Color Image Compression using Hybrid Wavelet Transform with Haar as Base Transform

This paper proposes color image compression method using hybrid wavelet transform and compares it with results obtained using hybrid transform and multi-resolution analysis. Haar wavelet is widely used in image compression. So here Haar transform is selected as base transform and combined with non-sinusoidal transforms like Slant, Walsh and Kekre transform. Hybrid Haar wavelet transforms is generated using Kekre’s hybrid wavelet generation algorithm. Different sizes of component transforms are used to generate hybrid wavelet transform. Haar (32x32)-Slant (8x8) gives less error as compared to Haar-Walsh and Haar-Kekre Hybrid wavelet. Performance of hybrid wavelet is compared with hybrid transform and multi-resolution by varying the size of component transforms. Mean Absolute Error (MAE) and Average Fractional Change in Pixel Value (AFCPV) are used to compare visual quality of an image. Structural Similarity Index (SSIM) of Haar-Slant hybrid wavelet is computed on 16x16 blocked images and compared with its hybrid transform and multi-resolution analysis. Least RMSE value obtained at compression ratio 32 by HaarSlant hybrid wavelet with size 32-8 is 10.53. Mean absolute error is 7.32 in Haar-Slant hybrid wavelet with component size 16-16. Least AFCPV is 0.344 with component size 32-8 for the same.