Method and apparatus for detecting fades in digital video sequences
First Claim
1. A method for compressing a fade within a sequence of digital motion video frames comprising the steps of:
- (a) selecting first and second frames from said sequence for processing;
(b) determining a first luminosity difference value from said first and second frames;
(c) detecting a fade within said sequence by comparing said first luminosity difference value to at least one predetermined threshold; and
(d) compressing at least one of said selected frames in accordance with the result of step (c).
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Abstract
A method and apparatus for detecting a fade within a sequence of digital motion video frames. A first frame and a previous frame are selected from the sequence as first and second regions, respectively, for processing. The mean of the first region and the mean of the second region are each calculated and the relative mean change between the means is determined. A fade is detected if the relative mean change exceeds a first predetermined threshold. Alternatively, a fade is detected if the relative mean change is less than the first predetermined threshold but greater than a second predetermined threshold and the magnitude of the difference between the means is greater than a third predetermined threshold.
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Citations
27 Claims
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1. A method for compressing a fade within a sequence of digital motion video frames comprising the steps of:
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(a) selecting first and second frames from said sequence for processing; (b) determining a first luminosity difference value from said first and second frames; (c) detecting a fade within said sequence by comparing said first luminosity difference value to at least one predetermined threshold; and (d) compressing at least one of said selected frames in accordance with the result of step (c). - View Dependent Claims (2, 3, 4)
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5. A method for processing a sequence of digital motion video frames having at least one flagged fade frame comprising the steps of:
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(a) determining whether said at least one flagged fade frame is a single fade frame; (b) if said at least one flagged fade frame is a single fade frame then i. calculating a relative mean change for said single fade frame; ii. comparing said relative mean change against a predetermined threshold; and iii. unflagging said single fade frame if the magnitude of said relative mean change is less than said predetermined threshold. - View Dependent Claims (6)
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7. An apparatus for compressing a fade within a sequence of digital motion video frames comprising:
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(a) means for providing first and second frames from said sequence for processing; (b) means for determining at least one luminosity difference value from said first and second frames; (c) fade detector means for detecting a fade within said sequence by comparing said at least one luminosity difference value to at least one predetermined threshold; and (d) means for compressing at least one of said selected frames in accordance with the result of said fade detector means. - View Dependent Claims (8, 9, 10)
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11. A apparatus for processing a sequence of digital motion video frames having at least one flagged fade frame comprising:
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(a) means for determining whether said at least one flagged fade frame is a single fade frame; (b) means for calculating a first luminosity difference value for a single fade frame; (c) means for comparing said first luminosity difference value against a predetermined threshold; and (d) means for unflagging said single fade frame if the magnitude of first luminosity difference value is less than said predetermined threshold. - View Dependent Claims (12, 13)
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14. A method for detecting a fade frame within a sequence of digital motion video frames comprising the steps of:
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(a) selecting a frame from said sequence as a first region for processing; and (b) selecting a previous frame from said sequence as a second region for processing; (c) calculating the means of said first region; (d) calculating the mean of said second region; (e) determining the magnitude of the difference between the results of steps (c) and (d); (f) determining a relative mean change between said first and second regions in accordance with the result of step (e); (g) comparing said relative means change to a first predetermined threshold; (h) detecting a fade if said relative means change exceeds a first predetermined threshold; (i) if a fade is detected in step (h) then; (1) dividing said selected frame and said previous frame into corresponding regions; (2) selecting a region from said selected frame as a first region for processing and a corresponding region in said previous frame as a second region for processing; (3) repeating steps (c) to (g); (4) if said relative mean change exceeds said first predetermined threshold, then incrementing a counter; (5) repeating steps (i) (1) to (i) (4) for remaining corresponding regions in said selected and previous frames; and (6) flagging said selected frame as a fade frame if said counter divided by the number of regions in said selected frame exceeds a predetermined percentage.
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15. An apparatus for detecting a fade within a sequence of digital motion video frames comprising:
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(a) means for providing a selected frame from said sequence as a first region for processing; (b) means for providing a previous frame from said sequence as a second region for processing; (c) first calculating means or calculating the mean of said first region; (d) second calculating means for calculating the mean of said second region; (e) difference means for determining the magnitude of the difference between the mean of said first region and the mean of said second region; (f) relative difference means for determining the relative mean change between said first region and said second region; (g) first comparing means for comparing said relative means change to a first predetermined threshold; (h) means for detecting the presence of a fade if said relative means change exceeds said first predetermined threshold; (i) frame dividing means for dividing said selected frame and said previous frame into corresponding regions; (j) means for selecting a region from said selected frame as a first region for processing; (k) means for selecting a region from said previous frame as a second region for processing; (l) means for incrementing a counter if the relative means change between said first region and said second region exceeds said first predetermined threshold; and (m) fade frame flagging means for flagging said selected frame as a fade frame if said counter divided by the number of regions in said selected frame exceeds a predetermined percentage.
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16. A method for detecting a fade within a sequence of digital motion video frames comprising the steps of:
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(a) selecting first and second frames from said sequence for processing; (b) determining a first luminosity difference value between said first and second frames, and determining a second luminosity difference value between said first and second frames; and (c) detecting a fade by comparing said first luminosity difference value to at least one predetermined threshold and by comparing said second luminosity difference value to a second predetermined threshold. - View Dependent Claims (17, 18, 19, 20, 21)
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22. An apparatus for detecting a fade within a sequence of digital motion video frames comprising:
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(a) means for providing first and second frames from said sequence for processing; (b) means for determining at least one luminosity difference value from said first and second frames, and means for determining a second luminosity difference value from said first and second frames; and (c) fade detector means for detecting a fade by comparing said at least one luminosity difference value to at least one predetermined threshold and by comparing said second luminosity difference value to a second predetermined threshold. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification