Snapshot Systems & Hyperspectral Imaging

Hyperspectral imaging, the combination of spectral and spatial information, has enabled advances in fields as diverse as precision farming, machine vision and biomedical imaging. A hyperspectral camera produces a 3D data cube composed of 2D spatial (x, y) and 1D (λ) spectral data. It is typically characterized by the spectral range, the number of spectral channels and the spatial size of the entire image. The data cubes are acquired either by scanning techniques such as push-broom sensors or, in a term proposed by Hagen et al. (2012), snapshot technology for non-scanning spectral cameras, meaning the complete data cube is gathered with one sensor readout.

We coined the phrase hyperspectral snapshot cameras in the past to describe the unique technology of our cameras. Recently this term has become an umbrella definition for all non-scanning imaging spectroscopy techniques, however, there are different technologies available to choose from. To make the distinction clearer, we now refer to our cameras as spectral video cameras, i.e., True Snapshot HSI. In this article True Snapshot HSI is compared to Snapshot-imitating HSI and Scanning HSI

True Snapshot HSI

True Video Spectroscopy

While the data cubes from all snapshot and scanning cameras are similar, comparable and in many cases substitutable, the image production itself makes a big difference. One of the biggest differences is the light efficiency. A true snapshot imaging spectrometer like the multipoint or light field approach collects the entire 3D data cube (all spectral pixels) in a single integration period. The available incoming light is completely utilized and not reduced to one line (push-broom scanning) or one single wavelength pass (tunable filters) at one given time unit. The better light efficiency provides excellent signal qualities and higher signal-to-noise ratios in the shortest time. Time is the second advantage because a snapshot imaging spectrometer captures the entire image in a few milliseconds or less, which makes it a game-changer in real-time imaging and video spectroscopy.

Cubert’s video imaging technology combines its high resolution and small size with high-speed spectral imaging, forming the basic requirements for true video spectroscopy. In fact, snapshots capture static moments, while real-life situations often encompass an array of changes, such as motions, actions, and processes. Machine vision and inspections are more easily and accurately applied to industrial processes using a camera technology that can keep the pace of such processes. Image-based quality assessment or event mapping for moving objects can support higher accuracies i.e. in food industry, pharmacy, or color characterization. Finally, our cameras can feed automated inspection systems, crucial decision algorithms, process control and robot guidance with time critical industrial processes.

Snapshot-imitating HSI

High Adaptability

Until today, high resolution hyperspectral cameras have involved high acquisition costs and a complex and time-consuming usability. This made it difficult for industry to integrate the technology efficiently to machine vision systems. Acquiring hyperspectral images that are accurate recorded and provide reliable image information on the same time always has been a challenge, which is the reason why cameras recently have mainly been used in R&D environments for top-level research and the development of new applications.

The light field approach Cubert has developed is a game changer. With its easiness of use, its speed, and the high potential of downsizing the technology to cost regions of common digital cameras the ULTRIS becomes accessible for decision makers in industry. On the long run, we even see a high potential for mobile applications. Hyperspectral video systems combined with strong retrieval algorithms can provide helpful information in almost real-time, bringing this complex technology to everyday use finally.

Scanning HSI