Using MTF for automated gated imaging system in turbid medium

This paper introduces an auto-tuning range-gated imaging system in turbid medium. The automated gated imaging system is able to auto-tune the best image quality by using the MTF evaluation technique. For a typical gated system, the gated images are recorded into video format in increasing gate opening time, each frame of the video recorded is basically to "slice" the targets at different distance from camera (based on time of light). Each frame would only able to show the targets within the specifically "sliced" target distance, which limits the capability of gated imaging system. Thus, it is necessary to develop auto-tuning system that will overcome the limitation in turbid water condition. In this paper, all enhanced target images within the field of view (FOV) are fused into one 3D image, and this will increase the efficiency of the study and works under turbid medium condition. Works had been done in selecting a quantitative image quality index for automated tuning system so that images with better quality can be detected accurately in turbid conditions. The non-reference measuring index-Modulation Transfer Function (MTF) can perform better in analyzing images under turbid condition thus is selected for this application. Experiment results show that the mid-band spatial frequencies from 21 to 61 demonstrate the degradation of image quality due to the turbid water backscattering noises. Thus, we propose to use MTF in the auto-tuning system to select best quality target from multiple images that scan thru the various gate timing. Subsequently, image fusion is performed to fuse multiple gate opening time images into a 3D extended targets turbid condition.