An illumination-independent edge detection and fuzzy enhancement algorithm based on wavelet transform is proposed to extract edges out of a non-uniform weak illumination image. By educing the image wavelet transform formula from the image formation model and CCD camera imaging formula

the pixels’ wavelet module coefficients in the edge area of the image are analyzed and compared

and an illumination-independent wavelet edge detection formula insensitive to illumination is designed. Then

the fuzzy enhancement operator is proposed

which increases the difference between the edges

backgroud and noise by taking into account the wavelet module magnitude and gradient direction.Finally

through the synthetic and real images experiments

the performance of proposed edge detection method is evaluated. It is concluded that the edge detection evaluation criterion

F

of the proposed method for step edge is 0.984 3

the location accuracy

E

d

is 0.126 5

and the mean error of the cross ratio computed by the detected feature circles edge is 3.72×10

-3. The experimental results prove that this edge detection method works well for the non-uniform weak illumination images.