Moving vector extractor
First Claim
Patent Images
1. A moving vector extractor comprising:
- a timer generating a control signal having a predetermined timing;
an image processor for receiving an input image signal which represents a physical image and for generating, responsive to said control signal, a plurality of brightness signals which represent said physical image at a plurality of successive image frames;
a representative point memory for extracting and storing representative points from said brightness signals according to said control signal generated by said timer, said representative points having corresponding brightness values;
subtracting means for calculating a difference between said brightness values of said stored representative points which are in proximate image frames;
absolute value calculating means for calculating an absolute value of said difference calculated by said subtracting means;
density gradient calculating means for calculating a density gradient in a neighborhood of said representative points;
weighting means for weighting said absolute value of said difference according to said calculated density gradient;
accumulating means for accumulating said absolute value of said weighted difference;
an accumulation memory for storing two-dimensionally an accumulated result obtained by said accumulating means corresponding to said input image signal;
a minimum value detecting means for detecting a minimum value from accumulated results stored in said accumulating means; and
moving vector extracting means for extracting a moving vector based on said detected minimum value.
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Abstract
A moving vector extractor for detecting a shaking of an image through a video camera in order to improve accuracy of the detection. Even when the image is dark or of low density gradient as a whole, a density gradient value around representative point is calculated. Basic data of moving vector of the difference value between successive frames is obtained by calculating an absolute value or a squared value. The basic data of the moving vector is weighted according to a density gradient value so as to improve the precision of moving vector extraction.
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Citations
34 Claims
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1. A moving vector extractor comprising:
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a timer generating a control signal having a predetermined timing; an image processor for receiving an input image signal which represents a physical image and for generating, responsive to said control signal, a plurality of brightness signals which represent said physical image at a plurality of successive image frames; a representative point memory for extracting and storing representative points from said brightness signals according to said control signal generated by said timer, said representative points having corresponding brightness values; subtracting means for calculating a difference between said brightness values of said stored representative points which are in proximate image frames; absolute value calculating means for calculating an absolute value of said difference calculated by said subtracting means; density gradient calculating means for calculating a density gradient in a neighborhood of said representative points; weighting means for weighting said absolute value of said difference according to said calculated density gradient; accumulating means for accumulating said absolute value of said weighted difference; an accumulation memory for storing two-dimensionally an accumulated result obtained by said accumulating means corresponding to said input image signal; a minimum value detecting means for detecting a minimum value from accumulated results stored in said accumulating means; and moving vector extracting means for extracting a moving vector based on said detected minimum value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A video camera comprising;
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lens means for receiving an input image; moving vector extractor means for extracting a moving vector from said input image comprising; (a) difference means for calculating a difference value corresponding to brightnesses of representative points in successive frames of said input image, each of said representative points being in a predetermined area of each of said successive frames, said successive frames being a predetermined time period away from each other, (b) density means for calculating a density gradient value around each of said representative points, (c) indicating means for calculating an indicator value, said indicator value indicating said difference value as a positive value, (d) weighting means for weighting said indicator value according to said density gradient value, thereby generating a weighted indicator value, and (e) accumulating means for accumulating a summation of said weighted indicator value for each of said representative points and determining a local minimum in said summation, thereby extracting said moving vector from a positional relationship between said local minimum and said representative points; actuator means for moving said lens means in a horizontal and a vertical direction; and control means for controlling said movement of said actuator means in response to said moving vector extractor means. - View Dependent Claims (12)
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13. A moving vector extractor comprising:
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an image processor for electronically generating an image output signal representative of a physical image; image difference accumulation means for receiving said image output signal and for electronically generating signals, based on said image output signal, which are representative of time-varying differences of predetermined points in said physical image, said generated signals being responsive to local density gradients which correspond to said predetermined points; and vector determination means for identifying a moving vector according to successive signals from said image difference accumulation means. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A moving vector extractor comprising:
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a timer generating a control signal at predetermined intervals; an image processor for providing, responsive to said control signal, an image output signal representative of a physical image as an image frame, said output signal comprising a plurality of multi-valued portions, each multi-valued portion being representative of a point in said physical image; difference means for calculating a difference value corresponding to the brightness of representative points in successive frames of an input image, each of said representative points being in a predetermined area of said image and being represented by one of said plurality of multi-valued portions of said image output signal; density means for calculating a density gradient value around each of said representative points; indicator means for calculating an indicator value, said indicator value being based on a positive representation of said difference value; weighting means for weighting said indicator value according to said density gradient value, thereby generating a weighted indicator value; accumulating means for accumulating a summation of weighted indicator values including said weighted indicator value for each representative point, for determining a local minimum in said summation and for providing an accumulator output signal indicative of said local minimum; and means for generating a signal representing a moving vector from a positional relationship between said local minimum and said representative points. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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Specification