Abstract: A method of correcting an image signal generated by a charge coupled device (CCD) image sensor in an imaging system is provided. The imaging system stores a number of gamma correction curves, each of which includes a respective correction factor for increasing contrast in a dark portion of the image signal. The method includes: measuring gray scale value of each pixel of the CCD image sensor; estimating a contrast level of an object scene to be imaged using the measured gray scale values; and correcting the image signal using a corresponding gamma correction curve depending on the estimated contrast level of the object scene.

Abstract: An image input scanner having two scan heads for simultaneous scanning of both sides of a sheet includes two calibration surfaces. A first calibration surface is disposed on the carriage on which a first scan head is mounted. A second calibration surface is disposed on the document handler.

Abstract: An image reading apparatus includes a document placing table having a transparent member, a document pressing member, an image reading unit, a scanning unit that is disposed on a side opposite to a document placing surface of the transparent member and reciprocates in a predetermined direction along the transparent member with the image reading unit mounted thereon, an open/closed state detecting unit that detects open and closed states of the document pressing member, a control unit that controls an image reading operation of the image reading unit and a reciprocation movement of the scanning unit, and a reference member that serves as a luminance reference of the image reading unit. When the open/closed state detecting unit detects the open state of the document pressing member, the control unit set a predetermined light intensity set value to a light intensity value of light irradiated from the light source at the time of image reading.

Abstract: Disclosed in an image reading apparatus including a reading unit to obtain an image data by irradiating a document with a light and reading an image of the document, a paper thickness detection unit to detect a thickness of the document to be read by the reading unit, a process unit to process the image data which is obtained by the reading unit based on a parameter and a control unit to carry out a control of changing the parameter of the process unit according to the thickness of the document which is detected by the paper thickness detection unit.

Abstract: The image reader according to the present invention is able to set the accurate threshold level free of influence of dirt and dust even when the reference “white” level is requested for shading correction during the acceleration while the carriage is being accelerated without increasing the averaging frequency when the reflected light from the white board is read for shading correction. In addition, because the distance between the head end of the transparent glass and the home position as well as the distance between the home position and the reading window are shortened, the size of the image reader is reduced.

Abstract: Images at two or more correction levels are output as corrected images for a given image, and a user is allowed to select a preferred corrected image. Based on the selection result of the user, an image to be corrected which is different from the given image is corrected.

Abstract: A screen correction method and image pick-up device suitable for use in, for example, digital cameras. Horizontal and vertical signals from a signal generator (SG) are supplied to a semiconductor image pick-up device (CCD) via a timing generator (TG). Horizontal and vertical counter values from the signal generator are supplied to a distance calculation block, and the distance from optical axis center position information, provided from terminals 5X, 5Y, is calculated. This calculated distance value d is supplied to a converter (conv), and a distance value, converted according to information from the terminal on the number of pixels of the semiconductor image pick-up device, is supplied to a lookup table (LUT), to output the correction coefficients according to the distance from, for example, the optical axis center position.

Abstract: A black level correcting device includes: an A/D converting section converting a result of subtracting a feedback signal from an input pixel signal into a pixel value to be output; and a feedback controlling section generating the feedback signal and having a holding section, a feedback gain adjusting section, etc. The holding section clamps a maintaining level to the level of the feedback signal while pixel signals of OB pixels are output, and maintains and outputs the maintaining level while pixel signals of valid pixels are output. The feedback gain adjusting section multiplies the feedback signal by clamp accelerating gain in synchronization with starting readout of the pixel signals from the OB pixels. Accordingly, clamp time of the holding section is shortened, enabling stabilization of the maintaining level at a convergence level before starting readout of the pixel signals from the valid pixels. Consequently, a sag can be reduced.

Abstract: A scanner has a calibration target that can be moved in front of the scanline during a scan. This enables multiple calibrations during a scan. A full-color calibration can be performed during scanning without the need for a separate array of photosensors. Scanning can start as soon as the lamp provides sufficient light for scanning, without waiting for the lamp to stabilize. It is not necessary to keep the lamp on, or to keep the lamp warm.

Abstract: A movable calibration device for a sheet-fed scanner includes a calibration sheet and a cam. A scanning module scans an image on the calibration sheet for calibrating the sheet-fed scanner. The cam, driven by a motor, moves the calibration sheet into and out of a scan window of the scanning module. The calibration sheet can be moved out of the scan window without reversing the rotational direction of the motor. The entire calibration sheet is moved in a linear path.

Abstract: Disclosed are a keystone correction method and a display apparatus using the same. The keystone correction method can include receiving a plurality of pixel data included in an image signal of a frame; computing a coordinate and data of a correction pixel from 3 row-directionally successive pixel data of the received pixel data; repeating the step of computing the coordinate and data of the correction pixel from all pixels of a row in the frame; and repeating the step of repeating the step of computing the coordinate and data of the correction pixel for all rows in the frame. With the present invention, the keystone can be corrected by using a minimum resource.

Abstract: An image processing apparatus includes an image sensor formed from a plurality of areas each including a plurality of pixels, and a corrector adapted to correct signals from the plurality of areas of the image sensor. The corrector has a plurality of correction data smaller in number than the areas, and performs correction by selectively using the correction data for each area of the image sensor.

Abstract: When a reference image to which a document image is judged as being similar for the first time is not the first document sheet of the document type which contains this reference image, error occurrence is concluded so that the page number indicated by a counter is set to be an error occurrence position. In case that the reference image to which the document image is similar is the last document sheet of the document type, when the number of document images having been counted up by the time when this document image is judged as being similar to the reference image does not correspond with the number of reference images contained in the document type, error occurrence is concluded so that the page number indicated by a counter is set to be an error occurrence position.

Abstract: An image reading apparatus is provided which allows a reading device fixed at a reading position to read images from a document while transporting the document. The apparatus includes a correcting unit adapted to perform correction processing associated with image reading performed by the reading device; a calculating unit adapted to calculate a time interval from one document to the next document that are being transported; a scheduling unit adapted to divide the correction processing into a plurality of steps and schedule the execution of the steps on the basis of the calculated time interval; and an executing unit adapted to sequentially execute the steps scheduled by the scheduling unit every time a document passes through the reading position.

Abstract: An image reading apparatus capable of generating accurate shading correction data while removing noise. A shading reference plate is arranged at a location having different optical distance between the location and an image sensor in an image reading unit from optical distance between original reading position and said image sensor. The shading reference plate is read by the image reading unit whereby secondary reference data is acquired, and a reference sheet is read which is put on a position substantially identical to the original reading position whereby primary reference data is acquired. Primary and secondary correction data is generated based on the primary and secondary reference data, and correction coefficient data is generated based on the primary and secondary correction data. Shading correction data is generated based on read data of the shading reference plate and the correction coefficient data.

Abstract: A multiple-background device for a scanner and a calibration device utilizing the same principle are disclosed. The multiple-background device includes a shaft, a low-reflectance portion and a high-reflectance portion are formed along the length of the shaft. Thereby the shaft can provide various background colors, and the optical module can acquire a plurality of scan lines by means of rotating the shaft for image calibration.

Abstract: In an image reading apparatus according to the invention, the switching frequency of a switching power supply is set to a value equal to integral multiples of a reading frequency corresponding to each line, thereby correcting, for example, uneven image density due to ripples in a power supply voltage. Further, the switching of the switching power supply is synchronized with a horizontal synchronizing signal output from a scanner, thereby causing the positions of the ripples to correspond between lines for correcting, for example, uneven image density.

Abstract: The present invention provides a technique that makes it possible to realize highly accurate shading correction regardless of presence of dust or the like in a shading correction plate without preventing a reduction in a size of an apparatus. An image scanning apparatus determines an area where dust is present in a reference area, which is an object of scanning of reference data used for shading correction in the image scanning apparatus, scans the reference data from an area excluding the area where it is determined that dust is present, and performs shading correction on the basis of the reference data scanned from the area excluding the area where it is determined that dust is present.

Abstract: In an image scanning system which includes an image scanning apparatus for scanning an image using a solid-state image sensing element, and an image processing apparatus, the scanned image undergoes image correction. The image scanning apparatus informs the image processing apparatus of image scan characteristic data such as linearity characteristic data unique to itself. The image processing apparatus executes a correction process of an image scanned by the image scanning apparatus using the received image scan characteristic data.

Abstract: In a sheet-fed scanner capable of scanning multiple scan lines as a calibration standard for an image signal, a scanning module scans a document, which is fed across a scan region by a sheet-feeding mechanism, and a stationary calibration sheet in the scan region. The scanning module includes an image sensor, a lens and at least one reflecting mirror. An actuator actuates the reflecting mirror to enable the image sensor to sense a plurality of scan lines on the calibration sheet through the lens and the reflecting mirror in order to obtain a calibration standard for the image signal of the document. The calibration standard is adopted to calibrate an image signal of the document, and with this invention, it is possible to avert any flaws in image quality caused by the contaminated calibration sheet.

Abstract: In a sheet-fed scanner capable of switching backgrounds, a scanning module scans a document, which is transported by a sheet-feeding mechanism across a scan region, and a stationary background component, which has a plurality of sections having different reflectivities and is disposed in the scan region. The scanning module includes an image sensor, a lens and at least one reflecting mirror. An actuator actuates the at least one reflecting mirror to enable the image sensor to selectively sense one of the sections of the background component as a scan background for the document through the lens and the at least one reflecting mirror.

Abstract: The present invention relates to an image processing apparatus, which calculates the histogram of an image on the basis of moving image information that is input in real time, and corrects and outputs the brightness of the image using the histogram in real time. The apparatus for controlling the brightness of moving image signals according to the present invention includes a cumulative difference function detection means, an image storage means and a brightness adjustment means. The cumulative difference function detection means calculates a cumulative difference function using upper n bits of each input image. The image storage means stores therein the input image. The brightness adjustment means adjusts the brightness of the image in real time using the cumulative difference function calculated by the cumulative difference function detection means when the input image stored in the image storage means is displayed.

Abstract: An image reading apparatus for reading an image on an original document by irradiating it with light and photoelectrically converting reflected light from it by an image pickup unit, including: an original document guide member positionable opposite to the image pickup unit, with a conveyance position of the original document therebetween; a white reference member that is positionable, the same as the original document guide member, and has a reference white color; an achromatic constant-density reference member that is positionable, the same as the original document guide member, and has a reference achromatic constant-density; a drive unit that moves one of the three members so as to be positioned opposite to the image pickup unit; and a control unit that controls execution of detection processings for dust detection from data obtained by moving, as described above, the achromatic constant-density reference member and the white reference member by reading them.

Abstract: An image processing apparatus for automatically improving the contrast of an input image that is obtained from a digital camera or the like, and obtaining a sharper and clearing image. A contrast improvement unit (11) performs a contrast improvement process on the input image by comparing an object pixel in the input image with pixels in the surrounding area. An image combination unit (12) combines the enhanced image obtained by the contrast improvement process with the input image. The combined image is then output to a desired device such as a printer by an image output unit (13).

Abstract: A sheet-fed scanning device includes a scanning module, a sheet-feeding module, a driving module, a calibration sheet moving module, and a calibration sheet. The sheet-feeding module transports a document across a scan region, in which the scanning module scans the document. The driving module drives the sheet-feeding module and the calibration sheet moving module. The calibration sheet is moved to the scan region before the document is transported, is gradually moved away from the scan region as the document is being transported so that the scanning module scans a plurality of scan lines on the calibration sheet for calibration, and is moved completely out of the scan region when the document reaches the scan region, such that the scanning module scans the document thereafter. The calibration sheet cannot be moved back to the scan region until the driving module reverses.

Abstract: A method is disclosed for designing two separable filters, LPP & HPP, that approximates the circularly symmetric frequency response achievable using a non-separable filter. The method selects a cut-off frequency and designs a 1-D low pass filter. Next, the method obtains a low pass 2-D filter and generates a 2-D contour plot therefor. The method designs a 1-D high pass filter and obtains a 2-D high pass filter and a 2-D contour plot therefor. A 2-D filter is generated having the dimensions of the 2-D high pass filter with the only non-zero entry of value 1 located at the center. A matrix is created by subtracting the 2-D high pass filter from the 2-D filter. The low pass 2-D filter is convolved with the matrix to obtain an approximation to a desired circular symmetry.

Abstract: A document reading apparatus arranged to reduce inconsistencies in the output signals of its linear image sensor is provided. The document reading apparatus includes a linear image sensor, a light source control circuit, and a light source driver. The light source control circuit has a pulse generator that generates control pulses having a prescribed frequency and a pulse period that is shorter than an accumulation period of the linear image sensor, the accumulation period being indicated by a timing signal that represents the accumulation period and a non-accumulation period. The light source control circuit also has a synchronization output unit that outputs a prescribed number of trigger pulses in synchronization with the timing signal and the control pulses. The light source driver drives the light source in response to the trigger pulses.

Abstract: An apparatus and method for correcting a scanning error in a flatbed scanner, can minimize the scanning error due to deviations in position or scanning of a CCD (charge-coupled device) module by determining a scanning position, a scan region, and a scan rate for each flatbed scanner. The scanning error correcting apparatus includes a white shading plate having a black patch, a reading module for reading the white shading plate and the black patch, and a controller that compares information about the black patch read by the reading module with a predetermined reference value to correct the scanning error in the flatbed scanner. Thus, the apparatus and method can secure a scanning region in horizontal and vertical directions as wide as possible for each flatbed scanner and prevent occurrences of errors in a scanned image due to deviations of the CCD module.

Abstract: An image reading device includes a reference member, a reading unit, a first reference value setting unit, a detecting unit, a second reference value setting unit, a determining unit, and a pixel value setting unit. The reading unit scans an image on a document to obtain image data and scans the reference member to obtain reference data. The first reference value setting unit sets a first reference value based on the reference data. The detecting unit detects a usage state of the reading unit. The second reference value setting unit sets a second reference value in accordance with the usage state of the reading unit. The determining unit determines whether or not the first reference value is in a predetermined condition The pixel value setting unit sets a pixel value.

Abstract: A document reading device includes a document transport and, for reading a document image, an optical reader having a movable exposure which stops at a predetermined reading position and emits light onto the document. A guide member guides the document to the reading position to form a predetermined inclination angle with respect to a flat-plate face of a support, which supports the document being transported when it passes over the reading position. A transport path is formed with the support so that the document passing over the reading position is transported along the flat-plate face. A detection member detects a leading end position of the guide member, the predetermined reading position being set to within a predetermined distance in a transport direction from the leading end of the guide member, which is known beforehand to be stain-free.

Abstract: A scanning device includes a display part, a flat bed on which a manuscript is loaded, a white reference sheet provided at one side of the flat bed, a scanning head to divide the white reference sheet into a plurality of lines and to obtain shading data corresponding to the plurality of lines by scanning the plurality of lines, a storage part in which the shading data for the plurality of lines is stored, and a controller to calculate a maximum value and a minimum value of the shading data by comparing the shading data of each pixel at a same position in the scanning head from the plurality of lines, and to control the display part to display an error message if a difference between the maximum value and the minimum value of the shading data is out of a reference range.

Abstract: A CCD is such that a single image sensing area is produced by performing exposure four times in four areas. Four correction circuits are provided in association with respective ones of the four areas. Four items of image data obtained based upon respective ones of the four areas are input to corresponding correction circuits, which apply a correction to prevent image disturbance at the area boundaries. One frame of image data is generated from corrected image data of respective ones of the areas and the image data is recorded on a memory card.

Abstract: Method for shading one of a first plurality of sensing elements of an optical sensor. High-reflectivity and low-reflectivity reference values of the output signal of each of a second plurality of sensing elements of the sensor are obtained. An average or nominal high-reflectivity value of the high-reflectivity reference values for each sensing element of the second plurality is calculated. An average or nominal low-reflectivity value of the low-reflectivity reference values for each sensing element of the second plurality is calculated. An offset value for one of the sensing elements of the first plurality is calculated using at least the average or nominal high-reflectivity values and the average or nominal low-reflectivity values. The one sensing element of the first plurality is calibrated using at least the calculated offset value. In one example, the first plurality and the second plurality are identical.

Abstract: An image scanning device and a shading compensation method include reading out a second region of a reference white sheet spaced by a predetermined distance from a white roller prior to reading out a to-be-scanned document to generate a reference shading compensation value; comparing the generated reference shading compensation value and a stored initial sheet shading compensation value for the second region to calculate a final shading compensation value of a first region of the white roller; and compensating for image data of the read document according to the calculated final shading compensation value. Accordingly, the present invention generates a shading profile and compensates for shading distortions according to characteristic changes of an image readout unit, such as a CIS, thereby enabling more precise image data to be obtained.

Abstract: An image reading apparatus includes an image reading sensor reading an image from a document, a light source turned on at a time when the image is read from the document by the image reading sensor, a data acquisition unit acquiring white reference data and black reference data which are used for performing shading correction for the image read by the image reading sensor, and a white reference plate for acquiring the white reference data, wherein the image reading sensor moves relative to the white reference plate while facing the white reference plate when the white reference data and the black reference data are acquired by the data acquisition unit, wherein the light source is repeatedly turned on and turned off when the image reading sensor moves relative to the white reference plate, and wherein the data acquisition unit acquires the white reference data on the basis of a detection signal that can be acquired from the image reading sensor at a time when the light source is turned on and acquires the bla

Abstract: An image forming apparatus is disclosed. The image forming apparatus comprises an input unit through which a condition for reading image data of a document is input, a reading unit to read the image data under the reading condition, a first storage unit to store the image data read by the reading unit, a second storage unit to store information indicative of a relationship between the reading condition and an estimated volume of the image data to be stored in the first storage unit, a data volume estimating unit that estimates a volume of the image data to be read based on the reading condition and the information stored in the second storage unit, and a determining unit to determine whether to read the image data based on the estimated data volume and a volume of the image data that have already been stored in the first storage unit.

Abstract: The invention provides an image forming apparatus and an image forming method, capable of providing an image with little deterioration, even in case the image contrast has to be adjusted not for the purpose of image adjustment, such as for reducing the toner consumption amount or for preventing the leak in the charging device.

Abstract: An object of this invention is to suppress a decrease in reading efficiency while preventing image degradation. To achieve this object, an image reading apparatus includes a light source which illuminates an object, a sensor which photoelectrically converts light reflected by the object and reads information on the object, a first density reference member which serves as a reference for correcting an image signal obtained by reading an original by the sensor, a second density reference member which is different from the first density reference member, a comparison unit which compares the second signal obtained by reading the second density reference member by the sensor and the third signal obtained by reading again the second density reference member by the sensor, and a correction unit which corrects the image signal on the basis of the first signal obtained by reading the first density reference member by the sensor, and the comparison result of the comparison device.

Abstract: Image signals output from a linear image sensor which outputs charges accumulated in pixels in the right-side area and charges accumulated in pixels in the left-side area via different channels are subjected to discrepancy correction. First, a gray reference board is scanned by the linear image sensor while changing charging periods, and look up tables for converting signal levels of the respective channels are generated on the basis of signal levels obtained by scanning the gray reference board. A discrepancy correction is realized by converting levels of image signals output from the two terminals using the look up tables.

Abstract: A fluorescent color scanning method is disclosed to include the steps of: scanning a standard white to obtain a first reference white W1; reducing the scanning brightness and then scanning the standard white to obtain a second reference white W2; using the first reference white and second reference white to scan every scanning document and then storing the respective scanning results Pm and Qm; and comparing Qm to W2 so as to determine if the document contains a fluorescent color or not subject to: (i) determining that the document contains a fluorescent color if Qm>W2, and then converting Qm into the accurate color output Om; and (ii) determining that the document contains no fluorescent color if Qm?W2 and then using the value of Pm as the image output value.

Abstract: The present invention relates to an image reading apparatus comprising a conveying means for conveying a sheet to a reading position; a platen glass guiding the sheet conveyed at the reading position; a reading apparatus for reading through the platen glass an image on the sheet conveyed at the reading position; a sheet guide member disposed on a side opposite to the reading device with respect to the platen glass for forming a small gap with the platen glass; and a driving means for moving the reading device. The drive device can move the reading device to a main reading position for reading operation at a position at which the sheet conveyed to the reading position is in contact with the platen glass and to at least one sub reading position for reading operation at a position at which the sheet conveyed to the reading position is not in contact with the platen glass.

Abstract: A distance calculation method and an imaging device that can be applied to a digital camera. The method includes calculating a distance between a point corresponding to an optical axis of a lens sub-system of the imaging device and an input point, and using the calculated distance to correct defects such as shading that occur in formed images due to peripheral light fall-off in the lens sub-system. The distance is approximated by a polygon having five or more sides, preferably having 8 or 16 sides. The distance is calculated by a disclosed function having constant coefficients, so that distances can be calculated by simple hardware.

Abstract: A method and apparatus for classifying an input image as black and white or color is described. The method calculates a first ratio of a color pixel portion to a total pixel portion in the input image. Next, the method calculates a second ratio of the color pixel portion to a combined pixel portion in the input image, where the combined pixel portion comprises the color pixel portion and a dark black and white pixel portion. Finally, the method returns an indication the input image is black and white if the first ratio is less than a first threshold and the second ratio is less than a second threshold.

Abstract: In an image reading apparatus according to the present invention, a black reference plate used for shading correction includes a light shielding plate. When the light shielding plate shields an optical path leading to a CCD sensor, the light emitted from an illumination device is prevented from falling on the CCD sensor.

Abstract: In an optical-reading document board, an anti-reflection layer is formed by a transparent film and an anti-reflection film is bonded on a document-resting surface of a transparent glass plate. The anti-reflection layer is structured by a transparent film and an anti-reflection film bonded on one surface of the transparent film. The use of such an anti-reflection film greatly improves reflectivity to provide an averaged reflectivity of approximately 3% in the entirety. As a result, the transmissivity of light is 94% or greater. In connection with this, the conventional layer has a reflectivity of approximately 8%, and a transmissivity thereof is around 90%. This makes it possible to effectively utilize more of the light from the light source and thus greatly improve contrast.

Abstract: One processing section 131 executes a process of generating image data K representing a black image on the basis of the image data Y, M, and C, and sequentially executes a process of removing elements of the black image contained in the image data Y, from the image data Y, a process of removing the elements of the black image contained in the image data M, from the image data M, and a process of removing the elements of the black image contained in the image data C, from the image data C.

Abstract: A shading compensation circuit is provided which is capable of storing correction coefficients for shading compensation having optimal bit lengths, so that the data size of the correction coefficients can be reduced. The shading compensation circuit 10 for correcting the shading properties with respect to a horizontal direction and a vertical direction, has horizontal correction coefficient HHK and vertical correction coefficient VHK each having a bit length optimized according to a horizontal direction counter value HCT or a vertical direction counter value VCT. The horizontal and vertical correction coefficients HHK, VHK for the periphery of the image data are longer in bit length than the correction coefficients HHK, VHK for the center of the image data.

Abstract: An image processor includes a reading unit that moves a scanning optical system toward a reference white sheet to read the reference white sheet from a direction along which the scanning optical system returns to the carried document reading glass before reading one sheet of a document mounted on a carried document reading glass by an automatic document feeding unit in a sheet document reading mode of forming an image of the document carried by the automatic document feeding unit by an image sensor through the scanning optical system facing the carried document reading glass.

Abstract: A printer for executing printing on the basis of tone data representing a tone of one of a plurality of colors of ink, includes an input unit that inputs first tone data for a color represented by N bits per pixel and second tone data for a color represented by M bits per pixel, M being larger than N; a storage unit that stores the tone data input by the input unit, the storage unit including a plurality of storage areas, each storage area having a capacity that can store a group of the first tone data within a predetermined print range, wherein multiple storage areas are used to store the second tone data; and a print unit that executes printing on the basis of the tone data stored in the storage unit, the print unit being capable of processing both the first tone data and the second tone data.

Abstract: In image input devices such as digital still cameras, processing is speeded up and power consumption is reduced by arranging in a RPU (23) performing real time processing of a pixel data from a CCD (21), such that only special exceptional image processing not being prepared previously is subjected to a software program processing in a CPU (24) and, in post processing in which a general image processing is carried out, a pixel data temporarily stored in a main memory (29) is inputted again to the RPU (23) and then processed. This enables to sharply speed up processing, and minimize a prolonged processing in the CPU (24) to reduce power consumption, when compared to the case of executing by software problem processing.