How to create data for halftone prints

Abstract

To create dot printed matter data by seamless arrangement without a gap of individual dots as a dot printed matter having a complicated dot shape required for a security printed matter.SOLUTION: A method for creating a dot printed matter includes: disposing an object on a unit for forming dots; carrying out duplicate movement or split movement of the object if the entirety of the object is not included in the unit; and carrying out half tone screening by using the unit.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a method for creating data for halftone prints having a function of preventing counterfeiting and alteration in the field of security prints such as banknotes, passports, securities, and certificates. [Background technology]

[0002] It is important to implement measures to prevent counterfeiting and alteration in security printed materials such as banknotes, passports, securities, and certificates. For example, one of the counterfeit prevention measures is the use of geometric patterns composed of fine curved lines, which are used as background patterns and colored patterns. These background patterns and colored patterns function to prevent counterfeiting because they are difficult to extract with a color scanner or to reproduce with a copier.

[0003] However, when an image is composed of lines such as a background pattern or a colored pattern, it is not suitable for expressing continuous gradation (a line coverage ratio of 0% to 100%). Therefore, when continuous gradation is used in security prints, a continuous gradation image is applied to the areas that do not contain background patterns or colored patterns. To express continuous gradation images in prints, a technique called halftone screening is used to convert a grayscale image [1] into a halftone image [2], as shown in Figure 1, to make the image halftone.

[0004] For example, Non-Patent Document 1 describes a method for halftone screening using a page description language called PostScript. This method uses a rectangular array (hereinafter referred to as "unit [U]") of cells [c] each containing a threshold value (hereinafter referred to as "threshold value [3]") written as an 8-bit value in hexadecimal, as shown in Figure 2.

[0005] The process of halftone screening using unit [U] is shown in Figure 3. This process compares the density value [4] of the gradation image [1] with the threshold value [3] of unit [U] to generate a halftone image [2].

[0006] However, the above-mentioned halftone screening is based on dot shapes such as circles, ellipses, diamonds, and rectangles, which can be easily reproduced using existing platemaking or image processing techniques, and therefore does not meet the requirements for security printing, which requires anti-counterfeiting. Therefore, there has been a demand for halftone screening that can generate complex dot shapes that make counterfeiting difficult.

[0007] Therefore, the applicant has filed a patent application for a technology for halftone screening that generates complex halftone dot shapes, in which a unit [U], which is the smallest unit graphic area that constitutes a screen, as shown in Figure 4, has at least two subunits [5] with different arrangement directions, and halftone screening is performed by a step of generating information for defining a halftone dot shape within the subunit [5] by combining graphics generated by a function using a calculation means, and a step of outputting the information that defines the halftone dot shape as screen definition data (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 3855013 [Patent Document 2] Patent No. 6651198 [Non-patent literature]

[0009] [Non-Patent Document 1] Adobe PostScript3 "Halftones and Screens Technical Note #5602" (1997) Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the halftone screening of Patent Documents 1 and 2, as shown in Figure 4, a complex halftone dot shape is generated by expanding and arranging subunits [5] that divide the inside of a unit [U] into multiple parts, and since the halftone dot shape is complete in a single unit [U], when halftone screening is performed using such a unit [U], as shown in Figure 5, the continuity of the halftone dot shape becomes noticeable, resulting in insufficient complexity.

[0011] The present invention has been made in consideration of the above-mentioned problems, and relates to a method for creating data for halftone dot prints that enables gradation expression using seamlessly designed halftone dots as shown in Fig. 6, which is a configuration that makes the continuity of halftone dot shapes less noticeable. An example of such seamless designs is the traditional Edo Komon pattern, which has over several hundred design patterns, including patterns with cherry blossom motifs, such as scattered cherry blossoms, which have long been loved by Japanese people, as well as patterns with animal and vegetable motifs. Therefore, by utilizing various seamless designs, it is possible to realize more complex halftone dot prints in which the continuity of halftone dot shapes is less noticeable. [Means for solving the problem]

[0012] The method for creating data for halftone dot prints of the present invention is a method for creating data for halftone dot prints, which halftones a print area having a gradation image on at least a portion of a substrate using units formed by a plurality of objects, and includes the steps of: arranging a plurality of units formed by a collection of cells within the print area, with the units being arranged at regular intervals and in a certain shape, each unit being M or more cells (M is an integer of 2 or more) along a first direction and N or more cells (N is an integer of 2 or more) along a second direction different from the first direction; forming the plurality of objects at positions on the units where they do not overlap each other; checking whether the plurality of objects are arranged at positions straddling the boundary line between adjacent units; and when the plurality of objects are arranged at positions straddling the boundary line in the first direction or the second direction in the units, i) determining whether the objects formed at positions straddling the boundary line in the first direction in each unit are moved from one end side to the other end side in the first direction. and / or duplicating an object formed at a position straddling the boundary line in the second direction in each unit to a position shifted by the number of cells (N) from one end side to the other end side in the second direction, or ii) dividing an object formed at a position straddling the boundary line in each unit in the first or second direction at the boundary line of the unit, and shifting the object formed outside the unit from one end side to the other end side in the first or second direction by the number of cells (M or N) to move the object formed outside the unit into the unit; inputting an image that is the basis of the gradation image or reading an image that has been input in advance, and performing resampling processing; and creating data for a halftone print by halftone screening for the object formed by i) or ii).

[0013] Furthermore, a method for creating data for halftone dot prints of the present invention is a method for creating data for halftone dot prints in which a print area having a gradation image is halftone-doted on at least a portion of a substrate using units formed by a plurality of objects, and includes the steps of: arranging a plurality of units formed by a set of cells in the print area, the units being M or more cells (M is an integer of 2 or more) arranged along a first direction and N or more cells (N is an integer of 2 or more) arranged along a second direction different from the first direction, at a regular interval and with a regular shape; forming the plurality of objects at positions on the units where they do not overlap one another; checking whether the plurality of objects are arranged at positions straddling the boundary line between adjacent units in the first and second directions; and when the plurality of objects are arranged at positions straddling the boundary line between the first and second directions in each unit, iii) determining the number of cells from one end side in the first direction to the other end side in the first direction for the object formed at the position straddling the boundary line in the first direction in each unit. (M) to a position moved by the number of cells (N) from one end side to the other end side in the second direction, and from one end side to the other end side in the first direction and from one end side to the other end side in the second direction to positions moved by the number of cells (M, N), or iv) an object formed outside the boundary line of each unit is divided into an area formed within the unit, an area spanning only in the first direction, an area spanning only in the second direction, an area spanning only in the first direction and the second direction, and a step of dividing the area into areas spanning in the first direction and moving the area spanning only in the first direction from one end side to the other end side in the first direction by the number of cells (M), moving the area spanning only in the second direction from one end side to the other end side in the second direction by the number of cells (N), and moving the area spanning both the first direction and the second direction from one end side to the other end side in the first direction and from one end side to the other end side in the second direction by the number of cells (M and N); This is a method for creating data for halftone prints, characterized by comprising the steps of inputting an image that is the basis of a gradation image or reading an image that has been input in advance and performing a resampling process, and creating data for halftone prints that are created by halftone screening for the object formed by iii) or iv).

[0014] In addition, the step of forming an object on a unit in the method for creating data for halftone dot prints of the present invention is characterized by including a step of forming the object from a collection of cells having 8-bit density values, forming the object as a 0-degree rectangular array of m cells x n cells (where at least one of m and n is 2 or more, and m is an integer satisfying m≦M / 2 and n≦N / 2), and making the gradation difference between cells within the object at least 1 in 8-bit values.

[0015] Furthermore, the method of creating data for halftone dot prints of the present invention is a method of creating data for halftone dot prints, characterized by including a step of optimizing the density value of each unit. [Effects of the Invention]

[0016] The method for creating data for halftone dot prints of the present invention incorporates the concept of seamless design into the definition of units, and performs halftone screening on units in which objects straddle adjacent units, making it difficult to determine the continuity of the dot shapes. As a result, the complex dot shapes required for security prints can be obtained.

[0017] Furthermore, the method of creating data for halftone dot prints of the present invention is difficult to imitate due to the complex dot shapes, and is expected to improve the anti-counterfeiting effect in security prints. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 10 is a diagram showing an example in which a gradation image is converted into a halftone image. [Figure 2]FIG. 2 is a diagram showing the configuration of a unit. [Figure 3] 10A and 10B are schematic diagrams showing halftone screening processing using the unit. [Figure 4] FIG. 1 is a diagram showing the configuration of a unit in Patent Documents 1 and 2. [Figure 5] 1A and 1B are diagrams showing examples of halftone dot images disclosed in Patent Documents 1 and 2. [Figure 6] 10A and 10B are diagrams showing examples of seamless patterns. [Figure 7] FIG. 2 is a diagram showing the configuration of a unit according to the present invention. [Figure 8] A diagram showing the configuration of objects. [Figure 9] Flowchart diagram for creating a unit. [Figure 10] A diagram showing the creation of a unit. [Figure 11] A diagram showing the configuration of objects. [Figure 12] A diagram showing the arrangement of objects so that cells having density values ​​do not overlap each other. [Figure 13] FIG. 10 is a diagram showing a state in which an object is included in a unit. [Figure 14] A diagram showing a state in which an object crosses a unit boundary. [Figure 15] A diagram showing a copy move when an object crosses the left edge of a unit. [Figure 16] A diagram showing split movement when an object crosses the left edge of a unit. [Figure 17] A diagram showing a copy move when an object straddles the left and top edges of a unit. [Figure 18] A diagram showing quadrants when an object straddles the left and top edges of a unit. [Figure 19] A diagram showing split movement when an object straddles the left and top edges of a unit. [Figure 20] FIG. 1 is a flowchart for creating a halftone image. [Figure 21] Optimization flowchart diagram. [Figure 22] Flowchart diagram of halftone screening. [Figure 23] 1A and 1B are diagrams showing examples of halftone dot images according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The form for implementing the present invention will be described with reference to the drawings, but the present invention is not limited to the form for implementing the present invention described below, and various other embodiments are included as long as they are within the scope of the technical idea described in the claims.

[0020] Figure 7 shows a screen [6] used for halftone screening in the present invention. The structure of the screen [6] will be explained below.

[0021] The unit [U] is a basic unit that constitutes the screen [6]. The screen [6] is formed by repeatedly arranging these units [U]. In FIG. 7, an example is shown in which the unit [U] is square, but the shape of the unit [U] is not limited to a square, and may be other shapes such as a rectangle, as long as it can fill the plane without gaps.

[0022] An object [o] is composed of a rectangular array of cells [c], as shown in Figure 8. Each cell [c] of the object [o] has a density value [4] of 8 bits (0 to 255).

[0023] A unit [U] has at least two or more objects [o]. Furthermore, by arranging at least one of the objects [o] so that it straddles the boundary between adjacent units [U], a seamless design can be formed in which the boundary between each unit [U] is less noticeable.

[0024] 9 is a flowchart showing the process of creating a unit in the present invention. The method of creating a unit will be explained with reference to this flowchart.

[0025] As shown in Figure 10, a unit [U] is created along a virtual grid [7] as S01. For example, the unit [U] is composed of M cells [c] in the horizontal direction and N cells [c] in the vertical direction, that is, a rectangular array of M x N cells. Here, M and N are integers equal to or greater than 2. Each cell [c] has an 8-bit value of 255 as its density value [4].

[0026] In step S02, an object [o] is created to be placed in the unit [U]. The object [o] is composed of a rectangular array of m x n cells, for example, as shown in Figure 11, with m cells [c] in the horizontal direction and n cells [c] in the vertical direction.

[0027] Here, at least one of m and n is an integer greater than or equal to 2, and as mentioned above, since the unit [U] satisfies the condition that it has multiple objects [o], m≦M / 2 or n≦N / 2 are integers.

[0028] Furthermore, each cell [c] of the object [o] has a density value [4] of 0 to 254 in 8-bit values. Note that only density values ​​of 255 in 8-bit values ​​are treated as transparent attributes [8]. In this case, it is necessary to have density values ​​[4] of at least two levels or more within one object [o].

[0029] In step S03, the object [o] is placed in the unit [U]. As shown in Fig. 12, each object [o] is placed so that the cells [c] with a density value do not overlap with the cells [c] with a transparency attribute, but the cells [c] with a density value do not overlap with each other.

[0030] In S04, it is determined whether the entire object [o] is contained within the unit [U]. If the entire object [o] is contained within the unit [U], the process proceeds to S06. Note that Figure 13 shows the state in which the entire object [o] is contained within the unit [U].

[0031] If the entire object [o] is not contained within the unit [U], that is, if the object [o] crosses one or more of the boundaries of the unit [U], either up, down, left, or right, the process proceeds to S05. Note that Figure 14 shows the state in which the object [o] crosses the boundary line at the left edge of the unit [U].

[0032] In S05, an object placed in a unit is moved. There are two ways to move an object: duplicating the object and then moving it (hereafter referred to as "duplicate move"), or dividing the object at the boundary of the unit and then moving it (hereafter referred to as "divide move").

[0033] The object moving methods "copy move" and "split move" will be described below with reference to the drawings.

[0034] (When crossing the boundary line of one axis) This section explains the processing when an object crosses the boundary line of one axis of a unit. There are two conditions for an object to cross the boundary line of one axis of a unit: the first condition is when the object crosses the boundary line to the left or right, and the second condition is when the object crosses the boundary line to the top or bottom.

[0035] (Move copy) Figure 15 shows the duplication movement when object [o] crosses the boundary line at the left edge of unit [U], which is the first condition. In the first process, object [o] is duplicated at the same coordinates, and this duplicate is called the first duplicate object [o']. In the second process, the first duplicate object [o'] is translated to the right by M cell [c].

[0036] (Split Move) FIG. 16 shows the split movement when the object [o] crosses the boundary line at the left edge of the unit [U], which is one of the first conditions. As a first process, the object [o] is split at the left edge of the unit [U]. At this time, the split object [o] is defined as follows: the object to the left of the left edge of the unit [U] is defined as the first split object [o1], and the object [o] to the right of the left edge of the unit [U] is defined as the second split object [o2]. As a second process, only the first split object [o1] is translated M cells [c] to the right.

[0037] In the above, the case of copying and dividing an object from left to right under the first condition has been explained, but the same processing is also performed in the case of copying and dividing an object from right to left.

[0038] In addition, in the second condition, when the object crosses the boundary line of the unit vertically, the direction of movement of the object is changed to vertical and the number of cells moved is changed to N, but as with the first condition, the object is copied and moved or divided and moved.

[0039] (When crossing the boundary between two axes) Next, we will explain the processing when an object straddles the boundary between two axes of a unit.

[0040] (Move copy) Figure 17 shows the duplication and movement when object [o] straddles the boundary lines at the left and top edges of unit [U]. In the first process, object [o] is duplicated three times at the same coordinates, and these duplicates are called the first duplicate object [o'], the second duplicate object [o''], and the third duplicate object [o''''], respectively. In the second process, the first duplicate object [o'] is translated M cells [c] to the right. In the third process, the second duplicate object [o''] is translated downward N cells [c]. In the fourth process, the third duplicate object [o'''] is translated M cells [c] to the right and downward N cells [c].

[0041] (Split Move) Next, we will explain how to move an object [o] across the boundary lines at the left and top edges of a unit [U]. As a first process, as shown in FIG. 18, the object [o] is divided into four parts by two extensions: the left edge of the unit [U] and its extension, and the top edge of the unit [U] and its extension. The four divided objects are designated counterclockwise, starting from the upper right object, as the third divided object [o3], the fourth divided object [o4], the fifth divided object [o5], and the sixth divided object [o6]. FIG. 19 shows how to move the third divided object [o3], the fourth divided object [o4], and the fifth divided object [o5]. As a second process, the third divided object [o3] is translated downward by N cells [c]. As a third process, the fourth divided object [o4] is translated right by M cells [c] and downward by N cells [c]. As a fourth process, the fifth divided object [o5] is translated M cells [c] to the right.

[0042] The above describes the case of copying and dividing an object that straddles the left and top edges, but the same process applies to copying and dividing an object that straddles the right and top edges, the left and bottom edges, and the right and bottom edges.

[0043] In S06, it is determined whether or not a new object needs to be added. If a new object needs to be added, the processes from S02 to S05 are repeated.

[0044] Save the created unit as S07.

[0045] (Creating halftone images) 20 shows a flowchart of the process for performing halftone screening using the units created above to create a halftone image. The method for creating a halftone image will be explained with reference to this flowchart.

[0046] Load the unit created above as S1-01.

[0047] As S1-02, perform optimization on the unit, which will be described later.

[0048] As S1-03, obtain an image serving as the basis of the tone image using an imaging device (not shown) or the like, or read in a tone image input in advance. The tone image here is 8-bit format bitmap data serving as the basis for performing halftone screening, and when it is not 8-bit format bitmap data, it is converted into 8-bit format bitmap data.

[0049] As S1-04, perform resampling processing on the tone image read in S1-03 according to the resolution of the output halftone image. Note that resampling processing is a technique widely used in image processing and is an arithmetic process (e.g., bilinear method or bicubic method) for increasing or decreasing the number of pixels, which is the minimum unit of the image that the tone image has.

[0050] As S1-05, using the unit optimized in S1-02, perform halftone screening, which will be described later, on the tone image resampled in S1-04.

[0051] As S1-06, save the created halftone image and end the creation of the halftone image.

[0052] (Optimization of the unit) FIG. 21 shows a flowchart of the optimization process for converting the density values of the unit into threshold values. The optimization process of the unit will be described according to this flowchart.

[0053] As S2-01, define a histogram H. The histogram H is a one-dimensional array in a computer program that stores the number of cells of the respective density values of the unit read in S1-01.

[0054] As S2-02, execute the process of Loop 1. Loop 1 starts from y = 0 and is an iterative process of adding 1 to y while y < N.

[0055] As S2-03, execute the process of Loop 2. Loop 2 starts from x = 0 and, while x < M, is an iterative process of adding 1 to x. After the end of Loop 2, return to Loop 1.

[0056] As S2-04, substitute values into the histogram H defined above. As a result of this process, the histogram H will be in a form such as Table 1 shown below.

[0057] [Table 1]

[0058] As S2-05, define the cumulative array a. The cumulative array a is a one-dimensional array in a computer program that accumulates the number of cells in the histogram H.

[0059] As S2-06, substitute "0" into cumulative array a(0).

[0060] As S2-07, execute the process of Loop 3. Loop 3 starts from i = 1 and, while i < 256, is an iterative process of adding 1 to i. After the end of Loop 3, transfer to S2-09.

[0061] As S2-08, execute Equation 1 shown below to store the cumulative number of cells in each index (i) of the cumulative array a. As a result of this process, the cumulative array a will be in a form such as Table 2 shown below.

[0062] [Equation]

[0063] [Table 2]

[0064] As S2-09, execute the process of Loop 4. Loop 4 starts from y = 0 and, while y < N, is an iterative process of adding 1 to y.

[0065] As S2-10, execute the process of Loop 5. Loop 5 starts from x = 0 and, while x < M, is an iterative process of adding 1 to x. After the end of Loop 5, return to Loop 4.

[0066] As S2-11, execute the following Equation 2 to store 8-bit values (from 0 to 255) in the unit (U), which is a two-dimensional array. Note that the values after the decimal point generated in this arithmetic process are rounded to integer values.

[0067]

Equation

[0068] As S2-12, overwrite and save the unit.

[0069] Through the above optimization process, the density value of the unit is converted into a threshold value.

[0070] (Halftone Screening) Figure 22 shows the process of halftone screening in a flowchart. According to this flowchart diagram, halftone screening for converting a grayscale image into a dot image will be described.

[0071] As S3-01, substitute the number of horizontal pixels of the grayscale image obtained by executing the resampling process in S1-04 into the variable h. Also, substitute the number of vertical pixels of the grayscale image obtained by executing the resampling process into the variable v.

[0072] As S3-02, create a dot image D(h, v). This dot image D is a two-dimensional array in a computer program.

[0073] As S3-03, execute the process of Loop 1. Loop 1 starts from y = 0 and, while y < v, is an iterative process of adding 1 to y.

[0074] As S3-04, execute the process of Loop 2. Loop 2 starts from x = 0 and performs an iterative process of adding 1 to x while x < h. After the end of Loop 2, return to Loop 1.

[0075] As S3-05, substitute the remainder obtained by dividing x by the number of cells M in the horizontal direction of the unit into the variable dx, and substitute the remainder obtained by dividing y by the number of cells N in the vertical direction of the unit into the variable dy.

[0076] As S3-06, perform a process of comparing the density value of the resampled tone image in S1-04 with the value {255 - U(dx, dy)} obtained by tone-inverting the threshold value of the aforementioned unit. This process is a branching condition in computer programming, which returns "true" if the former is smaller than the latter, and returns "false" otherwise.

[0077] As S3-07, substitute "1" into the halftone image D(x, y).

[0078] As S3-08, substitute "0" into the halftone image D(x, y).

[0079] Through this halftone screening process, all pixels of the tone image are binarized (black and white), and a seamless halftone image as shown in Fig. 23 can be generated.

Explanation of Symbols

[0080] 1 Tone image 2 Halftone image 3 Threshold value 4 Density value 5 Sub-unit 6 Screen 7 Virtual grid 8 Transparent attribute U Unit c Cell o Object o′ First replicated object o′′ Second replicated object o′′′ Third replicated object o1 First segment object o2 Second segment object o3 Third segment object o4 Fourth segment object o5 Fifth segment object o6 Sixth division object

Claims

1. A method for creating data for a halftone print, which halftone-dots a print area having a gradation image on at least a portion of a substrate using units formed by a plurality of objects, comprising: a step of regularly arranging a plurality of units formed by a set of cells in the printing area, the units being M or more cells (M is an integer of 2 or more) arranged along a first direction and N or more cells (N is an integer of 2 or more) arranged along a second direction different from the first direction, at a constant pitch and in a constant shape; forming a plurality of the objects on the unit at positions where they do not overlap each other; a step of checking whether the plurality of objects are placed at positions straddling the boundary line where each of the units is placed adjacent to each other; When the plurality of objects are placed at positions straddling a boundary line in the first direction or the second direction in the unit, i) duplicating the object formed at a position straddling the boundary line in the first direction in each of the units to a position moved by the number (M) of cells from one end side to the other end side in the first direction, and / or duplicating the object formed at a position straddling the boundary line in the second direction in each of the units to a position moved by the number (N) of cells from one end side to the other end side in the second direction, or ii) dividing the objects formed in each of the units at positions straddling the boundary line in the first direction or the second direction along the boundary line of the unit, and moving the objects formed outside the units from one end side to the other end side in the first direction or the second direction by the number of cells (M or N), thereby moving the objects formed outside the units into the units; a step of inputting an image that is the basis of the gradation image or reading a previously input image, and performing a resampling process; and creating data for a halftone print by halftone screening the object formed by i) or ii).

2. A method for creating data for a halftone print, which halftone-dots a print area having a gradation image on at least a portion of a substrate using units formed by a plurality of objects, comprising: a step of regularly arranging a plurality of units formed by a set of cells in the printing area, the units being M or more cells (M is an integer of 2 or more) arranged along a first direction and N or more cells (N is an integer of 2 or more) arranged along a second direction different from the first direction, at a constant pitch and in a constant shape; forming a plurality of the objects on the unit at positions where they do not overlap each other; a step of checking whether the plurality of objects are placed at positions straddling the boundary line where each of the units is placed adjacent to each other; When the plurality of objects are arranged at positions straddling the boundary line between the first direction and the second direction in the unit, iii) The object formed at a position straddling the boundary line in the first direction and the second direction in each of the units is duplicated to a position moved by the number (M) of cells from one end side to the other end side in the first direction, duplicated to a position moved by the number (N) of cells from one end side to the other end side in the second direction, duplicated to a position moved by the number (M, N) of cells from one end side to the other end side in the first direction and from one end side to the other end side in the second direction, or iv) dividing the object formed outside the boundary line of each of the units into an area formed within the unit, an area spanning only the first direction, an area spanning only the second direction, and an area spanning both the first and second directions, and moving the area spanning only the first direction from one end side to the other end side in the first direction by the number (M) of cells, moving the area spanning only the second direction from one end side to the other end side in the second direction by the number (N) of cells, and moving the area spanning both the first direction and the second direction from one end side to the other end side in the first direction and from one end side to the other end side in the second direction by the numbers (M and N) of cells, thereby moving the object into the unit; a step of inputting an image that is the basis of the gradation image or reading a previously input image, and performing a resampling process; and creating data for a halftone print by halftone screening the object formed by iii) or iv).

3. 3. A method for creating data for halftone dot prints according to claim 1, characterized in that the step of forming the object on the unit includes a step of forming the object from a collection of cells having density values ​​of 8-bit values, forming the object as a 0-degree rectangular array of m cells x n cells (where at least one of m and n is 2 or more, and m is an integer satisfying m≦M / 2 and n≦N / 2), and making the gradation difference between the cells within the object at least 1 in 8-bit values.

4. 4. The method for creating data for halftone dot prints according to claim 1, further comprising a step of optimizing density values ​​of the units.

Images