Wavelet-based compression algorithm for still omnidirectional 3d integral images

Three dimensional (3D) integral imaging is a method that allows the display of full colour images with continuous parallax within a wide viewing zone. Due to the significant quantity of data required to represent a captured 3D integral image with high resolution, image compression becomes mandatory for the storage and transmission of integral images. This paper investigates the use of 2D discrete wavelet transform (2D-DWT) for the compression of omnidirectional 3D integral images (OII). The method requires the extraction of different viewpoint images from the integral image. A single viewpoint image is constructed by extracting one pixel from each microlens, then each viewpoint image is decomposed using a 2D-DWT. The resulting array of coefficients contains several frequency bands. The lower frequency bands of the viewpoint images are assembled and compressed using a 3D discrete cosine transform (3D-DCT) followed by Huffman coding. Whereas, the remaining higher bands are fed directly into a quantisation process followed by arithmetic coding. Simulations are performed on a set of several grey level 3D OII using a uniform scalar quantizer with deadzone. It was found that the algorithm achieves better rate-distortion performance and reconstructs the images with much better image quality at very low bit rates than previously reported 3D-DCT-based scheme.