Patent ID: 8294955

Claim:
An image reading apparatus which irradiates an image original with light, receives reflected light of the light, and reads the image original based on the received light, the apparatus comprising: light emitting means for respectively emitting light components of three primary colors; a line image sensor including light receiving means for receiving the light reflected by the image original irradiated with the light emitting means; lighting control means for controlling the light emitting means to read the image original using one of primary color reading performed by causing the light emitting means to line-sequentially irradiate the image original with the light components of three primary colors and read the image original while moving the line image sensor, and complementary color reading performed by causing the light emitting means to line-sequentially irradiate the image original with one of three different color combinations, which simultaneously includes two of the light components of three primary colors, and read the image original while moving the line image sensor; and image processing means for changing a filter to be used for image processing of image data obtained based on the reflected light received by the light receiving means, depending on whether line sequential reading of the image original is the primary color reading or the complementary color reading, and processing the image data, wherein a first filter used for image processing in the complementary color reading has a filter set value higher than a second filter set value of a second filter used for image processing in the primary color reading.