Journals >Infrared and Laser Engineering
Contents
2003
Volume: 32 Issue 1
24 Article(s)
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Research Article
Interaction between high-energy laser beam and free shear layer
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Based on the discussion of the law of the interaction between optic-field and fluid-field, and by using the physical model that high-energy laser beam cross through the two dimension super-sonic free shot flow, the disturbance of the fluid-field which caused by radiation heating and the changing of laser beam′s intensiBased on the discussion of the law of the interaction between optic-field and fluid-field, and by using the physical model that high-energy laser beam cross through the two dimension super-sonic free shot flow, the disturbance of the fluid-field which caused by radiation heating and the changing of laser beam′s intensity after the beam passes through the fluid field and propagates a long distance in the static atmosphere are discussed. The results show that there′s a distinctness influence of fluid-field on optic-field. Furthermore, if the interaction of high-speed fluid-field is with high-energy laser, the radiation heating can be neglected..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 46 (2003)
Beam control and relative problems in high-power laser technology
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The subject how to characterize high-power lasers is studied. The flattened Gaussian beam (FGB) is taken as an illustrative example, and the propagation of FGBs passing through unapertured and apertured paraxial ABCD optical systems is expressed in the analytical form. The beam characteristic parameters including the bThe subject how to characterize high-power lasers is studied. The flattened Gaussian beam (FGB) is taken as an illustrative example, and the propagation of FGBs passing through unapertured and apertured paraxial ABCD optical systems is expressed in the analytical form. The beam characteristic parameters including the beam propagation factor (M2 factor), kurtosis (K parameter) and power in the bucket (PIB) of FGBs are given and analyzed physically. Finally, it is pointed out that from a practical point of view the beam control of high-power lasers means that the power/energy focusability on the target, temporal and spatial profile, pointing stability and sustainability of beams should satisfy application requirements. It is a challenging subject in modern optics and laser technology..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 52 (2003)
Deflection angle measurement system using PSD for a 2 DOF laser scanner
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The basic principle and structural design of 2 DOF tip/tilt laser scanner are introduced. Two different methods to measure the 2 DOF deflection angle of the scanner are discussed, including their mathematical models, computing expression and optical systems. The aspects of PSD output signal processing circuit and samplThe basic principle and structural design of 2 DOF tip/tilt laser scanner are introduced. Two different methods to measure the 2 DOF deflection angle of the scanner are discussed, including their mathematical models, computing expression and optical systems. The aspects of PSD output signal processing circuit and sample-hold circuit to eliminate the environmental noise are presented. Displacement calibration demonstrates that the system can reach a wide measurement range of 30° and angle resolution of 0.01° as well as fast response and high stability..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 57 (2003)
Study on characterization and diagnosis of high-power laser beam quality
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For a long time, we have no standard methods for characterization and diagnosis of high-power laser beam quality, which brings great difficulties to the performance test of high-power laser systems. The systematic mehtods for characterization and diagnosis of high-power laser beam quality are presented in order to meetFor a long time, we have no standard methods for characterization and diagnosis of high-power laser beam quality, which brings great difficulties to the performance test of high-power laser systems. The systematic mehtods for characterization and diagnosis of high-power laser beam quality are presented in order to meet the necessity of accurately testing the performance of high-power laser systems..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 61 (2003)
Spathic micro-laser technology for laser proximity detection
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The details of a novel spathic micro-laser technology for laser proximity detection are analyzed. The study of the relative technology in the world is introduced. The performance of spathic micro-laser device (SMLD) and semiconductor laser device (SLD) is compared. The principle of laser fuze with multiple fixed fan beThe details of a novel spathic micro-laser technology for laser proximity detection are analyzed. The study of the relative technology in the world is introduced. The performance of spathic micro-laser device (SMLD) and semiconductor laser device (SLD) is compared. The principle of laser fuze with multiple fixed fan beams is described. The methods of target modeling of laser fuze are expounded. Some design keys of signal processing for discriminating air suspended matter (ASM) clutter are given..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 65 (2003)
Study on the refraction error of laser beam through the earth′s atmosphere
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The refractive error of ground-based laser attacking space targets such as satellites is discussed. The refractive index of atmosphere is variable according to the height. Based on the Snell law, the refractive error due to laser beam going through atmosphere is studied. The relationship between the refractive error anThe refractive error of ground-based laser attacking space targets such as satellites is discussed. The refractive index of atmosphere is variable according to the height. Based on the Snell law, the refractive error due to laser beam going through atmosphere is studied. The relationship between the refractive error and the initial elevation of laser beam is calculated by an example. According to the result, the refractive error is big when the elevation is low and the refractive error is small when the elevation is high. At last, some problems are also raised..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 69 (2003)
Loss and refraction of laser transmitting in the atmosphere
Loss and refraction of laser transmitting in the atmosphere play important roles in affecting laser atmosphere communication and laser anti-satellite. Methods to resolve parameters about loss and refraction of laser are given and the relative mathematic formulas of these parameters are obtained on the basis of ray theoLoss and refraction of laser transmitting in the atmosphere play important roles in affecting laser atmosphere communication and laser anti-satellite. Methods to resolve parameters about loss and refraction of laser are given and the relative mathematic formulas of these parameters are obtained on the basis of ray theory and value calculation. Furthermore, comparisons of different methods are discussed..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 73 (2003)
IR point target recognition from the bait by the signal processor of two waveband
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The characteristics of IR radiation of dim target and bait in high altitude are analyzed in details and the way of distinguishing the target from the bait by two wave-band signal processor is presented. According to the analysis result based on simulation experiment, a design of the signal processor of two IR waveband The characteristics of IR radiation of dim target and bait in high altitude are analyzed in details and the way of distinguishing the target from the bait by two wave-band signal processor is presented. According to the analysis result based on simulation experiment, a design of the signal processor of two IR waveband is given. The signal processor can process the image with 256×256 pixels in parallel pipeline and carry out the complex algorithm in real time, which is valuable to the capability that the missiles resist disturbance..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 78 (2003)
Research on modeling of the guided bomb of weathercock seeking type
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The guided bomb of weathercock seeking type is analyzed completely, and its complete mathematical model is established. The models include dynamics model, kinematics model, control system model, seeker model and weathercock seeker model, etc. The pilot study of the simulation about guided bomb of weathercock seeking tyThe guided bomb of weathercock seeking type is analyzed completely, and its complete mathematical model is established. The models include dynamics model, kinematics model, control system model, seeker model and weathercock seeker model, etc. The pilot study of the simulation about guided bomb of weathercock seeking type is presented, and it facilitates further research..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 82 (2003)
Simulation of microwave radiometric images on complex scene
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After the geometric relation between optical image and microwave radiometric image is analyzed, the optical image segmentation and classification are described and the method of giving shape from shading is given. Then the computation of the brightness temperature of the terrain and sky is presented, and the method of After the geometric relation between optical image and microwave radiometric image is analyzed, the optical image segmentation and classification are described and the method of giving shape from shading is given. Then the computation of the brightness temperature of the terrain and sky is presented, and the method of computing the antenna temperature of the terrain is given. A new technique is introduced to generate the microwave radiometric images on complex scene from the optical images. The technique is expected to be a useful tool to generate the source images of the matching navigation. For comparison, two passive microwave radiometric images are presented, which one is profiled by the 8 mm ground-based microwave radiometer and the other is generated by this technique..
Infrared and Laser Engineering
- Publication Date: Aug. 01, 2001
- Vol. 32, Issue 1, 87 (2003)
Visible watermarking technique based on luminance and texture features
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Digital watermarking is a technique for protection of ownership rights on multimedia product. By analyzing the characteristics of visible watermarking, an adaptive visible watermarking scheme based on the luminance and texture features is proposed. In order to adapt the scheme to both the color image and the gray imageDigital watermarking is a technique for protection of ownership rights on multimedia product. By analyzing the characteristics of visible watermarking, an adaptive visible watermarking scheme based on the luminance and texture features is proposed. In order to adapt the scheme to both the color image and the gray image, the YUV color model is employed. While embedding the watermarking into the image, the scaling factors are determined by the local luminance feature and texture features of the image. It can improve the embedding strength and the watermarking robustness. From the experimental results, the stego-images are extremely robust to common image processing such as median filter, JPEG compression and denoising after adding the stochastic noises. Meanwhile, the distributions of those gray-value histograms of stego-images are more concentrated than those of cover-images. It seems that removing the visible watermarking without damaging the cover-image is very difficult and time consuming.
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 92 (2003)
Improved digital watermarking technique based on DWT
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A watermarking technique based on DWT is presented and the method that makes the watermarking robust to signal processing operations is discussed in this paper. These are based on the following works. Firstly we use a new pseudo-random sequence. Secondly, watermark embedding is performed in the wavelet domain using a cA watermarking technique based on DWT is presented and the method that makes the watermarking robust to signal processing operations is discussed in this paper. These are based on the following works. Firstly we use a new pseudo-random sequence. Secondly, watermark embedding is performed in the wavelet domain using a content adaptive watermarking method based on MRF . Thirdly, a registration algorithm is proposed to improve the robustness to geometric transformations..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 96 (2003)
Fragile watermarking based on separable debluring
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A novel spatial region fragile watermarking algorithm based on the separable debluring is proposed. The watermarking message is hidden, firstly, in specific columns/rows of an image in a way similar to LSB. After a blur operation on the whole image, those columns/rows are discarded and replaced by random data to make tA novel spatial region fragile watermarking algorithm based on the separable debluring is proposed. The watermarking message is hidden, firstly, in specific columns/rows of an image in a way similar to LSB. After a blur operation on the whole image, those columns/rows are discarded and replaced by random data to make the marked columns/rows unpredictable. At the receiver′s side, with the knowledge of blur and locations of the hidden messages, the separable debluring method is used to exactly unveil the hidden messages.Unlike previously proposed techniques, this novel approach provides information on specific locations of the image that have been modified. This allows the user to make application-dependent decisions concerning whether an image still has credibility..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 101 (2003)
Numerical analysis of the responsivity of microbolometer
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The response of microbolometer which is bias is introduced. Not only the response model of microbolometer by DC bias but also a whole theoretical model of microbolometer by pulse bias is established. The numerical computation of them is also discussed. The simulation results under pulse bias are also given.The response of microbolometer which is bias is introduced. Not only the response model of microbolometer by DC bias but also a whole theoretical model of microbolometer by pulse bias is established. The numerical computation of them is also discussed. The simulation results under pulse bias are also given..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 105 (2003)
[in Chinese]
New algorithm of infrared image enhancement based on histogram nonlinear extension
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Because of the influence of conduction of heat and environment and the limitation of the infrared imaging system, the contrast of infrared image is low, and the edge is commonly. Hereinto, the typical example is that the distribution of image histogram is excessively concentrated. Algorithm of image nonlinear extensionBecause of the influence of conduction of heat and environment and the limitation of the infrared imaging system, the contrast of infrared image is low, and the edge is commonly. Hereinto, the typical example is that the distribution of image histogram is excessively concentrated. Algorithm of image nonlinear extension enhancement based on distributing characteristic of histogram is presented, which spreads the uneven longitudinal arranging idea of image pressing-extension digitalization into the uneven transverse extension of the image histogram. On the basis of presentation of algorithm, the enhancing effect of it is contrasted with that of histogram linear extension algorithm..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 1 (2003)
Approach on image contrast enhancement based on wavelet transform
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Image enhancement is an important issue of image processing technique, which is used to improve the visual quality of image. Pointing at the shortcoming of noise over-enhancement of traditional algorithm, a wavelet-based approach for image contrast enhancement is proposed. On the basis of taking full advantage of multiImage enhancement is an important issue of image processing technique, which is used to improve the visual quality of image. Pointing at the shortcoming of noise over-enhancement of traditional algorithm, a wavelet-based approach for image contrast enhancement is proposed. On the basis of taking full advantage of multiscale wavelet analysis, firstly the algorithm takes a step of wavelet shrinkage and then differently enhances the coefficients at each scale. To achieve a better visual effect, the algorithm takes in account human visual system while enhancing the wavelet coefficients. Experiment of the algorithm demonstrates that the algorithm avoids over-enhancement of noise while enhancing contrast of the image with good visual effect..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 4 (2003)
Study on recognition of aircraft status based on dynamic infrared images
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The system of infrared imaging fuze based on imaging seeker information can get a series of dynamic infrared images of target from the whole to a part and realize forward looking detection. The recognition of aircraft status is of great significance to fix aimpoint by imaging fuze. The moving characteristics of aircrafThe system of infrared imaging fuze based on imaging seeker information can get a series of dynamic infrared images of target from the whole to a part and realize forward looking detection. The recognition of aircraft status is of great significance to fix aimpoint by imaging fuze. The moving characteristics of aircraft in high speed encounter is analyzed and the rotating status of target image on image plane and the position of aircraft nose are obtained through genetic algorithm. The pitching status of aircraft is obtained by utilizing the distance information provided by measurement device, the length of target image and the system parameter of infrared detector. Finally, the recognition of aircraft status is realized by use of the invariability of azimuth angle and pitch angle of target axis during encounter of missile and target..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 8 (2003)
Image matching based on Chaos-genetic Algorithms
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Image matching is one of the basic problems in computer vision and image analysis. The traditional genetic algorithms tends to get into local optimization in image matching. An improved algorithms--Chaos-genetic Algorithms(CGA) is realized. The experiment shows this algorithm has higher precision and matching rateImage matching is one of the basic problems in computer vision and image analysis. The traditional genetic algorithms tends to get into local optimization in image matching. An improved algorithms--Chaos-genetic Algorithms(CGA) is realized. The experiment shows this algorithm has higher precision and matching rate.
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 13 (2003)
Improvement and comparative analysis of B&B algorithm in feature selection
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B&B is an optimal algorithm of feature subset selection. The high computational complexity of this algorithm is its inherent problem. B&B algorithm constructs a search tree, and then searches for the optimal feature subset in the tree. The previous research on B&B algorithm focused on simplifying the searchB&B is an optimal algorithm of feature subset selection. The high computational complexity of this algorithm is its inherent problem. B&B algorithm constructs a search tree, and then searches for the optimal feature subset in the tree. The previous research on B&B algorithm focused on simplifying the search tree in order to reduce the search complexity, and several improvements have already existed. A theoretical analysis of basic B&B algorithm and the previous improvements are given under a common framework in which all the algorithms are compared. Based on this analysis, an improved B&B algorithm--BBPP+--is proposed. Experimental comparison shows that BBPP+ is more efficient than all previous algorithms..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 17 (2003)
Method of multiscale segmentation of dynamic images and estimation of its parameters
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A new method of multiscale segmentation of images is introduced into framework of multiresolution segmentation of dynamic images. The new method includes two main components which are multiscale random field and sequential maximum posterior estimator. This method can reduce the burden of computation and the contextual A new method of multiscale segmentation of images is introduced into framework of multiresolution segmentation of dynamic images. The new method includes two main components which are multiscale random field and sequential maximum posterior estimator. This method can reduce the burden of computation and the contextual model can make the segmentation more accurate..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 23 (2003)
Real-time detection of small target in IR grey image based on mathematical morphology
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In the infrared imaging and tracking system, infrared grey image of small targets is disturbed by the background and noise, that results in low SNR. The grey information of the target is required in the post-processing of target recognition. The mathematical morphology based on algorithm to detect small targets is desiIn the infrared imaging and tracking system, infrared grey image of small targets is disturbed by the background and noise, that results in low SNR. The grey information of the target is required in the post-processing of target recognition. The mathematical morphology based on algorithm to detect small targets is designed for infrared grey image and implemented by field programmable gate array. It is shown that mathematical morphology filtering can significantly enhanc SNR of the target. In the filtering the disturbance is eliminated, and the grey information is remained. The algorithm is adaptable to real-time image processing. It is effective for detecting small targets in infrared grey image..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 28 (2003)
Adaptive thresholds edge detection for image based on wavelet transform
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In the system of Marr's theory on computer vision, image edge detection plays an important role. Research on the typical problem in computer vision, however, is very difficult because of the complexity and limitation of the available techniques. The main aim of this paper was trying to apply wavelets to image edge In the system of Marr's theory on computer vision, image edge detection plays an important role. Research on the typical problem in computer vision, however, is very difficult because of the complexity and limitation of the available techniques. The main aim of this paper was trying to apply wavelets to image edge detection since wavelet analysis technique is a breakthrough in mathematical tools and methods in recent decade. According to the meteyard of edge detection and consulting the design-aim of optimal edge-filter, this paper discussed the general rules of selecting the mother function of wavelet used in edge detection, then constructed a quadric B-spline wavelet and presented a method of adaptive thresholds edge detection for image based on wavelet transform. The algorithm was validated using computer simulation, and the result was better than that using fixed thresholds..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 32 (2003)
Analysis and improvement of invariance of Zernike momnents
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An improved Zernike moment used as a region- based shape descriptor is presented. The improved Zernike moment has not only rotation invariance, but also scale invariance that the original Zernike moment does not have. The experimental results show that the improved Zernike moment has better invariant poperties and can An improved Zernike moment used as a region- based shape descriptor is presented. The improved Zernike moment has not only rotation invariance, but also scale invariance that the original Zernike moment does not have. The experimental results show that the improved Zernike moment has better invariant poperties and can be used as region- based shape descriptor.
Infrared and Laser Engineering
- Publication Date: Apr. 28, 2006
- Vol. 32, Issue 1, 37 (2003)
Principle and application of photon counting imaging
A photon counting imaging system has extremely high sensitivity , high S/ N ratio and superior image quality.It has been proved to be very effective in detecting the ultra-weak light and applied to a variety of fields. The theory of a photon counting imaging system is introduced, and the technical requirements for its A photon counting imaging system has extremely high sensitivity , high S/ N ratio and superior image quality.It has been proved to be very effective in detecting the ultra-weak light and applied to a variety of fields. The theory of a photon counting imaging system is introduced, and the technical requirements for its components and its applications are discussed..
Infrared and Laser Engineering
- Publication Date: Feb. 01, 2003
- Vol. 32, Issue 1, 42 (2003)
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