JPH03265367A - Display processing system for reduced picture - Google Patents

Abstract

PURPOSE:To prevent blur or deformation of a character in an image data by applying multi-value display to a reduced picture of a binary original picture. CONSTITUTION:A magnification device 1 obtains an output picture element position according to the reduction and obtains the density of an output picture element by the distance and density of the picture element and a peripheral input picture. Then a rounding device 2 applies rounding processing to the density in matching with a gradation expression of a display device, displays the result on a display device 3 able to display the gradation display and the reduced picture to a binary input picture is subject to multi-gradation display. Thus, blur or black level deformation of a character or graph or the like at the reduction of the binary picture is prevented.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Field of Industrial Application) This invention relates to a reduced image display processing method characterized by pixel interpolation processing when reducing and displaying a binary input image. .

(Prior Art) Conventionally, there are various methods for image reduction, such as the nearest neighbor method, the logical sum method, and the linear interpolation method. FIG. 4 shows an example of reduction of a binary figure at a magnification of 3/4.

The grid points shown in FIG. 4(a) correspond to human pixel positions,
The x mark corresponds to the output pixel position. The input figure is shown in Figure 4 (a
), the output results of each processing method are shown in FIGS. 4(b) and 4(c). FIG. 4(b) shows the output result by the nearest neighbor annotation/linear interpolation method, and FIG. 4(c) shows the output result by the logical sum method.

(Problems to be Solved by the Invention) In the conventional image reduction processing means described above, when the input figure is a fine figure with a thin line width as shown in FIG. 4(a), the nearest neighbor method is used. In the case of processing means using linear interpolation method,
Lines are missing as shown in FIG. 4(b), while in the case of the logical sum method, blackouts occur as shown in FIG. 4(c).

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a display processing method for a reduced image that can prevent blurring of characters, figures, etc. and crushed shadows when reducing a binary image.

[Structure of the Invention rIi1 (Means and Effects for Solving the Problems) The present invention provides a scaling method in which the position of an output pixel is determined based on a reduction magnification, and the density of the output pixel is determined based on the distance and density between that pixel and surrounding input images. A device, a circuit for rounding the number of gradations according to the gradation expressive power of the display device, and a display device capable of displaying the gradation to display the result are provided to reduce the binary input image. This is a configuration that displays images in multiple gradations.Thus, when the input image is reduced, thin lines one dot wide in the input image are retained as intermediate gradations, and it also prevents blocked-up shadows and pseudo-multi-gradation in fine figures, etc. Moiré that occurs when reducing an image becomes less noticeable.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an apparatus in an embodiment of the present invention.

In FIG. 1, l is a variable magnification device, which determines the density of the reduced output pixel based on the distance between the manually generated pixel and the output pixel. A rounding device 2 rounds the density data obtained by the variable magnification device 1 in accordance with the gradation expressive power of the display device 3. 3
is a display device (DSP) capable of displaying gradations, which displays multi-gradation display data obtained through the variable magnification device 1 and rounding device 2.

FIG. 2 and FIG. 3 are respectively explanatory diagrams of the operation in one embodiment of the present invention.

The operation of an embodiment of the present invention will now be described with reference to FIGS. 1 to 3 above.

Here, a case where linear interpolation is used in the variable magnification device l shown in FIG. 1 will be explained.

When linear interpolation is performed using the concentration values at four grid points surrounding the coordinates (xO, yO) shown in Figure 2, the coordinates (xO, yO) are
The concentration value f'(xo, yO) of f'(xo, yO) is
O, yO)=f(x', y')(1-a)(β)+f
(x'+l, y')a (1-β)+f(x'
,y'+1)(11)β+f(x'+1.y'+l)aβ.

However, x'=[Xo], y'-cyo], +=xO
−[xO], β=yo −[yO], f(x', y')
is the density value at (x', y''), and [W] represents the largest integer not exceeding W.

If the input value is binary (0, 1) and the density value at the non-lattice point T of the input image as shown in Fig. 3 is found by linear interpolation, the reduction magnification is 3/4, a = β・1. /3 output value -1 (1-
1/3) t/a+t 1/3 L/3-1/30.3
It becomes 33.

Standardize this value to an 8-bit binary number (fixed decimal point),
The rounding device 2 normalizes the data, and the display device 3 outputs a multi-gradation display.

In this example, if the density obtained by interpolation is binarized using threshold values 0 and 5, the thin line 13 in FIG. 3 will be missing. Therefore, by displaying multiple gradations without binarizing, missing lines and blurring can be prevented to some extent.

As described above, the variable magnification device 1 determines the output pixel position according to the reduction magnification, the density of the output pixel is determined based on the distance and density between that pixel and the surrounding input image, and the rounding device 2 calculates the density of the output pixel. The number of gradations is rounded according to the gradation expressive power, and the result is displayed on the display device 3 capable of displaying gradations. When a value input image is reduced, a thin line with a width of one dot in the input image is maintained as an intermediate gradation, and crushed blacks of fine figures and the like and moire caused when a pseudo multi-gradation image is reduced are made less noticeable.

[Effects of the Invention] As detailed above, according to the present invention, when reducing a binary input image, each output pixel is means for determining the density of the image, a means for rounding the number of gradations according to the gradation expressiveness of the display device based on the density obtained by the same means, and a display device capable of displaying gradations for displaying the output image obtained by the same means. By having a configuration in which a reduced image of a binary original image is displayed in a multi-valued manner, it is possible to prevent blurring or blurring of characters in image data.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIGS. 2 and 3 are diagrams each explaining the operation of the above embodiment, and FIG. 4 is a diagram for explaining conventional image reduction processing means. . 1... Magnification variable device, 2... Rounding device, 3... Display device capable of displaying gradation (DSP).

Claims (1)

[Claims] When reducing a binary input image, there is a means for determining the density of each output pixel based on the distance between the input pixel to be reduced and the output pixel as a result of reduction, and the density determined by the means is It is equipped with means for rounding the number of gradations according to the gradation expressiveness, and a display device capable of displaying gradations for displaying the output image obtained by the means, and displays a reduced image of a binary original image in multi-value. A reduced image display processing method characterized by: