Contrast research on interpolation and subpixel imaging in CCD geometric superresolution reconstruction

In order to enhance the resolution of Charge Coupled Device (CCD) pixel with the pixel dimension and focal length of optical system unchanged, the problem of CCD geometric superresolution is educed. The problem is discussed in terms of software and hardware. In software, the bicubic interpolation is introduced, while in hardware, the subpixel imaging method is utilized. The subpixel imaging method integrates two uniform linear CCDs staggered by half dimension of pixel in one device. In operation, the line frequency is doubled. At last, the collected data is interweaved to synthesize a high resolution image. The two methods, bicubic interpolation and subpixel imaging, are simulated with Matlab7.0.1. The qualitative and quantitative analyses are given. The simulated results of lanczos and cubic spline interpolation methods are given simultaneously to show the performance of interpolation. The simulation result shows that the result images quality becomes better in both methods, but compared with bicubic interpolation method, the synthesized image PSNR gained from sub-pixel imaging is averagely enhanced by 2.1682 dB, while the elapsed time is reduced to be about one forth. The subpixel imaging method could significantly mitigate the image blur introduced by under-sample.