A high-efficiency acquisition method of LED-multispectral images based on frequency-division modulation and RGB camera

摘要

LED illumination based multispectral imaging (LEDMSI) is one of the promising techniques of fast and effective spectral image acquisition. RGB camera based LEDMSI can acquire 3-band images in a single exposure, which has practical, high-efficiency and low-cost advantages. Frequency-division modulation technology can achieve the simultaneous acquisition of multi-wavelength images. In this paper, a high-efficiency acquisition method of LED-multispectral images based on frequency-division modulation and RGB camera is proposed. And its effectiveness is verified by the experiment with dual-frequency modulation of six wavelengths (two multiplexed illuminations) as example. In the experiment, two multiplexed illuminations modulated by two carrier frequencies are used as the light source to acquire an image sequence, and grayscale images are obtained by "R/G/B'' 3-channel separation. Further, the Fast Fourier Transform is used to demodulate the time series of corresponding pixels of each grayscale image, the images of each multiplexed illumination are obtained, respectively. In the result and discussion section, the multispectral images obtained by the method in this paper is compared with the multispectral images obtained without combining frequency-division modulation. Through the result, it can be concluded that the method of combining frequency-division modulation with RGB camera is a high-efficiency acquisition method of high-quality multispectral images, which provides a reference for the LED-multispectral imaging technology.