Depth estimation using spectrally varying defocus blur

Abstract

This paper proposes a method to estimate depth from a single multispectral image by using a lens property known as chromatic aberration. Chromatic aberration causes light passing through a lens to be refracted depending on the wavelength. The refraction causes the angle of rays to vary depending on their wavelength and a change in focal length, which leads to a defocus blur for different wavelengths. We propose a theory to recover a continuous depth map from the blur in a single multispectral image that includes chromatic aberration. The proposed method needs only a standard wide-aperture lens, which naturally exhibits chromatic aberration, and a multispectral camera. Moreover, we use a simple yet effective depth-of-field synthesis method to calculate the derivatives and obtain all-in-focus images necessary to approximate spectral derivatives. We verified the effectiveness of the proposed method on various real-world scenes.