6533b82dfe1ef96bd1291ffe

RESEARCH PRODUCT

Improved color interpolation using discrete wavelet transform

subject

description

New approaches to Color Interpolation based on Discrete Wavelet Transform are described. The Bayer data are split into the three colour components; for each component the Wavelet Coefficient Interpolation (WCI) algorithm is applied and results are combined to obtain the final colour interpolated image. A further anti-aliasing algorithm can be applied in order to reduce false colours. A first approach consists of interpolating wavelet coefficients starting from a spatial analysis of the input image. It was considered an interpolation step based on threshold levels associated to the spatial correlation of the input image pixel. A second approach consists of interpolating wavelet coefficients starting from the analysis of known coefficients of the second transform level. The resolution of each wavelet transform level is double as regards the successive one, so we can suppose a correspondence among wavelet coefficients belong to successive sub-bands. Visual quality of the interpolated RGB images is improved, reducing the zipper and aliasing effects. Moreover, in an embedded systems, which use JPEG2000 compression, a low computational cost is achieved in both cases since only some threshold evaluations and the IDWT step are performed for the first approach, while the second one involves only the DWT and IDWT steps.