Design, implementation and performance analysis of cooled infrared cameras with single FPA depth estimation capabilities

摘要

Over the past years, a huge interest has grown in both the scientific and the industrial communities for miniaturized and functionalized cameras featuring new capabilities such as depth estimation or multispectral imaging. As a consequence, new optical architectures such as the plenoptic camera have been proposed and studied, primarily in the visible spectrum. These cameras usually include an optical element such as a microlens array or a prism array in order to obtain multiple sub-images of a same object point on the sensor, allowing for single snapshot image refocusing or depth estimation. In the meantime, recent developments in cooled infrared focal plane arrays technology have led to smaller pixel pitch and bigger formats, thus slowly reducing the resolution gap that existed between visible and infrared cameras. This gain in resolution enables the design of more functionalized infrared imaging systems, thus answering the critical need for more features in a limited volume, especially for military applications. However, the use of cooled infrared sensors brings an additional challenge to the design of such cameras because of the specific assembly in which the sensor has to be embedded called a dewar. In this paper we explain how we overcame these constraints to design and implement three different cooled infrared cameras with single focal plane array depth estimation capabilities. We then evaluate the performance of these cameras in terms of range and precision of the depth estimation and conclude on their potential applications.