Image contrast enhancement in automatic mode by nonlinear stretching

The problem of image enhancement in automatic mode is considered. A new method of contrast enhancement by adaptive nonlinear stretching using piecewise linear transformation of the brightness scale is proposed at which the average value of the brightness of transformed image is closest to the middle of the brightness range. The research of the effectiveness of the proposed and known methods of nonlinear stretching of monochrome images using the known no-reference metrics of integral contrast of image is carried out.