JPH05127634A - Image data input device and superimposition device - Google Patents

Abstract

PURPOSE:To provide an inexpensive device which superimpose an image, generated by using another image memory, in bit units on an image outputted on a monitor from a personal computer, etc. CONSTITUTION:Analog image signals of R, G, and B which are outputted from the personal computer, etc., to the monitor are compared with a specific voltage by a comparator which is not shown in a figure to generate digital image signals 111 (111R, 111G, and 111B). Each pixel of the image memory stored with the image data which are separately generated consists of four bits, three of which are outputted as digital image signals 112 (112R, 112G, and 112B) as picture element data of R, G, and B while the one remaining bit is outputted as a select signal SEL, so that they are supplied to a multiplexer 12. The multiplexer 12 selects the input image signals 111 or 112 according to the signal SEL and outputs them as composite image signals 113 (113R, 113G, and 113B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data capturing device for converting an analog image signal output from a personal computer or the like to a monitor CRT into a digital image signal, and to superimpose the digital image signal and separately prepared image data. The present invention relates to an image data superposing device. In the following figures, the same reference numerals indicate the same or corresponding parts.

[0002]

2. Description of the Related Art When displaying an image on a personal computer, except for a particularly expensive personal computer, a normal personal computer has a rough image (the number of pixels on a CRT screen is small) and a character or a simple graphic display. Takes less time, but it takes significantly longer to display complex images. Therefore, an image generation system having an image memory and an image processor and capable of generating fine image data at high speed, and a monitor CRT capable of displaying a fine image are separately prepared, and an image generated by a personal computer, such as a character (text) image, An image generated by the image generation system is observed on the monitor CRT.

FIG. 4 shows a configuration example of a conventional circuit for observing such a monitor output image of a personal computer and an image created separately. In the figure, 1 is a personal computer, 101 is an analog image signal output from the personal computer 1 for monitoring, 5 is the above-mentioned image generation system, 2 is an image memory, and 102 is an analog image output from the image generation system 5. signal,
Reference numeral 3 is a monitor CRT (also referred to as a monitor device), and 4 is a switching device such as a relay for switching an input signal 103 to the monitor device 3 to an output 101 on the personal computer side or an output 102 on the image memory side. Conventionally, as shown in FIG. 4, the signal 101 output from the personal computer 1 to the monitor device 3 and the image memory 1
The image signal 102 separately created using 02 is slowly switched by the switch 4 and the two generated images are observed separately on the monitor device 3.

[0004]

As described above, in the circuit of FIG. 4, since the switching device 4 such as a relay cannot be operated at high speed (switching speed is slow), dot units of an image are displayed on the monitor device. Was not realized.
Alternatively, even if it is realized, the cost is high and it is difficult to realize because an expensive A / D converter is used. Therefore, it is an object of the present invention to provide an image data capturing and superimposing apparatus capable of superimposing a generated image of a personal computer and an generated image of an image generating system using an image memory at low cost.

[0005]

In order to solve the above-mentioned problems, the image data capturing device according to the first aspect of the invention uses an analog image signal (such as 101) output from a personal computer or the like for CRT display at a predetermined voltage (comparison). And a means (analog comparator 11 or the like) for converting into a digital image signal (111 or the like) in comparison with a reference voltage R or the like,

The image data superimposing apparatus according to claim 2 is
Select one of a first digital image signal (111 or the like) and a second digital image signal (112 or the like) output in the same phase in the raster scanning order of the screen according to a selection signal (SEL or the like) A multiplexer (12 or the like) that outputs the image data, a display unit (a monitor 3 or the like) that displays the image signal selected by the multiplexer, a pixel data for each pixel, and whether or not the pixel data should be selected is displayed. An image memory (2 or the like) in which selection data is stored, and the pixel data output by raster-scanning the image memory is used as the second digital image signal, and the pixel data is also output by this scanning. Selection data is given to the multiplexer as the selection signal, and the first digital image signal and the pixel data of the image memory are displayed on the screen of the display means. So as to superimposed, also

The image data superposing apparatus according to claim 3 is
The image data superimposing device according to claim 2,
It is assumed that the first digital image signal is an output signal of the conversion means according to claim 1.

[0008]

The analog image signal output from the personal computer or the like to the monitor CRT is binarized by a comparator and taken in as a digital image signal. The captured digital image signal is combined with the separately created image data at a digital level through a multiplexer, converted into an analog image signal, and output to a monitor device.

[0009]

FIG. 3 shows a hardware circuit for converting an analog image signal into a digital image signal as an embodiment of the invention according to claim 1. In the figure, 101 (101
R, 101G, 101B) are analog image signals for each color of R, G, B output from a personal computer (not shown) to the monitor CRT, and 11 (11R, 11G, 11B) are for each of these three image signals. In the analog comparator provided, R is a reference voltage for comparison given to these three comparators. Also 111 (111R, 111G, 1
11B) is a digital image signal as a comparison output of the comparators 11R, 11G and 11B. That is, each of the comparators 11R, 11G, 11B receives the input analog image signals 101R, 101G, 101B and the reference voltage R, respectively.
Compare the voltage difference with. When the input voltage is higher than the reference voltage, the TTL level "H" signal is output, and when the input voltage is low, the "L" signal is output. As a result, a total of eight color digital image signals 111R, 111G, and 111B can be taken out from the comparators 11R, 11G, and 11B.

By using a plurality of stages of this analog comparator having different comparison reference voltages R in this circuit, more color data can be obtained.

FIG. 1 is a block diagram of an image signal superposition circuit as an embodiment of the invention according to claim 2. In FIG. In the figure, 111R, 111G and 111B are digital image signals output by the circuit of FIG. 3, 112 (112R,
112G, 112B) are digital image signals for each color of R, G, B output by raster scanning of the image memory 2,
A switch 12 selects either one of the two image signals 111 and 112 to select a combined image signal 113 (113R, 113R).
G, 113B) is a TTL level multiplexer, SEL is a selection signal that specifies signal selection of the multiplexer 12. The composite image signal 113 selected and output by the multiplexer 12 is converted into an analog image signal by means not shown and displayed on a monitor device not shown.

FIG. 2 is a block diagram of bit allocation for one pixel in the image memory 2. That is, in this example, each bit of the image memory 2 is composed of 4 bits b0 to b3,
Of these, the lower bits b0, b1, b2 become pixel data output as digital image signals 112R, 112G, 112B, respectively, and the most significant bit b3 is the selection signal S.
It is output as EL. As a result, the multiplexer 12 is set to 1 in accordance with the value "1" or "0" of the most significant bit b3.
Digital image signal 111 or 1 for each pixel
Select 12. If it is assumed that the digital image signal 111 is output as the same signal 113 when the selection signal SEL = "0" (that is, b3 = "0"), each of the image memories 2 equivalent to the area where the signal 111 is desired to be output. Data of SEL = "0" may be set in the most significant bit b3 of the pixel. Further, various superposition methods can be realized by using the selection signal SEL.

[0013]

According to the present invention, an analog image signal from a personal computer or the like is fetched as digital image data by an inexpensive method via a comparator and is superimposed on image data separately created using an image memory. It is possible to have a wide range of image processing, and it is possible to reduce the size and cost of the device. Specifically, there is an example in which an analog RGB signal from a personal computer is used for a text or cursor image and the text or cursor is superimposed on the image in the image memory.

[Brief description of drawings]

FIG. 1 is a configuration diagram as an embodiment of the invention according to claim 2;

2 is a configuration diagram of bit allocation for one pixel of the image memory of FIG.

FIG. 3 is a configuration diagram as an embodiment of the invention according to claim 1.

FIG. 4 is a configuration diagram of a conventional image signal superposition circuit.

[Explanation of symbols]

1 personal computer 2 image memory 3 monitor device 11 (11R, 11G, 11B) analog comparator 12 multiplexer 101 (101R, 101G, 101B) analog image signal 111 (111R, 111G, 111B) digital image signal 112 (112R, 112G, 112B) Digital image signal 113 (113R, 113G, 113B) Composite image signal R Comparative reference voltage SEL selection signal

Claims (3)

[Claims] 1. An image data capturing device comprising means for comparing an analog image signal output from a personal computer or the like for CRT display with a predetermined voltage and converting the analog image signal into a digital image signal. 2. A multiplexer that selects and outputs either one of a first digital image signal and a second digital image signal that are output in the same phase in raster scanning order of a screen according to a selection signal. The image signal selected by the multiplexer is displayed on the screen, pixel data for each pixel, and an image memory storing selection data indicating whether or not the pixel data should be selected are provided. The pixel data output by raster scanning the memory is used as the second digital image signal, and the selection data output by this scanning is also given to the multiplexers as the selection signals. An image data superimposing device characterized by superimposing the pixel data of the image memory on the screen of the display means. 3. The image data superposing apparatus according to claim 2, wherein the first digital image signal is used as an output signal of the converting means according to claim 1.