Image processing apparatus specifying first and second pixels, and generating processed image data in which the first and second pixels have first and second colors respectively

A non-transitory computer readable storage medium storing a set of program instructions for installation on and execution by a computer, the set of program instructions comprising:

• acquiring target image data representing a target image, the target image including a plurality of pixels, the plurality of pixels having respective ones of a plurality of pixel values, each of the plurality of pixel values having a gradation value, total levels of the gradation value being larger than three;
• specifying a plurality of target pixels from among the plurality of pixels;
• specifying a plurality of first pixels from among the plurality of target pixels, each of the plurality of first pixels being a candidate for a pixel representing a first color;
• specifying a plurality of peripheral pixels of each first pixel which is located within a prescribed range from the each first pixel;
• determining whether a specific condition is met for each peripheral pixel, the specific condition including a condition that the each peripheral pixel is a candidate for a pixel representing one of colors different from the first color, wherein a plurality of distant pixels of the each first pixel is located out of the prescribed range from the each first pixel, is not specified as a peripheral pixel of the each first pixel, and is free from determining whether the specific condition is met;
• specifying, as a second pixel, each of the plurality of peripheral pixels meeting the specific condition, the second pixel being a candidate for a pixel representing a second color different from the first color;
• and
• performing an image process on the target image data by using each of specified first pixels and each of specified second pixels to generate processed image data representing a processed image,
• wherein the processed image includes a plurality of first processed pixels, a plurality of second processed pixels, and a plurality of processed third pixels, the plurality of first processed pixels corresponding to respective ones of the specified first pixels and having the first color, the plurality of second processed pixels corresponding to respective ones of the specified second pixels and having the second color, each of the plurality of processed third pixels having a color different from the first color and the second color and corresponding to a pixel in the target image for which the determining whether the specific condition is met has not been performed.

An image processing method comprising:

• acquiring target image data representing a target image, the target image including a plurality of pixels, the plurality of pixels having respective ones of a plurality of pixel values, each of the plurality of pixel values having a gradation value, total levels of the gradation value being larger than three;
• specifying a plurality of target pixels from among the plurality of pixels;
• specifying a plurality of first pixels from among the plurality of target pixels, each of the plurality of first pixels being a candidate for a pixel representing a first color;
• specifying a plurality of peripheral pixels of each first pixel which is located within a prescribed range from the each first pixel;
• determining whether a specific condition is met for each peripheral pixel, the specific condition including a condition that the each peripheral pixel is a candidate for a pixel representing one of colors different from the first color, wherein a plurality of distant pixels of the each first pixel is located out of the prescribed range from the each first pixel, is not specified as a peripheral pixel of the each first pixel, and is free from determining whether the specific condition is met;
• specifying, as a second pixel, each of the plurality of peripheral pixels meeting the specific condition, the second pixel being a candidate for a pixel representing a second color different from the first color;
• and
• performing an image process on the target image data by using each of specified first pixels and each of specified second pixels to generate processed image data representing a processed image,
• wherein the processed image includes a plurality of first processed pixels, a plurality of second processed pixels, and a plurality of processed third pixels, the plurality of first processed pixels corresponding to respective ones of the specified first pixels and having the first color, the plurality of second processed pixels corresponding to respective ones of the specified second pixels and having the second color, each of the plurality of processed third pixels having a color different from the first color and the second color and corresponding to a pixel in the target image for which the determining whether the specific condition is met has not been performed.