Abstract:A new two-stage calibration method based on the close form solution and genetic algorithm was presented. In the first stage, the distortion parameters were ignored. The internal and external parameters were estimated by least square algorithm. In the second stage, the parameters estimated in the first stage were used as initial values. Taking account of the camera distortions, all parameters were optimized by genetic algorithm to get exact solutions. Because the algorithm optimized the rotation angles directly, the orthonormal constraints were easily satisfied in the present method. Moreover, the approach simplified the calibration process.

Abstract:The crucial procedure of contour extraction for corneal endothelium image is to segment cell regions from background. The single threshold algorithm is not effective because the image differs very much in illumination. In this paper, an adaptive thresholding algorithm with window n*n was introduced. It was then combined with the thinning algorithm to extract the cell contour. The processing results indicate the efficacy of the algorithm.

Abstract:The surface photovoltage (SPV) effect induced by the defect states in semi-insulating (SI) GaAs was studied. The PV response below the band edge was measured at room temperature with a dc optical biasing. The spectra were found to be strongly dependent on the surface recombination and were attributed to formation of the carrier concentration gradient near the surface region, showing that SPV is a very sensitive and nondestructive technique for characterizing the surface quality of the SI-GaAs wafers.

Abstract:This paper proposes a novel wavelet frame packet analysis approach for automatic retrieval of images in a colored natural image database. The approach effectively combines both the texture and color information and retrieve images in a progressive way. It can produce good performance in terms of both retrieval efficiency and retrieval effectiveness.

Abstract:Applying Randomized Hough Transform (RHT) directly to the detection of ellipses, five points were randomly sampled to determine the ellipse parameters, which produces a large amount of useless accumulations when processing complex images. To solve the problem, a new ellipse detection method using RHT was proposed, which uses two randomly picked points (with edge directions) and one searched point to calculate the ellipse parameters. In this method, only two points are randomly picked when calculating the ellipse parameters, furthermore, the searched point can be used to determine whether the parameters should be accumulated or not, therefore, the problem of useless sampling and accumulations is well solved. In comparison with other detection methods, this method has the advantages of high speed, small storage and high detection performance.

Abstract:An algorithm have been presented to retrieve land surface temperature from satellite radiative measurements, without requiring the channel land surface emissivities to be given previously. And by taking different errors in atmospheric temperature and moisture profiles into consideration in retrieval tests of land surface temperature, the atmospheric effect has been investigated, in order to see the possibility for the practical application of the retrieval algorithm. The results show that when the errors in atmospheric temperature and moisture are reasonable as usually could be obtained from radiosonde or satellite retrieval, the land surface temperatures might be determined with acceptable accuracies and the root mean square errors are less than 1K in most cases considered.

Abstract:A new face detection method based on color information and multi-stage neural networks was proposed. The system utilizes brightness and chrominance components of color images as the features of neural netwrok classifiers, and cascades multiple color components-based neural networks. Experimental results show that this method can detect human faces effectively and fast.

Abstract:A new type of multi-point multi-wavelength pyrometer for solid propellant rocket engine flame distribution measurement was developed successfully. The instrument can record the radiation fluxes of 8 wavelengths for uniformly distributed 6 points on the target surface, which are well defined by the holes on the field stop lens. The fast-response pyrometer with the specially designed synchronous data acquisition system can assure that the recorded thermal radiation fluxes of different spectrum region are of the same time and the same true temperature even with dramatically changed targets.

Abstract:The lattice dynamics of the ferroelectric semiconductor SnTe was investigated by using the rigid-ion model. Considering the screening effect of electrons on long-range Coulomb force, the abnormal dispersion relation was obtained.