A tiny VIS-NIR snapshot multispectral camera

Abstract

Spectral imaging can reveal a lot of hidden details about the world around us, but is currently confined to laboratory environments due to the need for complex, costly and bulky cameras. Imec has developed a unique spectral sensor concept in which the spectral unit is monolithically integrated on top of a standard CMOS image sensor at wafer level, hence enabling the design of compact, low cost and high acquisition speed spectral cameras with a high design flexibility. This flexibility has previously been demonstrated by imec in the form of three spectral camera architectures: firstly a high spatial and spectral resolution scanning camera, secondly a multichannel snapshot multispectral camera and thirdly a per-pixel mosaic snapshot spectral camera. These snapshot spectral cameras sense an entire multispectral data cube at one discrete point in time, extending the domain of spectral imaging towards dynamic, video-rate applications. This paper describes the integration of our per-pixel mosaic snapshot spectral sensors inside a tiny, portable and extremely user-friendly camera. Our prototype demonstrator cameras can acquire multispectral image cubes, either of 272x512 pixels over 16 bands in the VIS (470-620nm) or of 217x409 pixels over 25 bands in the VNIR (600-900nm) at 170 cubes per second for normal machine vision illumination levels. The cameras themselves are extremely compact based on Ximea xiQ cameras, measuring only 26x26x30mm, and can be operated from a laptop-based USB3 connection, making them easily deployable in very diverse environments.

Intraoperative hyperspectral determination of human tissue properties

“…12,13 Furthermore, hyperspectral cameras can be used with linescan or snapshot mode to acquire the dataset in a short amount of time, although with low resolution. 14,15 Alternatively, a filter wheel in front of the sensor or behind the light source can step through the hyperspectral space. 16,17 Since the method using the filter wheel allows higher resolution images, and this work does not aim at real-time results, we decided to use a filter-wheel setup.…”

Graph and Rank Regularized Matrix Recovery for Snapshot Spectral Image Demosaicing

“…A key design parameter in SSI is the type of spectral filters used for selecting the appropriate wavelengths. Unlike traditional approaches such as linear variable filters or liquid crystal tunable filters, Fabry-Pérot based SSI architectures, such as IMEC's snapshot imagers [6], [7], enable the design and fabrication of ranges of optimized filters at various wavelengths with flexible layouts and customizable spectral bandwidths. The integrated filter-detector approach reduces the number of discrete and bulky optical components, resulting in cost effective and extremely compact imaging systems.…”

“…To address the need for high resolution imaging, a new breed of HSI imaging architectures under the name of Snapshot Spectral Imaging (SSI) have been proposed, involving systems which sample the full 3D hyperspectral cube on every exposure [5], [6], [7]. Unlike traditional architectures, SSI approaches do not require moving parts like rotating mirrors, thus significantly reducing the complexity of the systems.…”

A Spectral Filter Array Camera for Clinical Monitoring and Diagnosis: Proof of Concept for Skin Oxygenation Imaging

“…Additionally to the adaptation of these sensors in academia [18][19][20][21][22][23][24] some commercially available products have been developed by PIXELTEQ [25], SILIOS Technologies [26] and IMEC [27]. Acquisition speed, ease of use and versatile spectral range makes SFA cameras interesting for the medical sector, especially for the quantification of dynamic processes [28].…”