Detection of curves with special shapes has been put on great interest in the fields of image processing and recognition. Some commonly used algorithms such as Hough Transform and Generalized Radon Transform are global search methods. When the number of parameters increases, their efficiencies decrease rapidly because of the expansion of parameter space. To solve this problem, a new method based on Genetic Algorithm is presented which combines a local search procedure to improve its performance. Experimental results show that the proposed method improves search efficiency greatly.
In this paper, a new video description method based on finite element method is proposed. In the method, a finite element mesh is utilized to approximate an original intraframe image, this mesh is also utilized to describe motion between consecutive interframes. By applying the method presented in this paper, drawbacks in the conventional block matching method can be alleviated, and new video coding scheme can be developed.
In this paper an integrated vision system for autonomous land vehicle is described. The vision system includes 2D vision, 3D vision, and information fusion. The task of 2D vision is to provide physical information and 3D vision is to detect obstacles in the surrounding. The 2D and 3D information fusion can generate a feasible region provided for vehicle.
`Rainbow Range Finder' is a method for rapidly acquiring 3D information based on spectral analysis. It uses a special light with continuous spectrum to project across the objects, and its image will present the regular change of colors. One color forms a line in the color image and responds to a light plane structured by a wave band in the spectrum. When all the light planes are calibrated and the camera model is known, we can calculated 3D coordinates of all image points in the scene. This paper mainly discusses the light plane calibration and color classification techniques for implementation of these methods.
A fast 3D reconstruction of space curve based on quadric segment and matching in trinocular vision is proposed in this paper. First by using the perspective invariance of zero curvature and corner points in curves, curves can be segmented into different quadric curves. Then match these segments among three images and reconstruct them respectively. Finally combine all reconstructed segments together to form continuous curves. The experiments illustrated that the reconstruction speed is higher than those which take points or lines as primitives and duality and a uniqueness solution can be ensured.
A 3D shape retrieval by orthographical reconstruction based on an one-shot active system is presented. First its basic ideas and mathematical analysis are presented. Then a new method to determine crucial system parameter is proposed. Finally a computer synthesized experiment is conducted to evaluate our method. The experiment result is promising.
A wide field CCD camera has been developed and mounted on a small size pilotless airplane for photogrammetric test. Since the focal length, relative aperture and swath of the camera are closely related to the size of the CCD pixel, and the resolution and signal to noise ratio of the camera are determined by the CCD characteristics. Great care has been paid on the selection of CCD at the beginning of the system design, and great effort has been made to decrease the output noise of the camera, which depends on CCD and circuit noise. As the pilotless airplane is small in size and light in weight, the effect of wind stream and direction to the plane attitude should be taken into account. This paper presents the design of the pilotless airborne wide field CCD camera. Two main parameters, namely the resolution and signal to noise ratio of the camera are discussed, and the effect of attitude variation of the plane to the image taken is analyzed, and measures taken to overcome the effect and flight test results are presented.
We propose a 3D image display system which can present real scenes with realistic motion parallax. In the sensing system, a scene is observed by using a camera matrix. An excellent stereo algorithm SEA which utilizes 3 X 3 image matrix recovers the depth information of the scene with the density and the sharpness required for high quality image generation. In the display system, following the viewing position of the observer, 2D images with proper motion parallax are generated and presented. A prototype system has been developed and evaluation of the system is examined.
In this paper, real terrain is regarded as a hierarchical structure, by simulating the two main processes in earth evolution: construction movement and erosion effect, we integrate findings of classical geometry, fractal geometry, wavelet theory and image processing technique to propose a realistic and feasible hierarchical method for 3D terrain generation. Given some specific terrain parameters, e.g. standard deviation of terrain elevation, relative length, mountain trend, terrain coarseness, `real' 3D terrain can be automatically generated on computer by simulating the process of terrain evolution.
A novel 3D-terrain construction algorithm is represented in this paper. Traditional construction algorithms based on terrain self-similitude often ignore its structural features. This algorithm not only guarantees the integral and local self-similitude of constructed terrain, but also describes its structural features realistically. Iterated function system is used to construct terrain structural lines first. Then heights are got and adjusted by washing- out algorithm. Structural features of constructed 3D-terrain with this algorithm is conforming to the natural scenes, so it is more similar to natural scenes.
3D route planning is a challenge problem due to its huge computational cost burden. There are many algorithms about route planning such as A* and dynamic programming. But these algorithms are planned only from 2D plus 1D, instead of 3D directly. Generally, they first search a 2D optimal route in the ground, then plan their altitudes in a vertical profile determined by 2D route planning. In this paper a 3D route planning method based on genetic algorithm is proposed to select a 3D route directly. Through the experiments with a natural 3D terrain map, it is concluded that the route planned by this algorithm is satisfactory.
Threat source such as radar, is one of the most important factors which must be considered in route planning. Some threat sources generate so large threat area that the whole planning field is covered by it. In these areas, some threat areas can be observed by threat source, called visible area while others can not be observed due to the overlapping of terrain, called invisible area. In order to lessen the route planning cost, invisible area should be utilized as more as possible. In this paper a fast route planning approach which uses invisible area and the high maneuverability of aircraft is presented. After the comparison of theoretical analysis with experimental results, it is concluded that our approach needs much less planning time than the traditional algorithm.
This paper presents a novel method to analyze the matching suitability of reference map for mission planning of unmanned aircraft navigated by scene matching. The method is based on the relationship between matching probability of reference map and that of its points. First it estimates the matching probabilities of every point of reference map, then the matching probability of reference map is calculated by summing up these probabilities with weight of probabilities of navigation position distribution. Finally the experimental result is shown to demonstrate the validity of the method.
In this paper, a characteristic function is defined and used to quantitatively characterize exponential stability of nonlinear continuous neural network. By utilizing the function, we address many important aspects of network, including global and local exponential stability; the estimates of the domain of attraction of stable equilibrium point; the estimates of convergent rate of the network trajectories. A sufficient and necessary condition for network to be locally exponentially stable is obtained. Our method is simple and practical, and our results generalize those in 1-3.
There are many approaches about 3D route planning such as A*, potential field, dynamic programming. All of them plan the route only in the way of space route planning. As well known, the shape of 3D terrain is one of intricate features in nature. Is there a relationship between flight route and 3D terrain? In this paper, we concentrately reveal this relationship and attempt to apply it to route planning, presenting a new approach of 3D route planning. Through the experiments in a natural 3D terrain map, it is concluded that this approach is efficient and very fast.
3D surface reconstruction is one of the hotspots in Computer Vision and Remote Sensing. Relative orientation is a important part of 3D surface reconstruction. The traditional method that finding the parameters of relative oriented model is Newton Method, but it is highly sensitive to the initial values of parameters. To overcome this shortage, we give a method of using penalty function to find the relative oriented model in this paper.
This article discussed the computerized automatic evaluation of weld radiographs. The radiation projection method (RPM) was introduced, and a modified calculation method based on RPM was proposed. The actual experimental results demonstrated that this new method improved the ability of RPM to suppress the interference of noise.
In this paper, a robustness analysis of discrete autonomous multi-agent system by linear matrix inequalities is proposed, the core equations and their inferences are given. And corresponding concurrent schemes for analyzing multiprocessing system are discussed.
Virtual Reality Systems can construct virtual environment which provide an interactive walkthrough experience. Traditionally, walkthrough is performed by modeling and rendering 3D computer graphics in real-time. Despite the rapid advance of computer graphics technique, the rendering engine usually places a limit on scene complexity and rendering quality. This paper presents a approach which uses the real-world image or synthesized image to comprise a virtual environment. The real-world image or synthesized image can be recorded by camera, or synthesized by off-line multispectral image processing for Landsat TM (Thematic Mapper) Imagery and SPOT HRV imagery. They are digitally warped on-the-fly to simulate walking forward/backward, to left/right and 360-degree watching around. We have developed a system HVS (Hyper Video System) based on these principles. HVS improves upon QuickTime VR and Surround Video in the walking forward/backward.
The article analyzes the present volume measuring and mapping system used for coal yard, and presents a principle which connects phase-modulating laser ranging with high- accurate angle scanning, to fulfill an effective system of measuring and mapping the volume of heaps of coal. This system can complete shape-mapping and volume-measuring over 200 m X 50 m coal yard within 20 minute, and the accuracy up to 0.5%. Also, some detail working principle, actual measuring result and performance analysis of the system are discussed in this article. Due to having solved the prompt (< 1/500) and accurate (3 cm) ranging problem under the condition of low-reflection objects ((rho) < 0.01), this system can be widely used for 3D measuring and mapping on bulky objects.
Lighting simulation and image synthesis for outdoor scenes is intractable due to the geometric and lighting complexity of such environment. In this paper we present an efficient framework to the problem of image synthesis for outdoor scene by combining the geometry-based and image-based rendering. With respect to the linearity of incident spectral power distribution and apparent reflectance, the receptor responses of an image under varying sun position and weather conditions can be calculated to generate the desired image. Our method is proved to be available and feasible for fixed scene and camera geometry.
This paper describes a scalable architecture model that is suitable for multimedia image storage. In the architecture, the storage system is connected with networks so that direct data transfer between the clients and the server is available. The clients can receive data from the storage subsystem directly without going through the server. Thus, the bottleneck of the server doesn't exist. The paper demonstrates the detailed storage architecture. Because of the new architecture, file system and lower level storage operations will change correspondingly. Therefore, corresponding file system support for the architecture is discussed.
From a dynamical system's point of view, we choose several sets of simple and special mathematical functions to generate complex computer images. We give examples of various patterns with special symmetry in different convergence conditions and coloring techniques.
A prototype was designed to simulate spectral packinghouse measurements in order to simplify fruit and vegetable damage assessment. A computerized spectrometer is used together with lenses and an externally controlled illumination in order to have a remote sensing simulator. A laser is introduced between the spectrometer and the lenses in order to mark the zone where the measurement is being taken. This facilitates further correlation work and can assure that the physical and remote sensing measurements are taken in the same place. Tomato ripening and mango anthracnose spectral signatures are shown.
In this paper, we analyze and compare the performance, both in spatial and frequency domains, of different moments. Our analysis shows that Legendre and Gaussian-Hermite moments better separate image features based on different spatial modes and Gaussian-Hermite moments are less sensitive to noise. Analysis on spectral performance shows that Legendre and Gaussian-Hermite moments separate different frequency bands more effectively than others. It is also shown that Gaussian-Hermite moments give an approach to construct orthogonal features from wavelet analysis results. Experimental results are reported.
This paper describes a new jigsaw puzzle solver using chromatic information as well as geometric shape. Three new puzzle assembly algorithms are developed and experimental results on their performance are provided.
In the simulation of tracking a target such as a ship with infrared imager in the sea environment, how to generate dynamic images of the target and background is the key issue. The radiation of the scene includes the radiation of the target, sky, and seawater. All of these radiation can be obtained with the software--LOWTRAN7. A method of laser quantification is used to convert the radiance into gray- scale. The gray-scale of anywhere and anytime is computed beforehand and stored as a database. Establishing the 3D model of the target and background is necessary. The scene can be established through 3D transformation. We program with OpenGL in Windows NT operating system. The material of the objects is emitted material and its value is equal to the gray-scale. During the course of animation, the material and the position of the scene changed frequently. It is interactive.
The squint side-looking imaging mode SAR has a squint angle at the side-looking direction. This imaging mode can obtain multi-resolution images of a same scene with the variation of squint angle. But the imaging mode has to overcome three problems: (1) compensate the range walk and curve; (2) develop a mapping technique that works even when the size, shape, and orientation of a resolution cell varies; and (3) fuse the different resolution images to obtain the best imaging results and the most messages of the imaging terrain. The paper analysis and present an imaging schedule including imaging algorithm, geometry correction method and a different resolution images fusion method.
At first, the radar target scattering center model and MUSIC algorithm are analyzed. How to efficiently set the parameters of the MUSIC algorithm is given through a great deal of simulated radar data in experiment. After that, according to measured data of two kinds of plane target on fully polarized and high range resolution radar system, author mainly investigated particular utilization of MUSIC algorithm in radar imaging, 2D radar images are generated for two targets measured in compact range. In the end, we draw a conclusion about the relationship between radar target scattering properties and imaging results.
This paper studies on the multiresolution analysis and classification of the textured synthetic aperture radar (SAR) image using the wavelet transform (WT). The tree- structured WT algorithm is first employed to decompose a real-world textured SAR image, and to quantify different texture types in the image. Then, the pyramid-structured WT algorithm is applied in the multiresolution classification of the image. The classification result obtained demonstrates the advantage of the WT in the textured SAR image classification.
Pseudo-random code continuous wave (PRC_CW) radar, which is low probability of intercept and has good ability of target detection in clutter, is widely used in fields of target detection, tracking, guiding, detecting underground, and so on. Temporal distribution function of land clutter was always studied and the backscatter from land was supposed spatially homogeneous. In fact, the backscatter from various resolution cells is obviously different, especially under complicated land background, since the number of clutter sources is too great. So it is very important for spatial correlation characteristic analysis of land clutter. In this paper, spatial correlation characteristic of land clutter for PRC_CW radar at X-band was analyzed. The time spread of radar echo exists while the radar works at low grazing angle. To PRC_CW radar, the time spread of radar echo results in that the receiving signal amplitude at a certain time is the sum of many spread codes. In this paper, spatial amplitude distribution and spatial correlation function of some typical land clutter under the condition of single code were firstly discussed. Then, we point out the problem of time spread of echo signal at low grazing angle and proposed a superposition method to simulate real clutter echo of PRC_CW radar. Finally we analyzed the spatial correlation characteristics of some typical land clutter.
In this paper, it is firstly pointed out that the raining, as an object in the air, will cause the time spread of radar echo signal. For the pseudo-random code continuous wave (PRC_CW) radar, working with transmitting and receiving continuous EM waves, the echo signal at a specified moment will be the superposition of some spread echo signals in a period of time before this specified moment. A superposition algorithm was proposed to calculate the PRC_CW radar signal. Based on the former previous results on the characteristics of rain clutter, the amplitude fluctuation and the spectrum of the echo signal of the PRC_CW radar are investigated with simulation method.
The Doppler frequency rate is an important parameter in synthetic aperture radar imaging, which is used to perform the azimuth compression. The Doppler frequency rate can be estimated through the measurement of the sensor trajectory and attitude or through the analysis of the characteristics of the target echoes. The latter method will generally give a high accuracy. Currently, there are quite a few techniques for estimating the Doppler frequency rate, with some having a high accuracy but requiring a large amount of computation, and others requiring a smaller amount of computation but having a lower accuracy. Based on the concept of minimum entropy, a new technique for estimating the Doppler frequency rate is proposed which not only gives a high accuracy but also requires a small amount of computation.
In this paper, the principle of how to make us of the inter- intro FM waveform to achieve a high range resolution has been analyzed and the formulas for a point target and an extended target have been derived. On the basis of the derived formulas, the two ways to process radar echoes for a high range resolution image have been typically discussed.
The technique of millimeter monopulse radar 3D imaging of maneuvering targets is presented, and some key techniques to obtain high quality image are discussed. The efficient of the proposed method is confirmed by simulation results.
Range-Instantaneous-Doppler Algorithm (RIDA) should be used in ISAR imaging when the target is maneuvering. With the assumption that Doppler shift of scatterers is low-order polynomial, an adaptive LFM `CLEAN' technique to estimate the instantaneous frequency is proposed, where scatterer Migration Through Resolution Cell is also considered. The final RID images of the real maneuvering aircraft are obtained, which confirms the effectiveness of the proposed technique.
2D phase unwrapping is the key technique in SAR interferometry. This paper discusses a phase unwrapping algorithm based on fringe line detection. Improvements are presented in order to use this method in areas with intensely fluctuated fringe lines. Results on X-SAR interferometric data are obtained. They confirm the excellent performance of the procedure.
A new numerical model to predict the IR radiative temperature of the ground with different mulch is presented. Based on the energy and water balance principle, the mulched and unmulched ground surface boundary conditions for both heat and water flow are described. The temperature of mulched and unmulched soil region and mulch surface are determined to predict the surface radiative temperature of the ground background. The inputs required for the numerical simulations are weather data, soil thermal and hydraulic properties, and mulch data. Numerical experiments are performed to examine the effect of soil type, mulch kind, and weather conditions on the spatial variations in radiative temperature. 24-hours continuous simulations for each combination of different soil type, mulch kind and mulch width show that the soil type, mulch kind and width, and weather conditions can evidently affect the radiative feature of the ground surface.
128 X 128 diffractive microlens arrays have been designed by considering the independent optical and processing parameters for 3 - 5 micrometers wavelength with a microlens size of 100 micrometers . The lens F number and array pitch are 1.5 and 100 micrometers , respectively. The diffractive microlens arrays have been fabricated on the surface of Si substrates by successive photolithography and Ar+ ion-beam-etching technique. The practical processes and fabrication method are discussed. The optical characteristics and measurements of the diffractive microlens arrays are presented.
Acquiring 3D color model of human head is desired in many applications. In this paper, we introduce a scheme to obtain 3D color information of human head from image sequence in 3D laser color scanner. Structured light technology is employed to measure depth. We study the relationship among the object's images in different position. Synthesizing these information, we can obtain the shape of hair area from contour image. True color information of sample points can be acquired from the specified image in image sequence. The result of experiment is satisfactory.
Basing on the analysis and simulation of a-Si TFT/PIN coupled unit, we obtained optimized design for structure parameters of detecting unit and material parameters suitable for detecting spectrum. In order to satisfy the low-temperature process of a-Si TFT and a-Si PIN, polyimide (PI) film has been used as the insulator in the TFT/PIN array. We have investigated process compatibility between a- Si TFT and a-Si PIN preparation and fine pattern for low- temperature PI film. As a result, we obtained 2D a-Si TFT/PIN image sensor (6 X 12 pixels) which has signal readout and sensor function. We tested and analyzed its static characteristic. The results indicate that the characteristics of PIN photodiode and TFT switch are better, and the performance of illumination response of the 2D image sensor is good. We propose to apply the image sensor into neural network system in order to decrease cross-coupling between pixels and increase parallel processing rate.
Spatial resolution improvement of digital images has significant applications in remote sensing and computer vision. In this paper, a general iterative method is proposed to improve the spatial resolution from low- resolution images in spatial domain. The general method of interpolation and simulated sampling is formed based on the iterative methods for signal reconstruction from nonuniform sampling and the methods of projection onto convex sets by defining convex sets of the sampled images and projection onto the sets, and using a general parallel projection method to find the common points of the sets. The method can be applied to multiframe images with different spatial resolution, various image radiance, relative geometric distortion, additive random noise, and some other general imaging style. Some experiments with resolution test pattern and multiangular remote sensing images performed the convergence and the effectiveness of the algorithms.
The key motivation for visual interpretation of hand gestures is to introduce this natural and intuitive communication mode to human computer interaction. Visual interpretation of hand gesture had typically made use of high-level parametric models representing the body parts such as arms, figures, palms etc. and their connections to each other. Such 3D model-based interpretation has been successful in some case; however, heavy computation makes this approach a very difficult task. By use of variable- order parameterized models of image motion and robust dominant motion regression, in this paper, we propose a motion-based segmentation scheme to feature extraction of hand gestures. The proposed scheme can directly estimate image motion of an object in two unsegmented images and obtain fine segmentation of that object from background at the same time. Based on inter-frame image motion parameters and the fine segmentation, we can construct various motion features, shape features, or their combinations for the purpose of hand gesture interpretation. With these features 12 kind of hand gestures used in our experiment can be reliably interpreted.
Optimization-based derivative-free line search methods are presented to locate all the corners of 2D polygon images for pattern recognition and image matching purposes. These optimization-based methods are also used to approximate a 2D non-polygon object by a polygon to desired accuracy. Experimental results are presented to compare these methods.
Imaging Spectrometer is a new remote sensing tool. Unlike conventional remote sensing, the Imaging Spectrometer can provide data in narrow, contiguous spectral bands across the solar reflected portion of the electromagnetic spectrum 0.4 um to 2.5 um. Appearance of the Imaging Spectrometer are providing opportunities for acquiring ever-increasing volumes of information as well as making more types of geological information potentially derivable. In order to capture the full range of geological information contained in huge volumes of sea-like data effectively, we have to develop new analytical tool for processing of hyperspectral remote sensing data. In this paper, authors generalized the basic theory and method of hyperspectral data processing, and pointed out the advantages and deficiencies of the various theoretical models. In addition, a practical experiment of data processing was conducted to perform the analytical processing technology developed in the paper. A error analysis was reported, some interesting suggestions were given.
In this paper, we present the output probability density functions of generalized open-closing (GOC) and generalized close-opening (GCO) filters under the different input distributions such as uniform, Gaussian and biexponential distributions, and calculate their digital features (expectations and variances). Then, we apply these filters to restore an image corrupted by impulsive noise and further test their efficiency in noise-suppressing and detail- preserving characteristics. The simulation results show that the GOC and GCO filter have good performances.
In this paper, a new method for extracting ellipses from an image is presented. It includes two steps, finding the candidate regions and rectifying the detected regions' position, estimating the ellipses' parameters. It's calculation amount is less than many other methods, and it is very immune to the noise. Specially, it has strong ability to extract multi incomplete and concentric ellipses from an image.
VQ (Vector Quantization) reduce the bit rate by exploiting the correlation in the data. To improve the performance of a compression algorithm based on VQ, this paper introduced a more efficient scanning method, i.e. Peanoscanning, which maintains better correlation in 2D data than that of raster scan, and then a hierarchical VQ based on the characteristics of image data is presented, at last we reduced the blocking effect by a smoothing algorithm.
In order to achieve high compression ratios while maintaining high visual quality, this paper propose a new hybrid zerotree and DPCM based wavelet coding scheme for still image. We further exploit the dependencies between neighboring pixels in the same subband and the dependencies between descendants and ancestors in this paper, and we apply an explicit quantizer to each coefficient, then we transfer and encode data by bitplane progressively to maintain an embedded characteristic.
In this paper, we propose an translation- and scale- invariant adaptive wavelet transform, and according to this adaptive wavelet decomposition, we construct a stable multiresolution feature vector of images which is translation-invariant and scale-invariant. At end, we give some experiment results to demonstrate the stability of this feature vector under translation and scale transform.
Discrete-Amplitude Multiresolution Analysis (DAM) is a new kind of multiresolution analysis that uses signal quantization resolution as its scale. In this paper, a new efficient image coding method that utilizes the DAM's 2 bits recomposing theory of arbitrary continuous signal is realized. The problem of how to choose the coding direction, which is important for the 2D image data while not exists in the 1D data processing, is emphasized. The problems appeared with the application of DAM on image data are also analyzed. The experimental results proved that DAM image coding is a simple, easy-approaching and efficient coding method and it should have more potential application in image processing.
The application of mathematical morphology to edge enhancement of images is studied in this paper, and a morphological edge enhancing operator and its anti-noises counterpart are also presented. This morphological operator enhances the gradients of edges while attenuates noises and preserves edges. It is showed by computer simulations that the gradient of edges is enhanced by the morphological edge enhancing operator and, then, the structure and feature of images are strengthened and edges can be easily extracted.
The typed association of objects for image analysis via structured quotient set is presented in this paper. From a landscape point of view, the elements of spatial structure are organized into some distinct patches, which are the smallest homogeneous units of landscape at the spatial scale we can see. The main advantage of such patches is that it gives us the typed association of objects. In order to remark the relationship between the components of an image corresponding to the patch, the notion of diffusion- concentration is introduced, whose practical meaning in the patch is to join a pixel to one another and determine the weights of the links. Another research goal is to explore the properties of variogram function, from which the weights of neurons for growing collection of the typed association of objects by quotient set can be derived.
This paper presents a new algorithm for the fast hough transform. Compared with others, this algorithm not only has a faster speed but also has advantages such as avoiding erroneous solutions, eliminating redundant points, detecting straight lines of different sizes, and selecting threshold automatically etc. We will discuss the performance of this algorithm and will also show its efficiency with examples.
A new segmentation algorithm of forward-looking infrared (FLIR) images is presented, which first uses median subtraction filter to enhance targets and suppress backgrounds, then uses MBS algorithm to perform segmentation. This algorithm can obtain a precise and accurate segmentation of a target from low contrast FLIR images in complex background. Experimental results compared with MBS algorithm are given. We find that the proposed algorithm shows much better segmentation performance than MBS algorithm in complex background.
Using the 3D scanner, a large quantity of 3D data set of the scanned object is generally acquired. It isn't very convenient to transform and to process such a large data set. So compression is necessary. In this paper the 3D data compressing of the human head surface is considered. A 2D curve compressing algorithm is extended to 3D space and is improved by adopting an adaptive threshold method. Experiments show that both the compressing rate and the reconstructing effect are satisfactory.