Panasonic Develops Hyperspectral Imaging Technology with the World's Highest Sensitivity

With the evolution of image recognition technology, the application of machine vision is expanding, including industrial use of image data for efficiency, labor saving, and energy saving. Since machine vision recognizes images on a computer, information that humans cannot perceive, such as continuous color changes (spectral information), can be used to make analyses. Images with spectral information, known as hyperspectral images, are expected to play a role in expanding the application fields of machine vision.

In conventional hyperspectral imaging, optical elements such as prisms and filters that selectively pass light of a specific color (i.e., wavelength) have been used. However, since these methods detect light separately in each wavelength, there is a physical restriction in that light utilization efficiency (i.e., the sensitivity) decreases in inverse proportion to the number of wavelengths. Therefore, illumination with a brightness comparable to that of the outdoors on a sunny day (illuminance of 10,000 lux or more) was required to shoot, which decreases usability and versatility.

The newly developed hyperspectral imaging technology employs compressed sensing, which efficiently acquires observation data by "thinning out" and reconstructing data to restore data to what it was before thinning out through image post-processing. The compressed sensing technology is also used in MRI examinations in the medical field as well as black hole observations. A special filter that transmits multiple wavelengths of light to appropriately thin out data is implemented on an image sensor (Fig. 1), and the image reconstruction is carried out by a uniquely optimized algorithm for digital image processing. By leaving a part of the color-separating functions to the software, Panasonic Holdings have overcome the trade-off between the number of wavelengths and sensitivity, the fundamental issue of conventional technology. This approach has made it possible to capture hyperspectral images with the world's highest sensitivity (Fig. 2) and video (Fig. 3) under indoor illumination (550 lux).

Utilizing the developed technology, Panasonic Holdings will collaborate with our partners to provide new spectral sensing solutions, including highly accurate image analysis and recognition, and to expand machine vision applications with highly sensitive hyperspectral imaging technology.