Applied Mechanics and Materials Vols. 246-247

Abstract: Monitor psychological parameters of driver to detect fatigue state is an effective approach to prevent traffic accident. Heart rate variability (HRV) has its particular advantage comparing with other methods, such as its accuracy and conveniences. ECG is a regular signal to obtain HRV, but during driving condition, electrodes and wires need to be placed on driver’s body and may disturb the driver’s normal driving behavior. Since ballistocardiogram (BCG) can reflect heart movement, so HRV can also be extracted from BCG. This paper gives a novel noninvasive method to detect driver’s BCG. Using PVDF sensor which is embedded in safety belt to get driver's BCG and designing hardware and software to amplify and convert it to digital signal for next processing. The result shows that the proposed device can obtain the driver’s BCG properly and the HRV of the driver can be calculated accurately and conveniently, so the design is reasonable.

Abstract: Many geologic hazards, such as rock burst coal and gas outburst, have an inevitable connection with microseismic phenomena in rock mass. In order to provide accurate evidence of underground safety monitoring, inspecting microseismic signal is a good way to make sure the range and the level of underground rock breaking. Previous microseismic system using DSP or singlechip can’t obtain the desired data collection, neither for the achievement of advanced algorithm. The real-time microseismic monitoring system realizes the acquisition of multiple microseismic signals and uses wavelet transform algorithm, which gives full scope to the advantages of virtual instruments. The monitoring result was very similar to actual rock burst and the error of orientation results was minor to prescriptive upper limit, which means this new system completes the monitoring of real-time microseismic emission effectively.

Abstract: This article presented a rotary self-check phase unwrapping algorithm. The algorithm was mainly to process phase unwrapping for the phase main value got from Interferometer in accurately measuring object surface topography, and then accurately restored the object surface topography. The object surface topography measured by Interferometer generally tended to be smooth, the phase unwrapping was not difficult without noise interference. The algorithm processed phase unwrapping by the path of gradually rotational diffusion from the middle to the around in the wrapped phase map, at the same time the check for the error was carried out. It used the median filter technology to process the phase unwrapping error, and avoided the transmission of phase unwrapping error, had a greater inhibitory effect on the noises. This method did not identify the residuals, had small amount of operations, and Unwrapping velocity was several times faster than the fastest traditional branch blocking algorithm.

Abstract: A new method for saliency detection is presented. Based on the sparse coding model, we propose a power spectral filter to eliminate the second-order residual correlation, which suppress the global repeated items effectively. In addition, aim to modeling the mechanism of the human retina prior response to high-contrast stimuli, the effect of color context is considered. Experimental result indicates that our method has high-quality detection performance with respect to the ability not only to highlight the salient objects in complex environment but also to pop up them uniformly.

Abstract: Ocular retinal imaging is a major diagnostic modality for retinal disease, and can play a critical role for diagnosing systemic diseases such as diabetes and eye-specific diseases such as macular degeneration and diabetic retinopathy, the leading causes of blindness. In order to get high-resolution retinal imaging and develop the low-cost and compact retinal imaging system, we employ micro adaptive optics, which is consisted of wavefront sensor, wavefront corrector and control system. In this paper, the theory, design and testing of the ocular retinal microscopy is detailed, with an emphasis on the eye wavefront aberration describing, aberration detecting method with Hartmann-Shack wavefront sensing and close-loop aberration compensating by micromachined membrane deformable mirrors(MMDM).The ocular retinal microscopy experimental setup is built, the retinal cell imaging had been snapped. It is showed in this work that the ocular retinal microscopy based on adaptive optics system can enable diffraction-limited imaging of micro-scale features of the retina, through real-time compensation of aberrations introduced by the eye.

Abstract: This paper presents an image detection algorithm for navigation route of cotton harvester. Two cameras were respectively installed on the leftmost and rightmost picker unit, and images were captured during working process respectively. Firstly, the color characteristics among harvested field, un-harvested field, outside-field and the end of field were analyzed, then the target features of different fields was extracted using the color difference 3B-R-G. Secondly, candidate point group was determined by looking for the critical point of peak from the lowest trough point to un-harvested field and associating with the detection result of the anterior frame. Lastly, navigation line was obtained by using passing a Known Point Hough Transform (PKPHT). Results show that the navigation line detected using this algorithm can fit the boundary line and the edge of field accurately, the average processing time is56.10ms/f, and the algorithm can meet the actual production needs of cotton harvester.

Abstract: analyzes the detection technique of complex profile for high speed cutting, establishes the concept of the correct detectability in the detection of curved surface, put forward the detection method, detection principle and error criterion of point-to-point, point-to-line based on geometry topology relation .

Abstract: In the field of satellite communications, spectrum analyzer is one of the primary means of frequency monitoring, and it plays an important role in ensuring communication quality. According to the principle of the superheterodyne spectrum analyzer, the design and realization of a spectrum acquisition unit based on MSP430F149 MCU is given in this paper. Comparing the test results with those of the Agilent N9020 spectrum analyzer, the comparison shows that in the intermediate frequency signal monitoring, the spectrum analyzer designed in this paper has reached the current performance level of the mainstream spectrum analyzer.

Abstract: In order to realize automatic operation for a wheat planter in a field, an algorithm was developed in the research to detect navigation line under sowing operating environment with weak navigation information based on machine vision. Wavelet transform, linear analysis and front and rear frame interrelated were used to get candidate points at regional boundary in the image. Then linear fitting of the candidate points was carried out using the Passing a Known Point Hough Transform. Sowing videos captured under different natural conditions, in different regions were used to test the performance of the algorithm. Results show that the algorithm is able to detect ridge line, sowing line and field end accurately, steadily and quickly, the average processing time for each frame is about 30ms.

Abstract: Purposes: To improve the mixing effect in micro-scale for detecting liver cells status timely in bioreactor and improving liver cells growth environment to ensure efficacy of the bio-artificial liver support system(BLASS). Methods: Alanine aminotransferase(ALT) was chosen as an indicator to evaluate the status of liver cells by detecting the absorbance of ALT. A double-layer micro-mixer was designed and optimized to achieve efficiently mix between serum and ALT detection reagent. Results: The simulated results show that the optimized size of the micro-mixer is that the junction length L is 25 μm and the confluence width W is 50 μm. In this structure, satisfactory mixing effect can be achieved. Conclusions: This micro-mixer combines the superiority of active and passive mixer to achieve fast, efficient and easy control mixing. It laies the foundation for online monitoring of liver cells and will help to improve the viability of liver cell in the bioreactor.