Canon Kabushiki Kaisha

Mitsugu Hanabusa

Tsutomu Takayama

Kengo Kinumura

Atsuko Kashiwazaki

Masato Koshimizu

Ryuji Nogami

Upon processing a visible light image signal and infrared image signal respectively obtained by illuminating a transparent document with light beams coming from a visible light lamp for mainly emitting visible light and an infrared lamp for mainly emitting infrared light, and photoelectrically converting optical images of the transparent document, a histogram is generated on the basis of the infrared image signal, a threshold value is calculated based on the histogram, and infrared image signal components equal to or smaller than the threshold value are extracted by comparing the calculated threshold value and infrared image signal components. Visible light image signal components corresponding to the extracted infrared image signal components are interpolated using surrounding visible light image signal components.

Signal processing method, signal processing apparatus, and image reading apparatus

This invention has as its object to obtain a high-quality read image from which dust or scratches have been removed by an image reading apparatus which reads image information on a transparent original by synchronously scanning a light source unit and image reading unit. To this end, upon reading a transparent original, infrared LED chips on a dust/scratch detection LED substrate and a transparent original illumination lamp are turned on to make alignment between the LED substrate and the image reading unit, and dust/scratch detection image information is obtained by synchronously moving the light source unit and image reading unit in the subscanning direction. Subsequently, alignment between the transparent original illumination lamp and image reading unit is made, and image information of the transparent original is obtained by synchronously moving the light source unit and image reading unit in the subscanning direction.

Image reading apparatus, method of controlling image reading apparatus, program, and computer readable storage medium

An image reading apparatus having a visible light source for emitting visible light, an invisible light source for emitting invisible light, an imaging optical system for irradiating a document by these light sources to form optical images of the document, and a CCD for photoelectrically converting the optical images of the document turns on the visible light source to acquire a visible light image signal by the CCD. Then, the apparatus turns on the invisible light source to acquire an invisible light image signal by the CCD. After the invisible light image signal is acquired, the apparatus turns off the invisible light source, and turns on the visible light source regardless of whether to read the document.

Image processing for correcting defects of read image

In a method of controlling an image reading apparatus, which has an illumination unit adapted to irradiate an object with first and second light rays in different frequency ranges, and a light-receiving unit adapted to receive light coming from the object, and to output a signal, and reads an image of the object by moving the illumination unit and light-receiving unit relative to the object, the light-receiving unit outputs a first signal in response to irradiation with the first light ray, and outputs a second signal in response to irradiation with the second light ray. Upon reading image information for one line by the image reading apparatus, the second light ray is controlled to be sequentially turned on at a plurality of timings to sandwich the ON timing of the first light ray, and image signals for one line corresponding to the first and second light rays are obtained by averaging or adding respective pieces of image information obtained at the plurality of timings for each of the first and second signals.

Image signal correction light source that can cope with dust and scratch on transparent document, and its control

This invention has an object of reading a high-quality image by detecting and correcting dust or scratches present on a transparent original in an image reading apparatus for reading, e.g., a transparent original. To achieve this object, an original illumination unit in the image reading apparatus for reading an original includes at least a first light source for emitting light in a visible region, a second light source for emitting light in a n invisible region, and a light guide plate which has these light sources arranged at end faces and has first and second light guide patterns for guiding light beams from the first and second light sources to the entire light-emitting surface.

Image reading apparatus and illumination apparatus

In an image reading apparatus for reading a transparent original, the object of the present invention is to obtain a high-quality read image from which dust or scratch is removed. In order to achieve this object, in the image reading apparatus for reading the transparent original, a transparent original illumination unit has the first and second surfaces on the same side. On the first surface, at least one light source for emitting light in at least a visible range is arranged. On the second surface, at least one light source including a plurality of infrared light sources arrayed in series to emit light in an infrared range is arranged. The first and second surfaces are arranged at positions different from an effective light-emitting region, and includes a light guide plate and reflecting sheet for substantially uniformly emitting incident light from the same side portion to an entire surface.

Growing community of inventors

Tokyo, Japan

Mitsugu Hanabusa