LAUSR

Abstract. The traditional frame accumulation technology can effectively reduce the random noise and improve the signal-to-noise ratio in the image. A frame accumulation technology with superimposed sawtooth-shaped-function can reduce the quantization noise and increase the grayscale resolution. However, in the case of continuous operating environment, it is not suitable because constant amplitude light used must be turned off for taking pure and shadowy images, which are generated by superimposed shaped light. To solve this problem, we propose an improved method named dual optical signals with different periods (DOSDP) to improve grayscale resolution of an image. The method does not need to capture signals twice. In other situations, where it is not appropriate to directly superimpose a shaped function optical signal to an object, a piece of glass is installed on the light path between the camera and the object so that the superimposed light can enter the camera through the glass reflection. Furthermore, our method allows superimposed signals to be nonlinear. Experimental results show that DOSDP method can effectively improve quality of the image.