An image data monitor apparatus has a CCD for reading image data of a document, an input buffer for receiving the pixel data from the CCD, an image processor for processing the data received from the CCD for printing out an image or the like, a circuit including a counter for extracting the designated pixel data, a keyboard for setting a desired mode, LEDs for displaying the extracted pixel data and other data, and a CPU for controlling the operation of the overall system. Various data such as maximum and minimum values of, an average value of or a maximum difference between the pixel data can be monitored at high speed upon selecting a corresponding mode. Desired data processing can be performed based on the monitored data.
An image reading apparatus such as a color copying apparatus has a plurality of sensing CCD chips for converting an image of an object into an electrical signal, each sensing CCD chip having a plurality of sensing elements. The apparatus also has a circuit for converting the electrical signal into digital data. A first adjusting circuit is provided for conducting either an operation for obtaining level matching of the electrical signal converted by the sensing chips, or an operation for controlling the gain of the electrical signal converted by the sensing chips. The apparatus further has a second adjusting circuit for effecting compensation for fluctuation of characteristics of the sensing elements of the sensing chips, by making use of the digital data converted by the converting circuit, the second adjusting circuit being adapted for effecting the compensation on the basis of electrical signals which are produced as a result of conversion by the sensing chips from two objects having different levels of density from each other, such as white and black levels. An analog-to-digital converter may also be provided to convert analog data into digital data. In that case, first adjusting means will adjust the analog data discretely, through a step smaller than the quantizing step used in the A/D conversion, and a second adjusting means may preferably further adjust the analog data in accordance with digital data obtained through the A/D conversion.
An image reading apparatus such as a color copying apparatus has a plurality of sensing CCD chips for converting an image of an object into an electrical signal, each sensing CCD chip having a plurality of sensing elements. The apparatus also has a circuit for converting the electrical signal into digital data. A first adjusting circuit is provided for conducting either an operation for obtaining level matching of the electrical signal converted by the sensing chips, or an operation for controlling the gain of the electrical signal converted by the sensing chips. The apparatus further has a second adjusting circuit for effecting compensation for fluctuation of characteristics of the sensing elements of the sensing chips, by making use of the digital data converted by the converting circuit, the second adjusting circuit being adapted for effecting the compensation on the basis of electrical signals which are produced as a result of conversion by the sensing chips from two objects having different levels of density from each other, such as white and black levels. An analog-to digital converter may also be provided to convert analog data into digital data may also be provided. In that case, first adjusting means will adjust the analog data discretely, through a step smaller than the quantizing step used in the A/D conversion, and a second adjusting means may preferably further adjust the analog data in accordance with digital data obtained through the A/D conversion.
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.
