A Haar Wavelet-Based Perceptual Similarity Index for Image Quality Assessment

TL;DR

This paper introduces HaarPSI, a new, computationally efficient image quality assessment index based on Haar wavelet coefficients, which correlates well with human perception and outperforms existing measures on benchmark datasets.

Contribution

The paper presents HaarPSI, a novel perceptual similarity index utilizing Haar wavelet decomposition, offering improved correlation with human judgment and computational simplicity.

Findings

HaarPSI outperforms SSIM, FSIM, and VSI in correlation with human scores.

HaarPSI is computationally inexpensive and suitable for real-world applications.

Validated on four large benchmark databases with diverse distortions.

Abstract

In most practical situations, the compression or transmission of images and videos creates distortions that will eventually be perceived by a human observer. Vice versa, image and video restoration techniques, such as inpainting or denoising, aim to enhance the quality of experience of human viewers. Correctly assessing the similarity between an image and an undistorted reference image as subjectively experienced by a human viewer can thus lead to significant improvements in any transmission, compression, or restoration system. This paper introduces the Haar wavelet-based perceptual similarity index (HaarPSI), a novel and computationally inexpensive similarity measure for full reference image quality assessment. The HaarPSI utilizes the coefficients obtained from a Haar wavelet decomposition to assess local similarities between two images, as well as the relative importance of image areas. The consistency of the HaarPSI with the human quality of experience was validated on four large benchmark databases containing thousands of differently distorted images. On these databases, the HaarPSI achieves higher correlations with human opinion scores than state-of-the-art full reference similarity measures like the structural similarity index (SSIM), the feature similarity index (FSIM), and the visual saliency-based index (VSI). Along with the simple computational structure and the short execution time, these experimental results suggest a high applicability of the HaarPSI in real world tasks.