US6281875B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gradient-based pixel interpolation
Assignee: Canon Inc
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Filing: 1998-04-29
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Granted: 2001-08-28
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Expires: 2018-04-29
Abstract
Abstract In a method for determining a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, calculating a position in the source image based on position of a target pixel in the destination image, testing the presence of a diagonal gradient in the source image at the position determined in the calculating step, the testing step testing for the presence of a diagonal gradient by reference to values of pixels in the source image that surround the position calculated in the calculating step, responsive to the presence of a diagonal gradient in the testing step, calculating a data value for the target pixel based on interpolation of data values for diagonally-adjacent pixels in the source image, and responsive to the absence of a diagonal gradient in the testing step, calculating a data value for the target pixel based on interpolation of data values for at least all four surrounding pixels in the source image.
Inventors
- 👤 Jun Zhao
- 👤 Jonathan Hui
- 👤 Tong Zheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 01:58
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/4007; G06T11/00; G06T11/10
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
208 words
A method for determining a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, comprising the steps of: calculating a position in the source image based on a position of the target pixel in the destination image; testing for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values for pixels in the source image that surround the position calculated in said calculating step; responsive to the presence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image; and responsive to the absence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 2
Independent Claim
208 words
A method for determining a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, comprising the steps of: calculating a position in the source image based on a position of the target pixel in the destination image; testing for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values for pixels in the source image that surround the position calculated in said calculating step; responsive to the presence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image; and responsive to the absence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 3
Dependent Claim
89 words
A method according to claim 1 , wherein in said step of testing for the presence of a diagonal gradient, testing is based on data values for four pixels surrounding the calculated position in the source image, and wherein testing for the presence of a diagonal gradient comprises the steps of comparing data values of a first diagonal pair of the four pixels to determine whether they are similar, and comparing data values of the second pair of the four surrounding pixels to determine whether they are significantly different.
Claim 4
Dependent Claim
23 words
A method according to claim 1 , wherein in a case where a diagonal gradient is present, interpolation is across the diagonal gradient.
Claim 5
Dependent Claim
23 words
A method according to claim 1 , wherein in a case where a diagonal gradient is present, interpolation is along the diagonal gradient.
Claim 6
Dependent Claim
39 words
A method according to claim 1 , further comprising the step of determining a data value for the target pixel without using interpolation in a case that a pixel in the source image coincides exactly with the calculated position.
Claim 7
Dependent Claim
41 words
A method according to claim 1 , wherein calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises a two-step linear interpolation.
Claim 8
Dependent Claim
40 words
A method according to claim 1 , wherein calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises a bi-linear interpolation.
Claim 9
Dependent Claim
40 words
A method according to claim 1 , wherein calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises a bi-cubic interpolation.
Claim 10
Dependent Claim
18 words
A method according to claim 1 , wherein the source image and the destination image are gray-scale images.
Claim 11
Dependent Claim
32 words
A method according to claim 1 , wherein the source image and the destination image are both single color planes of color images, each of the color images comprising multiple color planes.
Claim 12
Independent Claim
251 words
An apparatus for determining a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, comprising: a memory including a region for storing the source image, a region for storing the destination image, and a region for storing executable process steps; and a processor for executing the executable process steps; wherein the executable process steps include steps of: (a) calculating a position in the source image based on a position of a target pixel in the destination image, (b) testing for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values of pixels in the source image that surround the position calculated in said calculating step, (c) responsive to the presence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image, and (d) responsive to the absence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 13
Independent Claim
251 words
An apparatus for determining a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, comprising: a memory including a region for storing the source image, a region for storing the destination image, and a region for storing executable process steps; and a processor for executing the executable process steps; wherein the executable process steps include steps of: (a) calculating a position in the source image based on a position of a target pixel in the destination image, (b) testing for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values of pixels in the source image that surround the position calculated in said calculating step, (c) responsive to the presence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image, and (d) responsive to the absence of a diagonal gradient in said testing step, calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 14
Dependent Claim
92 words
An apparatus according to claim 11 , wherein in said step of testing for the presence of a diagonal gradient, testing is based on data values for four pixels surrounding the calculated position in the source image, and wherein said step of testing for the presence of a diagonal gradient comprises the steps of comparing data values of a first diagonal pair of the four pixels to determine whether they are similar, and comparing data values of the second pair of the four surrounding pixels to determine whether they are significantly different.
Claim 15
Dependent Claim
23 words
An apparatus according to claim 11 , wherein in a case where a diagonal gradient is present, interpolation is across the diagonal gradient.
Claim 16
Dependent Claim
23 words
An apparatus according to claim 11 , wherein in a case where a diagonal gradient is present, interpolation is along the diagonal gradient.
Claim 17
Dependent Claim
39 words
An apparatus according to claim 11 , further comprising the step of determining a data value for the target pixel without using interpolation in a case that a pixel in the source image coincides exactly with the calculated position.
Claim 18
Dependent Claim
41 words
An apparatus according to claim 11 , wherein calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises a two-step linear interpolation.
Claim 19
Dependent Claim
40 words
An apparatus according to claim 11 , wherein calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises a bi-linear interpolation.
Claim 20
Dependent Claim
40 words
An apparatus according to claim 11 , wherein calculating a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises a bi-cubic interpolation.
Claim 21
Dependent Claim
18 words
An apparatus according to claim 11 , wherein the source image and the destination image are gray-scale images.
Claim 22
Dependent Claim
32 words
An apparatus according to claim 11 , wherein the source image and the destination image are both single color planes of color images, each of the color images comprising multiple color planes.
Claim 23
Dependent Claim
231 words
Computer-executable process steps stored on a computer-readable medium, the computer executable process steps to determine a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, the computer-executable process steps comprising: code to calculate a position in the source image based on a position of a target pixel in the destination image; code to test for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values for pixels in the source image that surround the position calculated by said code to calculate; code to calculate, responsive to the presence of a diagonal gradient in said code to test, a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image; and code to calculate, responsive to the absence of a diagonal gradient in said code to test, a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 24
Dependent Claim
231 words
Computer-executable process steps stored on a computer-readable medium, the computer executable process steps to determine a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, the computer-executable process steps comprising: code to calculate a position in the source image based on a position of a target pixel in the destination image; code to test for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values for pixels in the source image that surround the position calculated by said code to calculate; code to calculate, responsive to the presence of a diagonal gradient in said code to test, a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image; and code to calculate, responsive to the absence of a diagonal gradient in said code to test, a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 25
Dependent Claim
91 words
Computer-executable process steps according to claim 21 , wherein said code to test for the presence of a diagonal gradient tests based on values for four pixels surrounding the calculated position in the source image, and wherein said code to test for the presence of a diagonal gradient comprises code to compare data values of a first diagonal pair of the four pixels to determine whether they are similar, and code to compare data values of the second pair of the four surrounding pixels to determine whether they are significantly different.
Claim 26
Dependent Claim
24 words
Computer-executable process steps according to claim 21 , wherein in a case where a diagonal gradient is present, interpolation is across the diagonal gradient.
Claim 27
Dependent Claim
24 words
Computer-executable process steps according to claim 21 , wherein in a case where a diagonal gradient is present, interpolation is along the diagonal gradient.
Claim 28
Dependent Claim
39 words
Computer-executable process steps according to claim 21 , further comprising code to determine a data value for the target pixel without using interpolation in a case that a pixel in the source image coincides exactly with the calculated position.
Claim 29
Dependent Claim
48 words
Computer-executable process steps according to claim 21 , wherein said code to calculate a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises code to perform a two-step linear interpolation.
Claim 30
Dependent Claim
47 words
Computer-executable process steps according to claim 21 , wherein said code to calculate a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises code to perform a bi-linear interpolation.
Claim 31
Dependent Claim
47 words
Computer-executable process steps according to claim 21 , wherein said code to calculate a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image comprises code to perform a bi-cubic interpolation.
Claim 32
Dependent Claim
19 words
Computer-executable process steps according to claim 21 , wherein the source image and the destination image are gray-scale images.
Claim 33
Dependent Claim
33 words
Computer-executable process steps according to claim 21 , wherein the source image and the destination image are both single color planes of color images, each of the color images comprising multiple color planes.
Claim 34
Dependent Claim
235 words
A computer-readable medium which stores computer-executable process steps, the computer-executable process steps to determine a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, the computer-executable process steps comprising: a calculating step to calculate a position in the source image based on a position of a target pixel in the destination image; a testing step to test for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values of pixels in the source image that surround the position calculated in said calculating step; a calculating step to calculate, responsive to the presence of a diagonal gradient in said testing step, a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image; and a calculating step to calculate, responsive to the absence of a diagonal gradient in said testing step, a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 35
Dependent Claim
235 words
A computer-readable medium which stores computer-executable process steps, the computer-executable process steps to determine a data value for a target pixel in a destination image based on data values for pixels in a source image, with the destination image being scaled relative to the source image, the computer-executable process steps comprising: a calculating step to calculate a position in the source image based on a position of a target pixel in the destination image; a testing step to test for a presence of a diagonal gradient in the source image at the position determined in said calculating step so as to select a method of interpolation based exclusively on the presence or absence of said diagonal gradient, said testing step testing for the presence of a diagonal gradient by reference to data values of pixels in the source image that surround the position calculated in said calculating step; a calculating step to calculate, responsive to the presence of a diagonal gradient in said testing step, a data value for the target pixel based on interpolation of data values for pixels diagonally adjacent to the calculated position in the source image; and a calculating step to calculate, responsive to the absence of a diagonal gradient in said testing step, a data value for the target pixel based on interpolation of data values for at least all four pixels surrounding the calculated position in the source image.
Claim 36
Dependent Claim
95 words
A computer-readable medium according to claim 31 , wherein in said testing step to test for the presence of a diagonal gradient, testing is based on data values for four pixels surrounding the calculated position in the source image, and wherein said testing step to rest for the presence of a diagonal gradient comprises the steps of comparing data values of a first diagonal pair of the four pixels to determine whether they are similar, and comparing data values of the second pair of the four surrounding pixels to determine whether they are significantly different.
Claim 37
Dependent Claim
24 words
A computer-readable medium according to claim 31 , wherein in a case where a diagonal gradient is present, interpolation is across the diagonal gradient.
Claim 38
Dependent Claim
24 words
A computer-readable medium according to claim 31 , wherein in a case where a diagonal gradient is present, interpolation is along the diagonal gradient.
Claim 39
Dependent Claim
41 words
A computer-readable medium according to claim 31 , further comprising a determining step to determine a data value for the target pixel without using interpolation in a case that a pixel in the source image coincides exactly with the calculated position.
Claim 40
Dependent Claim
45 words
A computer-readable medium according to claim 31 , wherein the calculating step to calculate a data value for the target pixel based on interpolation of data values for at least all pixels surrounding the calculated position in the source image comprises a two-step linear interpolation.
Claim 41
Dependent Claim
44 words
A computer-readable medium according to claim 31 , wherein the calculating step to calculate a data value for the target pixel based on interpolation of data values for at least all pixels surrounding the calculated position in the source image comprises a bi-linear interpolation.
Claim 42
Dependent Claim
44 words
A computer-readable medium according to claim 31 , wherein the calculating step to calculate a data value for the target pixel based on interpolation of data values for at least all pixels surrounding the calculated position in the source image comprises a bi-cubic interpolation.
Claim 43
Dependent Claim
19 words
A computer-readable medium according to claim 31 , wherein the source image and the destination image are gray-scale images.
Claim 44
Dependent Claim
33 words
A computer-readable medium according to claim 31 , wherein the source image and the destination image are both single color planes of color images, each of the color images comprising multiple color planes.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-27 | 2005-02-26 | 2005-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-27 | 2009-02-26 | 2009-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-27 | 2013-02-26 | 2013-08-28 | $7700.00 | Window Closed / Lapsed |