Image reading apparatus, non-transitory computer-readable medium for image reading apparatus, and method for controlling image reading apparatus

In an image reading apparatus, in a case where the processor determines that the original image to be obtained represents a book document, the processor determines whether a value satisfies a prescribed condition. The value is based on a difference between a first density distribution of an image in a first partial region of the entire image and a second density distribution of an image in a second partial region of the entire image. The first partial region includes a part of a dark region. The dark region extends in an extending direction. The first partial region extends in a crossing direction crossing the extending direction. The second partial region includes another part of the dark region and extends in the crossing direction. In a case where the value satisfies the prescribed condition, the processor controls the reading device to interrupt reading the entire image.