TEMPORAL FILTERING OF VIDEO SIGNALS
First Claim
1. A method, comprising the steps of:
- receiving a segment of a video;
calculating a rear modulation signal for the received segment;
calculating a difference in intensity between the rear modulation signal of the received segment and a rear modulation signal of a previous frame corresponding to the received segment; and
modifying the rear modulation signal for the received segment with a filtering limit R to obtain an actual rear modulation signal for the received segment.
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Accused Products
Abstract
A process for reducing noise and temporal artifacts (e.g. walking LEDs) on a dual modulation display system by applying temporal filtering to rear modulation signals of a sequence of video frames. Flare and dimming rates are calculated for a current frame in the video. If a flare rate threshold is exceeded, an intensity of the backlight is limited to a predetermined flare rate. If a dimming rate threshold is exceeded, the backlight intensity is limited to a predetermined dimming rate. The limitations are applied, for example, on an element-by-element basis. In the event of a scene change, the limitations do not need to be applied. A forward modulation signal is calculated by taking into account any applied backlight limitations.
71 Citations
26 Claims
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1. A method, comprising the steps of:
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receiving a segment of a video; calculating a rear modulation signal for the received segment; calculating a difference in intensity between the rear modulation signal of the received segment and a rear modulation signal of a previous frame corresponding to the received segment; and modifying the rear modulation signal for the received segment with a filtering limit R to obtain an actual rear modulation signal for the received segment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An high dynamic range display, comprising:
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a front modulator unit; a rear modulation unit comprising an array of individually controllable backlights having a resolution lower than a resolution of the front modulation unit and configured to project modulated light onto the front modulation unit; and a controller coupled to the rear modulation unit and configured to prepare a rear modulation signal and transmit it to the rear modulation unit, said rear modulation signal limited according to at least one of a flare rate and a dimming rate. - View Dependent Claims (18, 19)
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- 20. A controller configured to provide control signals to each individually controllable light element of a light element array, said control signals comprising an amount of light derived from a video signal and limited in intensity if at least one of a flare rate threshold and a dimming rate threshold are exceeded.
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26. A display comprising:
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an LCD panel; an array of backlight elements configured to project modulated light onto the LCD panel, wherein a resolution of the backlight elements is lower than a resolution of the LCD panel; and a controller comprising a processing device configured to provide a light intensity to each backlight element, the light intensity of an individual backlight unit corresponding to an intensity in a portion of a video image to be displayed on the display and illuminated by the backlight element; the controller further comprising means for reducing artifacts resulting from the difference in resolution between the backlight elements and the LCD panel, including, means for detecting a flare rate in at least a segment of the video image compared to a corresponding segment of the video image previously displayed, means for detecting a dimming rate in at least a segment of the video image compared to a corresponding segment of the video image previously displayed, and means for limiting the light intensity of an individual backlight element if the light intensity of the individual backlight element per the video image exceeds at least one of the flare rate and the dimming rate.
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Specification