Image processing device and computer-readable storage medium storing computer-readable instructions

1. An image processing device comprising:

a processor configured to:

generate text image data representing a text image based on original image data representing an original image; and

generate background image data representing a background image based on the original image data, wherein the background image represents an image in which text in the original image has disappeared,

wherein to generate background image data representing the background image data based on the original image data, the processor is configured to:

generate distribution data representing a tone value distribution of target image data as a processing target;

determine a specific range on the distribution data;

perform a correction process on the target image data for setting a value of a first-type pixel having a tone value within the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, and setting a value of a second-type pixel having a tone value out of the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed,

wherein the specific range includes a plurality of consecutive tone values,

wherein the plurality of consecutive tone values included within the specific range include a peak tone value that is included in a tone value distribution of the original image data and corresponds to a background of the text; and

wherein, to determine the specific range, the processor is configured to:

set a first width of the specific range, the first width determined from first distribution data representing a first dispersion of values of a plurality of pixels representing a background in the target image data; and

set a second width of the specific range, the second width determined from second distribution at a representing a second dispersion of values of the plurality of pixels representing the background in the target image data, the second dispersion being larger than the first dispersion;

wherein the second width is larger than the first width.

2. The image processing device according to claim 1 , wherein to perform the correction process the processor is configured to:

change a value of a first pixel that is the second-type pixel having a first tone value out of the specific range before the correction process is performed to a second tone value within the specific range, and

change a value of a second pixel that is the second-type pixel having a third tone value out of the specific range before the correction process is performed to a fourth tone value within the specific range, the third tone value being closer to the peak tone value than the first tone value and the fourth tone value being closer to the peak tone value than the second tone value.

3. The image processing device according to claim 1 , wherein to perform the correction process, the processor is configured to:

change a value of the second-type pixel having the tone value out of the specific range before the correction process is performed, to a tone value randomly selected from the plurality of consecutive tone values within the specific range.

4. The image processing device according to claim 1 , wherein to perform the correction process, the processor is configured to:

change a value of the first-type pixel having the tone value within the specific range before the correction process is performed, to a tone value within the specific range; and

change a value of the second-type pixel having the tone value out of the specific range before the correction process is performed, to a tone value within the specific range.

5. The image processing device according to claim 1 , wherein to perform the correction process, the processor is configured to:

change a value of the second-type pixel having the tone value out of the specific range before the correction process is performed, to a tone value within the specific range while not changing a value of the first-type pixel having the tone value within the specific range before the correction process is performed.

6. The image processing device according to claim 5 , wherein, based on the tone value of the first-type pixel being within the specific range, the correction process retains the same pixel value as was associated with the target pixel prior to the correction process.

7. The image processing device according to claim 5 , wherein, based on the tone value of the first-type pixel being within the specific range, the correction process reassigns to the first-type pixel the tone value of the first-type pixel.

8. The image processing device according to claim 1 , wherein the correction process is performed on the original image data as the target image data.

9. The image processing device according to claim 1 , wherein, to generate the background image data, the processor is configured to:

generate intermediate image data based on the original image data by changing a value of a text constituting pixel that constitutes the text in the original image to the peak tone value, and

wherein the correction process is performed on the intermediate image data as the target image data.

10. The image processing device according to claim 1 , wherein the target image data comprises a plurality of component image data corresponding to a plurality of color components, and

wherein the correction process is performed on each of the plurality of component image data.

11. The image processing device according to claim 1 , wherein the processor is further configured to compress the background image data.

12. An image processing device comprising:

a processor configured to:

obtain background image data representing a background image, wherein the background image represents an image including an outline of text; and

generate distribution data representing a tone value distribution of the background image data; and

determine the specific range based on the distribution data; and

perform a correction process on the background image data for setting a value of a first-type pixel having a tone value within the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, and setting a value of a second-type pixel having a tone value out of the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, wherein the correction process includes a process for reducing obtrusiveness of the outline of the text in the background image,

wherein the specific range includes a plurality of consecutive tone values,

wherein the plurality of consecutive tone values included within the specific range include a peak tone value that is included in a tone value distribution of the background image data and corresponds to a background of the outline of the text; and

wherein to determine the specific range, the processor is configured to:

set a first width of the specific range, the first width determined from first distribution data representing a first dispersion of values of a plurality of pixels representing a background in the target image data; and

set a second width of the specific range, the second width determined from second distribution data representing a second dispersion of the values of the plurality of pixels representing the background in the target image data, the second dispersion being larger than the first dispersion;

wherein the second width is larger than the first width.

13. A non-transitory computer-readable storage medium storing computer-readable instructions that, when executed, cause a processor to perform a method comprising:

generating text image data representing a text image based on original image data representing an original image; and

generating background image data representing a background image based on the original image data, wherein the background image represents an image in which text in the original image has disappeared,

wherein the generating of the background image data comprises:

performing a correction process on target image data setting a value of a first-type pixel having a tone value within a specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, and a value of a second-type pixel having a tone value out of the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed,

wherein the specific range includes a plurality of consecutive tone values, and

wherein the plurality of consecutive tone values included within the specific range include a peak tone value that is included in a tone value distribution of the original image data and corresponds to a background of the text;

wherein the generating of the background image data comprises:

generating distribution data representing a tone value distribution of the target image data; and

determining the specific range based on the distribution data;

wherein the determining of the specific range comprises:

setting a width of the specific range, the first width determined from first distribution data representing a first dispersion of values of a plurality of pixels representing a background in the target image data; and

setting a second width of the specific range, the second width determined from second distribution data representing a second dispersion of values of the plurality of pixels representing the background in the target image data, the second dispersion being larger than the first dispersion;

wherein the second width is larger than the first width.

14. The non-transitory computer-readable storage medium according to claim 13 , wherein the performing of the correction process comprises:

changing a value of a first pixel that is the second-type pixel having a first tone value out of the specific range before the correction process is performed to a second tone value within the specific range, and

changing a value of a second pixel that is the second-type pixel having a third tone value out of the specific range before the correction process is performed to a fourth tone value within the specific range, the third tone value being closer to the peak tone value than the first tone value and the fourth tone value being closer to the peak tone value than the second tone value.

15. The non-transitory computer-readable storage medium according to claim 13 , wherein the performing of the correction process comprises:

changing a value of the second-type pixel having the tone value out of the specific range before the correction process is performed, to a tone value randomly selected from the plurality of consecutive tone values within the specific range.

16. The non-transitory computer-readable storage medium according to claim 13 , wherein the performing of the correction process comprises:

changing a value of the first-type pixel having the tone value within the specific range before the correction process is performed, to a tone value within the specific range; and

changing a value of the second-type pixel having the tone value out of the specific range before the correction process is performed, to a tone value within the specific range.

17. The non-transitory computer-readable storage medium according to claim 13 , wherein the performing of the correction process comprises:

changing a value of the second-type pixel having the tone value out of the specific range before the correction process is performed, to a tone value within the specific range while not changing a value of the first-type pixel having the tone value within the specific range before the correction process is performed.

18. The non-transitory computer-readable storage medium according to claim 13 , wherein the correction process is performed on the original image data as the target image data.

19. The non-transitory computer-readable storage medium according to claim 13 , wherein the generating of the background image data comprises:

generating intermediate image data based on the original image data by changing a value of a text constituting pixel that constitutes the text in the original image to the peak tone value, and

wherein the correction process is performed on the intermediate image data as the target image data.

20. The non-transitory computer-readable storage medium according to claim 13 , wherein the target image data comprises a plurality of component image data corresponding to a plurality of color components, and

wherein the correction process is performed on each of the plurality of component image data.

21. The non-transitory computer-readable storage medium according to claim 13 , wherein the processor is further configured to perform compressing the background image data.

22. A non-transitory computer-readable storage medium storing computer-readable instructions that, when executed, cause a processor to perform a method comprising:

obtaining background image data representing a background image, wherein the background image represents an image including an outline of text; and

performing a correction process on the background image data for setting a value of a first-type pixel having a tone value within a specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, and a value of a second-type pixel having a tone value out of the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, wherein the correction process includes a process for reducing obtrusiveness of the outline of the text in the background image,

wherein the specific range includes a plurality of consecutive tone values, and

wherein the plurality of consecutive tone values included within the specific range include a peak tone value that is included in a tone value distribution of the background image data and corresponds to a background of the outline of the text;

wherein the processor is further configured to perform:

generating distribution data representing a tone value distribution of the background image data; and

determining the specific range based on the distribution data;

wherein the determining of the specific range comprises:

setting a first width of the specific range, the first width determined from first distribution data representing a first dispersion of values of a plurality of pixels representing a background in the target image data; and

setting a second width of the specific range, the second width determined from second distribution data representing a second dispersion of values of the plurality of pixels representing the background in the target image data, the second dispersion being larger than the first dispersion;

wherein the second width is larger than the first width.

23. An image processing device comprising:

a processor configured to:

generate text image data representing a text image based on original image data representing an original image; and

generate background image data representing a background image based on the original image data, wherein the background image represents an image in which text in the original image has disappeared,

wherein to generate background image data representing the background image data based on the original image data, the processor is configured to:

generate intermediate image data based on the original image data by changing a value of a text constituting pixel that constitutes the text in the original image to a peak tone value, wherein the peak tone value is included in a tone value distribution of the original image data and corresponds to a background of the text;

perform a correction process on the generated intermediate image for setting a value of a first-type pixel having a tone value within a specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, and setting a value of a second-type pixel having a tone value out of the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed,

wherein the specific range includes a plurality of consecutive tone values, and

wherein the plurality of consecutive tone values included within the specific range include the peak tone value that is included in the tone value distribution of the original image data and corresponds to a background of the text.

24. The image processing device according to claim 23 , wherein, to generate the background image data, the processor is configured to:

generate distribution data representing a tone value distribution of the intermediate image data; and

determine the specific range based on the distribution data.

25. The image processing device according to claim 23 , wherein the intermediate image data comprises a plurality of component image data corresponding to a plurality of color components, and

wherein the correction process is performed on each of the plurality of component image data.

26. The image processing device according to claim 23 , wherein the processor is further configured to compress the background image data.

27. A non-transitory computer-readable storage medium storing computer-readable instructions that, when executed, cause a processor to perform a method comprising:

generating text image data representing a text image based on original image data representing an original image; and

generating background image data representing a background image based on the original image data, wherein the background image represents an image in which text in the original image has disappeared,

wherein the generating of the background image data comprises:

performing a correction process on target image data setting a value of a first-type pixel having a tone value within a specific range before the correction process is performed to a tone value within the specific range after the correction process is performed, and a value of a second-type pixel having a tone value out of the specific range before the correction process is performed to a tone value within the specific range after the correction process is performed,

wherein the specific range includes a plurality of consecutive tone values, and

wherein the plurality of consecutive tone values included within the specific range include a peak tone value that is included in a tone value distribution of the original image data and corresponds to a background of the text;

wherein the generating of the background image data comprises:

generating intermediate image data based on the original image data by changing a value of a text constituting pixel that constitutes the text in the original image to the peak tone value, wherein the peak tone value is included in the tone value distribution of the original image data and corresponds to the background of the text, and

wherein the correction process is performed on the intermediate image data as the target image data.

28. The non-transitory computer-readable storage medium according to claim 27 , wherein the generating of the background image data comprises:

generating distribution data representing a tone value distribution of the intermediate image data; and

determining the specific range based on the distribution data.

29. The non-transitory computer-readable storage medium according to claim 27 , wherein the intermediate image data comprises a plurality of component image data corresponding to a plurality of color components, and

wherein the correction process is performed on each of the plurality of component image data.

30. The non-transitory computer-readable storage medium according to claim 27 , wherein the processor is further configured to perform compressing the background image data.