JPH04249297A - Image display device - Google Patents

Abstract

PURPOSE:To compose and display characters or a graphic in an easy-to-see state at the part of a multilevel image masked with a mask pattern which is stored in a mask memory. CONSTITUTION:An image data processor 9 processes the output data 6 of an image memory 3 stored with the multilevel image by division by a specific value or conversion using a look-up table and outputs the result to a switch 9. The switch 9 switches the output data 8 of the image data processor 7 and the output data 6 of a screen memory 3 with the output data 5 of the mask memory 2 and outputs it to a video signal converter 11. Further, the output data 4 of a graphic memory 1 stored with the characters or figure and the output data 10 of the switch 9 are converted by a video signal converter 11 into a video signal 12, which is outputted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly to an image display device for displaying a multivalued image and characters or graphics in a superimposed manner on the same screen.

0002

2. Description of the Related Art Conventionally, this type of image display device either simply superimposes characters and figures on a multivalued image, or inverts the black and white of the characters or figures that overlap a portion of the multivalued image where the value is greater than a predetermined value. , the brightness of the text or figure was made higher than the maximum brightness of the multivalued image, or the multivalued image surrounding the displayed text or figure was completely masked for display.

0003

[Problems to be Solved by the Invention] The conventional image display device described above either simply superimposes characters and figures on a multivalued image, or
Reverse the black and white of characters or figures that overlap the part of the multi-valued image where the value is greater than a predetermined value, increase the brightness of the text or figure to be higher than the maximum brightness of the multi-valued image, or increase the brightness of the characters or figures around the displayed text or figure. Since the value image is completely masked and displayed, if the brightness of the multivalued image is high, the brightness difference between it and the text or figure will be small, and if the shape of the multivalued image is complex, the brightness of the text or figure will be reduced. The drawback is that when complex changes or multivalued images are masked, the masked parts become completely invisible, making them very difficult to see.

0004

[Means for Solving the Problems] An image display device of the present invention includes a graphic memory for storing character and graphic data, an image memory for storing multivalued image data, and a mask for masking the output of the image memory. a mask memory for storing data; a processing section for processing the output of the image memory; a switching section for switching between the output of the image memory and the output processed by the processing section using the output of the mask memory; a video signal converter that combines the output and the output of the switching device and converts it into a video signal, and the processing section has a divider that divides the content read from the image memory by a prespecified value. Alternatively, the processing section includes a converter that converts the content read from the image memory using a lookup table in which conversion content is written in advance.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram schematically showing an example of the process of image synthesis in this embodiment.

In FIG. 1, the image display device of this embodiment includes a graphic memory 1 for storing character and graphic data, an image memory 3 for storing multivalued image data, and a mask for masking the output of the image memory 3. A mask memory 2 that stores data, an image data processor 7 that includes a converter that converts the output of the image memory 3 according to a lookup table, and an image data processor 7 that uses the output of the mask memory 2 and the output of the image memory 3. a switch 9 that switches between the processed output and a video signal converter 1 that combines the output of the graphic memory 1 and the output of the switch 9 and converts it into a video signal.
1.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 and 2.
This will be explained using the following.

Now, the character data shown in FIG. 2(a) is stored in the graphic 1, the mask data shown in FIG. 2(b) is stored in the mask memory 2, and the image data shown in FIG. 2(c) is stored in the graphic 1. Assuming that the image data is stored in the image memory 3, the image data processor 7 converts the output data 6 of the image memory 3 into the image data shown in FIG. 2(d) using a converter according to a built-in lookup table. The switch 9 switches between the output data 8 of the image data processor 7 and the output data 6 of the image memory 3 based on the output data 5 of the mask memory 2 and outputs the same to the video signal converter 11.

The video signal converter 11 converts the output data 4 of the graphic memory 1 and the output data 10 of the switch 9 into a video signal 12 of the image shown in FIG. 2(f), and outputs the video signal 12.

As a result, the brightness of the mask pattern portion output from the mask memory 2 is darkened, and the characters from the graphic memory 1 are displayed therein, so that the characters are displayed in an easy-to-read manner together with the image from the image memory 3.

In this embodiment, the image data processor 7 has been described as having a built-in converter for converting the image data output from the image memory 3 according to the lookup table. Even if there is a built-in divider that divides the data by a prespecified value,
Effects similar to those described above can be obtained.

[0013]

As explained above, the present invention is capable of outputting a multivalued image from an image memory and a multivalued image of the image memory by outputting a mask memory in which mask data corresponding to a character or graphic display area is written. Switch the output to an output that has been processed to darken the multivalued image to the extent that it does not impair the legibility of characters or figures by dividing the output or converting it using a lookup table, and then combine the switched output with the output of the graphic memory. By converting the image into a video signal, the multi-value image surrounding the text or figure is displayed darkly, making it easy to see even if the original multi-value image is of high brightness or has a complex shape. In addition, since the masked part of the multivalued image is also displayed darkly, it has the effect of making the display easier to see than when the masked part of the multivalued image is completely erased. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram schematically showing an example of the process of image synthesis in this embodiment.

[Explanation of symbols]

1 Graphic memory 2 Mask memory 3 Image memory 4 Output data 5 Output data 6 Output data 7 Image data processor 8 Output data 9 Switcher 10 Output data 11 Video signal converter 12 Video signal

Claims (3)

[Claims] 1. A graphic memory that stores character and graphic data, an image memory that stores multivalued image data, a mask memory that stores mask data for masking the output of the image memory, and a mask memory that stores mask data for masking the output of the image memory. a processing section that processes the output; a switching section that switches between the output of the image memory and the output processed by the processing section based on the output of the mask memory; and a switching section that synthesizes the output of the graphic memory and the output of the switching device. An image display device comprising: a video signal converter for converting into a video signal. 2. The image display device according to claim 1, wherein the processing section includes a divider that divides the content read from the image memory by a predetermined value. 3. The processing unit includes a converter that converts the content read from the image memory using a lookup table in which conversion content is written in advance.
The image display device described.