Computational multi-focus imaging combining sparse model with color dependent phase mask

Abstract

A method for extended depth of field imaging based on image acquisition through a thin binary phase plate followed by fast automatic computational post-processing is presented. By placing a wavelength dependent optical mask inside the pupil of a conventional camera lens, one acquires a unique response for each of the three main color channels, which adds valuable information that allows blind reconstruction of blurred images without the need of an iterative search process for estimating the blurring kernel. The presented simulation as well as capture of a real life scene show how acquiring a one-shot image focused at a single plane, enable generating a de-blurred scene over an extended range in space.

Extended DoF and achromatic inverse imaging for lens and lensless MPM camera based on Wiener filtering of defocused OTFs

“…Note that I o;k c and I s;k c;δ correspond to the sets of the true and observed blurred images with items marked by the index k for different images and by c for color channels. Moreover, the norm k • k 2 2 is Euclidean defined for the complex-valued variables in the Fourier domain. Thus, we wish to find H c such that the corresponding estimates (H c • I s;k c;δ ) would be close to FT of the corresponding true images I o;k c .…”

Theoretical and experimental analysis of co-designed binary phase masks for enhancing the depth of field of panchromatic cameras

“…To mitigate 1 this problem, studies have been carried out to use these masks with RGB sensors, optimizing them differently to make them effective in increasing the DoF at three different wavelengths. [17][18][19][20][21] RGB sensors associated with the co-design of chromatic optics have also been used for various applications (motion deblurring, 22 depth estimation 23,24 ). Moreover, several empirical studies on panchromatic imaging applications have shown that the binary phase masks can, in fact, perform correctly in the presence of wide spectrum illumination.…”

Experimental validation of hybrid optical–digital imaging system for extended depth-of-field based on co-optimized binary phase masks

“…Among the many possible phase mask struc-tures, binary annular phase masks have the advantage of being easier to manufacture than nonrotationally symmetric masks, such as cubic phase masks. 15 They have been implemented in practice and have shown good performance on specific applications in infrared 16,17 and visible imaging systems [18][19][20][21] . A systematic study of their theoretical performance and of their robustness to aberrations has been done in a previous work 11 where we addressed in particular the fundamental questions of the maximum DoF reachable with these masks and of the minimum number of rings necessary to reach a given level of performance.…”