The checkerboard is a frequently used pattern in camera calibration, an essential process to get intrinsic parameters for more accurate information from images. An automatic checkerboard detection method that can detect multiple checkerboards in a single image is proposed. It contains a corner extraction approach using self-correlation and a structure recovery solution using constraints related to adjacent corners and checkerboard block edges. The method utilizes the central symmetric feature of the checkerboard crossings as well as the spatial relationship of neighboring checkerboard corners and the grayscale distribution of their neighboring pixels. Five public datasets are used in the experiments to evaluate the method. Results show high detection rates and a short average runtime of the proposed method. In addition, the camera calibration accuracy also presents the effectiveness of the proposed detection method with reprojected pixel errors smaller than 0.5 pixels.
An approach for carrying out depth profile measurement of an object with the plenoptic camera is proposed. A single plenoptic image consists of multiple lenslet images. To begin with, these images are processed directly with a refocusing technique to obtain the depth map, which does not need to align and decode the plenoptic image. Then, a linear depth calibration is applied based on the optical structure of the plenoptic camera for depth profile reconstruction. One significant improvement of the proposed method concerns the resolution of the depth map. Unlike the traditional method, our resolution is not limited by the number of microlenses inside the camera, and the depth map can be globally optimized. We validated the method with experiments on depth map reconstruction, depth calibration, and depth profile measurement, with the results indicating that the proposed approach is both efficient and accurate.
A reflection TIE system consisting of a reflecting microscope and a 4f relay system is presented in this paper, with which the transport of intensity equation (TIE) is applied to reconstruct the three-dimensional (3D) profile of opaque micro objects like wafer structures for 3D inspection. As the shape of an object can affect the phases of waves, the 3D information of the object can be easily acquired with the multiple phases at different refocusing planes. By electronically controlled refocusing, multi-focal images can be captured and used in solving TIE to obtain the phase and depth of the object. In order to validate the accuracy and efficiency of the proposed system, the phase and depth values of several samples are calculated, and the experimental results is presented to demonstrate the performance of the system.
Remote sensing for unmanned aerial vehicles (UAVs) is becoming the preferred method for Earth observations. Data and command communication between an airborne remote sensing load and the ground terminal is crucial for the realization of real-time and smart observation for remote sensing. However, the current remote sensing observation equipment for UAVs cannot meet these requirements. In order to solve this problem, a real-time and smart remote control and data transmission system for UAVs is designed. The design and implementation of several key functions are presented, including multitask and multithread data transmission, transmission resumption, and task scheduling by priority.
Drought has been a frequently happened type of disaster in China, and it has caused massive losses to people's lives.
Especially the drought happened in Shandong province in the late 2010, which was recognized as the severest in the past
five hundred years in some areas. Evaluation must be done in order to make proper rescue plans. Instead of collecting
data site by site, remote sensing is an efficient way to acquire data in a large area, which is very helpful for drought
identification. Some normal ways in remote sensing for drought analysis are explained and compared in this paper, and
then the VSWI method is chosen to evaluation the drought in Shandong province. Because of its free data policy and
wide availability, the data sets acquired by Terra-MODIS are chosen to identify the drought severity in Shandong
province. From the drought severity level images we can see that almost the whole area of Shandong province was lack
of water except the Weishan Lake and eastern coastline regions where large area of water exists. The southwest region,
including Heze and Jining, is in moderate drought condition, where it is used to be an important grain-producing area.
This drought condition will inevitably put a negative effect on its grain production. The central and southern areas were
in severe drought condition, but fortunately these areas are of hills and mountains, so the drought will only affect the
lives of residents. The northern parts, including Dezhou and Bingzhou areas, were also in severe drought condition, and
these regions are also important for grain-producing, so the severe drought disaster will lead to a sharp grain output cut.
This analysis results will not only shed light on the rescue process, but also give the government some clues on how to
maintain the grain supply safety.
KEYWORDS: Data modeling, Systems modeling, Process modeling, Prototyping, Logic, Databases, Data storage, Human-machine interfaces, Decision support systems, Computer programming
Models are often thought as the abstraction of object, phenomenon, system and process. But the present model base system is good at the abstraction of process which starts from the input data to the results. And it falls short of the model composition. Based on the object-oriented methods, this paper aims to discuss a new application-oriented model base system. The structure of model interface parameter is abstracted into descriptive model (DM) which can be regarded a bridge between different models. Using object-oriented method, a series researches has been made focused on DM, and
establish the application-oriented model-base system. The model working flow and user-oriented model inheritance mechanism were designed for applying and maintaining the model resource easily. A prototype system was designed and developed, and an application demonstration is shown to verify its feasibility.
In the land vehicle positioning and tracking system, the vehicle moving route is sometimes positioned outside the vehicle
running road because of the GPS positioning errors. It may cause the tracking system unavailable. In order to improve
the positioning accuracy of vehicle tracking system, a current statistical model is employed as the vehicle moving model.
At the same time, the map-matching algorithm with the nearest location and the suitable moving angle is proposed to
amend GPS measured data. The algorithm can determine the best matching road by making full use of the road
geographic information of electronic map. Simulation results show that the vehicle tracking system has high positioning
accuracy besides the navigation function.
It is the coexisting time between film and digital imaging. Both film aerial camera and digital one have their particular
imaging principles, characteristics and complementarities between them. In this paper, a new convertible aerial camera is
developed to integrate film and CCD sensors, named as twice-imaging scheme. Some experiments have been carried out
for the feasibility of the scheme. This convertible aerial camera system has both film and digital advantages. It can be
used in different aspects of aerial remote sensing, surveying and mapping.
Due to the affection of large moving object in the video image, the ordinary image stabilization algorithms can't get
precise motion vector of the image. In this paper, a new image stabilization method that explicitly deals with video
images containing large moving object is given out. It detects a rough area containing moving object first. Then this area
will be got rid of from source image. Finally, a feature area taken from the rest part is used to calculate the image motion.
For the affection of moving object has been eliminated, motion vector's precision of the image is improved greatly.
With maturation of UAV (Unmanned Aerial Vehicle) key techniques, the UAV aviation is more stable than before. That
shows us the possibility of reconnaissance in atrocious environment. Here the structure of an UAV remote sensing
platform is given out first. Then the control system modules of aerial remote sensing and their functions with each
realization are discussed in detail. The experiments show that the system can satisfy the needs for aerial remote sensing
task.
Laser Radar (LADAR) achieves more applications on aerial aided-navigation in mountainous areas for its good
performance. But plain areas encounter terrain elevation's slow variation and occasional unavailability of Digital Feature
Analysis Database (DFAD), which as necessary reference. Looking for replaceable map source and extracting common
characters for matching, are the fundamental circles of imaging LADAR aided navigation research. In this paper aerial
high-resolution remote sensing (RS) images are applied as substitute for DFAD, and the edge factor is chosen out by
synthetically analyzing RS images' and imaging LADAR point cloud'scharacters. Then edge extraction algorithm based
on multi-scale wavelet is explored to reflect their common features, and weighted Hausdorff distance method is applied
to match for positioning. At last the high-resolution RS images and imaging LADAR data of the same area are assumed
for simulation experiment, which testifies the validity of the methods proposed above.
TERCOM, ICP and TIEM algorithms, which mathematically all apply correlation matching mode, have been developed
for positioning in underwater Terrain-aided Navigation System (TANS), but how to virtually improve their performance
is still research puzzle now. Analyzing the characters of terrain reference data's distribution and vehicles prowling
underwater, we find that grid spacing and accumulation sequence are two decisional elements of underwater TANS.
Then the modified Maximum a Posteriori (MAP) estimation algorithm (M-MAP) from super-resolution images
reconstruction is creatively explored for implementing interpolation to enhance the accuracy of non-surveyed points'
deep-determination, and basic error mechanism model (EMM) based on Mean Absolute Difference (MAD) algorithm is
deduced which can reflect the relationship of underwater TANS's inner factors. Simulation experiments indicate that
adopting appropriate fundamental factors can effectively boost up underwater TANS's navigation competence based on the algorithms listed above.
An approach of fast image mosaic is presented, which involves image matching and image intensity smoothing. Image
matching includes two procedures, i.e. rough matching and fine matching. In rough matching, the overlapped regions of
two adjacent images to be mosaicked are segmented to binary image at first. Then the binary images are filtered by open
operation of mathematic morphologic method. In the binary image region of the reference image, feature template is
searched and extracted on a given rule. Via XOR operation of the feature template and search region, some possible
matching positions in the overlapped region of the other image are got. In the fine matching, the sequential similarity
detection algorithm (SSDA) is adopted to perform matching computation in the small regions near the positions got in
the rough matching, and then the relative position offsets in X-orientation and Y-orientation between the two adjacent
images are got. Based on the result of the image matching, the two images are stitched. An approach of seam-line
smoothing is adopted to adjust the intensity of the overlapped area. Simulation experimental results show that the
approach greatly improves the operation speed, while the precision remains fine, so it can be applied in real-time
mosaicking.
In remote sensing, angle information and polarization attach great importance to the precise discrimination of land objects. This paper deals with the performance of soil reflectance spectrum dependent on such factors as incidence zenith angle, wave band, polarization, water content and soil type. Our results show that soil reflectance spectrum in 2π space is strongly affected by incidence zenith angle and water content, as well as by the other factors. In the end, the cause of such spectrum performance is analyzed.
The objective of this paper is the description of the development and the validation, using airborne hyper-spectral imagery
data, of a non-conventional technique for the vegetation information extraction. The proposed approach namely the universal
pattern decomposition method (UPDM) is tailored for hyper-spectral imagery analysis, which can be explained using two
analysis methods: spectral mixing analysis and multivariate analysis. For the former, the UPDM expresses the spectrum of
each pixel as the linear sum of three fixed, standard spectral patterns (i.e., the patterns of water, vegetation, and soil); each
coefficient represents the ratio of spectral patterns of three components. If we think of the UPDM as multivariate analysis,
standard patterns are interpreted as an oblique coordinate system, and coefficients are thought of as the coordinates of a
pixel's reflectance. The later explanation is much more comprehensible than the former for the reason of additional
supplementary pattern presence when necessary. The vegetation index based on the UPDM (VIUPD) is expressed as a linear
sum of the pattern decomposition coefficients. Here, the VIUPD was used to examine vegetation amounts and degree of
terrestrial vegetation vigor; VIUPD results were compared with results by the normalized difference vegetation index
(NDVI), and an enhanced vegetation index (EVI). This paper described the calculation of VIUPD, using AVIRIS airborne
remotely sensed data. The results showed that the VIUPD reflects vegetation and vegetation activity more sensitively than
the NDVI and EVI.
Terrain contour matching (TERCOM) algorithm is the main one in the conventional terrain aided navigation system. When it has been directly applied to the submarine terrain aided navigation (STAN) system, the accuracy and stability are primely reduced. To solve these problems, the detail analyses about the particularities of the STAN and the disadvantages of the conventional TERCOM algorithm have been made. The improvement for the TERCOM algorithm on the measurement function, the water depth survey error and the scheme to prevent fail positioning has been done. Moreover, experiments with pedestrian simulation confirm the effectiveness of the improved TERCOM algorithm. The system achieves higher positioning precision than that of conventional one.
As a new type of aviation remote sensing earth observation system, the UAVRSS (Unmanned Aerial Vehicle Remote Sensing System) has some special characteristics for getting the digital remote sensing images. Through some real flying experiments of the UAVRSS, the data and the images were obtained. These data and the images were analyzed by three methods from three aspects in this paper. The result shows that it is viable that using the UAV with remote sensing system to achieve the remote sensing works.
Remote sensing signal reflected from natural background is of important significance in the field of geography. However the signal we can get is always polluted by additive noise. Since it has been proved that the remote sensing signal reflected from natural background always has some fractal characteristics, just like the background it came from, it is possible for us to deal with it with the theory of fractal. For the perfect analytical function on both time and scale, the wavelet theory is used to analyze the remote sensing signals in this paper. Shannon entropy represents how much information in an information source, so it is possible to estimate the remote sensing signal from noise based on the radio of information entropy at different scales. In this paper, the Shannon entropy of remote sensing signals' wavelet coefficients and that of additive noise in different scales are discussed respectively. And then a method for estimating the Shannon entropy of signal's wavelet coefficients is discussed. Finally, the wavelet coefficients belonging to signal are estimated, and the signal is estimated from the added noise at last. In order to demonstrate the effectiveness of this method, some simulation studies are performed in this paper. Since it doesn't need to estimate the fractal parameter of remote sensing signal, this method is suitable in many situations.
With the integration of GIS, IT technology and wireless communication techniques, LBS is fast developing and caused wide concern. Personal navigation is the critical application of LBS. It has higher requirement of data quality, positioning accuracy and multi-model services. The study discusses the key techniques of a personal navigation oriented LBS system. As an example for service platform of China Unicom, NAVISTAR especially emphasizes the importance of spatial data organization. Based-on CDMA1X network, it adopts gpsOne\MS-Assisted dynamic positioning technique, and puts forward a data organization solution to realize multi-scale representation.
In order to research the global change and analyze the characteristics of land surface or atmosphere, an Earth Observation Station usually needs a high-definition large screen to display the satellite remote sensing image. Under the development of digital imaging technology, this application can be put into practice. In this paper, the optical engine, a key technique in the digital imaging, is introduced. Then the basic principle and technical difficulties of optical engine are discussed in detail. It is testified that the optical engine technique can make the satellite remote sensing image displayed in high-definition model.
In this paper the authors analyzed the data collection of seabed terrain, the influence factors on measurement precision and the data computation in time or frequency domain. In order to estimate the noise embedded in the received data, the structure and algorithm of characteristic matching filter based on the entropy concept is developed and discussed in detail. It is shown that the noise data can be removed effectively and the high precision seabed terrain be simulated by the filtering method.
Virtual object registration is one of the critical technologies in augment reality. A projection algorithm for virtual object registration, based on coordinate transition and 3D projection in 3D space, is described in detail. Combined with 3D-fidudial vision-based registration, the discussed algorithm can successfully accomplish the registration of augment reality.
The research, on the damage mechanism to the high-space target by the ground laser, aims to determine the saturation or damage threshold of optic-electro sensors on the target. The laser beam to the target is relationship with the following features: The speediness of the energy accumulation and the laser tracking stability in long distance. The speediness needs high peak-power in the shortest time, while the stability needs high speed-precision ability to the servo system on earth. Obviously, the pulse laser is more effective than the continuous laser when considering the speediness. Here for the 10.6 ? m CO2 laser, the interfering effects are dealt with to the target in 500km space. Provided that the turbulent air does not influence the laser beam, the power of periodic rectangle-pulse laser arriving on the space object is evaluated first. Then the laser staring time on the object is calculated. Third, the laser energy accumulation on the space object is analyzed, and last the saturation or damage threshold ofthe object is determined.
Highly c-axis oriented Rh-doped BaTiO3 thin films were grown on MgO substrates by pulsed laser deposition using a single-crystal Rh:BaTiO3 target. THE 150 nm-thick films were deposited at 800 degrees C under the oxygen pressure of 7 by 10-2 Pa. The structural properties of the samples were characterized by x-ray diffraction and atomic force microscopy. The full width at half-maximum of the (002) Rh:BaTiO3 rocking curve and the root-mean-square surface roughness within the 5 by 5 micrometers 2 area were 0.520 degrees and 0.85 nm, respectively. The nonlinear optical properties of the films were determined by a single beam z-scan at a wavelength of 532 nm with laser duration of 10 ns. The result shows that Rh:BaTiO3 thin films exhibit a great nonlinear optical response with the real and imaginary parts of the third-order nonlinear optical susceptibility (chi) (3) being 3.59 X 10-7 esu and 4.01 X 10-8 esu, respectively.
A stable adaptive controller is reported here for a class of system with state dependent parasitic effects such as friction. The methodology is constructive, and ensures stable and convergent performance. The control design is applicable to a class of dynamic systems working at low speed with the cited parasitic effects. The design is verified by simulation and a hardware example case.
The microfabrication of optical and micromechanical elements requires a high degree of accuracy in order to obtain the required efficiency in the functionality of the element. An easy, nondestructive 3D characterization of the batch fabricated elements after each fabrication step is needed to ensure a reliable engineering control over the whole process. We demonstrate the versatility of a stand-alone AFM which can be used as a flexible tool for the nondestructive characterization of all steps of a fabrication sequence of microfabricated optical and micromechanical elements without the necessity to specially prepare the samples under test.
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