JPS6327984A - Image reducing device - Google Patents

Abstract

PURPOSE:To suppress a decrease in the fidelity of a reduced image to its original image by ORing the original image with its shifted image and thinning out the resulting image according to a reduction rate. CONSTITUTION:When a character code is inputted from an external personal computer to the interface part 11 of an image signal generating device, a CPU 12a reads the character code and generates a corresponding character pattern by a character pattern ROM 13. Simultaneously, an image handler 14 shifts, ORs, and thins out the character pattern in word units based or the reduction rate specified by an operator. The image reduced to half by said processing is stored in a bit map memory 15. Character codes inputted to the interface part 11 in series are processed respectively as mentioned above. Thus, the image of one page is formed on a memory 15 and then a video signal is outputted to a recording part through an interface part 17 to prevent the fidelity to the original image from decreasing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reduction device that suppresses deterioration in fidelity to an original image.

[Conventional technology]

2. Description of the Related Art Some conventional image reduction devices generate a reduced image by thinning out bits of an original image according to a reduction ratio, for example. FIG. 5(A) shows one word (16 bits) of the original image, where the shaded area represents a ``1'' bit and the other bits represent a ``0'' bit. Here, by thinning out the even-numbered bits in the line direction, the 8 bits shown in FIG.
Bit data can be obtained. In the same way, by thinning out even-numbered lines in the vertical direction, an image reduced in size to 1/2 in both the vertical and horizontal directions can be obtained.

[Problem that the invention seeks to solve]

However, according to the conventional image reduction device, FIG.
As shown in (b), if "1" bits are concentrated in the bit position to be thinned out, the pattern of the original image may disappear from the reduced image, reducing the fidelity to the original image. There is the inconvenience of doing so.

[Means for solving problems]

The present invention has been made in view of the above, and in order to suppress a decrease in the fidelity of a reduced image with respect to the original image, a logical sum is calculated between the original image and a shifted image obtained by shifting the original image, and this logical sum is calculated. The present invention provides an image reduction device that thins out images according to a reduction ratio.

Hereinafter, the image reduction device according to the present invention will be explained in detail.

〔Example〕

FIG. 1 shows an embodiment of the present invention, which includes an image signal generating device 1 (a network may be configured by a LAN) that outputs an image signal by inputting a character code from an external device such as a personal computer, and an image signal generating device 1 (a network may be configured by a LAN). A recording section 2 receives image signals, print commands, etc. from the signal generator 1 and prints them on the recording paper 5, and also provides a clock signal, a line synchronization signal, a status signal, etc. to the image signal generator 1, and the image signal generator 1 , a power supply circuit 3 for supplying power to the recording section 2, etc., and a display panel 4 for operating the printer.

FIG. 2 shows the image signal generator 1, which receives a character code from an external personal computer, for example, R5232.
An interface unit 11 that receives data according to the C standard, a control unit 12 that performs system control, a character pattern ROM 13 that stores character patterns and pixel patterns, and an image handler that reduces character patterns and pixel patterns according to a reduction rate. 14, a bitmap memory 15 for storing character patterns and pixel patterns reduced by the image handler 14 in page units, and a bitmap memory 15.
It has a memory controller 16 that controls access timing, an interface section 17 that outputs image signals to the recording section, and an output interface section 18 that outputs signals to the display panel. The control unit 12 includes a CPU 12a that controls various operations, a RAM 12b that temporarily stores data and calculation results for various operations, a ROM 12C that stores various programs and attribute tables, and manually inputs signals from operation keys in parallel. It has a parallel input/output circuit 12d that outputs signals in parallel to the display section, and a DMA controller 12C that performs access control in data transfer between memories.

Figure 3 (a) shows one word (16 bits) of the character pattern generated from the character pattern ROM 13. D
) shows the image shifted by one focus by the image handler 14, FIG. 3(c) shows the logical sum image of the images (a) and (b), and FIG. Sum image 9 An image reduced to 1/2 by thinning out the even-numbered bits is shown.

In the above configuration, the operation will be explained as follows. When a character code is input from an external personal computer or the like to the interface unit 11 of the image signal generating device 1, the CPU 12a reads the character code and generates a corresponding character pattern from the character pattern R○M13. At the same time, the image handler 14 performs word-by-word processing based on the reduction ratio specified by the operator in FIGS.
) The character pattern is subjected to the shift, logical sum, and thinning processing shown in (). The image reduced to 172 by this processing is stored in the bitmap memory 15. Each character code serially input to the interface section 11 is subjected to such processing.

When an image for one page is thereby formed in the bitmap memory 15, an image signal is outputted to the recording section via the interface section 17.

FIG. 4 shows the recording unit 2, 20 is a laser light source that emits a laser beam 22, 21 and 25 are polarizers, 23
2 is a modulator having an image signal input terminal 24, 26 is a rotating polygon mirror, 27 is an fθ lens, 28 is a photosensitive drum, 29 is a developing device, and 30 is a transfer device.

In the recording section 2 having the above configuration, when an image signal is input from the interface section 17 to the input terminal 24 of the modulator 23, a laser beam 2 is emitted from the laser light source 20.
2 is modulated according to the image signal. This laser beam 22 is scan-controlled by a rotating polygon mirror 26 and exposes a photoreceptor drum 28 through an rθ lens 27. The photoreceptor drum 28 is charged before exposure, and as a result of this exposure, an electrostatic latent image corresponding to the image of Bitmap Memo January 5 is formed on the photoreceptor drum 28. This electrostatic latent image is developed with toner by the developing device 29 and transferred onto the recording paper 5 by the transfer device 30. The toner image on the recording paper 5 is fixed by a fixing device (not shown), and recording of the image is completed.

〔Effect of the invention〕

As explained above, according to the image reduction device of the present invention, the original image and the shifted image obtained by shifting the original image are logically summed, and the image resulting from this logical sum is thinned out according to the reduction ratio. It is possible to suppress a decrease in the fidelity of the reduced image with respect to the original image.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention. FIG. 2 is an explanatory diagram showing the image signal generation device in FIG. 1. Figure 3 (A), (U), (C), (D)
is an explanatory diagram showing image reduction processing. FIG. 4 is an explanatory diagram showing a laser recording section. FIGS. 5(A) and 5(U) are explanatory diagrams showing conventional image reduction processing. Explanation of symbols - Image signal generator 2 - Recording section 11 Interface section 12 Control section

Claims (1)

[Scope of Claims] An image reduction device that generates a reduced image by thinning out bits of an original image according to a reduction ratio, comprising: a shifting unit that shifts the original image to generate a shifted image; the original image and the shifted image; An image reduction device comprising: a logical sum means for generating a logical sum image by a logical sum; and a reducing means for generating a reduced image by thinning out bits of the logical sum image according to a reduction ratio.