Journals >Journal of Infrared and Millimeter Waves
Contents
2003
Volume: 22 Issue 6
18 Article(s)
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Research Article
OPTICAL SPECTRA OF LOW-DIMENSIONAL SEMICONDUCTORS
[in Chinese], [in Chinese], G, and [in Chinese]
We have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in thWe have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in the optical spectrum are determined by the density of electronic states of the system, and the symmetries and intensities of these peaks can be improved by reducing the dimensionality of the system. Optical gain requires in general a population inversion, whereas for a quantum-dot system, there exists a threshold value of the population inversion..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 6, 401 (2003)
THE APPLICATION OF ACTIVE INFRARED TECHNOLOGY IN REAL-TIME AND ON-LINE WELD METAL DETECTION
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Starting with the nature of welding seams, the artical studiws Changes of the microstructures and chemical components of welding seams duning the process of welding, then discuss the effects of these changes on active infrared images of reflection. Through theoretical and experimental analyses, it is well known that acStarting with the nature of welding seams, the artical studiws Changes of the microstructures and chemical components of welding seams duning the process of welding, then discuss the effects of these changes on active infrared images of reflection. Through theoretical and experimental analyses, it is well known that active infrared technology can be applied in the investigation of industrial welding seams. The method put forth in the article mainly aims at the practical application of industries, and is characterized by rapid, of high precision, on-line in real time. The precision is up to 0.1mm. It takes only 0.02s to segment an active infrared image on a P-700 personal computer..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 406 (2003)
PERFORMANCE OF DUAL-AMPLITUDE PULSE INTERVAL MODULATION FOR WIRELESS INFRARED COMMUNICATIONS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A novel dual-amplitude pulse interval modulation (DAPIM) for optical wireless communications is discussed. The symbol structure, the spectral properties, the bandwidth requirement and error performance of DAPIM in a nondispersive channel are presented. DAPIM shows a better compromise between bandwidth and power requireA novel dual-amplitude pulse interval modulation (DAPIM) for optical wireless communications is discussed. The symbol structure, the spectral properties, the bandwidth requirement and error performance of DAPIM in a nondispersive channel are presented. DAPIM shows a better compromise between bandwidth and power requirements compared with OOK, PPM, and PIM. DAPIM with 5 bits and 6 bits persymbol is attractive in terms of optical power and bandwidth requirements..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 411 (2003)
STUDY ON TWO-POINT MULTI-SECTION IRFPA NONUNIFORMITY CORRECTION ALGORITHM
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on analyzing the mechanism of the IRFPA′s nonuniformity and several nonuniformity correction algorithms. the method of two-point multi-section for IRFPA nonuniformity correction was presented. The two-point multi-section method has higher precision than two-point correction algorithm and has lower operation load Based on analyzing the mechanism of the IRFPA′s nonuniformity and several nonuniformity correction algorithms. the method of two-point multi-section for IRFPA nonuniformity correction was presented. The two-point multi-section method has higher precision than two-point correction algorithm and has lower operation load than multi-point correction algorithm. The appliance of the two-point multi-section method to infrared multi-band camera showed that the method has the merit of low operation load, high precision and strong practicability..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 415 (2003)
DEPOSITION PROCESS STUDY OF VANADIUM OXIDE THIN FILMS FOR MICROBOLOMETER
[in Chinese], [in Chinese], and [in Chinese]
Vanadium oxide thin films were deposited onto quartz glass and silicon substrates by radio frequency reactive sputtering methods. The surface morphology, structural features and properties of films were studied by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS), atomic force spectroscopy(AFM), spectrophotoVanadium oxide thin films were deposited onto quartz glass and silicon substrates by radio frequency reactive sputtering methods. The surface morphology, structural features and properties of films were studied by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS), atomic force spectroscopy(AFM), spectrophotometer and resistance measurement methods to ensure the growth of the deposited films. These investigation shown that the deposited thin film has TCR value over 1.8% per degree centigrade and square resistance of 22±5kΩ/□..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 419 (2003)
ANALYSIS OF MODULATING CHOPPER USED IN PYROELECTRIC UNCOOLED FPA THERMAL IMAGER--CHOPPER AND DETECTOR PIXELS' SIGNAL READOUT MODE
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The Archimedes spiral cord modulating chopper's figure and its working states were simulated. The detector pixels' exposure time, exposal sequence, signal read-out mode and its impact on the following signal uniformity processing were analyzed. Result shows that the detector's exposure non-uniformity and thThe Archimedes spiral cord modulating chopper's figure and its working states were simulated. The detector pixels' exposure time, exposal sequence, signal read-out mode and its impact on the following signal uniformity processing were analyzed. Result shows that the detector's exposure non-uniformity and the signal readout mode directly affect the following signal's uniformity processing; the parameter of Archimedes spiral cord, the detector's geometrical dimension, the relative position between the chopper and the detector will affect the detector′s exposal sequence and uniformity. We should synthetically consider the effect of the chopper's parameters when designing the whole thermal imaging system and electronic processing system..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 423 (2003)
HISTOGRAM DOUBLE EQUALIZATION IN INFRARED IMAGE
[in Chinese], [in Chinese], and [in Chinese]
A new technique of histogram double equalization for the infrared thermal image is presented. At the same time of having histogram equalization, the gray redundance is removed and the gray level is reconstructed with equal interval in the whole display region. Then the continuous gray images are obtained. The problem oA new technique of histogram double equalization for the infrared thermal image is presented. At the same time of having histogram equalization, the gray redundance is removed and the gray level is reconstructed with equal interval in the whole display region. Then the continuous gray images are obtained. The problem of the large dynamic range of input signal against the small dynamic range of output display is solved in the signal processing in infrared thermal image system. Theoretical and experimental results.
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 428 (2003)
SIMULATION AND DESIGN OF A NOVEL CHAIN BUNCHING CAVITY FOR GYROKLYSTRON AMPLIFIER
[in Chinese], and [in Chinese]
A novel chain bunching cavity of gyroklystron amplifier, which is the clustered-cavity with TE mode, is studied. Analysis and calculations have been done by using three-dimensional electromagnetic code. The effect of loss medium on Q factor of bunching cavity is discussed, and the influence of the number of coupling-hoA novel chain bunching cavity of gyroklystron amplifier, which is the clustered-cavity with TE mode, is studied. Analysis and calculations have been done by using three-dimensional electromagnetic code. The effect of loss medium on Q factor of bunching cavity is discussed, and the influence of the number of coupling-holes on resonance characteristic is also analyzed. Simulation results are in good agreement with cold-test experiment. Finally, a chain bunching cavity is designed for the developing Ka-band frequency-tripling gyroklystron amplifier..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 431 (2003)
DETERMINATION OF THE OPTICAL THICKNESS AND EFFECTIVE RADIUS OF WATER CLOUDS BY FY-1C DATA
[in Chinese], [in Chinese], and [in Chinese]
The inversion experiment is presented for determining the optical thickness and effective radius of water clouds from channel 1(0.58～0.68μm), channel 3(3.55～3.95μm) and channel 6(1.58～1.64μm) of FY-1C CHRPT data. The results show that the reflection function function of clouds at a nonabsorbing band (such as channel 1)The inversion experiment is presented for determining the optical thickness and effective radius of water clouds from channel 1(0.58～0.68μm), channel 3(3.55～3.95μm) and channel 6(1.58～1.64μm) of FY-1C CHRPT data. The results show that the reflection function function of clouds at a nonabsorbing band (such as channel 1) in the visible wavelength region is primarily a function of the cloud optical thickness, while the reflection function at a water (or ice) absorbing band (such as channel 6) in the near infrared is primarily a function of cloud particle size. The cloud optical thickness and effective particle radius of water clouds can be determined solely from reflection function measurements at channel 1 and channel 6 or from function measurements at channel 1 and brightness temperature at channel 3 of FY-1C/CHPRT data when cloud optical thickness is thicker..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 436 (2003)
NEW GEOMETRIC ACTIVECONTOUR FOR MEDICAL IMAGE SEGMENTATION
[in Chinese], and [in Chinese]
Generally, thesegmentation of a medical image is difficult, because the medical image is often corruptedby norrupted by noise, and the anatomical shape in the medical image is complicated. Inthis paper presents a new geometric active contour scheme for medical image segmentation.First, we regularize the attraction forcGenerally, thesegmentation of a medical image is difficult, because the medical image is often corruptedby norrupted by noise, and the anatomical shape in the medical image is complicated. Inthis paper presents a new geometric active contour scheme for medical image segmentation.First, we regularize the attraction force field in the geometric active contour model toextend the capture range of the object boundaries, and improve the ability of convergenceto the concavities. Then, using a multi-scale scheme improve the boundary detectionaccuracy. In addition, combining the regularization and the multi-scale method, theproposed scheme can effectively suppress and eliminate the noise and the spurious edges inthe medical images. Furthermore, the topology of the deforming curve can naturally changewithout and special topolygy handing procedures added to the scheme. This permitssynchronously extracting several anatomical structures. The experiments on some medicalimages obtained from different medical imaging methods demonstrate that the proposedapproach is competent for medical image segmentation..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 22, Issue 6, 441 (2003)
THE ROBUST IMAGE REGIRSTRATION METHOD BY COMBINING FEATURE AND SPATIAL-TEMPORAL CORRELATION
[in Chinese], [in Chinese], and [in Chinese]
A product correlation algorithm of image registration based on feature and spatial-temporal correlation was presented. At first edge features of real-time images and base image are extracted by using Bubble wavelet. Then, the base image is shifted according to position guided by inertia system, in order to make theposiA product correlation algorithm of image registration based on feature and spatial-temporal correlation was presented. At first edge features of real-time images and base image are extracted by using Bubble wavelet. Then, the base image is shifted according to position guided by inertia system, in order to make theposition of real-time image in base image to be same. Finally, owing to the direct ratio between probability of registration and area of registration, the sequential product correlation matrix is added, and the registration position is searched in the added matrix. This method has overcome the shortcoming that the probability of registration decreasing with the increasing of the area owing to geometric distortion, and has improved the probability, precision and robustness of registration..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 447 (2003)
FAST RESTORATION ALGORITHM FOR TURBULENCE-DEGRADED IMAGES BASED ON WAVELET DECOMPOSITION
[in Chinese], and [in Chinese]
A new method based on wavelet decomposition is presented for the restoration of turbulence-degraded images. For this method, two turbulence-degraded images are used as the inputs, for which the multi-scale decompositions are made using wavelet transform. The discrete values of the two turbulence PSFs in large scales caA new method based on wavelet decomposition is presented for the restoration of turbulence-degraded images. For this method, two turbulence-degraded images are used as the inputs, for which the multi-scale decompositions are made using wavelet transform. The discrete values of the two turbulence PSFs in large scales can be estimated by mean of the Fourier frequency spectrum of the images in low frequency subbands. Removing blur is performed in the low frequency subbands of the images while reducing noise and preserving edges are made in the high frequency subbands. The experimental results show that the proposed method is highly effective for it not only greatly reduces the computational complexity and speeds up the restoration but also enhances the quality of restoration and the ability of resisting-noise well..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 451 (2003)
TWO-STEP STRETCH PROCESSING METHOD FOR MMW HIGH-RESOLUTION RADAR
[in Chinese], and [in Chinese]
By transmitting wide band LFM pulse and using stretch method, high resolution range profile of target can be obtained, and the range of still object can be exactly measured. While, the ranging precision and the quality of range profile may be influenced by the velocity of the object. To overcome these shortcomings two-By transmitting wide band LFM pulse and using stretch method, high resolution range profile of target can be obtained, and the range of still object can be exactly measured. While, the ranging precision and the quality of range profile may be influenced by the velocity of the object. To overcome these shortcomings two-step stretch processing method can be used. Theoretic derivation and the simulation results, that shows that by using this method range estimation with high precision and velocity roughly estimation can be obtained, are presented. By using these estimation values, the range tracking, profile.
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 457 (2003)
ELECTRIC TRANSPORTATION PROPERTIES OF THE HIGH SPEED ROTATING EXACT ELEXTRIC RING UNDER HIGH TEMPERATURE AND VACUUNM ENVIRONMENT
[in Chinese], and [in Chinese]
The HJT-K-6 type of electric ring was installed on a device with its vacuum of 0.133Pa. The voltage signal transported by this ring was measured under the circumstance with its temperature varied from 30℃ to 100℃, rotate speed of 0.16m/s, 0.32m/s,0.63m/s and 1.25m/s respectively. The voltage singal and the singal to noThe HJT-K-6 type of electric ring was installed on a device with its vacuum of 0.133Pa. The voltage signal transported by this ring was measured under the circumstance with its temperature varied from 30℃ to 100℃, rotate speed of 0.16m/s, 0.32m/s,0.63m/s and 1.25m/s respectively. The voltage singal and the singal to noise were recorded by the X-Y recorder. The result shows that its noise will increase with the increasing of the temperature and the rotate speed. Its signal to noise is not less than 278∶1 even under the circumstance with its temperature of 100℃ and rotate speed of 1.25 m/s. It shows that the HJT-K-6 type of exact electric ring can transport the voltage signal well in the applications. Thus, it can be widely used under the similar circumstance..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 461 (2003)
SEGMENTATION OF FLIR IMAGES BY GENETIC ALGORITHM AND FUZZY ENTROPY
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A FLIR image segmentation algorithm based on genetic algorithm and fuzzy set theory was presented. The method defines different member function for the object and background of the image to transform the image into fuzzy domain with maximum fuzzy entropy. The procedure for finding combination of a, b and c is implementA FLIR image segmentation algorithm based on genetic algorithm and fuzzy set theory was presented. The method defines different member function for the object and background of the image to transform the image into fuzzy domain with maximum fuzzy entropy. The procedure for finding combination of a, b and c is implemented by genetic algorithm, thresholding image into object and background by maximizing the fuzzy entropy. The experiment results show that our proposed method gives better performance and higher calculation speed than other general methods with good real-time by using genetic algorithm..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 465 (2003)
DEDUCING THE PROPERTIES OF CdZnTe WAFERS BY IR TRANSMISSION
[in Chinese], [in Chinese], and [in Chinese]
Several Cd 0.9 Zn 0.1 Te wafers with different properties are characterized by FTIR transmission. It is found that the IR transmission can be used qualitatively to deduce the quality of the Cd 0.9 Zn 0.1 Te wafers. The wafers with higher transmission have homogenized concentration distribution, lower dislocation densitSeveral Cd 0.9 Zn 0.1 Te wafers with different properties are characterized by FTIR transmission. It is found that the IR transmission can be used qualitatively to deduce the quality of the Cd 0.9 Zn 0.1 Te wafers. The wafers with higher transmission have homogenized concentration distribution, lower dislocation density, and higher resistivity. According to the variation of IR transmission with wavenumber, IR transmission spectra can be classified into four types with different qualities. These results are initially analyzed based on the mechanism of Cd 0.9 Zn 0.1 Te IR absorption..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 469 (2003)
MILLIMETED WAVE WAVEGUIDE-TO-MICROSTRIP TRANSITION DESIGN
[in Chinese], [in Chinese], and [in Chinese]
A Ka-band antipodal finline waveguide-to-microstrip transition was analyzed and simulated by HFSS software. The several factors of simulation result for affecting performance of transition are analyzed, and a design curve of transition available for project application is obtained. Based on the curve, the waveguide-to-A Ka-band antipodal finline waveguide-to-microstrip transition was analyzed and simulated by HFSS software. The several factors of simulation result for affecting performance of transition are analyzed, and a design curve of transition available for project application is obtained. Based on the curve, the waveguide-to-microstrip transition is designed. The insertion loss of transition is below 1 dB in the Ka-band. Experimental results coincide well with the design curve..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 473 (2003)
ADAPTIVE NULLING BASED ON SPACE EQUALIZATION METHOD
[in Chinese], and [in Chinese]
The space equalization method (SEM) is put forward in this paper to eliminate the amplitude and phase errors among antennas caused by mechanical manufacturing errors and array edge effects. After array mutual coupling calibration (MCC), an adaptive nulling algorithm based on SEM is derived, which greatly improves jammeThe space equalization method (SEM) is put forward in this paper to eliminate the amplitude and phase errors among antennas caused by mechanical manufacturing errors and array edge effects. After array mutual coupling calibration (MCC), an adaptive nulling algorithm based on SEM is derived, which greatly improves jammer cancellation performances. The experimental results demonstrate the advantage of SEM..
Journal of Infrared and Millimeter Waves
- Publication Date: Dec. 01, 2003
- Vol. 22, Issue 6, 477 (2003)
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