In the real-time image processing system of the airborne infrared camera, how to process a large amount of data and information in a limited time and effectively meet the real-time requirements of the system is a problem that needs to be solved as soon as possible. Based on this, this article meets the needs of system modularization design ideas, and proposes a real-time image processing system design based on CMOS, using DSP and FPGA as the core devices to realize the corresponding hardware circuit design, and using high-demand tracking in the real-time image processing system algorithm. The experimental results show that the functions and performance of the designed real-time image processing system can meet the expected demand, and it is practical and reliable.
Irradiating experiments with a 532nm laser were conducted to investigate the effect of integration time on crosstalk line intensity for IT-CCD. Crosstalk lines were observed in all the experimental images with different integration times when laser power was high enough. Crosstalk line gray value was calculated by eliminating the impact of background light and main spot. Calculation results show that crosstalk line intensity is independence of integration time while proportional to laser power. According to the working principle of IT-CCD image sensor, the formation mechanism of crosstalk line is the quantitative overflow of stored charges from photodiode to vertical CCD in the process of vertical transfer. According to the working principle of electric shutter, the reason of the independence of integration time on crosstalk line intensity is that the period of shutter pulse is an invariant. This research enriches the knowledge of crosstalk effects for IT-CCD, and provides important support for deep searching the mechanism of laser jamming on CCD.
The beam quality factor (M2 parameter) of output laser in a three-core and seven-core conventional photonic lantern excited by incoherent sources is analyzed based on analytical and numerical method. Theoretical results show that the limitation of output laser beam quality is M2=1.75 for a three-core photonic lantern and M2=2.70 for a seven-core photonic lantern. Both the mode evolution process and beam quality factors of these two kinds of photonic lanterns are verified by numerical calculations. It is shown that good beam quality of the theoretical limitations can be realized only if the adiabatic conditions are satisfied very well. These results are very meaningful for practical application of high brightness incoherent beam combining based on conventional photonic lanterns.
It is a key problem to get the high resolution and large field of view of dynamic measurement in the ladar technology. In this paper, Charge Coupled Device was synthesized with seams to be a display unit. A reconstruction method is proposed which combines the principles of synthetic aperture and phase retrieval to detect the particle target. Then the non-integer pixel stitching error in a synthetic-aperture ladar with seams is corrected by a method based on the shift theorem of the Fourier transform. In the X experiment, the correlation coefficient of surface l is 0.73217 between the reconstructed image and the simulated particles target image. The pictures from the experiment depicts the particle is not only clearly visible at the normal region but also at the seams. The target information can be recovered well of the high resolution and large field of view with this method.
In this experiment, the visible array CMOS image sensor irradiated by 532 nm pulse laser was carried out. The experimental results revealed that, with the increase of the incident power density, regular lightspot arrays appear around the main laser spot. When the laser energy density continued to increase, the phenomenon of asymmetric crosstalk appears in the image. It is analyzed that, the reason for the formation of spot array of CMOS image sensor is that after the laser was reflected by the CMOS photosensitive surface, it was reflected back to the CMOS photosensitive surface by the window glass and imaged on the photosensitive surface again. By analyzing the characteristic parameters of crosstalk line, it was considered that the crosstalk of CMOS image was the result of superposition of optical crosstalk and charge crosstalk.
The laser-induced damage of GaAs/Ge single heterojunction solar cells is investigated. The solar cells were irradiated by a continuous wave laser at the wavelength of 532 nm. Results indicate that the GaAs/Ge solar cells would mostly be damaged when laser is focused on its grid lines. Theoretically, the continuous wave laser at the wavelength of 532 nm is absorbed at the surface of solar cells. The continual temperature rise decomposed the material GaAs and melted the material Ge. The melted metal Ge connected the solar cells grid lines and the rear electrode, the solar cell became completely invalid. The major damage of continuous wave mainly comes from both the thermal melting and the thermal stress effects. The huge temperature gradient on the surface of the solar cells generated the crack, and even rupture. Concentric iridescent ring appeared on the damaged surfaces when observed with an optical microscope(OM) of broad spectrum. The damaged surface film was characterized by X-ray photoelectron spectroscopy(XPS) and the Contour Meter. The component of the concentric iridescent is GeO2 film, when the light irradiated on the film and interfered, the concentric iridescent generated. The different ring indicated the thickness of oxide was different. When the film was corroded by HCl, the iridescent disappeared. The formation mechanism of the film and the cause of the concentric iridescent ring were analyzed. These experimental conclusions are tested and verified by scanning electron microscope with energy dispersive spectroscopy and X-ray photoelectron spectroscopy.
A new approach is presented to reduce turbulence-induced scintillation by use of a phase-locked beams array composed of linearly polarized beams with different polarization angles. The noninterference of orthogonal polarizations suggests that the beams array mentioned above can act effectively as a two-mode partially coherent beam, and the percentage of a single mode is controllable by changing the polarization angles of the beams. Numerical calculation using a multiple-phase screen method is performed to analyze the on-axis scintillation index σI2 and mean received intensity 〈I〉 for the beams array propagating through weak, moderate, and strong turbulence. The effects of different polarization angles on σI2 and 〈I〉 at the receiver are studied. When the turbulence is weak, numerical calculations show that both σI2 and 〈I〉 are closely related to the polarization angles of the beams. And there will be a smaller scintillation index for a phase-locked beams array comprising beams with different polarization angles as compared to a uniformly polarized beams array. As the beams are phase-locked, the mean received intensity provided by them is larger than that provided by an incoherent beams array. For it is quite easy to change the polarization angles, phase-locked beams array comprising beams with different polarization angles can be a promising source in the applications that need a balance between scintillation and mean received intensity in weak turbulence conditions. When the turbulence is moderately strong, incoherent beams array is actually a better choice, because the scintillation index is smaller and the mean received intensity is as much, compared to a phase-locked beams array.
Single-heterogeneous junction GaAs/Ge solar cells induced by 532nm laser with the pulse width of 12ns are investigated. Results indicate that the GaAs/Ge solar cells would mostly be damaged when laser is focused on its grid lines. Its surface damage morphology initially occurs at 0.35J/cm2 by the single laser pulse with nanosecond duration. Theoretically, the nanosecond laser pulse leaded damage mainly comes from both the thermal and the mechanical effects. These experimental conclusions are tested and verified by scanning electron microscope with energy dispersive spectroscopy and X-ray photoelectron spectroscopy.
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