Compression of color digital hologram using wavelet thresholds and two-times quantization

An improved compression method of color digital hologram by using wavelet transform is proposed, and the image without color aliasing and distortion can be reconstructed from compressed digital hologram. With the presented method, wavelet decomposition, threshold, and quantization are used in the spectrum of hologram to reduce redundancy, then quantization and entropy coding are used in the spatial domain of hologram to remove coding redundancy further. Three different threshold methods for decomposition coefficients are used, and the high compression ratio as 83, 75 and 87 can be obtained respectively with the encoded color digital hologram. Meanwhile, the quality of the images reconstructed from digital hologram is minimally lost visually. •Through wavelet decomposition of spatial and frequency domain information, the compression ratio is improved by twice quantization.•The wavelet decomposition coefficients are optimized to further improve the quality of the reconstructed image.•The processing process of color hologram is considered to avoid color aliasing in the reconstructed image.