A 3D scanning system based on single Kinect sensor is constructed for the application of fast 3D modeling of actual objects. After the scanning model is optimized by geometric repair and smoothing, the 3D model can be processed directly by 3D modeling software. The standard model of known size is scanned and modeled, and the obtained digital model is analyzed in the 3D processing software. The experimental results show that the scanning accuracy of the 3D scanning system constructed in this paper is better than 1%, which can meet the need of rapid 3D modeling of objects in most cases.
One of the most important qualifications of laser range finder is the ranging distance. The ranging distance of laser range finder is usually supplied with a atmosphere condition. To reach the qualification of ranging distance, the manufacturers always increase the laser emitting power which the laser range finders can work not only in the ranging distance. It is important to find the real ranging distance in different visibility especially for military application. The maximum ranging distances in different visibility were discussed in the paper. First, the power of different types of laser range finder was got by experiment. The power of two models of laser range finder was got, and the power of same model but two serial numbers was obtained. Then, the fluctuation regularity was discussed. Then, the maximum ranging distances in different visibility were got by numerical simulation. The maximum ranging distances of laser range finder with same model but two serial numbers were calculated. The figures of maximum ranging distances varying with visibility were obtained. It was showed that the maximum ranging distances of laser range finder with same model but two serial numbers were different.
As one of the main weapons, impulse laser rangefinders have become the main object of the electro-optical countermeasures. So its real maximum range (defined as utmost operating range in the paper) becomes the most concerned index to evaluate the performance of electro-optical countermeasure weapons. A method for calculating laser rangefinders′ utmost operating range by its sensitivity in different weather is obtained. Then a method by experiment for getting the sensitivity is supplied. By analyzing the experiment data which the detectivity is 40%-60%, the laser rangefinders′ sensitivity is in the range of 1.7×10-5 W to 9.8×10-5 W. For the reason that in order to get an exact utmost operating range, the experiment accuracy of sensitivity is very important, in the last part of paper, the factors which influence the experiment accuracy of sensitivity are analyzed, such as circuit of automatic gain control, the fluctuation of laser power, incident angle of laser.
Since the image of the moving target takes on sub-pixel attribute in the super-wide infrared staring warning system, the time correlation of the tareget track in the sequence images decreases, and it brings difficult to the correlation processing. Thus, the nearest correlation method is put forward firstly, and then the problem of track cross is solved through setting “false target” during the tracking course. The multi-life processing method, which synthetizes target information accumulation, single-pixel life, and average single-pixel continuance, is put forward to avoid the target’s emporary disappearance. This method solves the target time-domain response problem in the fisheye staring detection system. In this paper, some algorithms based on the sequence images are discussed aiming at the target track decision, , including target track register, target correlation processing, target elimination decision, target maintaining processing, and target start processing.
KEYWORDS: Avalanche photodetectors, Signal detection, Interference (communication), Single photon detectors, Single photon, Temperature metrology, Sensors, Signal to noise ratio, Photodetectors, Avalanche photodiodes
One type of single-photon detector that without cooler, which is mainly consisted by noise voltage control circuit and precise pulse width detection circuit, is presented. The noise voltage control circuit is using the characteristic the noise rapid increase in avalanche voltage. The detector signal after forward and video amplifier is measured. When noise voltage exceed a certain range, the bias voltage would be decreased; when noise signal minished, the bias voltage would be increased. So the bias voltage of APD is dynamically fixed by certain voltage. When the avalanche voltage changes with the temperature, the noise character nearby avalanche is resemble. So the bias voltage could be stabilized based on noise character. The detector’s output SNR would descend greatly if there was no cooler, and the phonon avalanche signal would not measured efficiently by the tradition extent detection. Considering the difference of time width between photon avalanche signal and noise signal, the precise pulse width detection method is adopted. It can filter the narrow noise signal and only detect photon avalanche signal which has larger pulse width efficiently.
A real-time system for optical axis of the varifocal photoelectric reconnaissance and tracking system is designed in this paper. Two images are acquired by the DSP processing system before and after zooming the focal length, and the varifocal and shifting coefficients are calculated real-timely through extracting the feature points and affine transform, etc, while the rotation coefficient equals to zero basically. The shifting parameter can be used to calibrate the optical axis, and its calibration precision is less than one pixel. The system can reduce the requirement of mechanical processing technology and mechanical tolerance greatly in the production procedure of the photoelectric reconnaissance and tracking system with a long focal length, and can make the system easer to implement.
A real-time recursive filtering processor using the core of digital commix chip HSP48212 was presented and designed
assisted by FIFO memorizer and CPLD logic parse circuit, which realized real-time recursive filtering of 12bit infrared
image. It has much notable virtue such as simple structure, strong real-time capability, controllable logic during operation
process, and synchronal clock. It used in infrared fish-eye staring reconnaissance system for image real-time reduce
noise and obtain perfect effect.
We introduce a multi-point and real-time method for corrects the nonuniformity of uncooled IRFPA. First of all, all pixels are classified to different kinds according to their response characteristics in the system. Then we figure out the correction parameter of each subsection of every kind response curve. Not only the correction precision of this method is higher than two-point correction algorithms, but also it solves the difficult, such as needing lots of correction parameter, the system will be very complex and hard to realize, etc. of common multi-point method. It has marked merits as follow: high correction precision, easy to realize and the real-time characteristic.
A new type of design for the thermal imaging radiometer is presented in this paper. The new system has many advantages, such as that the apparent temperature configuration of the measured object is showed with image manner, that measure results and parameters of system status is displayed with graphics intuitively, that measure data can be saved easily and conducted further process, etc. Besides these, it has very nicer imaging radiation measure capability, high automatization degree. Its orientation is easy, and field experimental operation is convenient. With so many advantages, it offers an effective method to realize the spatial distributed measure for a target’s infrared radiation, the measure for its variation per hour and the measure for its intensity and dynamic range of the radiation.
Automation and intelligent function in performance testing of optical instrument are the key problems in modern detection technology. In this paper a testing system based on the detection in laboratory is proposed and has successfully realized the detection of multi-optical axes’ parallelism. This system is on the base of optics, mechanics and electricity, and combines the modern computer technology to gather and process the data obtained in the experiment, finally high-precision quantified results can be gotten, so these results can provide reliable data for the alignment of optical axes. The paper introduces the whole testing system’s design options, system composition, operational principle and software design in detail, and it’s technical difficulties and emphases are also analyzed and discussed.
In infrared imager system of using infrared focal sensor, for the responsivity heterogeneity among focal plan image elements and sensors and amplifiers can not be made in model of one to one, this kind of system asks for compensation of the heterogeneity of sensor response. Measuring the heterogeneity of focal plane image elements response accurately is the key to assure the quality of compensation. The article introduces a new method of measuring the heterogeneity of focal plane image elements response. It avoids the affect of black body radiate plane's spatial heterogeneity on the measuring result and gets higher measuring precision.
This paper introduces some new methods for measuring parameters of the telescope system with CCD device such as OTF, parallax, diopter and so on. It doesn’t need man’s subjective judgment. The computer accomplishes the assignment to display, print and save the results automatically. So, these methods have some advantages: high accuracy, digital display, and autoimmunization. Basing on the mentioned theory analysis in the paper, we have realized the digitization checkout of a lot of parameters on same instrument.
Injected-current density and carrier distribution are crucially important factors in Vertical-cavity surface-emitting laser (VCSEL) characteristics, affecting the laser emission wavelength, distribution of transverse-mode, threshold voltage, available output power and operating laser lifetime. Using a method of finding self-consistent solution for the carrier-diffusion and Poisson's equations, of calculating beginning from electrode voltage and of taking into account the whole structure of distributed Bragg reflectors (DBR), we have studied the two-dimensional current density and carrier distribution characteristics of VCSEL. The calculated results show that the injected-current density and carrier distribution determined by the confined-layer depth in VCSEL. The deeper confined-layer in VCSEL is, the more notable current density and carrier distribution are limited in the active region. So the strong confinement benefits to concentrate the current density in the active region to a higher level, at the same time ofthe reduction ofthe threshold.
A new method of measuring the PRN of CCD device is presented the PRN of CCD device can be determined quickly and accurately by this method, the effect of illuminance distribution nonuniformity on the measurement of CCD device PRN is eliminated.
This paper is to present a new intelligent target for use in shooting practice in a simulated laser training system. It has many notable characteristics, including novel structure and high precision. It can distinguish and display the ring- number and the orientation automatically. It is low in cost and has many uses.
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