Computational imaging with an extended field of view. (23rd August 2021)

• Record Type: Journal Article
• Authors: Malik, Ritika; Elangovan, Ravikrishnan; Khare, Kedar
• Is Part Of: Journal of optics. Volume 23:Number 8(2021)
• Publication Date: 2021-08-23
• Subjects: computational imaging -- multiple-point impulse response -- extended field of view -- coded aperture -- random convolution -- PSF engineering -- compressive imaging; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8986/ac0ff6
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: The recorded field of view of any digital imaging system is limited by the physical size of the sensor array. While it is a common knowledge that the image field exists beyond the boundaries of the sensor array, there is generally no way to measure it unless the imaging system (or the object) is translated laterally. We propose a single-shot computational imaging system with a multiple-point impulse response that is able to effectively increase the physical size of the sensor array. The image recorded on the array sensor is not visually meaningful but can be used to recover the image field beyond the native sensor boundary via a sparsity based iterative algorithm, as we demonstrate in this work. The system concept can be considered analogous to structured illumination imaging; however, the structuring is performed here in the Fourier space in order to recover an extended image field. The effective increase in the sensor size depends on the extent of the impulses in the engineered multiple point impulse response. The achievable sensor size extension is therefore limited by the resolution of the phase mask that is introduced in the Fourier plane of the imaging system. We present a simulation study where the individual impulses in the designed impulse response extend over the original array sensor size, thereby doubling the effective sensor dimensions (a four times increase in the number of pixels) without affecting the image resolution. Both binary and gray-scale objects have been considered in our study in order to illustrate that the quality of the extended field of view image depends on the sparsity of the object under consideration. The concept of extended field of view computational imaging as presented here may find a number of practical applications.