Most time-to-contact approaches were concentrated in visible light before, where the image feature points were stable, and can be traced between serial frames, so can time-to-contact estimation be obtained from object scale change rate. But in infrared, it is hard to get the stable feature which can be used to trace between images. In this paper, a new method of time-to-contact estimation is proposed. According to the characteristic of infrared image, which is hard to extract feature points but relative easier to segment, the OTSU segmentation method is developed to obtain the area of target, and then the interframe change ratio of the area is used to estimate the time-to-contact information. At last, an adaptive correction method is presented to increase the precision.