Principle investigations on polarization image sensors

With the appearance of cameras containing newly developed polarized image sensors, which include an on-chip polarizer array placement, there is an upcoming need to characterize these cameras according to a uniform standard. These polarizer arrays consist of 2×2 matrices with four different angled polarizers, placed on top of each pixel. Therefore, this setup differs from the traditionally used multi camera and multi-polarizer setups. In terms of characterizing cameras, the EMVA 1288 standard already provides a widely established guideline on how to characterize monochrome and color digital cameras with linear photo response characteristics. The aim of this paper is to characterize a polarization camera, which takes advantage of these newly developed sensors, within the framework of the EMVA 1288 standard. Therefore, a measuring setup is constructed to be able to isolate the response characteristics of the individual pixels of the polarizer arrays. The measuring setup is built in accordance to the EMVA 1288 standard, thus consisting of a monochromatic light source, a measurement tube and a photodiode. In addition, a rotatable linear polarizing filter is being placed in front of the image sensor, to be able to control the polarization direction of the incident light. The results obtained will then be evaluated and interpreted, and proposals for an extension of the EMVA 1288 standard for the characterization of polarization cameras will be given, based on the experience gained throughout the characterization.