Scale-based approach for image quality evaluation
Kamesh R. Namuduri, Romain Murenzi, Lance Kaplan · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1998
In images, anomalies such as edges or object boundaries take on a perceptual significance that is far greater than their numerical energy contribution to the image. Wavelet transform highlights these anomalies by representing them with significant coefficients. The contribution of a wavelet coefficient to the perceptual quality of the image is related to its magnitude. Degradation in image quality due to image compression reflects in the form of reduction in the magnitude of the wavelet coefficients. Since, significant wavelet coefficients appear across different scales and orientations, it is important to observe the wavelet transform at different scales and orientations. In this paper, the wavelet transform of a given image and the reconstructed images at various quality levels are represented in the form of energy density plots suggested in reference one. A quality metric is proposed based on the absolute difference between the energy densities corresponding to the original and reconstructed images. Preliminary results obtained using the scale-based image quality evaluation strategy are reported.