The processing of target image using image processing technology, can realize the non-contact online detecting circuit board, thus greatly improve the detection efficiency, reducing the defective rate. This paper provides the detection system based on the methods of pre-processing the standard circuit board image and the circuit board image to be detected, two value segmentation, morphological image processing, image registration and poor shadow detection processing, among them ,image registration is the key. In order to improve the processing speed to achieve real-time processing, image registration using rapid processing algorithm. Analysis of the experimental results, the method can detect the defects on the circuit board to be detected accurately, and can achieve the automatic real-time detection purposes.
Through the analyzing of the color, motion, parallax and the degree of clarity in scene-all the elements presented on the 2D video, People can produce 3D video smoothly. The paper introduces a kind of pick-up algorithm of depth map, the method of combining the abstraction of motion in depth based on the block matching and the abstraction of background in depth on the basis of background subtraction. The extracted map can be applied to the video conversion technology of "2D to 3D".
Synchronization is very important for any digital transmission technology. It can almost be said the core of any control system, so the synchronization algorithm is precisely the premise to transmit data correctly. This point is especially important for OFDM system. Synchronous error is the biggest shortcoming of OFDM system, the performance of the receiver is closely related to if we can get the accurate synchronization signal.
This paper makes a brief introduction on the current development trend of software radio and digital down converter status. The basic theoretical knowledge: Band-pass sampling theorem, digital signal orthogonal transformation theory, multi-rate signal processing theory. Based on these theories, use MATLAB complete the design and verification of mixing module, the extraction module (CIC filter, half-band filter and FIR filters), finally verify the correctness of the design, and implement DDC.
PID control is one of the earliest control strategy and till has the most widely use in the industrial process at the present. The PID parameter tuning and optimizing decide what the control performance of the control system can achieve. PID parameter tuning is the core content in control system design. In this paper, aiming at the complexity of PID parameter tuning process, the critical ratio method was optimized and propose a simple and effective method of tuning PID parameters. By simulation, this method turn out to be simple and effective, good real-time performance.
This paper studies and analyzes the BER performance of the OFDM system, and completes the system simulation on this basis, measures and calculates the BER through the SNR, the Doppler effect and the Short Guard Interval. During the simulation, we use BPSK, QPSK and 16PSK modulation techniques, and choose the Gaussian white noise channel. Using SNR, Doppler effect and Short Guard Interval effects to OFDM signal can improve the system performance.
The OFDM system modulates signal by using a plurality of spectrum aliasing orthogonal sub-carriers, so it is extremely sensitive to carrier frequency offset, and any tiny frequency offset may destroy the orthogonality of the sub-carriers, thereby seriously affecting the performance of the system. So carrier frequency offset is the primary problem for the OFDM technology, and in recent years it has also become a focus for researchers. Accurate frequency synchronization is the precondition for the OFDM system to work properly. The main purpose of this paper is to seek a more reliable and viable carrier frequency offset estimation algorithm on the results of previous studies.
Chromatic dispersion and nonlinearity effect are the two important factors affecting the optical pulse which propagates in the optical fiber. The former makes the pulse broaden, the latter mainly broaden pulse spectrum. Therefore, the linear and nonlinear dispersive propagation and control of optical pulses in the fiber has always been an important research topic of concern. In this paper, Starting from the nonlinear Schrodinger equation of the optical pulse and neglecting the chromatic dispersion, under the situation of chirp and chirp-free Gaussian pulse, we analytical analyzed, calculated and simulated the frequency chirp, pulse broadening factor and waveform of the Gaussian optical pulses in dispersion fiber. And numerical studied the waveform evolution of chirp-free super-Gaussian optical pulse with distance, analyzed the influence of optical pulse propagation by dispersion in different shapes and different initial chirp.
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