HK1002718B - Device for displaying a composite image - Google Patents

Description

The invention relates to a device for displaying a digital complete image on a screen of a display device composed of several natural moving and/or synthetic partial images supplied by different sources.

The display of an image on a screen of a display device is achieved by a large number of lines, e.g. 625, which are deflected by an electron beam. When the electron beam has deflected all the lines of the screen, the whole process repeats. In order for the electron beam to regularly deflect the lines, it must be synchronized in horizontal and vertical direction.

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GB-A-20 99 269 is known to combine a complete image from several synthetic subimages supplied by memory, with each image element in the memory associated with a priority value and the image element with the highest priority value being accessed to a video data bus to be displayed on a screen.

The purpose of the invention is to create a process and device of the type described above which allows an improved overall representation of at least two partial images generated from different sources on a screen.

To address this problem, a device according to the invention has the features of claim 1, which allows images to be displayed, in particular, on high-resolution displays that can be composed in steps from image point to image point, line to line and image to image at the image point frequency of some 10 MHz from alternating sub-images from different sources, with the image sources being able to operate asynchronously and at different image generation frequencies.

The subclaim protects advantageous versions of the invention.

The invention is explained in more detail below by means of a drawing on an example of an embodiment.

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The buffers 11 to 19, which normally contain images or partial images, are not read out in sequence or according to another fixed scheme and displayed on the monitor 30, but the monitor image can in principle be composed point by point from points of different sources 1 and/or 2 and/or 3. This is done by providing a control calculator 24 from a loaded mask memory 21 whose contents are fed to a control network 23 at the image point frequency. The control network 23 connects each bit of the mask memory output register 22 to the control part 31 39 of the buffer memory 11 to 19 of a source 1, 2 and 3 .

If several points of the image are fed back to back and several lines or pieces of lines between them from the same source, then partial images are produced.

If the buffer storage is controlled by four additional loadable registers or counters 40, sub-images of various formats can be used as a source and inserted into the overall picture at any point, since by properly prepositioning the counters 40 the starting point of the sub-image (top left corner) to the overall picture representing the image can be determined, one of the counters indicating the line shift, the second the shift of the image point in the line and the other counters running each up to the end of the line or to the last line of the sub-image.

The counters 40 are pre-loaded via the data collection lines (bus) 41 according to the image size and the desired image position in the overall image.

The control information provided by the mask memory 21 finally causes the buffer memory 11 to 19 control to transmit the grey or colour value of the image point being displayed from the selected source via the data acquisition line 42 to the interface circuit 25.

The grayscale values or colours required for the display are thus transferred to the interface circuit 25 point by point, regardless of the size of the whole image in relation to the size of the sub-images and the way in which the sub-images or parts of the sub-images are put together.

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Claims (4)

1. A device for displaying a composite digital image on a VDU screen (30), the composite image consisting of a number of natural moving and/or synthetic partial images delivered by various sources (1, 2, 3), each source (1, 2, 3) having an associated buffer memory (11 to 19) controllable via a control stage (31 to 39), wherein there is provided a common mask memory (21) which is chargeable from a control computer (24) and which comprises an output register (22) for outputting control information in order to select an image dot for display, the data word width of the output register (22) corresponding to the number of sources (1, 2, 3), and wherein exactly one bit is set per data word, in that a control network (23) is provided into which said control information is fed at the scanning rate of the image dots in one line of the composite image, wherein further the output register (22) of the mask memory (21) is connected via the control network (23) to the control stage (31 to 39) of the buffer memory (11 to 19) of each source (1, 2, 3), and wherein the outputs of the buffer memories (11 to 19) are connected to the screen (30) via a data bus and an interface circuit (25).
2. A device according to claim 1, characterised in that television cameras (1) and/or raster graphic generators (2) and/or mass memories (3) for digital image data are provided as the sources.
3. A device according to claim 1 or 2, characterised in that the screen is designed to reproduce a larger number of image dots than each individual source (1, 2, 3) can make available.
4. A device according to any one of claims 1 to 3, characterised in that the sources comprise a plurality of cameras (1) adjusted to one another at appropriate angles of view and so disposed as to display on the screen continuously side by side or one beneath another an image of an object or a landscape as a composite picture with a much larger angle of view than the natural angle.