# Coupled Learning for Facial Deblur

## TL;DR

This paper introduces a coupled learning approach for facial deblurring that models PSFs and sharp face images as linear combinations of orthogonal basis sets, improving recognition accuracy.

## Contribution

The paper proposes a novel coupled learning algorithm that jointly estimates PSFs and intrinsic face images using predefined orthogonal bases, enhancing deblurring robustness.

## Key findings

- Improved facial image sharpness and recognition accuracy.
- Effective handling of various blur types through candidate generation.
- Demonstrated superior performance on multiple face recognition datasets.

## Abstract

Blur in facial images significantly impedes the efficiency of recognition approaches. However, most existing blind deconvolution methods cannot generate satisfactory results due to their dependence on strong edges, which are sufficient in natural images but not in facial images. In this paper, we represent point spread functions (PSFs) by the linear combination of a set of pre-defined orthogonal PSFs, and similarly, an estimated intrinsic (EI) sharp face image is represented by the linear combination of a set of pre-defined orthogonal face images. In doing so, PSF and EI estimation is simplified to discovering two sets of linear combination coefficients, which are simultaneously found by our proposed coupled learning algorithm. To make our method robust to different types of blurry face images, we generate several candidate PSFs and EIs for a test image, and then, a non-blind deconvolution method is adopted to generate more EIs by those candidate PSFs. Finally, we deploy a blind image quality assessment metric to automatically select the optimal EI. Thorough experiments on the facial recognition technology database, extended Yale face database B, CMU pose, illumination, and expression (PIE) database, and face recognition grand challenge database version 2.0 demonstrate that the proposed approach effectively restores intrinsic sharp face images and, consequently, improves the performance of face recognition.