Earticle

The next generation wireless communication system requires a higher standard in order to provide the customers with high quality of services they demanded. Orthogonal Frequency Division Multiplexing (OFDM) is an attractive modulation method and is a strong candidate for the modulation technique of future wireless systems which can be implemented easily. In this paper an effort is made to analyze how well an OFDM system will perform when transmitted over an Additive White Gaussian Noise (AWGN) channel in terms of Bit Error Rate (BER), it has also been observed that pulse shaping the channels present in an OFDM system promises to improve the overall performance of the system in terms of the BER of the received signals, different window function like Rectangular, Blackman, Gaussian, Hamming, Hanning and Kaiser and some of the self modified pulse shapes have been used to study the BER performance due to any one of the pulse shapes.

In order to solve the restriction of the two common calibration modes applied in digital close-range industrial photogrammetry, a new camera calibration method based on orientation points was proposed. Firstly, image sequences were obtained applying a calibration plate with five orientation points. The ellipse detection criteria were applied to eliminate the redundant information from images after pretreatment and all target points was determined as well. Then according to the special geometric relationship between orientation points, target points were matched exactly from object space to image space. Finally camera parameters were solved and optimized by the Gauss-Newton algorithm. In laboratory, the proposed theory was proved robust in Matlab2010 and could meet the measurement accuracy requirements.

In this paper, we put forward an effective algorithm for edge detection based on combination of multi-shape/scale Mathematical morphology and wavelet transformation. Firstly, the bimodal method and multi-threshold method were combined for the image segmentation. Then, the image edge was detected by the algorithm. Finally, the angle between the bolt and manipulator was calculated using the rotation conversion matrix. With the systematic error and correlation coefficient, the calculated angle was verified. Experimental results show that the method can protect the edge integrity of the nut image, with fast processing speed and strong anti-noise ability. The work in this paper provides a theoretical basis for the automatic recognition in the large ball valve sealing bolt system.