Detection and/or enhancement of contrast differences in digital image data
US8873880B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 2010 |
| Grant date | Oct 28, 2014 |
| Priority date | — |
| Expiry date | Oct 5, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/20016
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for obtaining and/or enhancing local contrast differences (LD) in digital image input data (in), wherein a local contrast measure (SADap) approximating a two-dimensional sum of absolute difference (SAD) measure is obtained by obtaining a first-dimension sum of absolute difference measure (energyVk(m, n)) representing a sum of absolute difference (SAD) in a first dimension of at least one image region, and obtaining the local contrast measure (SADap) as a second-dimension convoluted first-dimension sum of absolute difference measure by convoluting the first-dimension sum of absolute difference measure (energyVk(m, n)) in a second dimension of the at least one image region, is proposed, wherein the step of obtaining the local contrast measure (SADap) as the second-dimension convoluted first-dimension sum of absolute differences measure further includes an addition step wherein an energy term (Δlpfk(j)) representing a first-order difference on a distance (J) of a low pass filtered signal used in obtaining the first-dimension sum of absolute differences measure (energyVk(m, n)) and in obtaining the second-dimension convoluted first-dimension sum of absolute differences measure…
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