JPH0462680A - Method for reducing picture - Google Patents

Abstract

PURPOSE:To truely reproduce picture information from an original also in a reduced picture by adding a correcting value to a number obtained through a random number generating means every respective line. CONSTITUTION:For picture elements erased for reducing a picture, the specified ones are assigned according to a certain defined rule. Then, in a certain line, one number is obtained from among the numbers of 0 to 9 through a random number generating means, the lines front and rear each other are shifted at random in a main scanning direction mutually by adding the above one number to the respective picture elements of the applying line, the picture element of the same number is scarcely removed continuously and picture information to an original is reduce-reproduced precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reduction method for processing and reducing image data obtained by reading a document.

[Prior Art] In the conventional method of processing and reducing image data obtained by reading a document, the pixels to be erased for reduction have a certain regularity, and each line has the same number. pixels were targeted.

For example, as shown in FIG. 2, when the reduction ratio is 0.7, every second or third pixel to be erased is erased.

[Problems to be solved by the invention] However, in such conventional image reduction methods,
For example, in Figure 2, the fourth pixel is erased, but if that pixel happens to be the image data of a thin vertical line, the thin line will disappear from the reduced image, and the original will be It will not be reproduced accurately. As described above, there is a problem in that the reduced image does not reproduce the original, or even if it reproduces it, it is inaccurate or unclear.

[Purpose of the Invention] The present invention has been made in view of the problems in the conventional technology.The pixels erased for reduction become pixels with different numbers for each adjacent line, and the original It is an object of the present invention to provide an image reduction method in which image information is faithfully reproduced even in a reduced image, and does not become missing, inaccurate, or unclear.

[Means for Solving the Problems] The gist of the present invention for achieving the above object is as follows: (1) Sequentially adding the reduction ratio Z, and calculating the n-th numerical value nx obtained by the calculation. The integer part Wn of Z = Rn is the (n-1)th number (n-1) x Z = R
In an image reduction method that reduces the size of an image by thinning out the n-th pixel when the integer part W,−, of nl is the same, each line has a different number of corrections than at least the adjacent previous line. Set the value and apply the correction value to the nth
An image reduction method characterized by adding the th numerical value n×Z=Rn.

(2) The image reduction method according to item 1, wherein the number of correction values is one number obtained from a predetermined range of positive integers via random number generation means.

(3) Sequentially adding the reduction ratio Z, the integer part Wn of the n-th numerical value n×Z=Rn obtained by the operation
is the (n-1)th number (n-1)×Z=Rn
In an image reduction method that reduces the n-th pixel by thinning out the integer part Wfi-, of m×Z=Rn, the m-th line has the decimal part Y and An image reduction method that adds as a correction value.

exists in

[Operation] Specific pixels to be erased to reduce an image are specified according to a certain set of rules.

Therefore, in a certain line, for example, one number is obtained from among the numbers from θ to 9 through a random number generating means, and by adding this one number to each pixel of the line, successive lines are randomly shifted from each other in the main scanning direction, and pixels with the same number are rarely erased successively.
Image information regarding the original is accurately reduced and reproduced.

[Example] Next, as a first example, a case will be shown in which each 3(n+1)+1 pixel is erased and reduced, however, the reduction rate is approximately 0.
7, where n is a positive integer including 0.

First, a portion of each pixel up to the third line is shown when no correction value is added.

LI L2 L3 Pixel No. 4☆4 7 ☆7 10 ☆10☆1 ☆4 ☆ 7 0 ☆ 1 13 ☆13☆13☆13 In the above, the pixels marked with ☆ are omitted, and the pixels at the same position in the sub-scanning direction are It has been erased. However, Ll etc. indicate line numbers.

Therefore, this time, based on the same rules, pixels to be erased are designated and one correction value is added to each line.

LI L2 L3 Pixel N.

4 ☆4 7 Fri 7 8 8 9☆ 10 9 9 meals 10 11 10 Combined 10 11 1211
11 12☆13 12 12☆ 13 14 13 ☆13 14 15 According to the above table, the pixels to be erased are not lined up in the sub-scanning direction,
Therefore, a specific vertical thin line will not disappear in the reduced image, or the reduced image will not be inaccurate.

In the table above, one is added to each line in sequence,
The correction value to be added may be a random number obtained from a random number generating means.

Next, as a second example, the reduction ratio 2 is sequentially added, and the nth numerical value nxZ obtained by the operation is
==The integer part W of R7 is the (n-1)th numerical value (
n 1 ) When the integer part W of XZ=Ra−+ is the same as
FIG. 1 shows the case where the decimal part Y of is added as a correction value. However, the reduction rate Z=0.7 and the pixels marked with circles in FIG. 6 are the pixels to be erased. Also, line number 0
The values shown are hypothetical values calculated by the above method without any operations.

In this way, by shifting each line in the main scanning direction, specific image information does not disappear or become unclear, and an accurate reduced image can be obtained.

Note that it goes without saying that the method for selecting the correction value is not limited to the one mentioned in this embodiment.

[Effects of the Invention] According to the image reduction method according to the present invention, since the number obtained through the random number generation means is added as a correction value for each line, the pixels to be erased are Therefore, specific image information in the reduced image will not be missing, unclear, or inaccurate due to erasure of specific pixels in the sub-scanning direction. This has the effect that the image information can be faithfully reproduced even in a reduced image.

[Brief explanation of drawings]

FIG. 1 is a diagram of the erasing method of the second embodiment showing the actual reduction, and FIG. 2 is a diagram of the erasing method according to the conventional method.

Claims (4)

[Claims] (1) The reduction ratio Z is sequentially added, and the integer part W_n of the n-th numerical value n×Z=R_n obtained by the operation is the (n-1)th numerical value (n-1)× Z=R_n_-
When it is the same as the integer part W_n_−_1 of _1, the nth
In an image reduction method in which the image is reduced by thinning out the n-th pixel, a correction value that is different from at least the adjacent previous line is set for each line, and the correction value is set as the n-th value n× An image reduction method characterized by adding Z=R_n. (2) The image reduction method according to claim 1, wherein the number of correction values is one number obtained from a predetermined range of positive integers through random number generation means. (3) Sequentially add the reduction ratio Z, and the integer part W_n of the n-th numerical value n×Z=R_n obtained by this operation is the integer part W_n of the (n-1)-th numerical value (n-1 )×Z=R_n_-
When it is the same as the integer part W_n_−_1 of _1, the nth
A method for reducing an image by thinning out the pixel of the image, characterized in that a decimal part Y_m of m×Z=R_m is added to the m-th line as a correction value. (4) In an image reduction method that reduces pixels by thinning out pixels in one line that are set corresponding to a reduction rate Z, each line has at least a different number of correction values from the adjacent previous line. A method for reducing an image, characterized in that the pixel set as the thinned out pixel is varied depending on the correction value.