An image processing apparatus includes a reading unit and a controller. The reading unit radiates light to a target from two directions with different angles and reads images of the target. The controller performs, when controlling the reading unit to acquire the two images of the target, control such that a resolution of the image read by radiating the light to the target from one of the two directions is lower than a resolution of the image read by radiating the light to the target from the other one of the two directions.

Provided is an optical head that includes a base substrate and a line head. The line head includes a plurality of sub-line heads electrically independent of one another and arranged on the base substrate in parallel with a first direction. Each of the plurality of sub-line heads includes a circuit substrate unit that constitutes a portion of the base substrate, and an optical-element array that includes a plurality of optical elements each arranged on the circuit substrate unit at least in parallel with a second direction that is a direction of a length of each of the plurality of sub-line heads.

An image processing apparatus includes a reading unit and a controller. The reading unit radiates light to a target from two directions with different angles and reads images of the target. The controller performs, when controlling the reading unit to acquire the two images of the target, control such that a resolution of the image read by radiating the light to the target from one of the two directions is lower than a resolution of the image read by radiating the light to the target from the other one of the two directions.

[Solving Means] An optical head includes a base substrate and a line head. The line head includes a plurality of sub-line heads electrically independent of one another and arranged on the base substrate in parallel with a first direction. Each of the plurality of sub-line heads includes a circuit substrate unit that constitutes a portion of the base substrate, and an optical-element array that includes a plurality of optical elements each arranged on the circuit substrate unit at least in parallel with a second direction that is a direction of a length of each of the plurality of sub-line heads.

According to one embodiment, an image reading apparatus includes: a first illumination device for irradiating light at a first angle onto a sheet that is being conveyed; a second illumination device for irradiating light at a second angle onto the sheet that is being conveyed; illumination controllers for switching between a first irradiation state in which light is irradiated from the first illumination unit and the second illumination unit onto the sheet and a second irradiation state in which light is irradiated from only either the first illumination device or the second illumination device to the sheet; an imaging device for acquiring a first comparable image in the first irradiation state and for acquiring a second comparable image in the second irradiation state; and a defect detector for detecting a defect of the sheet based on the difference between the first comparable image and the second comparable image.