Canon Kabushiki Kaisha

Tsutomu Takayama

Toshio Kaji

Akihiko Tojo

Takao Kinoshita

Kengo Kinumura

Seiji Hashimoto

Nobuyoshi Tanaka

Mitsugu Hanabusa

Masao Suzuki

Shigeo Yamagata

Yasuyuki Yamazaki

Atsuko Kashiwazaki

Tokuzo Kato

Yuji Sakaegi

Kenichi Kondo

Masashi Hori

Toshihiko Kudo

Kazuhiro Matsunaga

Kan Takaiwa

Takashi Sugiura

Kazuhito Ohashi

Masafumi Kamei

Noriyoshi Chizawa

Yukitoshi Takeuchi

Tomoichirou Ohta

Masato Koshimizu

Seiichirou Satomura

Shoichi Inoue

Shoji Arafune

Yukio Yoshida

A construction is achieved at low cost which reduces the loss of gradation in a dark portion of an image that has been subjected to gamma correction in accordance with characteristics of a display. In an image reading apparatus, to make it possible to more finely reproduce the gradation in the dark portion, the number of gradations expressed by an signal obtained by a CCD is reduced by performing non-linear gamma correction using a gamma coefficient below one, and the resulting signal is transferred to a computer serving as a host computer. In the computer, the transferred signal is subjected to gamma correction using a gamma coefficient that is an inverse of the gamma coefficient used in the image reading apparatus, thereby canceling out the influence of the gamma correction performed in the image reading apparatus.

Image processing system, image processing apparatus, image processing method, and storage medium thereof

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

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

An image input apparatus for reading an original image by moving an optical unit with a motor used as a drive source is arranged such that, in repeatedly reading the original image from one and the same reading position with the optical unit, information on a start position at which a preceding round of reading has begun and a driving state of the motor obtained at that time is stored by a system controller, and the amount of moving the optical unit backward for the repeated reading is decided on the basis of the information stored. The arrangement enhances the repeatability of reading in the sub-scanning direction and image input can be made with a better resolution than the intrinsic resolution of the image input apparatus.

Image input apparatus and method for controlling the same

To provide an image reading apparatus provided with a pixel shifting mechanism for shifting an image incoming to a line sensor in a main scanning direction by substantial &frac12; of a pixel pitch, a scanning mechanism for scanning the line sensor in a sub-scanning direction and a control unit for performing scanning operation two times at a pitch almost equal to the pixel pitch at respective positions shifted to each other in the sub-scanning direction by a value equivalent to substantial &frac12; of the pixel pitch and causing the pixel shifting mechanism to perform the pixel shifting of &frac12; of the pixel pitch between first-time sub-scanning and second-time sub-scanning, and an image-signal generating unit for generating an image signal by averaging the pixel data values obtained through the two repetitions of sub-scanning between diagonal-directional adjacent pixels.

Image reading apparatus

A linear image sensor includes N arrays of photoelectric converting pixels, wherein N is an even integer at least equal to 2. Each array is formed by arranging, with a predetermined pixel pitch in a first direction of the array, a plurality of pixels, and each of the pixels is so shaped that the area per unit length of the pixel decreases progressively from the center of the pixel both in the first direction of the array and in a second direction perpendicular to the first direction. The N arrays themselves are provided with a mutual distance from each other of M/2 times the pixel pitch in the second direction and are mutually displaced by 1/N of the pixel pitch in the first direction so as to form a mutually interpolating arrangement, wherein M is a positive integer equal to at least 1 and wherein M and N are independent of each other.

Linear image sensor

Disclosed is an image pick-up device which uses a charge transfer type solid state image pick-up device, and further is provided with a shutter so as to form a high quality picture signal in such a manner that the smear is prevented by prohibiting the incidence of the light on the device while the charge is transferred in the device. Further, the device is driven by a clock signal for still photographing in order to obtain a high quality picture information for one frame surely. Further, the photographing parameter is automatically changed over or the monitor is changed over between the motion picture photographing mode and the still photographing mode.

Image pick-up device having switching over means, image pick-up means,

An object of this invention is to reduce level differences and errors in a luminance signal and color difference signals. In order to achieve the above object, an image pickup apparatus has an image sensor for photoelectrically converting an object image and a plurality of delay lines for delaying a video signal by one horizontal period, so that a video signal derived from an output including a clock leakage component from the image sensor is input to the plurality of delay lines, including an adjustment unit for adjusting the signal level of the video signal at an input or output of at least one of the plurality of delay lines.

Apparatus for reducing a level difference between image signals

An electronic still video camera wherein a pre-exposure period is utilized to generate control signals to control both exposure and color balance includes a photoelectric converter for producing an electrical signal corresponding to a received image. Exposure structure is provided for exposing the converter to the image, the amount of radiation admitted by the exposure structure being controllable. Color adjusting circuitry is provided for electrically altering the balance of different colors in the picture to be taken. Control circuitry is provided for controlling the exposure structure to provide a first exposure, and for deriving, from the output of the photoelectric converter corresponding to the first exposure, integrated values which are used to correct both an exposure period and the color balance in a subsequent picture-taking second exposure.

Electronic still video camera wherein a pre-exposure period is utilized

An image sensing apparatus includes an image sensing circuit, an inverting circuit for inverting a polarity of an output of the image sensing circuit, and a correcting circuit for correcting a black reference level of the output of the image sensing circuit in accordance with an operation of the inversion circuit.

Growing community of inventors

Kanagawa, Japan

Tsutomu Takayama