JPS61123363A - Monochromatic density rectification system - Google Patents

Abstract

PURPOSE:To attain a monochromatic image information not affected by such an outside factor as the way of irradiation of light, etc. to the paper by correcting the data from a memory of inputted paper in referring to white memory and black memory of the same address. CONSTITUTION:Image information (density level information) of white reference paper inputted from a camera scanner 1 is stored in a white memory 2. Image information of black reference paper inputted from the scanner 1 is stored in a black memory 3. When the paper as an object is inputted, its image information is stored in an input paper memory 4. An operation circuit 5 reads the data from the memory 2, memory 3 and the memory 4. Image information read out from the memory 4 is rectified by the data of memory 2 and the data of memory 3 of the same address. Thus, monochromatic image information not affected by such an outside factor as the irradiation way of light to the paper can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a white memory that stores image information when a white standard paper is input, and a white memory that stores image information when a black standard paper is input. A manual paper memory for storing image information when a target paper is input, and an arithmetic circuit. This invention relates to a black-and-white density correction method in which correction is performed with reference to .

[Conventional technology and problems]

In an image processing apparatus, light is irradiated onto a paper surface, the light reflected from the paper surface is converted into an analog electrical signal using COD, etc., and the analog electrical signal is further converted into a digital electrical signal and recorded. If the way the light is irradiated onto the paper is not uniform, for example, even if two points on the paper are white with the same reflectance, one may be perceived as blackish white and the other may be perceived as whitish white.

[Purpose of the invention]

The present invention is based on the above considerations, and it is an object of the present invention to provide a black-and-white density correction method that makes it possible to obtain black-and-white image information that is not affected by external factors such as the way light is irradiated onto the paper surface. The purpose is

[Means to achieve the purpose]

Therefore, the black and white density correction method of the present invention
It is equipped with a scanner, a white memory, a black memory, an input paper memory, and an arithmetic circuit, and the image information of the white reference paper manually input from the camera/scanner is inputted to the white memory from the camera/scanner. The image information of the black reference paper that has been input is stored in the black memory, and the image information of the target paper input from the camera/scanner is stored in the input paper memory, and the arithmetic circuit It is characterized by being configured to read data from the memory, black memory and input paper memory, and correct the data read from the input paper memory by referring to data in the white memory and black memory at the same number. That is.

[Embodiments of the invention]

To summarize, the present invention considers absolute white and absolute black, and corrects image information of a paper surface input from a camera/scanner based on these.

FIG. 1 is a block diagram of one embodiment of the present invention.

In FIG. 1, 1 is a camera/scanner, 2 is a white memory, 3 is a black memory, 4 is an input paper memory, and 5 is an arithmetic circuit. When a white reference paper is input from the camera/scanner 1, its image information (density level information) is stored in the white memory 2, and when a black reference paper is input from the camera/scanner 1, the image information is stored in the black memory 3. When a target page is input from the camera/scanner 1, the image information is stored in the manual page memory 4. It goes without saying that the image information of the point P on the paper is stored at the memory address corresponding to the coordinate value of the point P. The arithmetic circuit 5 reads data from the white memory 2, the black memory 3, and the input paper memory 5, and uses the image information read from the input paper memory using the data in the white memory 2 and the data in the black memory 3 at the same location. This is a correction. FIG. 2 is a diagram showing the correction processing performed by the arithmetic circuit 5. Arithmetic circuit 5
Then, the following processing is performed.

(2) Check whether the image information read from the white memory 2 indicates absolute white (value is 255). If YES, process ``■'' is performed, and if NO, process ``■'' is performed.

(2) Check whether the image information read from the black memory 3 indicates absolute black (value is O).

If Yes, process (2) is performed, and if No, process (2) is performed.

(2) Output the image information read from the input paper memory 4 as it is without correction.

(2) Correcting the image information read from the input paper memory 4 using a predetermined proportional calculation, and outputting the corrected image information.

Prior to inputting the desired paper surface, a black reference paper is input using the camera/scanner I to determine the density, and then a white reference paper is input and the density is measured.

Then, the target paper surface is input using the camera/scanner 1, the density is measured, and correction is performed based on the initially measured white and black density levels. As can be seen from FIG. 3, when performing correction, the white and black levels are not constant. Therefore, the values of the absolute white level and the absolute black level are determined, the white and black coordinates are corrected for each coordinate point, and then the density level of the input paper surface is corrected. Specifically, point A in FIG. 3 will be corrected and the actual value will be determined. Now, assume that the absolute black level is O1 and the absolute white level is 255. Since the value of point A is 100, the white level at that time is 2401, and the black level is 30, the actual value of point A can be found by the following calculation.

(100-30) + (240-30) = x +
255x=85 Therefore, the actual value of point A is 85.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, since correction is performed for each coordinate point, it is possible to obtain image information that always faithfully represents the target image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a diagram explaining the processing performed in the arithmetic circuit, and FIG. 3 is a white memory,
FIG. 7 is a diagram showing an example of image information read out from a black memory and an input paper memory. 1...Camera/scanner, 2...White memory, 3...
・Black memory, 4...Manual paper memory, 5...Arithmetic circuit.

Claims (1)

[Claims] The camera/scanner includes a white memory, a black memory, an input paper memory, and an arithmetic circuit, and the image information of the white reference paper inputted from the camera/scanner is stored in the white memory. The image information of the black reference paper input from the camera/scanner is stored in the black memory, and the image information of the target paper input from the camera/scanner is stored in the input paper memory, and the arithmetic circuit further comprises: The data is read from the white memory, the black memory, and the input paper memory, and the data read from the input paper memory is corrected by referring to the data in the white memory and black memory at the same location. Characteristic black and white density correction method.