JPS6255657A - Netting method for electronic composition generating photograph - Google Patents

Abstract

PURPOSE:To execute netting of an electronic composition generating photograph having an excellent gradation characteristic by executing the netting to a photograph original by dots of minimum and many picture elements, making it coincide with a picture element arrangement of an electronic composition by executing a picture element thinned-out processing, and applying a random selection. CONSTITUTION:When executing a composition of a monochrome photograph, first of all, with regard to each dot 6 of a pattern which has arranged regularly the dot consisting of 50 pieces of picture elements, by 'netting', net photograph information is generated by replac ing the variable density of a minute part of the corresponding photograph with a size of the number of ink adhering picture elements of the net point, and subsequently, a prescribed position coordinate in the form is given. In case of changing the number of picture elements after the processing, to 1/4 of that before the processing, as for a picture element thinned-out pattern, four kinds in the figures 1-4 are prepared in advance, and one of them is selected by a table of random numbers. A composition which has been generated in the beginning is divided into picture element groups which are determined from a thinned-out rate, and subsequently, a thinned-out pattern number is selected irregularly with regard to each picture element group, information related to whether a thinned-out part 5 is white or black is extracted, and an edition for an electronic composition is generated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for shading photographs published in publications such as newspapers and magazines, and in particular, when the publications are created by electronic typesetting, The present invention relates to a method of shading a photo for electronic typesetting, which is carried out to convert the pixel arrangement to a pixel arrangement corresponding to the typesetting.

[Conventional technology]

Traditionally, photo manuscripts published in publications that require typesetting, such as newspapers and magazines, are shaded using halftone dots made up of a large number of minute pixels that correspond to the typesetting, and then sent to print. However, in recent years, various processing techniques using computers have developed, and typesetting processing has come to be performed electronically.

In that case, generally speaking, the codes or IDs (identification numbers) of paper components such as text and photographs and the dimension attributes of those elements are used to layout these elements within the paper, and the intermediate results are displayed. While displaying the data, all electronic typesetting data is created, and image data such as characters and photographs are arranged according to the created electronic typesetting data to create image data for the paper and a block copy is created on a full page film.

[Problem that the invention seeks to solve]

In electronic typesetting, when ``shading'' is performed using a halftone dot consisting of P pixels, the gradation is (P+1
) level of expression. One of the problems when the number of pixels per halftone pixel decreases is the occurrence of false contours.
There is an outbreak of This is because the gradation level is small in areas in the image where the density level should normally change smoothly, so the change occurs in a step-like manner, appearing in a shape similar to that of equal-height pure, and the outline becomes unclear. It is something.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a method for shading photographs for electronic typesetting, which matches the pixel arrangement of electronic typesetting and has excellent gradation characteristics.

[Means for solving problems]

In the present invention, the means for solving the above problems is to first increase the scanning line density when hatching,
A halftone dot made up of many extremely small pixels is used.

After creating the required version, in order to convert it to the pixel arrangement of electronic typesetting, prepare multiple thinning patterns for a pixel group with the desired number and shape in advance, and randomly select one of them. By selecting and applying this method, it becomes a method for shading photographs for electronic typesetting that performs pixel thinning processing. Please note that the above photos can be monochrome or color.

[For production]

In the above pixel thinning process, if you want to reduce the number of pixels after processing to 1/Q of the number before processing, prepare Q patterns for a group of pixels with a round pixel count and shape, and add numbers to them. , using a random number table of the numbers, one of the patterns is randomly selected and converted into a pixel arrangement for electronic typesetting.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to examples and drawings.

In electronic typesetting, for example, the pixel size is 2.2 mils x
It is determined to be a 2.2 mils square. When typesetting a monochrome photograph, first, by "shading", for each halftone dot 6 of the pattern shown in FIG. The shading of the halftone dot is replaced with the size of the number of ink-attached pixels of the halftone dot to create halftone photographic information, and then the coordinates of a predetermined position in the forme are given. One halftone dot 6 is composed of 50 pixels,
When the pixel size is determined as described above, the resulting halftone photograph has a dot row density of 64.2 Ba/inch and an angle of 45 degrees with respect to the horizontal direction.

In color photosetting, four plates are created for one photo: yellow, magenta, cyan, and ink, and in printing, each plate is overprinted with ink corresponding to each plate. At this time, in consideration of moiré caused by overlapping each plate, each plate has the same halftone dot array density of 85 lines/inch, but has different angles as shown in FIG. 3.

When trying to format such color photographs electronically, the pixel positions are arranged like the eyes of the base, so if the halftone dot shape is fixed to one shape for each plate, it is usually difficult to do so. It is difficult to set the density and angle of the halftone dot row to desired values, and furthermore, the number of pixels P that constitutes one halftone dot is P=50× (64,28)2/(85)” −q
29, the gradation reproducibility deteriorates.

In the typesetting method in which the present invention is implemented, the required plate is first created by halftone dots made up of a large number of minute pixels, and then converted to the pixel arrangement of electronic typesetting by pixel thinning. Pixel thinning is used as one method of pixel density conversion, and by thinning, the size of the forme is not changed, but only the pixel size is changed.

In this pixel thinning process, for example, if you want to reduce the number of pixels after processing to 1/Q of the number before processing, prepare Q thinning patterns for a group of pixels with a certain number and shape in advance, and number them. If the pattern number is selected according to a random number table using a random number table, the gradation reproducibility after thinning is determined by the combination of the CP+1) level determined by the number of pixels P of each halftone dot and the density of neighboring halftone dots. As an effect, between each level, an additional 1
/(Q-1) level expression becomes possible. In other words, if the target image of the thinning pattern has periodicity in terms of position, the following states in which the thinned image can be white or black at positions that match the period are: (1) all pixels are white; . (2) The ratio of 1 pixel to 9 pixels becomes black. (3) The ratio of 2 pixels to 9 pixels becomes black.・・・
......(Q+1) All pixels are black (Q
+1) There is a street. Among these, (11 and (Q+1)) are included in the (P+1) level determined by the number of pixels composing each halftone dot, so subtracting them will result in (Q-1).This (2) In (Q-1) of ~(Q), as the average value of neighboring halftone dot densities, each step of the density determined from the number of pixels of each halftone dot is further refined < 1/ (Q-1) level t
It can be expressed as

FIG. 1 is an explanatory diagram showing an example of pixel thinning processing according to the present invention.
The case where it is set to 4 is shown. Therefore, as pixel thinning patterns, four patterns 1 to 4 in the figure are prepared in advance, and one of them is selected using a random number table.

First, the created halftone screen is divided into pixel groups determined by the thinning rate, and then a thinning pattern number is selected irregularly for each pixel group, information on whether the thinned out portion 5 is white or black is extracted, and electronic typesetting is performed. Create a version for.

〔Effect of the invention〕

As explained above, according to the present invention, a photo original is shaded using halftone dots made up of a large number of very small pixels,
By performing pixel thinning processing on this to match the pixel arrangement of electronic typesetting and applying random selection, it is possible to provide a method for shading photographs for electronic typesetting with excellent gradation characteristics.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of thinning processing according to the present invention,
FIG. 2 is an explanatory diagram of halftone dots in a monochrome photograph, and FIG. 3 is an explanatory diagram of halftone dot side angles in a color photograph.

Claims (1)

[Claims] A method of shading monochrome and color photographs used in electronic typesetting, in which the photograph is shaded using extremely small halftone dots made up of a large number of pixels, the desired plate is created, and then the desired A pixel thinning process is performed on a pixel group having a pixel number and shape according to a pattern randomly selected from a random number table from among a plurality of pre-prepared thinning patterns to convert it into an electronic typesetting pixel arrangement. A method for shading photographs for electronic typesetting.