An image processing apparatus includes a processor configured to, in a case of controlling an image capturer to image a document placed in a placement area without an instruction from a user in response to detection of placement of the document in the placement area, avoid imaging of the document placed in the placement area if the document placed in the placement area is identical to a document imaged last time.

An image reading apparatus comprises a platen, a support, a reader, an open/close unit, a first obtainer, a mark, a positioning member, and a determiner. A position of the mark on a pressing surface of the cover, is provided at a position at which, in a case where a sheet of a maximum size among standard sizes that can entirely fit in a readable range of the reader is positioned with respect to the positioning member, at least a portion of the mark is not hidden by the sheet as viewed from the reader.

Certain embodiments provide a document detecting device, including: a plate having an upper surface on which a document is placed; an imaging device that includes the upper surface in a photographing visual field range; and a controller that detects any one or more of a position, an angle, and a size of the document on the upper surface according to an image by the imaging device and fixed-size information of the document stored in advance.

According to one embodiment, there is provided an image processing apparatus including a reading unit and a determining unit. The reading unit generates sheet image data indicating image data of a sheet. The determining unit determines, on the basis of a degree of gradation in the sheet image data generated by the reading unit, whether a planar object adheres on the sheet read by the reading unit.

According to one embodiment, there is provided an image processing apparatus including a reading unit and a determining unit. The reading unit generates sheet image data indicating image data of a sheet. The determining unit determines, on the basis of a degree of gradation in the sheet image data generated by the reading unit, whether a planar object adheres on the sheet read by the reading unit.

An image scanning apparatus performs operations including: upon detection of a first angle, causing light to be emitted to an original and recording a distribution of reflected light of the emitted light as first read data; upon elapse of a predetermined time from detection of a second angle, causing light to be emitted to the original and recording a distribution of reflected light of the emitted light as second read data; detecting a closed state of a pressure plate based on the second read data; and upon determination of an angle of the pressure plate with respect to the platen being equal to or smaller than a third angle smaller than the second angle in the detection of the closed state, detecting a width of the original in an opening-closing direction of the pressure plate based on a difference between the first and second read data.

Certain embodiments provide a document detecting device, including: a plate having an upper surface on which a document is placed; an imaging device that includes the upper surface in a photographing visual field range; and a controller that detects any one or more of a position, an angle, and a size of the document on the upper surface according to an image by the imaging device and fixed-size information of the document stored in advance.

Certain embodiments provide a document detecting device, including: a plate having an upper surface on which a document is placed; an imaging device that includes the upper surface in a photographing visual field range; and a controller that detects any one or more of a position, an angle, and a size of the document on the upper surface according to an image by the imaging device and fixed-size information of the document stored in advance.

An image scanning apparatus performs operations including: upon detection of a first angle, causing light to be emitted to an original and recording a distribution of reflected light of the emitted light as first read data; upon elapse of a predetermined time from detection of a second angle, causing light to be emitted to the original and recording a distribution of reflected light of the emitted light as second read data; detecting a closed state of a pressure plate based on the second read data; and upon determination of an angle of the pressure plate with respect to the platen being equal to or smaller than a third angle smaller than the second angle in the detection of the closed state, detecting a width of the original in an opening-closing direction of the pressure plate based on a difference between the first and second read data.

In a document scanner, a housing has a transparent platen for supporting a document, and a driving mechanism drives a light source and an image sensor to move relatively to the transparent platen. In a light-emitting mode, a processor controls the light source to emit light to the document, and controls the image sensor to receive light and obtain a first image having first pixels. In a non-emitting mode, the processor controls the light source not to emit light, and controls the image sensor to receive light and obtain a second image having second pixels, wherein the second pixels respectively correspond to the first pixels. The processor judges whether a difference between a first visible light channel value of the first pixel and a second visible light channel value of the second pixel corresponding to the first pixel is greater than a threshold value to judge the first pixel as being corresponding to a document part or a non-document part. A document scanning method is also disclosed.