the image data corrected by the color ground edge correction unit 105 may undergo further image processing before being output to the plotter 531 as print data.

[0041] The acquisition unit 101, edge detection unit 102, color ground image determination unit 103, white ground edge correction unit 104, and color ground edge correction unit 105 described above are implemented by the execution of a program by the CPU 501 shown in Figure 2. However, these functional units are not limited to being implemented by the execution of a program by the CPU 501 shown in Figure 2; for example, they may be implemented by hardware such as integrated circuits, or by a combination of software and hardware.

[0042] Furthermore, the functional units of the controller 500 of the image forming apparatus 10 shown in Figure 3 are conceptual representations of their functions and are not limited to this configuration. For example, multiple functional units shown as independent functional units in Figure 3 may be configured as a single functional unit. Alternatively, the functions of one functional unit in Figure 3 may be divided into multiple functions and configured as multiple functional units.

[0043] (Image processing flow of an image forming apparatus) Figure 6 is a flowchart showing an example of the image processing flow of the image forming apparatus according to the embodiment. Figure 7 is a flowchart showing an example of the color ground pixel determination process flow of the image forming apparatus according to the embodiment. The image processing flow of the controller 500 of the image forming apparatus 10 will be described with reference to Figures 6 and 7.

[0044] <Step S11> The acquisition unit 101 of the controller 500 acquires image data (input image) to be processed. For example, the acquisition unit 101 acquires image data from the PC 20 via network 2 and network I / F 504b. Then, the process proceeds to step S12.

[0045] <Step S12> The edge detection unit 102 of the controller 500 performs a filter operation on each pixel of the image data acquired by the acquisition unit 101 to detect the edge portions of characters in the image data. That is, the edge detection unit 102 detects the pixels that represent the edge portions of characters in the image data at each pixel of the image data. Then, the process proceeds to step S13.

[0046] <Step S13> The color ground image determination unit 103 of the controller 500 determines whether the characters in the image data are white background characters, color background characters (i.e., white background characters), or something else by performing a filter operation on each pixel of the image data acquired by the acquisition unit 101. Specifically, the color ground image determination unit 103 determines by performing a filter operation on each pixel whether the pixel is a character pixel of white background characters, a background pixel of color background characters, or something else. The above determination process by the color ground image determination unit 103 (color ground pixel determination process) is executed according to the flow shown in Figure 7, as follows.

[0047] <<Step S131>> The color ground image determination unit 103 performs color conversion on the entire image data acquired by the acquisition unit 101. In this case, it is desirable for the color ground image determination unit 103 to convert the colors to a color space such as the Lab color space, which has a brightness direction. This allows the brightness of each image in the image data to be determined. However, although the detection accuracy for black or grayscale is inferior, this does not restrict conversion to a color space without a brightness direction. Then, the process proceeds to step S132.

[0048] <<Step S132>> The color ground image determination unit 103 performs a filtering operation on each pixel of the image data using a saturation detection filter to calculate the saturation of that pixel. Then, it proceeds to step S133.

[0049] <<Step S133>> The color ground image determination unit 103 performs a filtering operation on each pixel of the image data using a background detection filter. The color ground image determination unit 103 may also distinguish between characters on solid color and characters on halftones (an example of a halftone image) based on the calculation results of multiple background detection filters. Then, the process proceeds to step S134.

[0050] <<Step S134>> The color ground image determination unit 103 performs a filter operation on each pixel of the image data using a filter for detecting inner and outer edges, and determines whether the pixel is inside (i.e., part of the character) or outside (i.e., part of the background) the edge (boundary of the character) detected by the edge detection unit 102, based on either the brightness obtained in step S131 or the saturation calculated in step S132 for that pixel. The color ground image determination unit 103 may also determine whether it is inside or outside based on the positive or negative value of the filter operation result. Then, the process proceeds to step S135.

[0051] <<Step S135>> The colored ground image determination unit 103 determines, by performing a filter operation on each pixel, whether the pixel is a pixel in the character portion of the white ground character, a pixel in the background portion of the colored ground character, or any other pixel. Then, it proceeds to step S14 shown in Figure 6.

[0052] <Step S14> If the pixel is an edge portion detected by the edge detection unit 102 and is determined to be a character portion of a white background character by the color background image determination unit 103 (step S14: white background character), the process proceeds to step S15. If the pixel is an edge portion detected by the edge detection unit 102 and is determined to be a background portion of a color background character by the color background image determination unit 103 (step S14: color background character), the process proceeds to step S16. If it is any other pixel (step S14: other), no correction is made to the pixel value of the pixel, and the image processing is terminated.

[0053] <Step S15> The white background edge correction unit 104 corrects the pixel values ​​of pixels that are edge portions detected by the edge detection unit 102 and that have been determined by the color background image determination unit 103 to be part of the character portion of the white background character, using a predetermined set value to suppress the occurrence of white gaps. Through the correction by the white background edge correction unit 104, as shown in Figure 5(b) above, the occurrence of white gaps in the character portion of the edge portion of the white background character can be suppressed. This completes the image processing.

[0054] <Step S16> The color ground edge correction unit 105 corrects the pixel values ​​of pixels that are edge portions detected by the edge detection unit 102 and that have been determined by the color ground image determination unit 103 to be part of the background of the color ground characters, using a setting value different from the setting value used by the white ground edge correction unit 104, in order to suppress the occurrence of white gaps. Through the correction by the color ground edge correction unit 105, as shown in Figure 5(a) above, the occurrence of white gaps in the background portion of the edge portions of the color ground characters can be suppressed. This completes the image processing.

[0055] As described above, in the image forming apparatus 10 according to this embodiment, the edge detection unit 102 detects pixels in the edge portion of the image in the image data, the color background image determination unit 103 determines whether each pixel in the image data is a pixel in the character portion of white background characters, a pixel in the background portion of color background characters, or any other pixel, the white background edge correction unit 104 applies a correction to the pixel values ​​of pixels that are edge portions detected by the edge detection unit 102 and determined to be part of the image portion of white background characters by the color background image determination unit 103 to suppress the occurrence of white gaps using a predetermined setting value, and the color background edge correction unit 105 applies a correction to the pixel values ​​of pixels that are edge portions detected by the edge detection unit 102 and determined to be part of the background portion of color background characters by the color background image determination unit 103 to suppress the occurrence of white gaps using a different setting value than the setting value used by the white background edge correction unit 104. This makes it possible to suppress the occurrence of white gaps that occur near the edge portions of images such as characters on a color background.

[0056] Furthermore, each function of the embodiment described above can be realized by one or more processing circuits. Here, "processing circuit" includes processors programmed to execute each function by software, such as processors implemented by electronic circuits, as well as devices such as ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and conventional circuit modules designed to execute each of the functions described above.

[0057] Furthermore, the program executed by the image forming apparatus 10 of the above embodiment may be configured to be pre-installed and provided in ROM or the like.

[0058] Furthermore, the program executed by the image forming apparatus 10 of the above-described embodiment may be configured to be recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (Compact Disk-Recordable), or a DVD (Digital Versatile Disk) and provided as a computer program product.

[0059] Furthermore, the program executed by the image forming apparatus 10 of the above-described embodiment may be stored on a computer connected to a network such as the Internet and provided by downloading it via the network. Alternatively, the program executed by the image forming apparatus 10 of the above-described embodiment may be provided or distributed via a network such as the Internet.

[0060] Furthermore, the program executed in the image forming apparatus 10 of the above embodiment has a modular configuration that includes each of the functional units described above. In actual hardware, the CPU (processor) reads the program from ROM and executes it, thereby loading each of the functional units onto the main memory, and creating each functional unit on the main memory.

[0061] Examples of the present invention are as follows: <1> A detection unit that detects pixels at the edges of an image in the image data, A determination unit that determines whether each pixel in the aforementioned image data is a pixel in the image portion of a white ground image, a pixel in the background portion of a color ground image, or a pixel of another type, A first correction unit performs a correction on the pixel values ​​of pixels that are edge portions detected by the detection unit and that are determined by the determination unit to be image portions of the white background image, to suppress the occurrence of white gaps by a first set value. A second correction unit performs a correction on the pixel values ​​of pixels in the edge portion detected by the detection unit and determined by the determination unit to be in the background portion of the color ground image, using a second setting value different from the first setting value to suppress the occurrence of whiteouts. It is an image processing device equipped with [specific features / equipment]. <2> The determination unit performs the determination using the halftone image as the color ground image. <1> This is the image processing device described above. <3> The determination unit performs the determination based on the brightness of the text portion and background portion of the white ground image or the colored ground image. <1> or <2> This is the image processing device described above. <4> The second correction unit performs the correction using the second setting value, which corresponds to at least one of the brightness difference, color difference, or hue change amount between the image portion and the background portion of the color ground image. <1> ~ <3> The image processing device is one of the items described in any one of the above. <5> The determination unit performs the determination on the image data, converting the brightness direction into a color space, and the image data converted into a color space. <3> or <4> This is the image processing device described above. <6> The aforementioned white background image is white background text. The aforementioned colored ground image is a colored ground character. <1> ~ <5> The image processing device is one of the items described in any one of the above. <7> A detection unit that detects pixels at the edges of an image in the image data, A determination unit that determines whether each pixel in the aforementioned image data is a pixel in the image portion of a white ground image, a pixel in the background portion of a color ground image, or a pixel of another type, A first correction unit performs a correction on the pixel values ​​of pixels that are edge portions detected by the detection unit and that are determined by the determination unit to be image portions of the white background image, to suppress the occurrence of white gaps by a first set value. A second correction unit performs a correction on the pixel values ​​of pixels in the edge portion detected by the detection unit and determined by the determination unit to be in the background portion of the color ground image, using a second setting value different from the first setting value to suppress the occurrence of whiteouts. This is an image forming apparatus equipped with the following features. <8> On the computer, A detection step to detect pixels at the edges of an image in the image data, A determination step is performed to determine whether each pixel in the aforementioned image data is a pixel in the image portion of a white ground image, a pixel in the background portion of a color ground image, or a pixel of another type. A first correction step in which the pixel values ​​of the pixels that are detected as edge portions and that are determined to be part of the image portion of the white background image are corrected by a first set value to suppress the occurrence of whiteouts, A second correction step in which the pixel values ​​of the detected edge portion pixels, which are determined to be part of the background portion of the color ground image, are corrected by a second setting value different from the first setting value to suppress the occurrence of whiteouts, This is a program to execute [the command / action]. [Explanation of Symbols]

[0062] 1. Information Processing System 2 Network 10 Image forming apparatus 20 PC 101 Acquisition Department 102 Edge detection unit 103 Color Ground Image Determination Unit 104 White Ground Edge Correction Section 105-color ground edge correction unit 500 Controllers 501 CPU 502 System Memory (MEM-P) 503 Northbridge (NB) 504a Southbridge (SB) 504b Network Interface 504c USB I / F 504d Centronics I / F 504e Sensor Interface 505 AGP 506 ASIC 507 Local Memory (MEM-C) 508 Auxiliary storage 510 Operation display section 520 FCU 531 Plotter 532 Scanners [Prior art documents] [Patent Documents]

[0063] [Patent Document 1] Japanese Patent Publication No. 2002-086805

Claims

1. A detection unit that detects pixels at the edges of an image in the image data, A determination unit that determines whether each pixel in the aforementioned image data is a pixel in the image portion of a white ground image, a pixel in the background portion of a color ground image, or a pixel of another type, A first correction unit performs a correction on the pixel values ​​of pixels in the edge portion detected by the detection unit and determined by the determination unit to be part of the image portion of the white background image, using a first set value to suppress the occurrence of white gaps in the image portion. A second correction unit performs a correction on the pixel values ​​of pixels in the edge portion detected by the detection unit and determined by the determination unit to be in the background portion of the color ground image, using a second setting value different from the first setting value to suppress the occurrence of whiteout in the background portion. Equipped with an image processing device.

2. The image processing apparatus according to claim 1, wherein the determination unit performs the determination using the halftone image as the color ground image.

3. The image processing apparatus according to claim 1, wherein the determination unit performs the determination based on the brightness of the character portion and background portion of the white ground image or the colored ground image.

4. The image processing apparatus according to claim 1, wherein the second correction unit performs correction according to the second setting value corresponding to at least one of the brightness difference, color difference, or hue change amount between the image portion and the background portion of the color ground image.

5. The image processing apparatus according to claim 3 or 4, wherein the determination unit converts the image data into a color space with a brightness direction, and performs the determination on the image data converted into the color space.

6. The aforementioned white background image is white background text. The image processing apparatus according to any one of claims 1 to 4, wherein the colored ground image is colored ground characters.

7. A detection unit that detects pixels at the edges of an image in the image data, A determination unit that determines whether each pixel in the aforementioned image data is a pixel in the image portion of a white ground image, a pixel in the background portion of a color ground image, or a pixel of another type, A first correction unit performs a correction on the pixel values ​​of pixels in the edge portion detected by the detection unit and determined by the determination unit to be part of the image portion of the white background image, using a first set value to suppress the occurrence of white gaps in the image portion. A second correction unit performs a correction on the pixel values ​​of pixels in the edge portion detected by the detection unit and determined by the determination unit to be in the background portion of the color ground image, using a second setting value different from the first setting value to suppress the occurrence of whiteout in the background portion. An image forming apparatus equipped with [a specific feature].

8. On the computer, A detection step to detect pixels at the edges of an image in the image data, A determination step is performed to determine whether each pixel in the aforementioned image data is a pixel in the image portion of a white ground image, a pixel in the background portion of a color ground image, or a pixel of another type. A first correction step is performed on the pixel values ​​of the pixels of the detected edge portion that are determined to be part of the image portion of the white background image, by a first set value, to suppress the occurrence of whiteout in the image portion. A second correction step involves performing a correction on the pixel values ​​of the pixels in the detected edge portion that are determined to be in the background portion of the color ground image, using a second setting value different from the first setting value, to suppress the occurrence of whiteout in the background portion. A program to execute.

Images