Abstract: When maximum density of an output image is lowered by a gamma correction, the number of tones is reduced and the tonality of the output image declines. In order to solve this problem, a pattern generator (215) is caused to generate a toned pattern and the gain of a D/A converter of a PWM circuit (212) is controlled so as to output a test pattern having a density ranging from maximum pulse width Pff(50%) to maximum pulse width Pff(100%) for each color component (step S1). Image information that has been read (step S2) from the test pattern is converted to density information (step S3), and Pff is set (step S4) from the relationship between Pff and image density based upon coordinate information provided by the test pattern.

Abstract: An image forming apparatus and method in which, when a recording medium on which a gray-scale pattern has been formed is placed upon a platen in a skewed attitude, the resulting offset is corrected and image forming conditions are adjusted to obtain an ideal image. In one one such apparatus, a 256-tone pattern image of a designated color is formed on a recording medium. If the recording medium has been placed upon a platen in a skewed attitude when the pattern is to be read, the position of the pattern image is corrected, the gamma characteristics of a LUT are calculated based upon the correct pattern image and the calculated values for the LUT are set.

Abstract: This invention provides an image reading device capable of precise detection of the optical signal over a wide wavelength range, by forming a photoelectric converting unit for converting the visible light into an electrical signal and a photoelectric converting unit for converting the invisible light into an electrical signal, in monolithic manner on a single semiconductor chip.

Abstract: This invention relates to a method of setting anti-forgery information addition level while taking an apparatus individual difference into consideration. The method is employed by a data processing system including: an image processing apparatus 100 for processing an image; and a maintenance apparatus 120, connected with the image processing apparatus through a network 110, for setting a processing function of the image processing apparatus 100. The maintenance apparatus 120 determines an anti-forgery information addition level depending on an individual difference of apparatuses, such as an exhaustion level of the image processing apparatus 100. The addition level determined by the maintenance apparatus 120 is transmitted to the image processing apparatus 100. The image processing apparatus 100 adds anti-forgery information to an inputted image at the addition level transmitted by the maintenance apparatus 120.

Abstract: Image data supplied to an image forming apparatus are converted into image data linearly correlated with the image density, and the image ratio is calculated by dividing the number of pixels in which the toner is deposited at the image formation of thus converted image data on a print medium, with a value obtained by multiplying the total pixel number corresponding to the size of the print medium with the number of gradation levels per pixel. Then the toner amount consumed in the image formation based on the entered image data is determined by multiplying the image ratio, the size of the print medium to be used and the toner amount consumed per unit area in a solid image formation.

Abstract: An image forming apparatus that increases the relative resolution of a small image to be output for recording. When the image forming apparatus is used for copying an image of an original document, when the size of an image to be output is not greater than a predetermined size, a CPU controls a resolution switching unit for increasing the resolution to form an image with increased resolution.

Abstract: The invention intends to relatively increase resolution when the size of an image to be output for recording is small, enabling even a gradation image to be visually perceived with satisfactory quality. To this end, in a disclosed image forming apparatus for copying an image of an original document set on a reading apparatus, when the size of an image to be output is not larger than a predetermined size, a CPU controls a resolution switching section to increase resolution, thereby forming the image with the increased resolution.

Abstract: An image processing apparatus for performing pulse-width modulation processing based on input image data. A maximum pulse width of a pulse signal, which can be outputted as a modulation signal obtained by the pulse width modulation, is changed in accordance with an image processing mode.

Abstract: An image can be outputted with a high sharpness without deteriorating a resolution. In order to output an image of a high picture quality while suppressing the occurrence of a moire, an exposure amount is modulated in accordance with pixel density information of the image divided into pixels of a predetermined size by an exposure amount modulating unit in a light scanning unit, thereby expressing an image dark/light state. In this case, in a highlight density region in which a pixel density is equal to or less than ⅓ of the maximum image density, the density data of two adjoining pixels is modulated by one pixel and the other pixel is not recorded. In a density region in which the image density lies within a range from ⅓ to ½ of the maximum image density, a part of the density data of one of the two adjoining pixels is transposed to the other pixel.

Abstract: An image processor includes a first reader which obtains a first signal corresponding to visible information read on an original, and a second reader which obtains a second signal corresponding to invisible information on the original. A comparator compares the first and second signals to discriminate a predetermined pattern on the original.

Abstract: An image can be outputted with a high sharpness without deteriorating a resolution. In order to output an image of a high picture quality while suppressing the occurrence of a moire, an exposure amount is modulated in accordance with pixel density information of the image divided into pixels of a predetermined size by an exposure amount modulating unit in a light scanning unit, thereby expressing an image dark/light state. In this case, in a highlight density region in which a pixel density is equal to or less than ⅓ of the maximum image density, the density data of two adjoining pixels is modulated by one pixel and the other pixel is not recorded. In a density region in which the image density lies within a range from ⅓ to ½ of the maximum image density, a part of the density data of one of the two adjoining pixels is transposed to the other pixel.

Abstract: An image forming apparatus forms an image on a medium by using an output device. A pattern signal for forming a predetermined pattern image on the medium is generated, and image forming parameters for the output device are determined on the basis of the density of the pattern image formed on the medium. The determined image forming parameters are transmitted via bidirectional communication to an external computer or other image forming apparatus.

Abstract: A system which utilizes plural image forming apparatus, equalizes gradation characteristics of images commonly output from such plural image forming apparatus. When the system includes three color copying apparatus, at first a test pattern image based on data from a pattern generator is output from the color copying apparatus. The prepared image is read by the reader of the color copying apparatus, and, based on the read data, the correction data of a table (LUT) are calibrated for obtaining density data for a laser beam. The calibration of the correction data of the color copying apparatus are conducted in a similar manner using, however, the reader of the same copying apparatus for reading the test pattern. It is therefore, rendered possible to exclude the influence of the difference in the reader characteristics on the calibration, and to equalize the gradation characteristics when the copying apparatus are used as printers.

Abstract: An invisible information detection apparatus includes parts that irradiate a light onto a medium, detect infrared light generated from the medium, and judge a specific pattern consisting of a combination of two areas on the medium in accordance with the detection result. One of the areas represents higher reflectance than the reflectance of the medium in substantially the same infrared wavelength region, and the other area represents lower reflectance than that of the medium. An invisible information detection method comprises an irradiation step, a detection step and a judgment step. The judgment step judges a specific pattern of a combination of two areas on the medium in accordance with the result from the detection step. One of the areas represents higher reflectance, and the other area represents lower reflectance, as compared to the reflectance of the medium, in substantially the same infrared wavelength region.

Abstract: This invention provides an image reading device capable of precise detection of the optical signal over a wide wavelength range, by forming a photoelectric converting unit for converting the visible light into an electrical signal and a photoelectric converting unit for converting the invisible light into an electrical signal, in monolithic manner on a single semiconductor chip.

Abstract: An image processing apparatus for subjecting input image data to a density conversion includes three dot isolation circuits which subject the pixels on each of a plurality of lines adjoining in the sub-scan direction to a density conversion in accordance with a different predetermined conversion characteristic (LUT) for each line. Though each dot separation circuit deals with a different number of lines of image data to undergo a density conversion, the predetermined conversion characteristics can be set in advance in such a manner that the density values of a plurality of pixels on adjoining line will be preserved if an overall view of the reproduced image is taken.

Abstract: An object of the present invention is to provide an image processing apparatus and an image processing method both offering a high-precision and general-purpose capability of identifying an image and performing appropriate processing depending on whether identification is effected. In the image processing apparatus and image processing method, image data is detected in visible and invisible light reflected from each of a target pixel and surrounding pixels. Based on the image data detected in visible and invisible light, a specific pattern is identified. The specific pattern appears substantially the same in color as a surrounding area under visible light but different in characteristic therefrom under invisible light, which is identified using the image data of the target pixel and surrounding pixels provided by a detector. The image processing apparatus is controlled depending on whether the identification is effected.

Abstract: An image processing apparatus and method which inputs multivalued image data capable of m-level representation, performs image processing on the input data, and converts the processed data into multivalued image data capable of n-level (m<n) tonality. Upon forming an image on a print medium based on input image data, the image is formed such that the difference between an image density D(x) of the image formed on a print medium at a tonality level x and an image density D(x+1) of an image formed on the print medium at the next tonality level x+1 satisfies D(x+1) -D(x).ltoreq.A.times.D(x) (A.ltoreq.0.08) (A.ltoreq.0.08). Further, a pattern signal having a rectified sine wave having a predetermined period is generated, and a pulse-width modulated signal for generating a beam is generated by performing pulse-width modulation on the input image data based on the pattern signal.

Abstract: Visible information of the document sheet and information other the visible information are efficiently read by an image sensing apparatus including a first line sensor for reading the visible information of the document sheet and a second line sensor for reading the information other than the visible information.

Abstract: It is an object of the invention to stabilize a picture quality by a calibration. In an image forming method using an image forming apparatus having reading means for reading an original and image forming means for forming an image on a medium, a first calibration is manually performed with respect to a system including both of the reading means and the image forming means, and a second calibration is automatically performed with respect to the image forming means solely.