Sharpness evaluation function of wavelength-related multi-spectral image

In this paper, two objective sharpness functions which results match the subjective result very well are obtained, and it solved the problem of descripting the sharpness property in a multi-spectral image. The multi-spectral image of an international standard vision chart is obtained by a dispersion LCTF multi-spectral imaging system. Subjective experiment is designed and conducted to obtain the sharpness values of the channel image with different light wavelength, and 6 objective sharpness evaluation functions are used to calculate the sharpness/wavelength relationships. Experiment results show that only gray differential function and point sharpness function match the subjective experiment very well, and can be used to describe the sharpness property of the channel images of a dispersion multi-spectral imaging system. Moreover, concerning the computational speed, gray differential function is faster than point sharpness function.