Spectral imaging system based on guest-host liquid crystal adjustable optical filter

Abstract

The invention discloses a hyperspectral imaging system based on a guest-host liquid crystal adjustable optical filter. The system is composed of a novel guest-host liquid crystal adjustable optical filter, an imaging lens, a CCD, a signal generator, a data acquisition card and the like, wherein the key element is an adjustable optical filter based on guest-host liquid crystal. According to the invention, the hyperspectral imaging system is characterized in that liquid crystal molecules forming the adjustable filter are doped with dichroic dye, the dichroic dye is highly sensitive to polarization of incident light, and when the polarization direction of incident light is perpendicular to or parallel to the dye molecules, the absorption intensities are different; the driving voltage of the device is only about several volts, and the transmission spectrum can be rapidly adjusted in the visible light range; based on the adjustable device, a compact computational spectral imaging system can be realized by using algorithms such as linear regression, compressed sensing or machine learning; and compared with a traditional spectral imaging system, the system has the advantages of being high in imaging speed, high in transmittance, compact in structure, low in price, high in signal-to-noise ratio and the like.

Description

technical field [0001] The invention relates to a spectral imaging system based on a guest-host liquid crystal tunable filter, and the system can be applied to fields such as remote sensing, environment / resource monitoring, biomedical microscopic imaging, and portable spectral measurement. [0002] technical background [0003] Spectral imaging technology, as an imaging method that can obtain spectral information and image information at the same time, can obtain information that cannot be detected by existing traditional imaging technologies. increasingly important role. Traditional spectral imaging technology relies on mechanical scanning components for spectral detection, which is bulky, slow scanning, and not stable, and is not suitable for the development of miniaturization and compactness of devices. At present, staring spectral imaging systems based on tunable filters are superior to traditional mechanical spectral imaging systems in terms of device volume, scanning s...

AI Technical Summary

Problems solved by technology

However, there are two problems with this tunable filter

On the one hand, the transmittance of this device is very low, generally less than 10%.

The extremely low transmittance is mainly because there are too many unit devices constituting this filter, generally more than 5, and each element has at least two reflection interfaces, so more than 10 reflection interfaces will generate a lot of reflection, seriously affecting Device transmittance

The low transmittance makes the signal-to-noise ratio of the spectral imaging system based on this device not high, which limits its application in dark light, low reflectivity and other occasions; on the other hand, the price of this type of device is very expensive, Thorlabs The price of liquid crystal tunable filters in the visible light band is as high as 60,000 yuan. The high price makes its application scope limited to a few fields such as military affairs and scientific research.

For the domestic market, due to the extremely high process requirements of liquid crystal tunable filters, few companies have successfully developed this type of high-performance liquid crystal tunable filters

Images