JP5048399B2 - Image unevenness reducing method and apparatus - Google Patents

Description

  The present invention relates to an image unevenness reducing method and apparatus for reducing unevenness due to a difference in the total amount of color material on a color image in which a color is determined by a total amount of color material obtained by overlapping color materials for each pixel. About.

  Conventionally, in an image output device (image forming apparatus) such as an electrophotographic printer that uses toner as a color material and an ink jet printer that uses ink as a color material, and a printing machine, the color material is superimposed on paper (printing paper) An image is formed on a sheet (base material) such as, but according to the purpose of use, the flatness of the image should be as uniform as possible and the image should not be uneven (not like a relief) Is required.

  The flatness of the image, in other words, the degree of unevenness is determined by the total amount of color material forming each point (pixel) constituting the image. When the difference in the total color material amount of each pixel is small, the flatness of the image is maintained, and when the difference is large, unevenness is formed.

  As an image forming body, an image forming apparatus, and a receiving layer transfer material on which unevenness is formed (a relief is formed) to which the present invention can be applied, a dye receiving layer on a relief forming layer surface having a white reflection function is on demand. Receiving layer transfer material capable of obtaining a high design image having both white diffused light from the relief forming layer or white light in a specific angle range and a color material image by printing and forming an image by a printing method In addition, there are a transfer sheet, a color material receiving sheet with a relief layer, and an image formed product using these (Patent Document 1).

  The present invention can also be applied to a relief image forming apparatus using an ink useful for an ink jet system in which ink is ejected by generating bubbles with an electric heat exchanger (Patent Document 2).

  Furthermore, the first message image area printed with the optically changing ink on the surface of the base material, and the first message image area printed on the surface of the first message image area with the swelled ink. The present invention can also be applied to an image forming body having a configured second message image area (Patent Document 3).

  By the way, a technique related to a toner image forming method that gives a flat image without unevenness over the entire copy toner image has been proposed (Patent Document 4).

  In the technique according to Patent Document 4, after image formation, a flat image surface is formed by overlaying transparent ink so as to cancel out the unevenness of the relief.

JP 2006-218847 A JP-A-8-60054 JP 2006-123355 A Japanese Patent Laid-Open No. 5-6033

  However, the technique according to Patent Document 4 requires a coating process and a coating mechanism for transparent ink, resulting in an increase in image cost and a decrease in productivity.

  The present invention has been made in consideration of such a problem, and the color is determined by the total amount of the color material obtained by overlapping the color material for each pixel, and the total amount of the color material on the color image formed on the base material is determined. The present invention relates to an image unevenness reducing method and apparatus capable of reducing unevenness due to a difference.

  According to the image unevenness reducing method according to the present invention, when a color image whose color is determined by a total amount of color materials obtained by overlapping color materials for each pixel is formed on a substrate, the image on the image formed on the substrate is formed. The image unevenness reducing method for reducing unevenness due to the difference in the total amount of the color material includes the following features (1) to (3).

  (1) A process for obtaining a total color material amount range for each pixel position, a process for determining a target color material total quantity, and a color material total quantity closest to the target color material total quantity for each pixel position, for each pixel position. And determining the total amount of color material.

  According to the present invention, since the total color material amount closest to the target color material total amount is determined as the total color material amount for each pixel position, the unevenness amount of the image can be reduced.

  In addition, as a base material on which a color image in which a color is determined by a total amount of color materials obtained by overlapping color materials for each pixel is formed, a sheet such as paper, metal, resin, rubber, wood, and the like can be given.

  (2) In the invention having the above feature (1), in the process of obtaining the total color material amount range, the maximum value and the minimum value of the total color material amount for each pixel position are obtained.

  (3) In the invention having the feature (1), in the process of determining the total color material amount closest to the target color material total amount for each pixel position as the total color material amount for each pixel position, the color material The total amount of color material that can be obtained in the total amount range can be determined.

  The ground color is white if the base material is paper and white, but the white material can be easily obtained at a lower cost than the transparent color material.

  The image unevenness reducing device according to the present invention provides an image on the image formed on the base material when a color image whose color is determined by the total amount of the color material obtained by overlapping the color materials for each pixel is formed on the base material. In the image unevenness reducing apparatus for reducing unevenness due to a difference in total color material amount, a means for determining a total color material amount range for each pixel position, a means for determining a target total color material amount, and the target color material for each pixel position Means for determining a total color material amount closest to the total amount as a total color material amount for each pixel position.

  According to the present invention, since the total color material amount closest to the target color material total amount is determined as the total color material amount for each pixel position, the unevenness amount of the image can be reduced.

  According to the present invention, the unevenness due to the difference in the total amount of color material on the color image formed by determining the color based on the total amount of color material obtained by superimposing the color material for each pixel on the base material can be reduced by a certain amount. .

  Compared with the prior art, the cost of the color image can be reduced and the productivity can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of an image reproduction system 10 to which an image unevenness reducing method and apparatus according to an embodiment of the present invention are applied.

  The image reproduction system 10 basically includes a personal computer 12, a color scanner (image input device, image input device) 14 connected to the personal computer 12, and a color printer (image output device, image output device) 16. , A film printer (image output device, image output device) 18 and a colorimeter 20 for measuring a device independent value, here Lab.

  The color scanner 14 reads a color image from a color original Ia such as a color reversal film, and sends device values RGB (also referred to as RGB image data of three RGB colors) to the personal computer 12.

  The personal computer 12 is connected to an input device 30 such as a CPU 22, a memory 24, a color monitor 28, and a keyboard mouse through a bus, and further, an interface 32 that receives device values RGB from the color scanner 14, a color printer 16, or a film. An interface 34 for sending device values CMYK (also referred to as four-color CMYK image data) to the printer 18 and an interface 36 for receiving device independent values Lab as colorimetric values from the colorimeter 20 are connected.

  The memory 24 includes a DRAM (main memory), a flash memory (rewritable non-volatile memory), and the like. The CPU 22 executes programs stored in the memory 24 based on various inputs, thereby realizing various function implementation means. Works as. In this embodiment, the CPU 22 converts the device values RGB and CMYK, which are image data from the image input device, into device independent values Lab and the like, and converts the device independent values Lab and the like into device values CMYK and the like of the image output device. Means for obtaining a color material total amount range (color material total amount line segment) for each pixel position from the converted device values CMYK and the like (image data); a target color material for all pixel positions in the color material total amount range; Functions as a means for determining the total amount, a color material total amount determination means for each pixel position, a background color raising amount determination means for determining the amount of color material increase of the sheet background color (base color), and various other calculation means. .

  The film printer 18 outputs a printing film original plate (not shown) of each CMYK plate corresponding to the device value CMYK sent from the personal computer 12.

  Usually, CMYK plates are prepared from the printing film original plate, and the prepared plates are mounted on a rotary press, that is, the printing press 50, and each CMYK ink (color material) is applied to each plate. Applied. Then, each ink applied to each printing plate is superposed on the printing paper and transferred to complete a color printed matter Ib on which a color image is formed.

  Here, the work of producing the color printed material Ib using the printing machine 50 is a very large work and is expensive. For this reason, the color printer 16 as a color printing proofer is used for the purpose of confirming the finish of the color printed matter Ib before actual printing by the printing press 50. The color printer 16 outputs a hard copy Ic used as a color proof or the like on which a color image is formed.

  As shown in FIG. 2A, the memory 24 stores an A2B profile table 52 that converts device values RGB (scanner) obtained from the color scanner 14 into device independent values Lab.

  In order to create the A2B profile table 52, as shown in FIG. 1, instead of the color original Ia, a large number of color patch images Iq formed on the color chart Ie are read by the color scanner 14, and each color patch image is read. A device value RGB (color scanner) for each Iq is obtained, and the color patch image Iq is measured by the colorimeter 20 to obtain a device independent value Lab, which is taken into the memory 24 of the personal computer 12 through the interface 36.

  The CPU 22 creates an A2B profile table 52 (scanner) by associating the relationship between the device value RGB thus obtained and the device independent value Lab, and stores it in the memory 24.

  The memory 24 also stores a B2A profile table 54 shown in FIG. 2B for converting the device independent value Lab for the color printer 16 into the device value CMYK (color printer).

  In order to create this B2A profile table 54 (color printer), first, the CPU 22 needs to create an A2B profile table 58 (color printer) for the color printer 16 shown in FIG. 2C and store it in the memory 24.

  Here, how to create the A2B profile table 58 (color printer) of FIG. 2C will be described with reference to the flowchart of FIG.

  In creating the A2B profile table 58 for the color printer 16, for example, when creating a table of device independent values Lab corresponding to 10% increments in CMYK halftone data, the halftone value is set to 0, 10,. , 11 (C) × 11 (M) × 11 (Y) × 11 (K) = 14641 (equal to the number of grid points related to the combination of 10% increments) for the four CMYK colors changed to 100% It is necessary to obtain the device independent value Lab of the minute.

  However, in practice, as shown in step S 1, the CPU 22 generates device values CMYK corresponding only to characteristic hundreds of colors and supplies them to the color printer 16 through the interface 34. In step S2, the color printer 16 outputs a color chart Id in which corresponding color patch images Ip of several hundred colors are formed on the sheet 62 (see FIG. 1).

  Next, in step S3, each patch of the color patch image Ip formed on the color chart Id is color-measured through the colorimeter 20, and device independent values Lab relating to the grid points for several hundred colors are obtained. In step S 4, the device independent value Lab is taken into the memory 24 of the personal computer 12 through the interface 36.

Next, in step S5, the CPU 22 performs A2B shown in FIG. 2C for the color printer 16 related to the combination of the above-described 10% increments for 11 ⁴ = 14641 colors by interpolation processing of the device independent values Lab for several hundred colors. A profile table 58 is created.

  Next, a process (process) for creating a desired B2A profile table 54 (FIG. 2B) for the color printer 16 based on the created A2B profile table 58 for the color printer 16 is described with reference to the flowchart shown in FIG. explain.

  First, in step S11, the previously created A2B profile table 58 for the color printer 16 is searched (searched), and a set of device values CMYK (Ci, Mi, Yi, Determine if Ki) exists.

  More specifically, in the process of step S11, first, a set of device values CMYK (Ci, Mi, Yi, 0) corresponding to an arbitrary device independent value Lab when K = 0 is fixed, It is searched whether or not it exists in the A2B profile table 58 for the color printer 16.

  Next, each set of device values CMYK (Ci, Mi, Yi, 10), (Ci, Mi, Yi, 20),..., (Ci, when K = 10, 20,. Mi, Yi, 100) are searched for in the A2B profile table 58 for the color printer 16.

  Next, in the process of step S12, only the set (Ci, Mi, Yi, Ki) of existing device values CMYK in K = 0, 10, 20,..., 100 corresponding to the arbitrary device independent value Lab is obtained. A memory area is secured in the memory 24, stored in the secured memory area in correspondence with the arbitrary device independent value Lab, and a B2A profile table 54 for the color printer 16 shown in FIG. 2B is created.

  FIG. 5 shows a specific example of the B2A profile table 54 for the color printer 16 created as described above.

  In FIG. 5, device values CMYK corresponding to arbitrary device independent values Lab = (L, a, b) = (100, 0, 0) in the A2B profile table 58 for a color printer schematically represented by a cube. Only the device value (Ci, Mi, Yi, Ki) = (0, 0, 0, 0) exists in the set (Ci, Mi, Yi, Ki) (represented by a network percentage). The existing device value (Ci, Mi, Yi, Ki) = (0, 0, 0, 0) corresponds to the device independent value (L, a, b) = (100, 0, 0) in the B2A profile table 54 And “¥ 0” indicating that there is no more data is written.

  Similarly, a set (Ci, Mi, Yi, Ki) of device values CMYK corresponding to an arbitrary device independent value Lab = (L, a, b) = (10, 0, 0) is a device value (Ci, Mi). , Yi, Ki) = (28, 17, 16, 0), (0, 0, 0, 10), assuming that there are only two existing device values (Ci, Mi, Yi, Ki) = (28, 17, 16, 0), (0, 0, 0, 10) are stored in the B2A profile table 54 corresponding to the device independent value (L, a, b) = (10, 0, 0). In addition, “¥ 0” indicating that there is no more data is written.

  Further, a set (Ci, Mi, Yi, Ki) of device values CMYK corresponding to an arbitrary device independent value Lab = (L, a, b) = (50, 0, 0) is a device value (Ci, Mi, Yi, Ki) = (48, 37, 36, 0), (36, 28, 25, 10)... (0, 0, 0, 80). Ci, Mi, Yi, Ki) = (48, 37, 36, 0), (36, 28, 25, 10)... (0, 0, 0, 80) are stored in the B2A profile table 54 as device independent values (L , A, b) = (50, 0, 0) and stores “¥ 0” indicating that there is no more data.

  In FIG. 5, in the A2B profile table 58 for a color printer schematically represented by a cube, the device value CMYK exists within the range surrounded by the ellipsoid 60, and the color printer represented by the ellipsoid 60 and the cube. There is no device value CMYK corresponding to an arbitrary device independent value Lab between the A2B profile tables 58 for use. Conventionally, any device independent value Lab that does not exist has been stored in the memory without verification and the B2A profile table has been created, so the memory capacity has become enormous. As in the embodiment, the memory capacity can be significantly reduced by storing only the device values CMYK that exist corresponding to any device independent value Lab.

  As described above, the B2A profile table 54 for the color printer is created. Note that data of the B2A profile table 56 of the printing press 50 shown in FIG. 2D is created and stored in the memory 24 in the same manner as creating the B2A profile table 54 of the color printer 16. The B2A profile table 56 of the printing machine 50 is used by the film printer 18.

  Next, the color image read from the color original Ia by the color scanner 14 is formed on the sheet 62 as a color image with small unevenness (suppressed unevenness and less unevenness) on the hard copy Ic obtained from the color printer 16. The procedure of reproducing (forming) will be described with reference to the flowchart of FIG.

  In step S21, the CPU 22 reads a color image from the color original Ia through the color scanner 14 and captures it as a device value RGB, and refers to the captured device value RGB by referring to the A2B profile table 52 (scanner) in FIG. 2A. Conversion to independent value Lab (device value device independent value conversion means).

  Next, in step S22, based on the converted device independent value Lab, the maximum value and the minimum value of the total amount of color material that produces the same color at any pixel position xi (xi = 1, 2,..., N) on the color image. The color material total amount segment Ti (Ti = 1, 2,..., N) connecting the values, in other words, the device value CMYK of the color printer 16 is obtained with reference to the B2A profile table 54 shown in FIG.

  For example, when the device independent value Lab at an arbitrary pixel position xi is Lab = (50, 0, 0), a set of device values CMYK corresponding to (L, a, b) = (50, 0, 0) In other words, (Ci, Mi, Yi, Ki) is the device value CMYK that produces the same color. (Ci, Mi, Yi, Ki) = (48, 37, 36, 0), (36, 28, 25) , 10)... (0, 0, 0, 80).

  Here, each value of the device value CMYK is indicated by halftone%. Since the total color material amount is proportional to the total value (sum) of the mesh% of each value of the device value CMYK, for the sake of easy understanding, this total value is referred to as the total color material amount.

  Then, the total amount of each color material of the device value CMYK that develops Lab = (50, 0, 0) is (48 + 37 + 36 + 0 = 121), (36 + 28 + 25 + 10 = 99) (0 + 0 + 0 + 80 = 80). By connecting the maximum value and the minimum value of these nine color material total amounts, the color material total amount segment Ti can be obtained.

  If the concept of the total amount of color material is schematically shown, as shown in FIG. 7, a predetermined amount of four color material CMYK is superimposed on a sheet 62 such as paper to form a pixel. Incidentally, the maximum value is 121 and the minimum value is 80 out of the total amount of the three colorants that produce the same color specifically shown in FIG. Thus, the total amount of color material is proportional to the film thickness. Therefore, when the total amount of color material at any pixel position xi (xi = 1, 2,..., N) on the color image has the same value, the color image becomes flat and an image without unevenness is created. Since the total amount of the color material at any pixel position xi (xi = 1, 2,..., N) on the color image is as close as possible, an image with less unevenness can be obtained.

  FIG. 8 shows the color connecting the maximum value and the minimum value of the total amount of color material that produces the same color at an arbitrary pixel position xi (xi = 1, 2,..., N) on the color image, obtained in the process of step S22. A schematic distribution diagram of the total material mass segment Ti (Ti = 1, 2,..., N) is shown. Although it is actually two-dimensional, a one-dimensional distribution diagram is drawn here for easy understanding.

  Next, in step S23, a plane P parallel to the sheet 62 and crossing the color material total amount segment Ti as much as possible is searched, and the height of the searched plane P (color material total amount t) is obtained as the target color material total amount tmin. .

  Specifically, as shown in FIG. 9, the sum of squares of the distance di between the height of the plane P (color material total amount t) from the position of the sheet 62 and the near point in the color material total amount line segment Ti. By setting the height (color material total amount t) of the plane P that minimizes S (by the least square method) as the target color material total amount tmin, the amount of unevenness can be reduced on average.

In the example of FIG. 9, the height of the plane P (color material total amount t) that minimizes S = (d1 = 0) ² + d2 ² + d3 ² + (d4 = 0) ² + (d5 = 0) ² is the target color. The total material amount is tmin. Of course, not limited to the least square method, for example, the sum of the distance di (absolute value of di) between the height of the plane P (total color material amount t) and the near point in the color material total amount line segment Ti is minimized. The height of the plane P (color material total amount t) may be set as the target color material total amount tmin.

  Next, in step S24, for each pixel position xi, the total color material amount tia that is equal to or closest to the target color material total amount tmin is determined as the total color material amount t for each pixel position xi. In this case, as shown in FIG. 10, for each pixel position xi, the total color material amount t closest to the target color material total amount tmin is set to the total color material amount t for each pixel position xi (tia = t1a, t2a, t3a, t4a, t5a), in other words, the device value CMYK of the color printer 16 is determined. Here, the total color material amounts t2a, t3a are values actually stored in the B2A profile table 54, but the total color material amounts t1a, t4a, t5a may be unstored values. In this case, the stored value closest to the total color material amount t1a, t4a, t5a is selected.

  By sending the device value CMYK for each pixel position xi determined in this way from the personal computer 12 to the color printer 16, the color printer 16 can obtain a hard copy Ic on which a color image with reduced unevenness is formed. it can.

  As another process of step S24, as shown in FIG. 11, the background color of the sheet 62 is applied to the color material total amount line segment T3 in which the maximum value of the color material total amount line segment Ti is smaller than the target color material total amount tmin. The color material (usually white) is raised by the color material amount T0, and the maximum value of the color material total amount line segment T3 (the maximum value of the color material total amount component T3 ′ after the increase) becomes the target color material total amount tmin. To do. That is, the color material total line segment T3 is defined as a color material total line segment T3 ′ that is extended by extending the color material raised amount To by the background color of the sheet 62, and the color material total amount t at the pixel position x3 is determined as t = t3a ′. By doing so, although the color material for the ground color increases, the hard copy Ic on which the color image with the unevenness amount being further reduced as a whole can be obtained.

  Of course, when the total color material amount t varies greatly depending on the pixel position xi, such as when there is a white portion (ground color portion without color material) in the image, for example, processing for obtaining the target total color material amount tmin in step S23 Further, the plane is set so that the sum of the distances between the height of the plane P (total color material amount t) and the near point in the total color material amount segment Ti or the square sum of the distances is within a predetermined value. As described above, the color material of the background color of the sheet 62 is raised to the color material total amount segment Ti where the maximum value of the color material total amount segment Ti is small with respect to the height of P (color material total amount t). By including the process of lengthening the total amount line segment Ti, the color material for the ground color increases, but a hard copy Ic in which the unevenness of the image is further reduced can be obtained.

  Further, in FIG. 10, the total color material amount segments T3 and T4 are raised by the white color material amount so that the target color material total amount tmin (plane P) matches the total color material amount t2a (tmin = t2a). (By matching the maximum value t3a of the color material total amount line segment T3 and the maximum value of the color material total amount line segment T4 with the color material total amount t2a), the target color material total amount tmin at all image positions Xi is the color material total amount t2a. It is possible to obtain a hard copy Ic having a total color material amount of the same height and on which a color image having no unevenness is formed.

  As described above, according to the above-described embodiment, when the color printer (image output device) 16 forms on the sheet 62 a color image whose color is determined by the total color material amount t in which the color material is superimposed on each pixel. When the unevenness due to the difference in the total amount t of the color material on the image formed on the sheet 62 is reduced, the B2A profile table 54 is referred to for each pixel position xi and corresponds to the device independent value Lab at the pixel position xi. A process of obtaining a total color material amount line segment (color material total quantity range) Ti connecting the maximum value and the minimum value of the total color material quantity t that produces the same color {step S22, FIG. 8: a process of obtaining the total color material range}, and a sheet A process of searching for a plane P that is parallel to 62 and crosses the color material total amount segment Ti as much as possible, and determines the height of the searched plane P as a target color material total amount tmin (step S23, FIG. 9: Determination of target color material amount) Excessive ) And the total color material amount t1a, t4a, t5a equal to the target color material amount tmin or the total color material amount t2a, t3a closest to the target color material amount tmin in the total color material amount segment Ti for each pixel position Xi, And a process of determining the total color material amount for each pixel position Xi (step S24, FIG. 10: total color material amount determination process).

  For each pixel position xi, the color closest to the target color material total amount tmin, which is the height of the plane P that crosses the color material total amount segment Ti connecting the maximum and minimum color material total amount t that produces the same color as much as possible. Since the total material amount tia is determined as the total color material amount for each pixel position Xi, the unevenness amount of the image is, for example, the amount between the closest total color material amounts above and below the target total color material amount tmin (see FIG. 10 can be suppressed to t2a-t3a).

  In this case, in the process of obtaining the target color material total amount tmin, the sum of the distance between the height of the plane P and the near point in the color material total amount segment Ti, or the height of the plane P at which the sum of squares of the distance is minimized. By setting the target color material total amount tmin, the target color material total amount tmin can be easily determined, and the unevenness amount of the image can be reduced on average.

  The ground color is white if the sheet 62 is paper and white, but the white color material can be easily obtained at a lower cost than the transparent color material.

  According to the above-described embodiment, the unevenness due to the difference in the total amount of color material on the color image formed by determining the color based on the total amount of color material overlaid on the sheet 62 for each pixel is reduced by a certain amount. Can do. Since there is no need to use transparent toner that covers substantially the entire sheet as in the prior art, the cost of color images can be reduced, and productivity can be improved.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the contents described in this specification.

  For example, as a base material for forming a color image whose color is determined by the total amount of color materials overlaid for each pixel, metal, resin, rubber, wood, and the like can be used in addition to the sheet 62 such as paper.

1 is a configuration diagram of an image reproduction system to which an image unevenness reducing method and apparatus according to an embodiment of the present invention are applied. FIG. 2A is a schematic diagram of an A2B profile table that converts device values obtained from a color scanner into device independent values, FIG. 2B is a schematic diagram of a B2A profile table for a color printer that converts device independent values into device values, and FIG. FIG. 2D is a schematic diagram of a B2A profile table for a printing press that converts device independent values into device values. FIG. 2D is a schematic diagram of A2B profile tables that convert device values of color printers into device independent values. It is a flowchart which shows the detail of the preparation procedure of the A2B profile table for color printers. It is a flowchart which shows the process sequence which produces the B2A profile table for color printers based on the A2B profile table for color printers. It is explanatory drawing which shows the specific example of the B2A profile table for color printers. It is a flowchart which shows the procedure which reproduces the color image obtained from the color original with the color scanner as a color image with small unevenness on the hard copy obtained from the color printer. It is explanatory drawing of the coloring material total amount formed in piles on a sheet | seat. FIG. 6 is a schematic distribution diagram of a color material total amount line segment connecting a maximum value and a minimum value of a total color material amount that develops the same color at an arbitrary pixel position on a color image. It is explanatory drawing with which description of determination of the target color material amount is provided. It is explanatory drawing of the method of determining the color material total amount of the pixel position on a color image in order to make the unevenness | corrugation of an image small. It is explanatory drawing of the other method of determining the color material total amount of the pixel position on a color image in order to make the unevenness | corrugation of an image small.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image reproduction system 12 ... Personal computer 16 ... Color printer 52 ... A2B profile table (scanner)
54 ... B2A profile table (color printer)
58 ... A2B profile table (color printer)
62 ... Sheet

Claims (4)

When forming a color image on a substrate whose color is determined by the total amount of the color material overlaid on each pixel, unevenness due to the difference in the total amount of color material on the image formed on the substrate is reduced. In the image unevenness reducing method,
For each pixel position, a process of obtaining a color material total amount line connecting the maximum value and the minimum value of the total color material amount among a plurality of sets of color materials that develop the same color ;
Parallel to the substrate, the steps of the material total amount segment exploring plane transverse as possible, to determine the height from the substrate searched the plane as the target material total amount,
A process of determining, for each pixel position, a total color material amount within the range from the minimum value to the maximum value and equal to or closest to the target color material total amount, as the total color material amount for each pixel position. When,
An image unevenness reducing method comprising: The image unevenness reducing method according to claim 1,
In the process of determining the target color material total amount, the sum of the distance between the height of the plane and the near point with respect to the plane in the color material total amount line segment that does not cross the plane or the sum of squares of the distance is minimum. And determining the height of the flat surface as the target total color material amount . When forming a color image on a substrate whose color is determined by the total amount of the color material overlaid on each pixel, unevenness due to the difference in the total amount of color material on the image formed on the substrate is reduced. In the image unevenness reduction device,
Means for obtaining a color material total amount line segment connecting the maximum value and the minimum value of the total color material amount among a plurality of sets of color materials that develop the same color for each pixel position;
Parallel to the substrate, means for determining the searching the plane transverse as possible color material amount line, the height from the substrate searched the plane as the target material total amount,
Means for determining, for each pixel position, a total color material amount within the range from the minimum value to the maximum value and equal to or closest to the target color material total amount, as the total color material amount for each pixel position. When,
An image unevenness reducing apparatus comprising: In the image unevenness reducing device according to claim 3,
The means for determining the target color material total amount is a minimum sum of distances or a sum of squares of distances between the height of the plane and a near point with respect to the plane in the color material total amount line segment that does not cross the plane. An image unevenness reducing apparatus, wherein the height of the plane to be determined is determined as the target color material total amount.

Images