Snapshot Bayer pattern Hyperspectral image sensor

M. Willems
imec, BE

Keywords: snapshot multispectral camera, multispectral CMOS sensor, monolithic integration, mosaic focal plane array, per-pixel filters, snapshot acquisition

Summary:

This paper introduces a novel snapshot multispectral imager concept based on optical filters monolithically integrated on top of a standard CMOS image sensor. It overcomes the problems mentioned for scanning applications by snapshot acquisition, where an entire multispectral data cube is sensed at one discrete point in time. This is enabled by depositing interference filters per pixel directly on a CMOS image sensor, extending the traditional Bayer color imaging concept to multi- or hyperspectral imaging without a need for dedicated fore-optics. The monolithic deposition leads to a limited spectral crosstalk and a high degree of design flexibility. In turn, this enables systems ranging from application-specific, high spatial resolution cameras with 1 to 4 spectral filters, to hyperspectral snapshot cameras at medium spatial resolutions and filters laid out in cells of 4x4 to 6x6 or more. Through the use of monolithically integrated optical filters it further retains the qualities of compactness, low cost and high acquisition speed, differentiating it from other snapshot spectral cameras. Our prototype demonstrator camera can acquire multispectral image cubes of 272x512 pixels over 16 bands in the spectral range of 600-1000nm at 340 cubes per second for normal machine vision illumination levels.