Papers by Keyword: Detector

Abstract: Video-based fire detector is one of fire detecting methods. A key problem of video-based fire detector is to accurately recognize a fire and estimate the fire centroid. Then a fire detecting method based on Otsu and Canny algorithm was proposed for a video-based fire detector which was developed our latest work. Moreover, a candle flame and lighter flame were introduced to do fire detecting test to evaluate the proposed method. Experimental results showed that the method could well recognize the flame.

Abstract: The theoretical basis of the Infrared analyzer is expounded in this paper. To Lambert-Beer absorption law, the paper has made math derivation and gives introduction about Infrared absorption spectra of some common gas. The focus is on spectroscopic techniques involved in Infrared gas analyzer, optical path design of optical system and monitoring technology.

Abstract: It is a new method of pipeline detection that pipe detector based on laser. This paper introduces the laser inner diameter detector related principle, detail the state of development and the latest development of pipe detector based on laser designed and made by domestic and international companies, and contrastive analysis the function of pipe detector. The paper proposed development prospect and the main technical difficulties of the pipeline laser detector. The development direction of pipeline laser detector is high efficiency, high precision and high speed. However, the key technical difficulties of in pipe detector based on laser, such as centering problem, reliability and accuracy problem, data analysis and processing problems. Keywords:Pipeline; Laser; Detector; Inner diameter;

Abstract: In this paper, infrared data correction algorithm is suggested when the environmental conditions such as air temperature or detector substrate temperature are varying. To correct the infrared data, infrared detector measurement model is described by a parameter-dependent first-order input-output equation and the relations between infrared data and model environmental parameters are investigated first. By determining the parameters which dominate the influence on the infrared data, the coefficients of a model are obtained. By using only the measurements of ambient temperatures and detector substrate temperatures, infrared detector output data corrupted by environmental temperature variations are compensated based on the model instead of using any target temperature source equipments. It is shown through experiments that the proposed algorithm can reduce the influence of environmental temperatures on the infrared data.

Abstract: Meteorological data collection and monitoring is widely adopted in the traffic industry. Meteorological monitoring can ensure traffic safety and improve the traffic management level. According to the detection type the system is divided into several types: pavement visibility detector, road conditions detector, rainfall detector, wind speed and direction detector, etc. Subsequently the advantages and drawbacks or system working principle of various types are compared. Meanwhile the key issues and the future trend of development are presented.

Abstract: GaN ultraviolet photoelectric detector have advantages of high quantum efficiency, work at room temperature, high-temperature resistance, good corrosion resistance, resistance to radiation ability etc. Therefore, research of GaN ultraviolet photoelectric detector has important application value in the spacecraft, fire monitoring, ultraviolet communication and other fields. MSM Schottky type ultraviolet photoelectric detector has been prepared by a metal organic chemical vapor phase epitaxial deposition method in growth of high quality GaN semiconductor film on the sapphire substrate. Then optical and electrical properties of device have been studied by analyzing its illumination and light response performance. The detector sample has high pressure resistance and response degree. After annealed treatment, the ultraviolet detector has response peak for 0.19 A/W and response time for 70ns.

Abstract: The detecting distance is an important index, which is determined by many parameters. In the paper, the detecting distance is analyzed in the view of system, the detecting distance is simulated according to technical index of each part, and we can also calculate sending power of oscillator needed by detecting distance required.

Abstract: GaN ultraviolet photoelectric detecting technique has important application value in the spacecraft, fire monitoring, ultraviolet communication and other fields. In this paper, p-type GaN samples were obtained after rapid annealing of GaN mixing Mg at 700~800°C. Then, p-i-n type GaN ultraviolet photoelectric detectors were fabricated on Al2O3 substrates by metal organic chemical vapor phase epitaxial deposition method. The devices have better rectifying behavior which can be demonstrated by the I-V curve. The response time of the device is 1.6µs and its higher responsivity is 0.95A/W.

Abstract: In this article, we present propose a simple method to detect the minor fluid-environmental changes using ringing phenomenon generated by frequency sweeping in a single mode optical fiber resonator. The method is based on the fact that the insertion loss of the optical fiber resonator is determined by the environmental changes alone, which leads to the changes of cavity ringdown time of the fiber resonator. The method has several conspicuous advantages over the frequency-domain method, using which the minimal detectable optical loss is in the order of .We also show that the sensing system is insensitive to the temperature drifting, which overcome the main defect of fiber loop resonator, that it is extremely sensitive to temperature changes. The structure of the sensor is compact and stable due to the characteristic of optical fiber resonator, and it is easy to apply because the structure is not delicate and is easy to construct.

Abstract: Potentially low cost and large-area polycrystalline mercuric iodide (α-HgI2) is one of the preferred materials for the fabrication of room temperature X-ray and gamma-ray detectors. In this paper, polycrystalline α-HgI2 films have been grown through combining vertical deposition method with hot wall vapor phase deposition (HWPVD) method. X-ray diffraction (XRD), scan electron microscopes (SEM) and Raman spectrum were used to characterization the HgI2 films obtained, and I-V characteristics was also tested. Using the polycrystalline α-HgI2 films, we get the detector. According to the detector, on the one hand, a dark current test is made by using KEITHL EY 485 picoammeter; on the other hand, the Agilent 4294A precision impedance analyzer is taken to test the characteristic curve of its capacitor frequency.