Effect on measurement accuracy of transillumination using sawtooth-shaped-function optical signal

There exist lots of difficulties in optical transillumination of biological tissues, especially, low-level-light detection and low gray-scale resolution could reduce recognition accuracy of differences in tissue. Aiming at the problems, this paper proposes a method for optical transillumination using sawtooth-shaped-function optical signal and frame accumulation technology to explore the spatial information of heterogeneity in the tissue. Sawtooth-shaped-function optical signal combined with frame accumulation technology is applied to realize the low-level-light image detection, where frame accumulation technology improves the signal-to-noise ratio and detection sensitivity, and sawtooth-shaped-function signal improves gray-scale resolution. The results of the experiment applied on the flat-shaped phantom demonstrated that, compared with the constant intensity optical signal, the application of the sawtooth-shaped-function optical signal effectively improved the gray-scale resolution, thus improved the extraction accuracy on positional feature pixels of heterogeneity. In addition, the sawtooth-shaped-function optical signal reduces the light radiation per unit time and per unit area. Therefore, the proposed illuminated way is more suitable for the imaging of biological tissue.