Abstract: This invention is directed to a method capable of performing appropriate under color removal in image original reading. According to this method, under color removal of the original is performed as follows. A printing medium without any printed image is read by primary and complementary color readings. A brightness signal distribution is generated by converting, using a provisional table, each of image data generated by the reading methods. The lowest one of signal levels is selected from each of the distributions. In correspondence with each of the primary and complementary color readings, a conversion table is formed, which converts the image data to make a pixel value corresponding to the selected lowest one of the signal levels to a value representing white. Under color removal of the image data is performed using a corresponding conversion table in accordance with the reading method of the image original.

Abstract: What is disclosed is a novel system and method for adjusting the gray balance of a multifunction color marking device in order to change the device's neutral behavior to a desired level of acceptability. The gray balance aim curve is specified by: L*, L*(aim), a*(aim) and b*(aim), where L*(aim)=f1(L*), a*(aim)=f2(L*), and b*(aim)=f3(L*). After receiving the user-modified gray balance aim curve, the target color device constructs a 3-D N×N×N L*a*b* to L*a*b* pre-LUT to reflect the neutral aim change by transforming a neutral axis input of L*, a*=0 and b*=0 to L*(aim), a*(aim) and b*(aim). Colors further away from the neutral axis are shifted by a lesser amount. The pre-LUT is then concatenated with the current color LUT to produce an updated color LUT which is applied to the device to achieve the desired neutral behavior. The gray balance aim curve can also be based upon a pre-determined user preference.

Abstract: A method is provided for simulating the function of an image conversion device, comprising steps of reading input image data, recording the physical transformations of the base elements in at least one process step, emulating a predetermined number of processes, recording the final states of the base elements, collecting the base elements states following the last simulation step, transforming said collection into the simulation file and printing or displaying said simulation file. A system for implementing the method is also provided.

Abstract: What is disclosed is a novel system and method for minimizing dot visibility in color marking devices capable of dot-on-dot printing. The present method achieves minimum dot visibility for a given dispersed-dot screen by performing a CMYK to CMYKRGB conversion which uses less visible dots as much as possible before more visible dots are introduced. The output color dot coverages are calculated sequentially to minimize the coverage of more visible dots in a decreasing order of brightness. Resulting images have noticeably reduced halftone graininess, particularly in the mid to darker tone areas. The present method is also computationally efficient.

Abstract: An image forming apparatus using a plurality of colorants for image formation, includes a generation unit which generates bitmap data, in which each pixel has a gradation value of each color of the colorants, with respect to an object of the image formation; a classification unit which classifies the pixels into a plurality of predetermined groups based on the bitmap data and generates classification data corresponding to the classified groups for each pixel; a detection unit which detects, based on the classification data, a range, in which a correction processing of modifying the gradation values has to be executed, on the bitmap data; and a correction unit which executes the correction processing to the detected range, wherein the image formation is executed based on bitmap data after the correction processing.

Abstract: This disclosure describes methods for using embedded auxiliary signals in documents for copy detection and other applications. In on application, the auxiliary signal is formed as an array of elements selected from a set of print structures with properties that change differently in response to copy operations. These changes in properties of the print structures that carry the embedded auxiliary signal are automatically detectable. For example, the changes make the embedded auxiliary signal more or less detectable. The extent to which the auxiliary data is detected forms a detection metric used in combination with one or more other metrics to differentiate copies from originals. Examples of sets of properties of the print structures that change differently in response to copy operations include sets of colors (including different types of inks), sets of screens or dot structures that have varying dot gain, sets of structures with different aliasing effects, etc.

Abstract: A color conversion apparatus is for converting an input point defined in a three-dimensional first color space into an output point defined in a three-dimensional second color space. The color conversion apparatus includes: a position identifying unit; a first conversion unit; a second conversion unit; and an output point identifying unit. The position identifying unit identifies a two-dimensional position for the input point, the two-dimensional position being defined on a specific plane passing through a first white point, a first black point and the input point, the first white point and the first black point being defined in the first color space. The first conversion unit converts the input point into an intermediate point that is defined in a device-independent color space. The second conversion unit converts the intermediate point into a temporary output point that is defined in the three-dimensional second color space.

Abstract: A watermark information embedding apparatus generates a document image from electronic document data that has been input thereto, modifies the electronic document data based upon the document image and embeds information in the electronic document data. The apparatus includes a document image generator for generating a document image from the electronic document data; a document analyzer for detecting layout information of each constituent image in the generated document image; a normalization information calculation unit for calculating normalization information, which is for normalizing placement of each constituent image, based upon the detected layout information; a modification unit for modifying the electronic document data; and an embedding unit for embedding information in the modified electronic document data.

Abstract: With respect to color characterization of color printers, the present disclosure relates to the identification of colorant combinations for color patches in a color characterization target, which contains different color patches, and which is measured calorimetrically or spectrally to color-characterize the printer. A black ramp is printed and measured. Substantially uniform steps on the ramp are selected by applying principal component analysis to the measured values or color values derived from the measured values, and by using a first principal component thereof to select the substantially uniform steps. For each of the substantially uniform steps identified, the above procedure is repeated on all chromatic ramps with black ink at a corresponding black level. Color values of the color patches are populated by using multiple combinations of the substantially uniform steps of the black channel and of the chromatic channels at the corresponding black levels that meet an ink limit.

Abstract: Aspects of the disclosure provide a printing method that can utilize a lightly pigmented toner along with a darkly pigmented toner to improve the image quality. The method can include receiving a dataset corresponding to a printing of a printing system using a darkly pigmented toner. The printing system may have an undesirable optical density printing range for the darkly pigmented toner. Further, the method can include converting the dataset to a first dataset corresponding to a first printing of the printing system using the darkly pigmented toner, and a second dataset corresponding to a second printing of the printing system using a lightly pigmented toner. The first dataset can avoid the undesirable optical density printing range for the darkly pigmented toner, and a combination of the first printing and the second printing providing a substantially same printed optical density corresponding to the received dataset.

Abstract: In a computer system in which information represented by digital data is output to plural pages of recording medium, and then information on the plural pages of recording medium is read to use digital data representing the read information, authentication information is embedded in information of a start page selected by the computer system; a page number of the start page embedded the authentication information is notified to a user; information on the plural pages of recording medium is read, wherein the start page is positioned so as to be read first; digital data read from the plural pages of recording medium is authenticated based on the authentication information embedded in the start page; and a process for the digital data read from the plural pages of recording medium is controlled in accordance with a result of the authentication.

Abstract: There is provided a color conversion method. The method includes: a black correction step of converting the first black corresponding to the first color data having a tone value of 0 to the second black corresponding to the second color data having a tone value of 0 so that when the first black corresponding to the first color data having a tone value other than 0 is converted to a value smaller than a quantization threshold of tone values 0 and 1 of the second color data, a conversion destination becomes greater than or equal to the quantization threshold; a recording agent limit quantity calculating step of setting an upper limit of the sum of tone values for each pixel of the second color data with respect to a predetermined print medium; and a chromatic color correcting step of converting the second chromatic color so that the second color data after conversion in the black correction step does not exceed the upper limit.

Abstract: A method includes identifying multiple preferred color values in a destination color space. Each preferred color value is one of a set of colorimetrically equivalent color values. The destination color space has color values defined by a particular number of color components. The method further includes defining intermediate color values in an intermediate color space. The intermediate color values correspond to the multiple color values and the intermediate color space has a number of color components that is less than the particular number of color components of the destination color space. The method also includes identifying a known mapping from the destination color space to a source color space and using the intermediate color values and the known mapping to determine a conversion process for converting source color values to preferred color values.

Abstract: The subject application is directed to a system and method for sculpted gamut color conversion. First gamut data is received related to a first color gamut defined by a primary color space having no black component. Second gamut data is then received related to a second color gamut defined by a primary color space inclusive of a black component. At least one first color value of the first color gamut is then mapped to a second color value of a portion of the second color gamut disposed outside of the first gamut. At least one fractional black component value is then selected for each mapped color value. Non-black color data associated with each selected fractional black component is then identified. A sculpted gamut is then generated in accordance with each selected fractional black component and associated non-black color data. A color image is thereafter generated corresponding to received image data in accordance with the generated sculpted gamut.

Abstract: The present invention transforms a source device colorant value to a destination device colorant value, by determining whether all non-black colorant values of the source device colorant value are zero, transforming the source device colorant value to a colorimetric value using a source device model, transforming the colorimetric value to a gamut-mapped colorimetric value using a user-selectable gamut-mapping model, and selecting a destination device colorant value based on the determination. In a case where all of the non-black colorant values of the source device colorant value are zero, the destination device colorant value is selected so that its black colorant value reproduces a lightness of the gamut-mapped colorimetric value, and all of its non-black colorant values are zero. Otherwise, the destination device colorant value is selected so that a combination of its non-black and black colorant values reproduces the gamut-mapped colorimetric value.

Abstract: An image processing method includes creating a conversion table for converting a color in a device-independent color space into a color in a device color space based on a colorimetry result of a color patch output by a device. Creating the conversion table includes converting a color in a three-dimensional color space dependent on a device into a color in a four-dimensional device color space including black. Converting a color in the three-dimensional color space includes separating an input color in the three-dimensional device-dependent color space into color components of the four-dimensional device color space based on a gradation from the input color to black, using a black generation curve of a gray line set by a user and black generation curves set for individual primary colors of RGBCMY, and performing saturation-increase conversion on the color components in accordance with an amount of a black colorant.

Abstract: The subject application is directed to a system and method for visualization of black-component gamut sculpting. Parameter data is first received corresponding to parameters associated with the black replacement for a primary color system. Alternative color profiles are then generated according to the parameter data and characteristics of the primary color system. Image data is then received of an image defined in the primary color system. Renderings are then generated corresponding to the received image data, with each rendering uniquely corresponding to one of the alternative color profiles. Selection data is then received corresponding to a selected black replacement parameter selected in accordance with the generation of the renderings.

Abstract: A processing system includes a setting module for capturing Cyan, Magenta, Yellow and K data of a foreground and selecting one from the Cyan, Magenta, Yellow and K data in order to set gray values of remaining three of the Cyan, Magenta, Yellow and K data as “0”; a coupler module for capturing the Cyan, Magenta, Yellow and K data of the background and combining the Cyan data of the foreground and background into a Cyan data group, the Magenta data of the foreground and background into a Magenta data group, the Yellow data of the foreground and background into a Yellow data group and the K data of the foreground and background into a K data group; and a print module for printing, out the Cyan, Magenta, Yellow and K data groups one above another in an overlapping manner.

Abstract: This disclosure provides methods, apparatus and systems for generating a multidimensional printer profile for a color printer. Specifically, the disclosure provides a method to blend multiple GCR functions or strategies to produce a final GCR blended printer profile, for example a printer profile LUT.

Abstract: Embodiments of a method performed by an image capture device are provided. The method includes performing a calibration operation on a photosensor array of the image capture device using a background surface with a substantially uniform grey color and performing a scan operation to capture a scanned image from a medium using the background surface.

Abstract: A system that converts color coefficients between color spaces. During operation, the system receives a color profile comprising a lookup table which defines a conversion of color coefficients between a source color space and a destination color space, wherein the source color space includes a black color channel. Next, the system identifies a darkest output color value in the destination color space produced by the color profile, and also identifies entries in the lookup table corresponding to a maximum possible value for the black color channel of the source color space. The system then updates the identified entries with an achromatic equivalent of the identified darkest output color value, whereby source colors having the maximum possible value for the black color channel are mapped to the achromatic equivalent of the identified darkest output color value.

Abstract: An offset adjusting device includes a sample-hold unit that sample-holds an analog image signal obtained by converting reflected light from an original into an electric signal with a photoelectric conversion device to thereby obtain a sample-hold signal; an amplifying unit that amplifies the sample-hold signal to obtain an amplified signal; an analog-digital converter that digitizes the amplified signal to obtain a digital signal; a difference detecting unit that detects a difference between a black-level detection value of the digital signal and a black-level target value; an selecting unit that selects an adjustment coefficient among a plurality of adjustment coefficients based on comparison of the difference and a reference value; and a feedback unit that subjects an offset adjustment value based on the adjustment coefficient selected by the selecting unit to feedback processing.

Abstract: The present invention is to provide an image processing system and the method thereof capable of maintaining gradient characteristics near a black point of an output image, when performing color matching in a color printer, even if a source profile has a lower minimum lightness value of output color gamut. In the present invention, when a condition is matched by comparing the minimum lightness points of the source profile and output color gamut, a correction color conversion table is generated by correcting the minimum lightness point of the output color gamut to a correction target value set in advance. Color conversion is performed for an input image using the correction color conversion table.

Abstract: An image output device includes: a color conversion processing unit that converts output-use image data into image data of a standard CMYK color space; and a color correction processing unit that conducts color correction of the image data of the standard CMYK color space outputted from the color conversion processing unit, wherein the color correction processing unit includes a K correcting unit that conducts correction of the K component of the image data and a CMY correcting unit that conducts correction of the CMY components of the image data.

Abstract: An apparatus and method for converting color data are provided. The method includes generating a CMYK color gamut extended from a CMY color gamut that consists of a cyan (C) colorant, a magenta (M) colorant, and a yellow (Y) colorant, by use of the CMY color gamut and a black (K) colorant; mapping input colors using the generated CMYK color gamut; converting color data of the mapped input colors to CMY data; and converting the CMY data to CMYK data. Accordingly, natural representation and printing of low-lightness colors and high-saturation colors can be attained.

Abstract: An image reading apparatus is provided which includes a contact image sensor comprised of a plurality of sensor chips arranged in series, an analog image processor for processing an analog image signal from the contact image sensor, a unit for conducting black shading correction for each pixel and a unit for conducting white shading correction for each pixel. The image reading apparatus further includes a unit for digitally monitoring a black offset value corresponding to each chip with respect to the signal that has been processed by the analog image processor and a unit for adding and subtracting a black offset variation amount for each chip in the previous stage of the unit for conducting black shading correction for each pixel, and corrects black offset based on an instruction of a control unit.

Abstract: A method of converting black to composite/process black in a digital color print engine. A lightness adjustment is employed for converting input image (O, O, O, Kin) to Ko and initial values of Co, Mo, Yo are set equal to Ko and then converted to C1, M1, Y1, K1 by GCR strategy. Values of Cout, Mout, Yout, Kout are determined by Gray Balance Adjustment for values of C1, M1, Y1, K1 and inputted to the color print engine. The user may disable the conversion to composite black and print black ink/tones if desired. The user may also input different parameters for Lightness Adjustment, Gray Component Replacement and Gray Balance Adjustment.

Abstract: In an information processing method, input color data indicating a plurality of color components including a black color component is converted into output color data that indicates a plurality of color components including a black color component. A relationship between lightness levels and simple black colors is determined for an output device based on the characteristics of the output device. When input color data indicates a simple black color, output color data for the simple black color having a lightness level equivalent to the lightness level of the input color data is determined based on the relationship between lightness levels and simple black colors.

Abstract: For each combination of color material signals corresponding to an input image signal, a total color material use amount is calculated. On the other hand, on the basis of a predetermined target color, total color material use amounts are set which vary smoothly in accordance with a variation in the target color. Then, a determination is made as to which one of all the combinations of color material signals determined as described above corresponds to one of the set total color material use amounts which is the same as the total color material use amount corresponding to the input image signal. This combination is outputted to a printer as the optimum combination of color material signals corresponding to the input image signal.

Abstract: A method and system for mapping an input color value in an input color space to an output color value in an output color space comprising a lookup table mapping an input value to an output color value, the lookup table having n number of possible values for a first fixed color component and q number of possible values for a second fixed color component, wherein q and a number m of possible values for t color components in the input color space are less than n. Surrounding input values are determined in the lookup table in a t dimensional space, wherein each surrounding input value has a same value for the fixed color component(s). Surrounding output values to which the surrounding input values map are determined. The determined input and output surrounding values and the input value are used to estimate an output value corresponding to the received input value.

Abstract: A method of adapting color values, which have been produced for a first printing process to a second printing process, is performed so that the visual impressions of the colors in the two printing processes are identical. Starting from a first printing process adaptation U without maintaining the black build-up, which transforms the color values [C1,M1,Y1,K1] of the first printing process into color values [C2,M2,Y2,K2]U of the second printing process, and a second printing process adaptation V while maintaining the black build-up, which transforms the color values [C1,M1,Y1,K1] of the first printing process into color values [C2,M2,Y2,K2]V of the second printing process, a new printing process adaptation W is determined by weighted averaging of the transformed color values [C2,M2,Y2,K2]U and [C2,M2,Y2,K2]V.

Abstract: An apparatus for forming an image is disclosed which includes: an input device inputting image data; an image processor processing the inputted image data; an image forming device forming the image on a recording medium, based on the processed image data; a lightness setting device setting a lightness value of the image to be formed on the recording medium by the image forming device; a first corrector correcting the inputted image data according to a first correction characteristic; a first characteristic modifier modifying the first correction characteristic, in response to setting of increasing the lightness value by the lightness setting device; a second corrector correcting the processed image data according to a second correction characteristic; and a second characteristic modifier modifying the second correction characteristic, in response to setting of decreasing the lightness value by the lightness setting device.

Abstract: Input print data can assume one of a RGB color space, CMYK color space, and Gray color space. When graphic arts are principally to be printed, data of these color spaces is converted into CIE Color Space XYZ as a standard color space, and data of the standard color space is converted into a CMYK color space according to the Output Profile of a printer, which then prints the converted data. On the other hand, when office documents are principally to be printed, conversion into the standard color space is skipped, and input color space data is directly converted into a print color space CMYK, and the converted data is then printed.

Abstract: Color processing methods and apparatus are provided that blend the gray component replacement (“GCR”) level of arbitrarily-specified input color data with an estimate of the GCR level of an output profile, and then converts processed device-independent data to output CMYK data that has a GCR level that substantially matches the GCR level of the input CMYK data. Methods and apparatus in accordance with this invention may be used to receive CMYK data that approximates a spot color, and provide tints of spot colors using an output profile that has a GCR level that differs from the GCR level of the input color data.

Abstract: A first set-value calculating unit calculates a first set value of a black-level feedback based on a reflection amount that increases a speed of tracking to a black-level target value in a black-level feedback control. A second set-value calculating unit calculates a second set value of a black-level feedback based on a reflection amount that slows down a tracking to a black-level target value as compared to the speed of tracking of the first set-value calculating unit. A selecting unit selects and outputs any one of the first set value and the second set value and outputs selected value as a set value. A controlling unit controls selection of any one of the first set value and the second set value by the selecting unit based on the black differential value and a gain of the image data.

Abstract: An image processing apparatus has a generation section that generates color component of each pixel forming an image by of a usual method or a generation for black edge; a black edge determination section that determines whether or not each pixel is a black edge pixel forming the black edge based on peripheral pixels of the pixel; a dot detection section that detects dot information of each pixel based on peripheral pixels of the pixel; and a method instruction section that instructs the generation section on what method is to be used for generating color component based on results provided by the black edge determination section and the dot detection section, wherein the method instruction section instructs the generation section to generate color component of a pixel, which is not determined as the black edge pixel or whose detection result is a specific detection result, by the usual method.

Abstract: Disclosed are systems and methods for color calibration incorporating gray-component replacement, and more particularly, controlling gray component replacement in a color output device by applying a pre-defined transformation to a plurality of non-black channels to obtain at least one intermediate variable, and determining at least one output black (K) value from both the black channel input value and the intermediate variable, in order to provide control of gray component replacement in the color output device.

Abstract: A calibration system includes: an image formation unit that outputs a patch sheet having a plurality of patch patterns based on different gradation values for each color of color material that is used; a selection unit that receives an instruction to select a device from among a plurality of color measurement devices comprising a first color measurement device and a second color measurement device of a lower color measurement accuracy than that of the first color measurement device; a color measurement unit that receives data of a color measurement result for the patch sheet that is color-measured by the color measurement device selected by the selection instruction; a color measurement value determination unit that acquires color measurement values for each of the patch patterns on the basis of the color measurement result data received; and a color adjustment unit that generates color correction information of the image formation unit on the basis of the color measurement values acquired.

Abstract: A color data conversion apparatus and method. The color data conversion apparatus includes a K ratio calculator for outputting a K ratio that is calculated using entered color data; a K ratio adjuster for adjusting the calculated K ratio, which is output from the K ratio calculator, in reference to gamut boundary descriptors (GBDs) corresponding to a K ratio and outputting the adjusted K ratio as a final K ratio; and a CMY ratio calculator for calculating C, M, and Y ratios based on the final K ratio. When converting the entered color data to the CMYK data, the calculated K ratio can be adjusted to the K ratio printable by use of the K GBDs. Accordingly, the printing apparatus can substantially print according to the calculated K ratio and thus the degradation of the printing quality can be avoided.

Abstract: When color materials of more than four colors are used, a signal for the amount of toner used within a range appropriate for the apparatus and toner characteristic is generated using a color separation table. However, a printer receives print data of various formats, such as image data separated into signal values of more than four colors, or image data of a special format to which a six-color separation table cannot be applied. Hence, an image signal representing a combination of colors is input. The sum of the signal values of colors in each pixel of the image signal is calculated and compared with a limit value. When the sum exceeds the limit value, the signal values of base colors are replaced with that of a spot color based on a replacement table for replacing the signal values of the base colors with that of the spot color.

Abstract: In a high lightness region of a color hue corresponding to a basic color material, the high lightness region ranging from a lightness level corresponding to the maximum color saturation level that is reproducible by the basic color material to the highest lightness level, color separation data corresponding to the basic color material is generated. In an intermediate lightness region whose lightness level is lower than that of the high lightness region, color separation data corresponding to the basic color material and two color materials (one of them is preferably is a particular color material) that have color hues close to that of the basic color material is generated. This provides the advantage of enlarging the color gamut in the low lightness region of a basic color hue.

Abstract: A gray balancing technique wherein color data values are modified only if the color data values include a gray component.

Abstract: Gamut maximizing black generation for printers. Generating device dependent data from device independent data uses both chromatic curves and achromatic curves, which are independently controllable and which each include a color space curve and a black curve. The achromatic and chromatic curves are generated using a set of input parameters. Once the curves are generated, the final color space values are generated using an interpolation between the achromatic curves and the chromatic curves.

Abstract: A signal processing method for converting input color value information (Lab) represented in a uniform color space into a set of five output color levels of black, light black, and three chromatic colors (CMYKLk) is provided. A black output level (K) is determined based on the input color value information. Then, a light black output level (Lk) is determined based on the black output level and the input color value information. Output levels of the three chromatic colors (CMY) are also determined such that the determined output levels are colorimetrically consistent with the input color value information.

Abstract: The disclosure is directed to techniques for gamut mapping with modified black point compensation (BPC). The gamut mapping techniques promote well-distributed tone compression so that substantial loss of detail in highlight and shadow regions can be avoided. The gamut mapping techniques may be particularly useful in converting rich saturated images, such as RGB photographs, for presentation as much less saturated output, such as typical newsprint. Other example applications include conversion of CMYK Specifications for Web Offset Printing (SWOP) printing to CMYK Specifications for Newsprint Advertising Production (SNAP) newsprint, and conversion of RGB photos with camera profiling software to CMYK for all types of printing.

Abstract: A high-resolution printing method includes the steps of determining if a pixel of a plurality of pixels is a true black pixel and positioning the true black pixel in a predetermined column and a predetermined row of a print matrix.

Abstract: A method for designing a black generation transfer curve is described. A table is produced to convert a first signal in a first signal space to a second signal in a second signal space. Color measurement data of a device is obtained. The color measurement data relates to a signal-to-color response of the device. A black generation transfer curve is designed constrained by the color measurement data of the device.

Abstract: Embodiments of a process comprising receiving a plurality of offset analog signals, each corresponding to one of a plurality of black pixels in a pixel array; obtaining a corresponding digital value for each offset analog signal; computing an average of the digital values; and computing a black-level offset that, if applied to the digital values, would make the average of the digital values equal to a target value. Also disclosed are embodiments of an apparatus comprising an analog-to-digital converter coupled to an analog channel to receive offset analog black pixel signals from the analog channel and to obtain a corresponding digital value for each offset analog signal; circuitry and logic coupled to the analog-to-digital converter to average the digital values corresponding to the black pixels and compute a black-level offset that, if applied to the digital values of the black pixels, would make the average of the digital values of the black pixels equal to a target value.

Abstract: A color conversion table generation apparatus includes black-maintenance-provisional-output generating means for generating provisional CMYK values, black-maintenance-degree evaluating means for calculating an index indicating a degree of black maintenance and evaluating a degree of black maintenance on the basis of a result of the calculation, black-maintenance-CMY searching means for fixing a K value of the provisional CMYK values which satisfy predetermined constraints concerning the index and searching for other CMY values, and recording means for recording CMYK values calculated by combining CMY values searched and obtained by the black-maintenance-CMY searching means and the K value fixed during the search in the black maintenance color conversion table. According to the color conversion table generation apparatus, it is possible to more easily generate an optimum black maintenance color conversion table desired by a user than conventional apparatus.

Abstract: An image scanning apparatus comprising a plurality of image scanning sensors 21, 31, 41, and a CIS control chip 50 for controlling these image scanning sensors 21, 31, 41. The CIS control chip 50 has a trigger generator 54 for controlling operation of the image scanning sensors 21, 31, 41, a lamp control circuit 55, and a motor control circuit 56. The CIS control chip 50 also has an AFE 51 having a plurality of input terminals 51a to 51c for receiving the analog image signals from the first scanning sensor 21, second scanning sensor 31, and third scanning sensor 41, respectively and a gain/offset control circuit for adjusting the gain and offset of each line of analog data supplied from the image scanning sensors 21, 31, 41.