Interpolation Filter Design Based on All-Phase DST and Its Application to Image Demosaicking

Abstract

Based on a deep understanding of all-phase digital filter (APDF) design and all-phase biorthogonal transform (APBT), this paper will further study the windowed all-phase digital filter (WAPDF) and windowed all-phase biorthogonal transform (WAPBT), discuss the principle of the WAPBT, and provide a unified construction method of the all-phase transform (APT). Based on a type of orthogonal transform, i.e., discrete sine transform (DST), an interpolation filter called an all-phase DST (APDST) filter is constructed and used for image demosaicking; it is compared with bilinear interpolation and all-phase inverse discrete cosine transform (APIDCT) interpolation filters, to test its performance in image interpolation and provide analysis and discussion. The experimental results show that APIDCT and APDST filters with a size of 7 × 7 are similar in interpolation performance, but better than the bilinear interpolation method. In addition to its use in image interpolation demosaicking, the low-pass filter designed in this paper can also be widely used in image interpolation, image denoising, image resizing, and other fields of image processing.

Bivariate Thiele-Like Rational Interpolation Continued Fractions with Parameters Based on Virtual Points

“…The interpolation method also was applied to graphic image morphing and image processing [16][17][18][19][20][21][22][23][24]. In the paper [16], an effective directional Bayer color filter array demosaicking method based on residual interpolation is presented.…”

“…The proposed algorithm guaranteed the quality of color images and reduced the computational complexity. Zhou et al [17] developed an interpolation filter called an all-phase discrete sine transform filter and used it for image demosaicking. Min et al [18] proposed a nonlinear approximation method based on Taylor series to describe and approximate images with intensity inhomogeneity.…”