Exquisite CCD camera design for an optical computed tomography scanner

Abstract

The OCT (Optical Computed Tomography) in order to obtain the precise dose distribution relies on high accuracy (low noise) and high spatial resolution of the image capture system. Therefore, this study proposes a high-resolution CCD-based camera systems design. Part of the low noise, we propose a variety of CCD signal processing to eliminate noise, such as bias clamp, random noise and pixel response non-uniformity. According to the experiment results, our CCD signal processing algorithm can guarantee low noise output. At exposure time of 150ms, the coefficient of variation of the pixel is reduced from 12.37% to 0.51% by flat-field correction, in the same measurement standards, our system SNR (30.12dB) better than other brand CCD camera (25.31dB) and other brand CMOS camera (29.53dB). Part of the high spatial resolution, we propose high-performance camera design (optical lens, image sensor, image processing) to ensure high spatial resolution output. In MTF50 (Modulation Transfer Function 50%), our camera (1024×1024) get the 745LW/PH (Line Width/Picture Height), close to 73% of the limited resolution; another brand CCD camera (1024×768) of 358 LW/PH, about 46.6% of the limited resolution; another brand CMOS camera (3648×2736) of 1628 LW/PH, about 59.5% of the limited resolution. Therefore, our camera with a high precision and high spatial resolution design, it can to meet in OCT and increase accuracy of the dose distribution.