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AssigneeTP Vision Holding B.V.
InventorCHRIS DAMKAT
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In a method and device for improving image rendition by contrast and/or sharpness enhancement the sharpness enhancement is made dependent on the local average luminance value. A mix is made of spatially enhanced image signals is used, wherein for various signal differing spatial frequencies are boosted. The mixing factors for mixing of the boosted signals are dependent on a local average luminance value such that the distribution over frequency bands shifts to higher frequencies and sharper enhancement as the luminance value increases.
Method for converting input image data (I) into output image data (Ienhanced) wherein the input image data (I) is locally (x) filtered by an enhancement filter (22) with a spatial frequency response to provide a filtered signal, said filtered signal is multiplied with a gain (g) to provided a gain multiplied filtered signal (I′), a local average luminance value (lum) is established, wherein a spatial filter frequency (f) for which the spatial filter has maximum response and the gain (g) are determined as a function of the local average luminance value, wherein the spatial filter frequency (f) and the gain (g) increase for increasing local luminance value, wherein the gain multiplied filtered signal (I′) is added to the input image signal to provide the output image data, wherein first areas of the input image, that are included in a first spatial frequency range and that are included in a first luminance value range, are amplified more than second areas of the input image, that are included in the first spatial frequency range and that are included in a second luminance value range, and wherein the first luminance value range is higher than the second luminance value range.
A non-transitory computer-readable medium including computer program code that, when executed by a processor of a computer to convert input image data into output image data, the non-transitory computer-readable medium comprising:
Image conversion unit (20) for converting input image data (I) into output image data, comprising an input for input image data (I) and an output for output image data is, an enhancement filter (22) for locally (x) filtering the input image data (I), said filter having a spatial frequency response to provide a filtered signal, a multiplicator (23) for multiplying said filtered signal with a gain (g) to provided a gain multiplied filtered signal, a means (21) for establishing local average luminance values, and determining a spatial frequency (f) for which the frequency filter has maximum response and the gain (g) as a function of the local average luminance value (f=F1(lum,x), g=F2(lum,x)), wherein the spatial frequency (f) and the gain (g) increase for increasing local average luminance value, and a means for adding the gain multiplied filtered signal (I′) to the input image signal (I) for providing the output image data, wherein first areas of the input image, that are included in a first spatial frequency range and that are included in a first luminance value range, are amplified less than second areas of the input image, that are included in the first spatial frequency range and that are included in a second luminance value range, and wherein the first luminance value range is lower than the second luminance value range.
Dependencies are inferred from the claim text.