JPH04195265A - Image reading system - Google Patents

Abstract

PURPOSE:To perform image compression by a runlength system by fixing a bit in one dot line as '1' or '0', thinning the dot line representing '1' that is black, and expressing gradation falsely. CONSTITUTION:In a reading system expressing the gradation falsely by thinning a dot representing '1' that is a point of black according to the gradation of a read original, the bit in one dot line is fixed as '1' or '0'. The gradation is expressed falsely by thinning the dot line representing '1' that is black. Figure shows the explanation figure of image data in which an original provided with uniform gradation is read extending over 16 lateral dots and nine vertical dots. Also, the conversion of the image data read by false gradation expression to conventional gradation expression to invert '1' to '0' in one dot line can be easily performed by easy processing such as to switch data to the dot line data at every several dots.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading method, and particularly to pseudo-gradation representation.

[Conventional technology]

Conventionally, as an image reading method for pseudo-gradation expression, bits representing black in one dot line are thinned out at regular intervals to represent black or white points in a mesh pattern.

[Problem to be solved by the invention]

Therefore, in the conventional reading system, the 0" and "1' degrees in one dot line are reversed to represent the gradation, and the run-length image compression cannot be performed effectively.

[Means to solve the problem]

The image reading method of the present invention is a reading method that expresses pseudo gradations by thinning out bits indicating "'1 degrees", that is, black points, according to the shading of the read document. °“0′
This is achieved by keeping the dot line unchanged as 0°, and by thinning out the dot lines indicating 01°', that is, black, to express the gradation in a pseudo manner.

〔Example〕

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of image data read by the image reading method of the present invention. The input original has uniform density. The reading width is 111!16 dots.

It should be noted that converting the image data read using the above-mentioned pseudo gradation expression into a gradation expression in which °゛l'' and ゛0 in the conventional one-dot line are reversed is a simple process such as replacing the dot line data every few dots. This can be done by processing.

〔Effect of the invention〕

As explained above, the present invention provides “
By expressing white or black in units of dot lines and performing pseudo-gradation expression instead of arranging 0'' and 1 patterns, image compression using the run-length method is effective.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of image data obtained by reading a document having uniform density over 16 dots horizontally and 9 dots vertically using the method of the present invention. O...white dot, 1...black dot.

Claims (1)

[Claims] In a reading method that expresses a pseudo gradation by thinning out the bits that indicate "1" or black points according to the shading of the read document, the bits in one dot line are "1".
An image reading method characterized by expressing a pseudo gradation by thinning out the dot lines that indicate "1" or "black" and leaving them unchanged as "1" or "0".