IMAGE PROCESSOR AND STORAGE MEDIUM STORING PROGRAM

• US 20180084148A1
• Filed: 09/15/2017
• Published: 03/22/2018
• Est. Priority Date: 09/22/2016
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: YOSHIDA, Yasunari
• Granted Patent: US 10,205,850 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 1/4052 by error diffusion, i.e. transferring the binarising error to neighbouring dot decisions
• CPC Class Codes: H04N 1/4053 with threshold modulated relative to input image data or vice versa
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement
• CPC Class Codes: H04N 1/58 Edge or detail enhancement; Noise or error suppression, e.g. colour misregistration correction H04N1/62 takes precedence
• CPC Class Codes: H04N 1/6008 with primary colour signals, e.g. RGB or CMY(K)
• CPC Class Codes: H04N 2201/0082 Image hardcopy reproducer H04N2201/0091 - H04N2201/0094 take precedence

Abstract

An image processor sets the dot value to a value for forming a dot in a case where the dot forming condition is satisfied; sets the dot value to a value for forming no dot in a case where the dot forming condition is not satisfied and the target pixel is not the edge pixel; sets the dot value to a value for forming a dot in a case where the dot forming condition is not satisfied and a particular condition is satisfied; and sets a distribution error value to a smaller value than another error value in a case where the dot forming condition is not satisfied and the particular condition is satisfied and thereby the dot value is set to the value for forming a dot.

Claims

1. An image processor for a printer, comprising:

a processor; and

a memory storing instructions, the instructions, when executed by the processor, causing the processor to perform;

acquiring original image data representing an original image including a plurality of pixels, the original image data being indicative of a density of each of the plurality of pixels;

determining whether a dot forming condition of an error diffusion method is satisfied by using a density of a target pixel in the plurality of pixels and an error value distributed to the target pixel;

determining whether the target pixel is an edge pixel constituting an edge together with a surrounding pixel, the edge pixel having a higher density than a density of the surrounding pixel;

determining a dot value indicative of a dot formation state of the target pixel, the determining the dot value including;

setting the dot value to a value indicative of forming a dot in a case where the dot forming condition is satisfied;

setting the dot value to a value indicative of forming no dot in a case where the dot forming condition is not satisfied and the target pixel is not the edge pixel; and

setting the dot value to a value indicative of forming a dot in a case where the dot forming condition is not satisfied and a particular condition is satisfied, the particular condition including that the target pixel is the edge pixel;

setting a distribution error value to a smaller value than another error value in a case where the dot forming condition is not satisfied and the particular condition is satisfied and thereby the dot value of the target pixel is set to the value indicative of forming a dot, the distribution error value being an error value to be distributed from the target pixel to an unprocessed pixel, and the another error value being an error value to be distributed from the target pixel to the unprocessed pixel in a case where the dot value of the target pixel is set to the value indicative of forming no dot; and

generating print data including the dot value of each of the plurality of pixels determined by processing each of the plurality of pixels as the target pixel.

2. The image processor according to claim 1, wherein the instructions, when executed by the processor, cause the processor to perform:

in a case where the dot forming condition is not satisfied and the target pixel is the edge pixel and the density of the target pixel is higher than or equal to a first density, setting the dot value to the value indicative of forming a dot; and

in a case where the dot forming condition is not satisfied and the target pixel is the edge pixel and the density of the target pixel is lower than the first density, setting the dot value to the value indicative of forming no dot.

3. The image processor according to claim 2, wherein the instructions, when executed by the processor, cause the processor to perform:

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the first density, setting the dot value to a value indicative of forming a dot having a second density higher than the first density;

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the second density, setting the distribution error value to a first error value corresponding to a density of a dot having the second density; and

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the first density and lower than the second density, setting the distribution error value to a second error value corresponding to a density of a dot having a lower density than the second density.

4. The image processor according to claim 3, wherein the second error value is an error value corresponding to a density of an imaginary dot having the density of the target pixel.

5. The image processor according to claim 3, wherein the printer is configured to form dots of a plurality of sizes;

and

wherein the second density is a density of a dot of a smallest size in the plurality of sizes.

6. The image processor according to claim 2, wherein the instructions, when executed by the processor, cause the processor to perform:

determining that the dot forming condition is satisfied in a case where a corrected density is higher than or equal to a first threshold value, the corrected density being obtained by correcting the density of the target pixel by using an error value distributed to the target pixel; and

wherein the first density is higher than or equal to a density indicated by the first threshold value.

7. The image processor according to claim 1, wherein the instructions, when executed by the processor, cause the processor to perform:

in the case where the dot forming condition is satisfied, setting the dot value to a value indicative of forming a dot of a particular size;

in the case where the dot forming condition is not satisfied and the particular condition is satisfied, setting the dot value to the value indicative of forming a dot of the particular size; and

in response to setting the dot value of the target pixel to the value indicative of forming a dot of the particular size, setting the distribution error value to an error value corresponding to a density of a dot of the particular size, regardless of whether the dot forming condition is satisfied.

8. The image processor according to claim 7, wherein the instructions, when executed by the processor, cause the processor to perform:

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the density of the dot of the particular size, setting the dot value to the value indicative of forming the dot of the particular size.

9. The image processor according to claim 1, wherein the printer is configured to form a first dot and a second dot smaller than the first dot;

and

wherein the instructions, when executed by the processor, cause the processor to perform;

in a case where the dot forming condition of the first dot is satisfied, setting the dot value to a value indicative of forming the first dot;

in a case where the dot forming condition of the second dot is satisfied, setting the dot value to a value indicative of forming the second dot;

in a case where the dot forming condition of the first dot is not satisfied, the dot forming condition of the second dot is not satisfied, and the target pixel is not the edge pixel, setting the dot value to a value indicative of forming no dot; and

in a case where the dot forming condition of the second dot is not satisfied and the particular condition of the second dot is satisfied, setting the dot value to a value indicative of forming the second dot.

10. The image processor according to claim 9, wherein the instructions, when executed by the processor, cause the processor to perform:

in a case where the dot forming condition of the first dot is not satisfied, not setting the dot value to a value indicative of forming the first dot, regardless of whether the particular condition is satisfied.

11. The image processor according to claim 10, wherein the instructions, when executed by the processor, cause the processor to perform:

in the case where the dot forming condition of the first dot is not satisfied, setting the dot value to either a value indicative of forming a dot smaller than the first dot or a value indicative of forming no dot, regardless of whether the particular condition is satisfied.

12. The image processor according to claim 9, wherein the instructions, when executed by the processor, cause the processor to perform:

in a case where the dot forming condition of the first dot is not satisfied and the particular condition of the first dot is satisfied, setting the dot value to a value indicative of forming the first dot; and

in the case where the dot forming condition of the second dot is not satisfied and the particular condition of the second dot is satisfied, setting the dot value to a value indicative of forming the second dot.

13. The image processor according to claim 12, wherein the particular condition of the first dot is that the target pixel is the edge pixel and that the density of the target pixel is higher than or equal to a density of the first dot;

and

wherein the particular condition of the second dot is that the target pixel is the edge pixel and that the density of the target pixel is higher than or equal to a density of the second dot.

14. A non-transitory computer-readable storage medium storing a set of program instructions executable on an image processor for a printer, the set of program instructions comprising:

acquiring original image data representing an original image including a plurality of pixels, the original image data being indicative of a density of each of the plurality of pixels;

determining whether a dot forming condition of an error diffusion method is satisfied by using a density of a target pixel in the plurality of pixels and an error value distributed to the target pixel;

determining whether the target pixel is an edge pixel constituting an edge together with a surrounding pixel, the edge pixel having a higher density than a density of the surrounding pixel;

determining a dot value indicative of a dot formation state of the target pixel, the determining the dot value including;

setting the dot value to a value indicative of forming a dot in a case where the dot forming condition is satisfied;

setting the dot value to a value indicative of forming no dot in a case where the dot forming condition is not satisfied and the target pixel is not the edge pixel; and

setting the dot value to a value indicative of forming a dot in a case where the dot forming condition is not satisfied and a particular condition is satisfied, the particular condition including that the target pixel is the edge pixel;

setting a distribution error value to a smaller value than another error value in a case where the dot forming condition is not satisfied and the particular condition is satisfied and thereby the dot value of the target pixel is set to the value indicative of forming a dot, the distribution error value being an error value to be distributed from the target pixel to an unprocessed pixel, and the another error value being an error value to be distributed from the target pixel to the unprocessed pixel in a case where the dot value of the target pixel is set to the value indicative of forming no dot; and

generating print data including the dot value of each of the plurality of pixels determined by processing each of the plurality of pixels as the target pixel.

15. The non-transitory computer-readable storage medium according to claim 14, wherein the set of program instructions comprises:

in a case where the dot forming condition is not satisfied and the target pixel is the edge pixel and the density of the target pixel is higher than or equal to a first density, setting the dot value to the value indicative of forming a dot; and

in a case where the dot forming condition is not satisfied and the target pixel is the edge pixel and the density of the target pixel is lower than the first density, setting the dot value to the value indicative of forming no dot.

16. The non-transitory computer-readable storage medium according to claim 15, wherein the set of program instructions comprises:

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the first density, setting the dot value to a value indicative of forming a dot having a second density higher than the first density;

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the second density, setting the distribution error value to a first error value corresponding to a density of a dot having the second density; and

in a case where the dot forming condition is not satisfied, the target pixel is the edge pixel, and the density of the target pixel is higher than or equal to the first density and lower than the second density, setting the distribution error value to a second error value corresponding to a density of a dot having a lower density than the second density.

17. The non-transitory computer-readable storage medium according to claim 15, wherein the set of program instructions comprises:

determining that the dot forming condition is satisfied in a case where a corrected density is higher than or equal to a first threshold value, the corrected density being obtained by correcting the density of the target pixel by using an error value distributed to the target pixel; and

wherein the first density is higher than or equal to a density indicated by the first threshold value.

18. The non-transitory computer-readable storage medium according to claim 14, wherein the set of program instructions comprises:

in the case where the dot forming condition is satisfied, setting the dot value to a value indicative of forming a dot of a particular size;

in the case where the dot forming condition is not satisfied and the particular condition is satisfied, setting the dot value to the value indicative of forming a dot of the particular size; and

in response to setting the dot value of the target pixel to the value indicative of forming a dot of the particular size, setting the distribution error value to an error value corresponding to a density of a dot of the particular size, regardless of whether the dot forming condition is satisfied.

19. The non-transitory computer-readable storage medium according to claim 14, wherein the printer is configured to form a first dot and a second dot smaller than the first dot;

and

wherein the set of program instructions comprises;

in a case where the dot forming condition of the first dot is satisfied, setting the dot value to a value indicative of forming the first dot;

in a case where the dot forming condition of the second dot is satisfied, setting the dot value to a value indicative of forming the second dot;

in a case where the dot forming condition of the first dot is not satisfied, the dot forming condition of the second dot is not satisfied, and the target pixel is not the edge pixel, setting the dot value to a value indicative of forming no dot; and

in a case where the dot forming condition of the second dot is not satisfied and the particular condition of the second dot is satisfied, setting the dot value to a value indicative of forming the second dot.

20. The non-transitory computer-readable storage medium according to claim 19, wherein the set of program instructions comprises:

in a case where the dot forming condition of the first dot is not satisfied, not setting the dot value to a value indicative of forming the first dot, regardless of whether the particular condition is satisfied.