Belgian research lab IMEC has used micromachining to demonstrated a hyperspectral camera - a sensor in which every pixel is a spectrometer.
Hyperspectral cameras discriminate between different objects that cannot be accurately distinguished using traditional RGB methods.
The technology has been used for crop screening, food selection, skin cancer detection and target detection.
"However, currently available hyperspectral cameras are large, expensive and slow," said IMEC. "Therefore, they can often not be used for time-critical or high-throughput applications, and their use is thus limited to highly specialised research environments. IMEC's chip-based technology paves the way towards the industrial application of hyperspectral imaging, as it enables small, cost-efficient and fast solutions.
Presented at the SPIE Photonics West conference, the camera includes a set of MEMS spectral filters that are directly post-processed at wafer level on top of a commercially available CMOSIS CMV4000 (4Mpixel 180fps) image sensor.
It has 100 spectral bands between 560nm (green) and 1000nm (infra-red).
Filter bandwidth (full width half max) ranges from 3nm at 560nm to 20nm at 1000nm, and the transmission efficiency of the filters is around 85%.
Typical integration times in prototype are between 2 and 10ms under 450W halogen light illumination.
"Due to its integrated filter design and high spectral filter efficiency, the solution can obtain scanning speeds that are compatible with real industrial requirements," claimed IMEC. "The speed of the demonstrated system corresponds to an equivalent speed of 2,000 lines per second, significantly exceeding current state-of-the-art hyperspectral sensors."
To create custom hyperspectral cameras, said IMEC, a commercially-available sensor would be selected, or a custom-designed one designed, to match the pixel and maximal frame rate requirement, then an appropriate hyperspectral filter can be constructed to produce the right number of spectral bands and spectral resolution.