JPH02228180A - Video projector device - Google Patents

Abstract

PURPOSE:To prevent the discontinuous rise of luminance by applying luminance correction to the overlap part between adjacent images projected by plural video projectors. CONSTITUTION:Images projected to a screen 4 from video projectors 31 and 32 overlap in the connection part, and the luminance in this part is discontinuously higher. An extent of luminance correction for each picture element on one horizontal scanning line is stored in a memory by luminance correcting circuits 21 and 22. A counter 201 is counted up by a clock, whose period is the picture element period or is (n) times as long as this period, and is set by a horizontal blanking signal. The value of the counter 201 is used as the address to read the memory 202, and read contents are converted into an analog signal by a D/A converter 203. The video signal is modulated with the level of this signal by a multiplier 204 to correct the luminance of the video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in devices that use multiple video projectors.

[Summary of the invention]

The present invention provides an apparatus for displaying a large screen by continuously arranging a plurality of video projectors vertically or horizontally.
By applying brightness correction to the original video signal, it is possible to prevent the brightness from becoming discontinuous in the overlapping parts of adjacent images projected by a plurality of video projectors.

[Conventional technology]

FIG. 4 shows an example of the equipment configuration when a plurality of video projectors are used. FIG. 5 is a diagram showing the luminance distribution at that time. In operation, the left image is generated by the image generator 11 and displayed on the left side of the screen 4 by the video projector 31. on the other hand.

The right image is generated by the image generator 12 and displayed on the right side of the screen 4 by the video projector 32. This makes it possible to display images on a large screen, which could not be obtained with a single projector, without lowering the resolution. In addition, by connecting them vertically, horizontally, and horizontally, it is possible to display images on an even larger screen.

[Problem to be solved by the invention]

However, when multiple video projectors like this are connected and displayed, the luminance distribution of the nine displayed images is as shown in FIG. The brightness of AlA2 and the brightness of BI B2 are weighted in the B1A2 portion where the image BI B2 obtained by the above overlaps (see FIG. 5, E). As a result, the images become discontinuous, resulting in bright striped patterns and a sad-looking image.

[Means to solve the problem]

In order to solve these drawbacks, the present invention adds a brightness correction circuit to lower the brightness of the portion where the projected images overlap, thereby making the discontinuous points less noticeable.

The brightness correction circuit is 1, for example, AlA2 shown in Figure 1, /.
．． It has brightness correction characteristics like BIB2.

[Effect]

As a result, as shown in FIG. 1A, the brightness of the portion where the images of the projectors 31 and 32 become 1 changes continuously, resulting in a smooth image.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. FIG. 3 is a block diagram showing an example of a brightness correction circuit, in which 201 is a counter, 202 is a memory, 203 is a D/A converter, and 204 is an analog multiplier. Figure 2 is a block diagram of the overall configuration.

FIG. 1 is a brightness distribution diagram showing the relationship between screen A and image brightness port 9 composite image brightness C according to the present invention.

This operation will be explained below. A memory 202 stores brightness correction amounts for multiple pixels on one horizontal scanning line. A counter 201 counts up at a pixel period or n times its clock, and is clocked by a horizontal blanking signal. This counter 201 is used as an address in memory.
202 is read out and converted into an analog signal by a D/A converter 203. The brightness of the video signal is corrected by modulating the video signal using the signal level in a multiplier 204.

Also, when connecting images in the vertical direction, use the counter 20
1 clock is a horizontal synchronizing signal, and its reset can be easily realized by using a vertical blanking signal.

〔Effect of the invention〕

According to the present invention, when images projected by a plurality of projectors are successively connected, it is possible to prevent the brightness from becoming discontinuously high at the portion where two images overlap.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a luminance distribution according to the present invention, and FIG. 2 is a block diagram showing the overall configuration of an embodiment of the present invention. FIG. 3 is a diagram showing an example of the brightness correction circuit of the present invention. FIG. 4 is a block diagram of the conventional example, and FIG. 5 is a brightness distribution diagram of the conventional example. 21, 22: Brightness correction circuit, 201: Counter. 202: Memory, 203: D/A converter. Figure 1 Figure 3-)k

Claims (1)

[Claims] 1. In a device that displays a large screen by arranging multiple video projectors consecutively vertically or horizontally, the overlapping portion of adjacent images projected by multiple video projectors of the original video signal A video projector device characterized by applying brightness correction to.