Multispectral Camera

Ricoh has developed a multispectral camera that can acquire 2D spectral information as well as chromaticity and other color information for a subject in real-time. And it’s all packaged in a unique configuration similar in size to an ordinary FA camera.

A multispectral camera can acquire color information from a subject. Although systems using swappable color filters and prisms have been established as normal techniques for acquiring spectral information, with interchangeable color filters time to swap poses a barrier to real-time imaging. With prisms it’s to make the camera more compact.

Ricoh multispectral cameras use optical devices that can acquire spectral information in a single snapshot, together with image processor that generates an image for each set of the spectral band. As a result, spectral distribution and chromaticity for particular wavelengths can be computed in real-time. This makes it possible to precisely acquire the desired color information. In addition, color information can be acquired with a device similar in size to a conventional factory automation (FA) camera. Beyond use to detect subjects hard to distinguish from each other, our multispectral cameras can be used to inspect objects whose states change over time and to detect foreign matter. And in addition to FA, possible applications include the food, pharmaceutical, agricultural, and security industries.

The new multispectral cameras developed by Ricoh incorporate the following three technologies:
- A color filter that extracts multispectral information from an object
- A microlens array that distributes the multispectral information across sensor pixels
- An image processor that generates an image for each set of spectral information from the sensor image
Spectra and chromaticity are then computed from the multispectral information obtained in this way (see Figure 1).

Figure 1: Multispectral camera configuration

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Usage scenario 1: color inspection

By computing chromaticity, it becomes possible to conduct high-precision color inspections that outperform previous color photograph imaging inspections in which certain color determinations are impossible. Specifically, this technology can be used for color inspections of molded or painted products, and for surface color inspections of LCD, OLED, or other light-emitting displays.

Figure 2: Color inspection usage scenario

Usage scenario 2: state awareness

The state of a subject (freshness, purity, disease severity) can be quantitatively evaluated in ways that were not possible with previous color photography. By taking spectral images of individual subjects, the sweetness of produce and the freshness of food can be quantitatively evaluated from information derived from minute differences in color.

Figure 3: State awareness usage scenario

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