To solve the reduction of image quality caused by uneven illumination of cab,a method which can enhance driver video image quality has been proposed.Firstly,an image is transformed from RGB space into YCbCr space,the Cb and Cr elements remain unchanged and the Y element is divided into high-frequency part and low-frequency part which contains the whole illumination information.The low-frequency part is compensated by using Retinex theory and then by using Laplace sharpness and Gaussian smoothing on the Y elements to enhance image details and eliminate noise interference.After the above treatment,the Y element and the original Cb and Cr elements form a new image.Results show that compared with other traditional algorithms,the method can enhance images and details,which is benefit for detecting fatigue state.