Infrared image enhancement using adaptive trilateral contrast enhancement

• A multi-faceted contrast enhancement algorithm for thermal image is proposed.
• The mechanism relies on manipulation of image contrast, sharpness and intensity.
• Contrast and details enhancements are achieved with least enhancement defects.

A novel contrast enhancement method called adaptive trilateral contrast enhancement (ATCE) method is presented. Unlike conventional methods which exaggerate the contrast difference between fore- and background of an image as a means to improve image visual quality, ATCE method provides a multifaceted approach which involves enhancement of both image contrast and subtle image details. The designation of ``trilateral'' is derived from the working principle of ATCE which utilises three different types of image characteristics, namely, contrast, intensity and sharpness, to concurrently enhance the visual quality of an image. In the experiment on a set of infrared thermal images captured under low-light night time environment, ATCE is evaluated and compared to some existing contrast enhancement methods. The quantitative experimental results show that ATCE significantly surpasses other existing methods on the measure of enhancement by entropy.