JPH07129136A - Display device for OHP - Google Patents

Abstract

(57) [Summary] [Purpose] When displaying a drawing such as an operation menu on the screen of the computer as the original picture, the drawing can be displayed even if the original picture is a moving picture, and the drawing is displayed at an arbitrary position on the original picture. [Structure] An original image memory for storing an original image, a drawing memory for storing a drawing to be superimposed and displayed on the original image, and a control for storing control data for deciding whether to display the original image or the drawing on a pixel-by-pixel basis It has a memory, and further has an image switching circuit capable of switching between an original image and drawing according to the control data. [Effect] Even if the original image is a moving image, the drawing of the operation menu, cursor, handwriting line, time, etc. can be superimposed and displayed at an arbitrary position on the original image, and the original image can be saved and restored even when these images are drawn. Since it does not need to be performed, the superimposed display becomes easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an OHP display device having an image superimposing function.

[0002]

2. Description of the Related Art In a conventional OHP display device, when an image of an operation menu (hereinafter referred to as "drawing") is displayed on a computer screen (hereinafter referred to as "original image"), the first method is used. The original image is temporarily displayed on the OHP display device side and then the drawing is written and displayed in the same memory, or as a second method, disclosed in Japanese Patent Application No. 2-416671 filed by the applicant of the present application. As described above, the drawing is also displayed on the original image which becomes the moving image by the address conversion.

[0003]

According to the prior art, in the first method, the drawing cannot be displayed on the original image which becomes a moving image, and the memory for saving the original image and the saving time of the original image are used. And the disadvantage of requiring a recovery time, the second
The above method has a drawback that a large capacity of the address conversion table memory is required to display the drawing at an arbitrary position of the original image.

[0004]

The present invention has been made in view of the problems of the prior art, and is an OHP display device for connecting a computer and enlarging and projecting the same data as the screen of the computer by the OHP. A storage device that stores the screen data of the computer, a storage device that stores image data such as an operation menu that is displayed in an overlapping manner on the screen data stored in the storage device, and any of the screen data and the image data of the computer. A display device for OHP having a control memory for storing control data for determining whether to display or not, and an image switching circuit for switching between screen data and image data of the computer according to the control data is proposed. It is a thing.

[0005]

According to the present invention, even if the original image is a moving image, the drawing can be superimposed and displayed at an arbitrary position on the original image, and since the original image need not be saved, the superimposed display can be facilitated.

[0006]

The present invention will be described with reference to the accompanying drawings. Figure 1
As shown in the electrical block diagram of FIG. 1, a sampling & A / D conversion circuit 8 for arranging and sampling the analog video signal A from the connected computer 9 to obtain digital original image data is arranged. An original image memory 2 that stores the original image data F obtained by the sampling & A / D conversion circuit 8, a drawing memory 4 that stores drawing data D that is displayed by being superimposed on the original image, and either an original image or a drawing is displayed. A control memory 3 for storing control data E for determining whether or not each pixel is arranged.

An image switching circuit 6 for switching the display between the original image and the drawing and an LCD 5 for displaying the image are arranged. Further, a timing controller 7 for controlling the timings of writing and reading the various data and a CPU 1 for writing the drawing data D and the control data E are arranged. The original image memory 2, the drawing memory 4,
The control memory 3 is a bit map memory corresponding to the screen of the LCD 5.

Next, the actual operation will be described. The analog video signal A input from the connected computer 9 is converted into digital original image data F by the sampling & A / D conversion circuit 8. At this time, sampling is performed by the write timing signal C generated by the timing controller 7 based on the horizontal / vertical synchronizing signal B input together from the computer 9.

The obtained original image data F is stored in the original image memory 2 in synchronization with the write timing signal C. on the other hand,
The drawing data D such as an operation menu which is desired to be superimposed and displayed on the original image is written from the CPU 1 to an address corresponding to the display position of the drawing memory 4. And at the same time, CPU1
The control data E is written to the control memory 3 from. L
On the screen of the CD 5, 1 is written at the address corresponding to the display position of the control memory 3 for the portion where the operation menu or the like is to be displayed, and 0 is written for the portion where the original image is to be displayed.

The display on the LCD 5 is performed based on the read timing signal G generated by the timing controller 7. The original image data H in the original image memory 2, the drawing data J in the drawing memory 4 and the control data I in the control memory 3 are read in synchronization with the read timing signal G, and a logical operation is performed by the image switching circuit 6. . In the image switching circuit 6, when the control data I is 0, the original image data H is supplied to the LCD 5. When the control data I is 1, drawing data is supplied to the LCD 5. Therefore, as described above, by writing 1 in the address corresponding to the drawing of the operation menu or the like in the control memory 3, the drawing of the operation menu or the like is superimposed and displayed on the original image. When erasing the drawing such as the operation menu, 0 may be written from the CPU 1 to all the addresses corresponding to the drawing in the control memory 3. According to the above-described functions, the CPU 1 dynamically rewrites the drawing data D and the control data E so that the drawing of the cursor, the handwriting line, the time, etc. can be displayed without affecting the original image.

[0011]

According to the present invention, even if the original image is a moving image, the drawing of the operation menu, the cursor, the handwriting line, the time, etc. can be superimposed and displayed at an arbitrary position of the original image, and even when these drawings are drawn. Since it is not necessary to save and restore the original image, it is easy to display the overlay.

[Brief description of drawings]

FIG. 1 Block diagram of display device

[Explanation of symbols]

 1 CPU 2 Original Image Memory 3 Control Memory 4 Drawing Memory 5 LCD 6 Image Switching Circuit 7 Timing Controller 8 Sampling & A / D Conversion Circuit 9 Computer

Claims (1)

[Claims] 1. An OH for connecting a computer and enlarging and projecting the same data as the screen of the computer by an OHP.
A display device for P, a storage device for storing the screen data of the computer, a storage device for storing image data such as an operation menu to be superimposed and displayed on the screen data stored in the storage device, and the computer. An image switching circuit that has a control memory that stores control data for determining which of the screen data and the image data is to be displayed in pixel units, and that switches the screen data and the image data of the computer by the control data. An OHP display device characterized by having.