“Synergy effect” and its application in LED-multispectral imaging for improving image quality

Abstract

This paper proposes and demonstrates the multi-wavelength “synergy effect” in light emitting diode (LED)-multispectral images obtained by frequency-division modulation, which can be used to improve the image quality of each waveband. Taking three wavelengths in LED-multispectral imaging as an example, the following experiment was designed: The three different center wavelength (λ1, λ2 and λ3) LEDs modulated by sinusoidal signals with different frequencies are used as the light source to acquire image sequences. The time series composed of corresponding pixels of each frame are demodulated by Fourier transform (FT) to obtain the three single-waveband images ISλ1, ISλ2 and ISλ3 respectively. Similarly, at the same driving intensity, the above three LEDs are separately used as the light source to acquire image sequences, and three groups of images are obtained respectively. Then FT is used to perform demodulation in the same way and three single-waveband images IAλ1, IAλ2 and IAλ3 are obtained. By comparison, it can be concluded that the image quality of each waveband obtained by demodulating the three-wavelength images has been improved, which proves the “synergy effect” and provides a reference for improving the quality of multispectral images.