Identification of high temperature targets has great significance to environmental monitoring, disaster warning, resources investigation, and so on. It is also an important basis for the temperature inversion of high temperature targets. Factor analysis starts from the similarity matrix of variables or samples. It sums the multiple variables or multiple samples up to a few factors via performing correlation analysis on them. It can extract information with the least amount of information loss. R-mode factor analysis is conducted to ETM+ remote sensing imagery to get the relationship among band variables. The fire factor, which has indicative significance for the high temperature targets, is confirmed on the basis of factor loading matrix. The mixture tuned matched filtering method is adopted in this article to use factor scores to realize high temperature target recognition. The identification precision reaches 95% in the field confirmation.
We present a nonflowing laser light scattering method for automatically counting and classifying blood cells. A linear charge-coupled device (CCD) and a silicon photoelectric cell (which is placed behind a pinhole plate on the CCD) form a double-detector structure: the CCD is used to detect the scattered light intensity distribution of the blood cells and the silicon photoelectric cell to complete the focusing process. An isotropic sphere, with relative refractivity near 1, is used to model the blood cell. Mie theory is used to describe the scattering of white blood cells and platelets, and anomalous diffraction, red blood cells. To obtain the size distribution of blood cells from their scattered light intensity distribution, the nonnegative constraint least-squares (NNLS) method combined with the Powell method and the precision punishment method are used. Both numerical simulation and experimental results are presented. This method can be used not only to measure the mean and the distribution of red blood cell size, but also to divide the white blood cells into three classes: lymphocytes, middle-sized cells, and neutrocytes. The experimental results show a linear relationship between the blood cell (both white and red blood cells) concentration and the scattered light intensity, and therefore, the number of blood cells in a unit volume can be determined from this relationship
A portable transceiver for indoor wireless link that employs a transmitter of eye-safe infrared light-emitting diodes and a receiver of photodiode arrays with multichannel transimpedance-summer architecture is presented. The transmitter can attain a wide field of view (up to 55 deg half-angle) and high speed (up to 35 MHz) to support different intensity modulation schemes. The receiver can receive signals with a bit error rate (BER) of 10–4 at a plane of 2 m away from the transmitter, even at a point ±50 deg off the transmitter's vertical axis. The bit rate of the transceiver can achieve up to 40 Mbit/s in an indoor nondirected infrared wireless link, and can be extended to 100 Mbit/s when light-emitting diodes (LEDs) with higher cut frequency are used. The system is able to transmit real-time uncompressed video 320×240 in frame size.
This paper reports on the design considerations and implementations of construction of a receiver system for an infrared communication link using Light-Emitting-Diodes (LEDs). System configuration is non-directed line of sight (LOS) with single element receiver. The speed of the system constructed is 20 MHz (40 Mbps for on-off keying). In our design, the receiver consists of a multi-channel photo-detector array followed by multi-channels transimpedance amplifiers, a summer circuit for combining signals, low-pass filters(LPF) and high pass filters(HPF), and auto-gain control unit(AGC). The spectral match between photodiode and LED, looking angle of photodiode, rise time consideration of the photodiode, trade-off between transit rise time and photodiode effective area, etc, are also be discussed . A receiver module of speed response up to 20 MHz has been successfully constructed and the system is capable of receiving optical signal at a height of 2 m from the ceiling with coverage of a cell of 4 m in diameter.
In this paper, a non-destructive testing technique, based on electronic speckle pattern interferometry, is presented to measure 4-point bending of wood. The mechanical behavior of the wood, such as Poisson Ratio can be obtained from the test result. To measure the out of plane displacement produced by 4-point bending, the wood specimen which is 33 X 3 X 3 mm, is secured in a special loading device. The loading device can produce 4- point bending symmetrically. The device with the specimen is put in a Michelson electronic speckle pattern interferometer assembly. Speckle pattern is produced on the natural 'rough' surface of the wood when illuminated by laser. A series of laser speckle interferograms are captured by a CCD camera and then sequentially subtracted to reveal deformation of the surface. Correlation fringes can be obtained while the load is applied. Both experimental results and theoretical analysis are presented.
A simple and unique ESPI based system for real-time monitoring and measuring of thickness variation of semi-transparent membrane with an 'optically rough surface' is described in this paper. When membrane or film is illuminated by a coherent beam, a speckle pattern is produced on its rough surface. Reflected beams from both the bottom and top surfaces of the membrane combine and form a speckle interferometric pattern, which can be captured by CCD camera. Subtraction of sequentially captured images result in correlation fringes corresponding to thickness variation of the specimen. The beams reflected from both bottom and top surfaces serve as 'reference' beam for each other mutually. All the beams coming from the tested object possess an auto-reference feature and this makes the system more stable and simple.
A new technique has been developed for applying fiber optics to electronic speckle pattern interferometry (ESPI) to measure unbonded faults in the carbon/epoxy honeycomb composite. The fiberized ESPI system we designed is introduced in detail. This paper also develops the theoretical and experimental approach of singlemode fiber optics phase-step ESPI. This approach produces a significant improvement in fringe contrast and in reducing image processing computational effort. We adapted the singlemode fiber piezoelectric transducer as modulator and the two-step phase shifting method.
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