Wavefront coding: a modern method of achieving high-performance and/or low-cost imaging systems

Abstract

This paper gives a brief introduction into the background, application, and design of Wavefront Coding imaging systems. Wavefront Coding is a general technique of using generalized aspheric optics and digital signal processing to greatly increase the performance and/or reduce the cost of imaging systems. The type of aspheric optics employed results in optical imaging characteristics that are very insensitive to misfocus related aberrations. A sharp and clear image is not directly produced from the optics, however, digital signal processing applied to the sampled image produces a sharp and clear final image that is also insensitive to misfocus related aberrations. This paper gives an overview of Wavefront Coding and example images related to the two applications of machine vision/label reading and biometric imaging. Design techniques of Wavefront Coding are unique from that of traditional imaging system design since both the optics and digital processing characteristics of the system arejointly optimized for optimum system performance.

Computational filter-aperture approach for single-view multi-focusing

“…FA model: The idea of using multiple aperture lenses has been previously proposed using micro lens array and wave front coding [1] [2]. However, the imaging quality of these optical designs is fundamentally inferior to a camera system with a large single lens; the resolution of these small lens arrays is severely limited by diffraction.…”

Study on depth of field of wavefront coding imaging system

“…This technology not only can extend the DOF of imaging optical systems without losing the resolution, but also can decrease many kinds of aberrations and the errors which caused by the temperature change and the assembly, while reducing the size, weight, and cost of imaging systems also [2][3]. Currently, wavefront coding technology is used widely in many fields [4][5][6][7][8][9]. The cubic phase mask being introduced in the exit pupil of traditional optical system changes the shape of the wavefront and makes the MTF of the optical system to be defocus-independent.…”

<title>Wavefront coded zoom lens system</title>

“…Wavefront Coding is a new technique used to improve imaging performance by increasing the depth of focus and reducing the effects of misfocus and focus-related aberrations while allowing reduction of size, weight and cost of imaging systems 1 . This technique combines non-rotationally symmetric aspheric optics and digital image processing.…”