Abstract: To produce a correction table to be referred to when a quantum level data (QL data) as an input image data to a given image output device is converted into an image having a halftone dot percentage, reference QL data having a plurality of data values arranged at predetermined data intervals are inputted to the image output device; the halftone dot percentage of an output image from the image output device are measured; an approximation formula of a desired function form is determined to approximate the measured halftone dot percentage by the method of least squares, on the condition that the formula should go through preset starting and ending points; and the correction table is produced based on the resulted approximation formula.

Abstract: A basic gradation curve, a gray balance, and a black curve are selected, and a tone reproduction curve is generated based on a combination of the basic gradation curve, the gray balance, and the black curve which have been selected. Using the generated tone reproduction curve, a sample image is color-separated to generate a proof. The proof is checked, and, if necessary, the tone reproduction curve is corrected until an optimum tone reproduction curve is generated.

Abstract: An apparatus for processing an image data digitally comprises a storage device for storing therein a multiplier varying in accordance with a first image data obtained by digitally processing the image data, the length of the integral part of the first image data being n bits, a random number generating circuit for generating a random number falling on somewhere between zero and a positive number less than unity, an arithmetic circuit for performing arithmetic operations including a multiplication of the random number by the multiplier, and an adding circuit for adding the output of the arithmetic circuit to the first image data and outputting the least significant m bits (m.ltoreq.n) of the integral part of the so-added data as second image data for use in the next process.

Abstract: This invention is a method for forming halftone screen to prepare a multi-color separated halftone gradation image which is printable and reproducible by superposing an image signal obtained by scanning an original comprising continuous-tone color images with a halftone screen signal generated electrically, which comprises the steps of exposing and scanning a light spot of a predetermined size at a predetermined pitch to form halftone dots, and changing the number of said pitch so as to obtain an arbitrary screen line number.

Abstract: Disclosed herein is an image processing apparatus for determining the rate of UCR (under color removal) for each color by a function of each of color signals. The image processing apparatus basically comprises a device for determining the maximum value Max and the minimum value Min of each of input signals Yi, Mi and Ci, and a device for determining the rates of UCR indicative of Y.sub.U, M.sub.U and C.sub.U from the input signals Yi, Mi, Ci and the maximum value Max and the minimum value Min, using respective functions F.sub.Y, F.sub.M and F.sub.C. The above-described Y.sub.U, M.sub.U and C.sub.U can be determined in accordance with the following equations:Y.sub.U =F.sub.Y (Max, Min, Yi)M.sub.U =F.sub.M (Max, Min, Mi)C.sub.U =F.sub.C (Max, Min, Ci).

Abstract: This invention is a color scanner comprising an image reading means for reading an original stored in an original cassette by carrying out of a rough-scanning or main scanning, a signal processing means for signal-processing the main scan data of said original, which the main scan data obtained by said image reading means, a calculation setting means for obtaining characteristic values of said original on the basis of rough-scan data obtained by said rough-scanning, calculating original classification informations on the basis of the characteristic values, setting a signal processing conditions into said signal processing means, and outputting a certainty factor, an input means for inputting supplemental informations necessary when said certainty factor is low, and a recording means for recording the image on the basis of the output of the signal processing means. This invention relates to a method thereof.

Abstract: UCR (under color removal) amount is determined, which can satisfy printing conditions as desired easily and within short time. Gray balance for Y, M and C is inputted from input means 13. A control means 9 interpolates the inputted gray balance as necessary and instructs a test pattern generator 12 and an output unit 7 to output a test pattern so that matrix is formed by Y, M, C and K. Based on the outputted test pattern, a print plate is prepared, and a sample of matrix is prepared by 4-plate overlapping printing. Each density of matrix is measured, and said measured density value is inputted from the input means 13. The control unit 9 incorporates each density and calculates the amount of UCR, which satisfies the input gray balance from interrelation of the density of Y, M, C and K of the matrix.

Abstract: This invention is a method for forming halftone screen to prepare a multi-color separated halftone gradation image which is printable and reproducible by superposing an image signal obtained by scanning an original comprising continuous-tone color images with a halftone screen signal generated electrically, which comprises the steps of exposing and scanning a light spot of a predetermined size at a predetermined pitch to form halftone dots, and changing the number of said pitch so as to obtain an arbitrary screen line number.

Abstract: An image processing method in a color scanner which includes an original base adapted to receive therein an original cassette that accomodate a color original, a light source for linearly radiating the original cassette as received in the original base, image sensors for color separating a transmitting or reflected light in a linear region of the color original into R, G and B for detection, a signal processing section for processing RGB image signals outputted from the image sensors by linearly scanning the color original to output four color image data such as C, M, Y and black, a color monitor connected to the signal processing section for displaying images of the four color image data, a data input device for inputting data required for the signal processing section and for designating a position where the color monitor displays and an output device for half-toning the four color image data to prepare a printing color separating block, which comprises the steps of: preparing a density cumulated histogram