US5818964A
Expired / Lapsed
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Method and apparatus for selecting an adaptive filter for image data
Assignee: Texas Instruments Inc
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Filing: 1995-12-27
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Granted: 1998-10-06
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Expires: 2015-12-27
Abstract
Abstract A device and method for filtering out the noise generated due to coding of image data signals. The device has a threshold determining unit, a binary index unit, a filter selecting unit, and an adaptive filtering unit. The threshold determining unit 4 divides each pixel of the input image data into two gray levels. The binary indexes defined by the gray level are checked by a window with a prescribed size. If the region in the window is determined to be a homogeneous region, a heterogeneous region, or an impulse noise region (block 5), the filter selecting unit selects a filter corresponding to the determined region, and the image data is processed by the selected filter.
Inventors
- 👤 Yuji Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:36
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
111 words
A method of filtering noise from an input image data signal representing two-dimensionally arranged pixels, comprising the steps of: decoding the image data signal to form an arrav of pixels each having a color value, assigning a binary coded index value to each of the pixels in accordance with the color value and a threshold value to form a block of binary coded index values; evaluating a portion of the binary coded index values within the block of binary coded index values corresponding to a two-dimensional window of size M × N: and selecting a noise filter in accordance with the portion of binary coded index values contained in the window.
Claim 2
Independent Claim
111 words
A method of filtering noise from an input image data signal representing two-dimensionally arranged pixels, comprising the steps of: decoding the image data signal to form an arrav of pixels each having a color value, assigning a binary coded index value to each of the pixels in accordance with the color value and a threshold value to form a block of binary coded index values; evaluating a portion of the binary coded index values within the block of binary coded index values corresponding to a two-dimensional window of size M × N: and selecting a noise filter in accordance with the portion of binary coded index values contained in the window.
Claim 3
Dependent Claim
68 words
The method of claim 1 including the steps of dividing the image data signal into blocks with a size of P × Q (where P and Q are larger than M and N) before the binary coding step, determining a threshold for each block, and then assigning a binary coded index value to each of the pixels within each block using a threshold determined for each corresponding block.
Claim 4
Dependent Claim
31 words
The method of claim 1 wherein the threshold is determined by the intermediate value of the dynamic range of the color values of the pixels in the entire image data signal.
Claim 5
Dependent Claim
34 words
The method of claim 2 wherein each threshold is determined by the intermediate value in the dynamic range of the color values of the pixels of the image data signal in the corresponding block.
Claim 6
Dependent Claim
69 words
The method of claim 1 including the steps of examining the image data signal by a two-dimensional window of predetermined size, determining a region type according to whether the region of image data signal enclosed by the window is a homogeneous region, a heterogeneous region, or an impulse region, and applying a filter having M × N filter coefficients corresponding to the region type to the image data signal.
Claim 7
Dependent Claim
52 words
The method of claim 5 wherein when the region in the window is a homogeneous region a relatively strong smoothing filter is to the image data of the region, and when the region is a heterogeneous region a relatively weak smoothing filter is applied to the coded image data of the region.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the image data is obtained by decoding a compression-coded movie image.
Claim 9
Dependent Claim
18 words
The method of claim 1 wherein the binary coded index has a value of either "O" or "1".
Claim 10
Dependent Claim
40 words
The method of claim 1 wherein the step of selecting a filter further comprises assigning none-zero filter coefficients only to pixels within the two-dimensional window that have index values the same as a pixel in the center of the window.
Claim 11
Independent Claim
178 words
A device for reducing noise in an input image data signal representing two-dimensionally arranged pixels, each pixel having a color value, comprising: a threshold determining unit for determining a threshold value based on the range of color values of at least a portion of the pixels corresponding to a twodimensional block of size of P × Q; a binary index unit for assigning a binary coded index value to each of the pixels in the block of P × Q in accordance with the threshold value to form a block of binary coded index values of size P x Q; a filter selector unit for selecting a filter in response to a set of binary coded index values selected from the block of binary coded index values by a two-dimensional window of dimension M × N; and adaptive filtering unit for applying the selected filter to a set of pixel color values corresponding to the two-dimensional window of dimension M × N to form a resultant color value for a pixel in the center of the two-dimensional window.
Claim 12
Independent Claim
178 words
A device for reducing noise in an input image data signal representing two-dimensionally arranged pixels, each pixel having a color value, comprising: a threshold determining unit for determining a threshold value based on the range of color values of at least a portion of the pixels corresponding to a twodimensional block of size of P × Q; a binary index unit for assigning a binary coded index value to each of the pixels in the block of P × Q in accordance with the threshold value to form a block of binary coded index values of size P x Q; a filter selector unit for selecting a filter in response to a set of binary coded index values selected from the block of binary coded index values by a two-dimensional window of dimension M × N; and adaptive filtering unit for applying the selected filter to a set of pixel color values corresponding to the two-dimensional window of dimension M × N to form a resultant color value for a pixel in the center of the two-dimensional window.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-10-05 | 2002-04-06 | 2002-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-10-05 | 2006-04-06 | 2006-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-10-05 | 2010-04-06 | 2010-10-06 | $7700.00 | Window Closed / Lapsed |