Process and device for image display with automatic defect correction by feedback
First Claim
1. A process for image display, by means of a display on a screen, for providing automatic defect correction by an image acquisition device analyzing the screen through a spatial filter, comprising the steps of:
- performing an acquisition phase, comprising the steps of;
displaying a test image including bright isolated pixels distributed in the test image and with spatially fixed positions on the screen, wherein the spatial filter is adapted to be in alignment with the test image,detecting a maximum output signal when a pixel of the test image coincides with its expected position;
performing a spatial calibration stage where the bright isolated pixels of the test image display are brought into coincide with their expected positions on the screen, by correction values of horizontal and vertical scannings of the display on the basis of results of image analysis by the acquisition device;
storing the correction values for the pixels of the test image in a memory;
interpolating correction values for intermediate pixels by interpolation from correction values from nearby detected pixels; and
performing a continuation phase comprising the steps of;
displaying a sequence of video images wherein the sequence of video images displayed is acquired and analyzed through the spatial filter to update the scanning;
focusing and amplitude correcting where necessary and modifying the stored correction values in consequence based on results of the analysis.
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Abstract
An automatic defect correction drive utilizing feedback in an image display device. According to the present invention, during an acquisition phase, a test image constituted of bright points of known positions distributed on a screen is displayed. This displayed image is then analyzed via an image acquisition device, to deduce from it the scanning, focusing and amplitude corrections to be applied to the display, so that the test pixels displayed on the screen have their expected positions and characteristics. These corrections are then interpolated for the intermediate pixels between test points, and then, during a continuation phase, these corrections are updated.
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Citations
14 Claims
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1. A process for image display, by means of a display on a screen, for providing automatic defect correction by an image acquisition device analyzing the screen through a spatial filter, comprising the steps of:
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performing an acquisition phase, comprising the steps of; displaying a test image including bright isolated pixels distributed in the test image and with spatially fixed positions on the screen, wherein the spatial filter is adapted to be in alignment with the test image, detecting a maximum output signal when a pixel of the test image coincides with its expected position; performing a spatial calibration stage where the bright isolated pixels of the test image display are brought into coincide with their expected positions on the screen, by correction values of horizontal and vertical scannings of the display on the basis of results of image analysis by the acquisition device; storing the correction values for the pixels of the test image in a memory; interpolating correction values for intermediate pixels by interpolation from correction values from nearby detected pixels; and performing a continuation phase comprising the steps of; displaying a sequence of video images wherein the sequence of video images displayed is acquired and analyzed through the spatial filter to update the scanning; focusing and amplitude correcting where necessary and modifying the stored correction values in consequence based on results of the analysis. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An image display device with automatic defect correction for displaying an image on a screen, comprising:
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a source of a test image and a source of a sequence of images alternately connected to an input of an image memory during phases of acquisition and continuation; an image acquisition device comprising a spatial filter of a holed mask; means for analyzing the radiation received through the mask; a time base circuit; a window generator controlled by a processor and by the time base circuit and connected to a control input of a sampling circuit of a signal output from the acquisition device, in series with an analog converter and with a buffer memory system, wherein the window generator transfers the values of the output signal of the image analysis system, for the pixels selected, to a correction calculation processor; the correction calculation processor operating from signals read from the image memory and the buffer memory system; and a correction memory system with as many zones as possible types of corrections and as many addresses in each zone as image pixels on the screen, this correction memory system being accessible in read and write modes by the calculation processor, and its outputs being connected to corresponding correction inputs on the display, wherein stored correction values may be modified base on results of analysis performed by said means for analyzing. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification