Weidong Qiao

An improved Fourier-based sub-pixel image registration algorithm for raw image sequence of LASIS

Previous studies indicate that parallel computing for hyperspectral remote sensing synthetic image generation is quite feasible. However, due to the limitation of computing ability within single cluster, one can only generate three bands and a 1000*1000 pixels image in a reasonable time period even using a 40-50 node parallel computing cluster. In this paper, we discuss the capability of using Grid computing where the so-called eScience or cyberinfrastructure is utilized to integrate distributed computing resources to act as a single virtual computer with huge scientific computational abilities and storage spaces. The technique demonstrated in this paper demonstrates the feasibility of a Grid-Enabled Monte Carlo Hyperspectral Synthetic Image Remote Sensing Model (GRID-MCHSIM) for future coastal water quality remote sensing algorithm developments and detection of bottom features and targets in water.

Development of the control circuits for the TID-CCD stereo camera of the Chang'E-2 satellite based on FPGAs

The TDI-CCD Stereo Camera is the optical sensor on the Chang’E-2 (CE-2) satellite created for the Chinese Lunar Exploration Program. The camera was designed to acquire three-dimensional stereoscopic images of the lunar surface based upon three-line array photogrammetric theory. The primary objective of the camera is, (1) to obtain about 1-m pixel spatial resolution images of the preparative landing location from an ellipse orbit at an altitude of ~15km, and (2) to obtain about 7-m pixel spatial resolution global images of the Moon from a circular orbit at an altitude of ~100km. The focal plane of the camera is comprised of two TDI-CCDs. The control circuits of the camera are designed based on two SRAM-type FPGAs, XQR2V3000-4CG717. In this paper, a variable frequency control and multi-tap data readout technology for the TDI-CCD is presented, which is able to change the data processing capabilities according to the different orbit mode for the TDI-CCD stereo camera. By this way, the data rate of the camera is extremely reduced from 100Mbps to 25Mbps at high orbit mode, which is benefit to raise the reliability of the image transfer. The results of onboard flight validate that the proposed methodology is reasonable and reliable.

Multispectral image compression algorithm based on spectral clustering and wavelet transform

In this paper, a method based on spectral clustering and the discrete wavelet transform (DWT) is proposed, which is based on the problem of the high degree of space-time redundancy in the current multispectral image compression algorithm. First, the spectral images are grouped by spectral clustering methods, and the clusters of similar heights are grouped together to remove the redundancy of the spectra. Then, wavelet transform and coding of the class representative are performed, and the space redundancy is eliminated, and the difference composition is applied to the Karhunen-Loeve transform (KLT) and wavelet transform. Experimental results show that with JPEG2000 and upon KLT + DWT algorithm, compared with the method has better peak signal-to-noise ratio and compression ratio, and it is suitable for compression of different spectral bands.

Development of the electronics system prototype of the panoramic camera for space applications

The stereoscopic panoramic camera is a kind of important optical payload for space applications. It can image the full 360° in azimuth to the goal scene and obtain high resolution three-dimensional images. Many science investigations can be conducted by scientists with these images, such as the analysis for the planet terrain and the geology. This kind of payload has common features such as light-weight, miniaturization, and lower power consumption. This paper presents the development of a stereoscopic, panoramic imaging system for space applications, which is a typical staring binocular stereo imaging system and consists of two identical digital cameras. Each camera was build based upon a CMOS APS (Complementary Metal Oxide Semiconductor Active Pixel Sensors) and a high density FPGA (Field Programmable Gate Array). The camera has the features with the weight of about 210g and the power consumption of about 660mW. In this paper, the design details of the electronics for the specifications above are emphasized, and the designs and implements of the FPGA are particularly discussed. Finally, the verification and experiment results for the stereoscopic panoramic camera show that the design methodology is feasible.

Color interpolation algorithm of CCD based on green components and signal correlation

Signal CCD/CMOS sensors capture image information by covering the sensor surface with a color filter array(CFA). For each pixel, only one of three primary colors(red, green and blue) can pass through the color filter array(CFA). The other two missing color components are estimated by the values of the surrounding pixels. In Bayer array, the green components are half of the total pixels, but both red pixel and blue pixel components are quarter, so green components contain more information, which can be reference to color interpolation of red components and blue components. Based on this principle, in this paper, a simple and effective color interpolation algorithm based on green components and signal correlation for Bayer pattern images was proposed. The first step is to interpolate R, G and B components using the method-bilinear interpolation. The second step is to revise the results of bilinear interpolation by adding some green components on the results of bilinear interpolation. The calculation of the values to be added should consider the influence of correlation between the three channels. There are two major contributions in the paper. The first one is to demosaick G component more precisely. The second one is the spectral-spatial correlations between the three color channels is taken into consideration. At last, through MATLAB simulation experiments, experimental pictures and quantitative data for performance evaluation-Peak Signal to Noise Ratio(PSNR) were gotten. The results of simulation experiments show, compared with other color interpolation algorithms, the proposed algorithm performs well in both visual perception and PSNR measurement. And the proposed algorithm does not increase the complexity of calculation but ensures the real-time of system. Theory and experiments show the method is reasonable and has important engineering significance.