Research to Business
Offer: 669

Spectral cameras with increased luminous efficacy

Optical notch filters for spectral cameras allow recording in difficult lighting conditions and reduce image noise.

For the human eye, many materials, such as salt and sugar, can hardly be distinguished optically from each other. In industry and research, spectral cameras are used for this purpose, which can record more color channels than red, green and blue. The additional spectral information can be used to derive object properties and classify materials. Spectral cameras are also used, for example, to detect skin cancer or to monitor plant growth in agriculture.

State of the art

Up to now, narrow optical bandpass filters have been used for spectral images, which only capture a certain wavelength per image. In this way, images for different wavelengths are created and superimposed. The resulting image provides software-based information, for example on the molecular structure or chemical properties. Since narrow optical filters allow very little light to pass through, the exposure time must be increased accordingly. As a result, image noise increases and the camera may need to be strongly cooled. This applies in particular to low-light applications such as fluorescence analysis.


The Institute for Industrial Information Technology (IIIT) at KIT is currently developing a process in which optical notch filters are used. Each of these filters covers a large part of the optical spectrum. In contrast to the current method, individual wavelengths are omitted. The filters are combined in such a way that the overall image - if necessary by means of post-processing - provides the same information as the conventional image.


The central advantage is the higher luminous efficacy, which makes it possible to capture low-light scenes at an increased frame rate. Overall, the signal-to-noise ratio (SNR) is significantly increased. The conversion to notch filters is uncomplicated, as only the filters are replaced and, if necessary, the post-processing is adapted. The camera design remains identical.

Options for companies

The invention has already been tested by simulations and mathematically investigated. KIT is looking for industrial partners to develop and validate the technology prototypically.

Your contact person for this offer

Christopher Kling, Karlsruhe Institute of Technology (KIT)
Innovation Manager Mobility, Innovation and Relations Management (IRM)
Phone: +49 721 608-28460


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