Adaptive Sharpness Function for Real-Time Passive Automatic Focusing Systems Using Wavelet Transformation

摘要

When distance overlaid under low illumination environment, in order to obtain the best sharpness function of the image through the autofocus charge-coupled device (CCD) camera from diffuse and specula surface object, the four different bases transform of wavelet, such as Harr, Daubechies, Coiflets and Biorthogonal, are presented in this study. Meanwhile, to produce an adaptive sharpness function of an image and show its sharpness, especially in the vicinity of focus, the sobel edge-enhanced operator (sobel), gray-level amplitude operator (amplitude), sum-modulus-difference operator (smd), discrete cosine transformation (dct) and discrete wavelet transform vertical (dwt v) were compared further. It had been shown that, for an image to satisfy the pyramid profile of sharpness function, the significant decomposition of sharpness with discrete wavelet transformation was the best.