US 11,736,652 B2
Image processing apparatus, image processing method, and storage medium
Reiji Misawa, Chiba (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Jul. 30, 2021, as Appl. No. 17/390,341.
Claims priority of application No. 2020-133793 (JP), filed on Aug. 6, 2020.
Prior Publication US 2022/0046145 A1, Feb. 10, 2022
Int. Cl. H04N 1/62 (2006.01); H04N 1/58 (2006.01)
CPC H04N 1/62 (2013.01) [H04N 1/58 (2013.01); H04N 2201/0094 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a scanner that scans an image of an original document and generates image data; and
one or more controllers that:
execute color reduction processing of quantizing color of the generated image data;
execute an edge detection process for detecting one or more edge pixels indicating an edge portion of an image based on the image data having the quantized color; and
convert a pixel value of an edge pixel detected by the edge detection process,
wherein, in a case where the pixel value of the edge pixel which has been detected by the edge detection process is converted from a first pixel value to a second pixel value of which a luminance is lower than a luminance of the first pixel value by the color reduction processing, the one or more controllers convert the pixel value of the edge pixel which has been detected by the edge detection process to a pixel value of a pixel having a highest luminance among pixels surrounding the edge pixel which has been detected by the edge detection process, and
wherein, in a case where the pixel value of the edge pixel which has been detected by the edge detection process is converted from the first pixel value to a third pixel value of which a luminance is higher than the luminance of the first pixel value by the color reduction processing, the one or more controllers convert the pixel value of the edge pixel which has been detected by the edge detection process to a pixel value of a pixel having a lowest luminance among the pixels surrounding the edge pixel which has been detected by the edge detection process.