Novel scheme for infrared image enhancement based on Contourlet transform

Low contrast and large noise are two main characteristics of infrared image, considering this characteristics, a novel scheme for infrared image enhancement based on Contourlet transform is proposed. Firstly, Contourlet transform is performed on the original infrared image, we can obtain lowpass subband and bandpass subband at different scales and directions. At lowpass subband, the linear transformation based on the maximal and minimal coefficient of subband is applied to enhance the global contrast. At bandpass subband, the fuzzy nonlinear enhancement operator is used to enhance the high frequency subband coefficient, the objective characteristics of the texture is enhanced, but the background is suppressed. Finally, the inverse transform of Contourlet is applied to produce enhanced infrared image. Through simulation, the results show that the proposed scheme could enhance contrast and highlight the edge of the image texture information and details effectively.