| Summary: | 碩士 === 國立勤益科技大學 === 電子工程系 === 99 === A poorly-illuminated environment can significantly affect the contrast ratio, producing an unexpected image. This paper presents an effective method for image contrast enhancement based on adaptive power function. Our chief goal is to produce a contrast enhancement technique to recover an image, from a blurred and darkness, also improve visual quality of it. Sub-band coefficients were developed base on the method of adaptive power function. In our proposed method, the image contrast enhancement is modified by local mean and local variance before the adaptive power function is performed. In order to avoid the expensive time for traditional contrast enhancement algorithms, which search optimal gray transform parameters in the whole gray transform parameters space, a new criterion is proposed with sub-band processing. Nonlinear transform parameters are based on adaptive power function algorithm so as to obtain optimal gray transform parameters. Experimental results show that the proposed algorithm is capable of enhancing the contrast of the original image adaptively while extruding the details of objects simultaneously.
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