An image generating apparatus is provided with a first light source and a second light source, an image sensor, a mask including a light-transmitting part and a light-blocking part, and a dark image processing unit. The image sensor acquires a first image of the material when illuminated by the first light source, and acquires a second image of the material when illuminated by the second light source. The image sensor includes a first pixel region and a second pixel region. The light-blocking part is positioned between the first pixel region and the first light source. The light-blocking part is positioned between the first pixel region and the first light source. The dark image processing unit uses first pixel information corresponding to a first pixel region in the first image and second pixel information corresponding to a second pixel region in the second image to generate a third image.