Mozambique's continental margin in East Africa was formed during the break-off stage of the east and west Gondwana lands. Studying the geological structure and division of continent-ocean boundary(COB) in Mozambiq...Mozambique's continental margin in East Africa was formed during the break-off stage of the east and west Gondwana lands. Studying the geological structure and division of continent-ocean boundary(COB) in Mozambique's continental margin is considered of great significance to rebuild Gondwana land and understand its movement mode. Along these lines, in this work, the initial Moho was fit using the known Moho depth from reflection seismic profiles, and a 3D multi-point constrained gravity inversion was carried out. Thus, highaccuracy Moho depth and crustal thickness in the study area were acquired. According to the crustal structure distribution based on the inversion results, the continental crust at the narrowest position of the Mozambique Channel was detected. According to the analysis of the crustal thickness, the Mozambique ridge is generally oceanic crust and the COB of the whole Mozambique continental margin is divided.展开更多
A new method creating depth information for 2D/3D conversion was proposed. The distance between objects is determined by the distances between objects and light source position which is estimated by the analysis of th...A new method creating depth information for 2D/3D conversion was proposed. The distance between objects is determined by the distances between objects and light source position which is estimated by the analysis of the image. The estimated lighting value is used to normalize the image. A threshold value is determined by some weighted operation between the original image and the normalized image. By applying the threshold value to the original image, background area is removed. Depth information of interested area is calculated from the lighting changes. The final 3D images converted with the proposed method are used to verify its effectiveness.展开更多
An approach to the direct measure of stereoscopic (3D) videos with different accelerations was presented, using electroen- cephalography (EEG). In the study, subjects viewed 1-sec-long video clips with a stone ap-...An approach to the direct measure of stereoscopic (3D) videos with different accelerations was presented, using electroen- cephalography (EEG). In the study, subjects viewed 1-sec-long video clips with a stone ap- proaching straightforward and were required to perceive whether they were able to catch the outline of stone. Peak amplitude of each part was extracted from PO3 electrode located at the occipital region corresponding visual processing and cognition. Three components were conspicuously observed in the periods: 650-800 ms, 800-900 ms and 1150-1250 ms, which were called N310, N480 and N810 in this paper. N310 related to the perception to the initial stage of movement. Movement in- depth could be immediately perceived when initial speed was not less than 3 m/s. N480 related to the perception to acceleration/decel- eration. N810 related to the perception to the point a movement was about to vanish. Sub- jects couldn't perceive the outline with the fi- nal speed more than 3 rn/s. For 3 m/s, subjects were in a dilemma to judge with the detecting rate 54%. Together, component analysis com- bined with behavioral results, it was supposed that 3 m/s to be the threshold to completely perceive the outline.展开更多
Three-dimensional(3D)modeling is an important topic in computer graphics and computer vision.In recent years,the introduction of consumer-grade depth cameras has resulted in profound advances in 3D modeling.Starting w...Three-dimensional(3D)modeling is an important topic in computer graphics and computer vision.In recent years,the introduction of consumer-grade depth cameras has resulted in profound advances in 3D modeling.Starting with the basic data structure,this survey reviews the latest developments of 3D modeling based on depth cameras,including research works on camera tracking,3D object and scene reconstruction,and high-quality texture reconstruction.We also discuss the future work and possible solutions for 3D modeling based on the depth camera.展开更多
The snow depth on sea ice is an extremely critical part of the cryosphere.Monitoring and understanding changes of snow depth on Antarctic sea ice is beneficial for research on sea ice and global climate change.The Mic...The snow depth on sea ice is an extremely critical part of the cryosphere.Monitoring and understanding changes of snow depth on Antarctic sea ice is beneficial for research on sea ice and global climate change.The Microwave Radiation Imager(MWRI)sensor aboard the Chinese FengYun-3D(FY-3D)satellite has great potential for obtaining information of the spatial and temporal distribution of snow depth on the sea ice.By comparing in-situ snow depth measurements during the 35th Chinese Antarctic Research Expedition(CHINARE-35),we took advantage of the combination of multiple gradient ratio(GR(36V,10V)and GR(36V,18V))derived from the measured brightness temperature of FY-3D MWRI to estimate the snow depth.This method could simultaneously introduce the advantages of high and low GR in the snow depth retrieval model and perform well in both deep and shallow snow layers.Based on this,we constructed a novel model to retrieve the FY-3D MWRI snow depth on Antarctic sea ice.The new model validated by the ship-based observational snow depth data from CHINARE-35 and the snow depth measured by snow buoys from the Alfred Wegener Institute(AWI)suggest that the model proposed in this study performs better than traditional models,with root mean square deviations(RMSDs)of 8.59 cm and 7.71 cm,respectively.A comparison with the snow depth measured from Operation IceBridge(OIB)project indicates that FY-3D MWRI snow depth was more accurate than the released snow depth product from the U.S.National Snow and Ice Data Center(NSIDC)and the National Tibetan Plateau Data Center(NTPDC).The spatial distribution of the snow depth from FY-3D MWRI agrees basically with that from ICESat-2;this demonstrates its reliability for estimating Antarctic snow depth,and thus has great potential for understanding snow depth variations on Antarctic sea ice in the context of global climate change.展开更多
Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts ...Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts in the synthesized views. To solve this problem, a 3D video quality model base depth maps (D-3DV) for virtual view synthesis and depth map coding in the FTV applications is proposed. First, the relationships between distortions in coded depth map and rendered view are derived. Then, a precisely 3DV quality model based depth characteristics is develop for the synthesized virtual views. Finally, based on D-3DV model, a multilateral filtering is applied as a pre-processed filter to reduce rendering artifacts. The experimental results evaluated by objective and subjective methods indicate that the proposed D-3DV model can reduce bit-rate of depth coding and achieve better rendering quality.展开更多
Holoscopic 3D imaging is a true 3D imaging system mimics fly’s eye technique to acquire a true 3D optical model of a real scene. To reconstruct the 3D image computationally, an efficient implementation of an Auto-Fea...Holoscopic 3D imaging is a true 3D imaging system mimics fly’s eye technique to acquire a true 3D optical model of a real scene. To reconstruct the 3D image computationally, an efficient implementation of an Auto-Feature-Edge (AFE) descriptor algorithm is required that provides an individual feature detector for integration of 3D information to locate objects in the scene. The AFE descriptor plays a key role in simplifying the detection of both edge-based and region-based objects. The detector is based on a Multi-Quantize Adaptive Local Histogram Analysis (MQALHA) algorithm. This is distinctive for each Feature-Edge (FE) block i.e. the large contrast changes (gradients) in FE are easier to localise. The novelty of this work lies in generating a free-noise 3D-Map (3DM) according to a correlation analysis of region contours. This automatically combines the exploitation of the available depth estimation technique with edge-based feature shape recognition technique. The application area consists of two varied domains, which prove the efficiency and robustness of the approach: a) extracting a set of setting feature-edges, for both tracking and mapping process for 3D depthmap estimation, and b) separation and recognition of focus objects in the scene. Experimental results show that the proposed 3DM technique is performed efficiently compared to the state-of-the-art algorithms.展开更多
Prestack depth migration for seismic reflection data is commonly used tool for imaging complex geological structures such as salt domes, faults, thrust belts, and stratigraphic structures. Phase shift plus interpolati...Prestack depth migration for seismic reflection data is commonly used tool for imaging complex geological structures such as salt domes, faults, thrust belts, and stratigraphic structures. Phase shift plus interpolation (PSPI) algorithm is a useful tool to directly solve a wave equation and the results have natural properties of the wave equation. Amplitude and phase characteristics, in particular, are better preserved. The PSPI algorithm is widely used in hydrocarbon exploration because of its simplicity, efficiency, and reduced efforts for computation. However, meaningful depth image of 3D subsurface requires parallel computing to handle heavy computing time and great amount of input data. We implemented a parallelized version of 3D PSPI for prestack depth migration using Open-Multi-Processing (Open MP) library. We verified its performance through applications to 3D SEG/EAGE salt model with a small scale Linux cluster. Phase-shift was performed in the vertical and horizontal directions, respectively, and then interpolated at each node. This gave a single image gather according to shot gather. After summation of each single image gather, we got a 3D stacked image in the depth domain. The numerical model example shows good agree- ment with the original geological model.展开更多
Hand gesture recognition is a popular topic in computer vision and makes human-computer interaction more flexible and convenient.The representation of hand gestures is critical for recognition.In this paper,we propose...Hand gesture recognition is a popular topic in computer vision and makes human-computer interaction more flexible and convenient.The representation of hand gestures is critical for recognition.In this paper,we propose a new method to measure the similarity between hand gestures and exploit it for hand gesture recognition.The depth maps of hand gestures captured via the Kinect sensors are used in our method,where the 3D hand shapes can be segmented from the cluttered backgrounds.To extract the pattern of salient 3D shape features,we propose a new descriptor-3D Shape Context,for 3D hand gesture representation.The 3D Shape Context information of each 3D point is obtained in multiple scales because both local shape context and global shape distribution are necessary for recognition.The description of all the 3D points constructs the hand gesture representation,and hand gesture recognition is explored via dynamic time warping algorithm.Extensive experiments are conducted on multiple benchmark datasets.The experimental results verify that the proposed method is robust to noise,articulated variations,and rigid transformations.Our method outperforms state-of-the-art methods in the comparisons of accuracy and efficiency.展开更多
After the extension of depth modeling mode 4(DMM-4)in 3D high efficiency video coding(3D-HEVC),the computational complexity increases sharply,which causes the real-time performance of video coding to be impacted.To re...After the extension of depth modeling mode 4(DMM-4)in 3D high efficiency video coding(3D-HEVC),the computational complexity increases sharply,which causes the real-time performance of video coding to be impacted.To reduce the computational complexity of DMM-4,a simplified hardware-friendly contour prediction algorithm is proposed in this paper.Based on the similarity between texture and depth map,the proposed algorithm directly codes depth blocks to calculate edge regions to reduce the number of reference blocks.Through the verification of the test sequence on HTM16.1,the proposed algorithm coding time is reduced by 9.42%compared with the original algorithm.To avoid the time consuming of serial coding on HTM,a parallelization design of the proposed algorithm based on reconfigurable array processor(DPR-CODEC)is proposed.The parallelization design reduces the storage access time,configuration time and saves the storage cost.Verified with the Xilinx Virtex 6 FPGA,experimental results show that parallelization design is capable of processing HD 1080p at a speed above 30 frames per second.Compared with the related work,the scheme reduces the LUTs by 42.3%,the REG by 85.5%and the hardware resources by 66.7%.The data loading speedup ratio of parallel scheme can reach 3.4539.On average,the different sized templates serial/parallel speedup ratio of encoding time can reach 2.446.展开更多
We present the design of micro-helix metamaterial supporting high sound absorption characteristic by 3D printing. The sample structure which is fabricated out of polylactide (PLA) material, many micro-helix are arra...We present the design of micro-helix metamaterial supporting high sound absorption characteristic by 3D printing. The sample structure which is fabricated out of polylactide (PLA) material, many micro-helix are arranged by periodic arrays on XY plane. Experiment measurement results show that different geometrical dimensions of helix vestibule and cavity depth have a great effect on sound absorption coefficient. Physical mechanism depends on the friction and viscosity between the air and the helix vestibule. This work shows great potential of micro-structure metamaterial in noise control applications require light weight and large rigid of sound absorption.展开更多
This paper presents a method for hand gesture recognition based on 3D point cloud. Digital image processing technology is used in this research. Based on the 3D point from depth camera, the system firstly extracts som...This paper presents a method for hand gesture recognition based on 3D point cloud. Digital image processing technology is used in this research. Based on the 3D point from depth camera, the system firstly extracts some raw data of the hand. After the data segmentation and preprocessing, three kinds of appearance features are extracted, including the number of stretched fingers, the angles between fingers and the gesture region’s area distribution feature. Based on these features, the system implements the identification of the gestures by using decision tree method. The results of experiment demonstrate that the proposed method is pretty efficient to recognize common gestures with a high accuracy.展开更多
Background Depth sensor is an essential element in virtual and augmented reality devices to digitalize users'environment in real time.The current popular technologies include the stereo,structured light,and Time-o...Background Depth sensor is an essential element in virtual and augmented reality devices to digitalize users'environment in real time.The current popular technologies include the stereo,structured light,and Time-of-Flight(ToF).The stereo and structured light method require a baseline separation between multiple sensors for depth sensing,and both suffer from a limited measurement range.The ToF depth sensors have the largest depth range but the lowest depth map resolution.To overcome these problems,we propose a co-axial depth map sensor which is potentially more compact and cost-effective than conventional structured light depth cameras.Meanwhile,it can extend the depth range while maintaining a high depth map resolution.Also,it provides a high-resolution 2 D image along with the 3 D depth map.Methods This depth sensor is constructed with a projection path and an imaging path.Those two paths are combined by a beamsplitter for a co-axial design.In the projection path,a cylindrical lens is inserted to add extra power in one direction which creates an astigmatic pattern.For depth measurement,the astigmatic pattern is projected onto the test scene,and then the depth information can be calculated from the contrast change of the reflected pattern image in two orthogonal directions.To extend the depth measurement range,we use an electronically focus tunable lens at the system stop and tune the power to implement an extended depth range without compromising depth resolution.Results In the depth measurement simulation,we project a resolution target onto a white screen which is moving along the optical axis and then tune the focus tunable lens power for three depth measurement subranges,namely,near,middle and far.In each sub-range,as the test screen moves away from the depth sensor,the horizontal contrast keeps increasing while the vertical contrast keeps decreasing in the reflected image.Therefore,the depth information can be obtained by computing the contrast ratio between features in orthogonal directions.Conclusions The proposed depth map sensor could implement depth measurement for an extended depth range with a co-axial design.展开更多
Depth discontinuity edge affects the visual quality of synthesized images in 3D image warping.However,it suffers from accuracy degradation when up-sampled from low-resolution depth maps,especially at large scaling fac...Depth discontinuity edge affects the visual quality of synthesized images in 3D image warping.However,it suffers from accuracy degradation when up-sampled from low-resolution depth maps,especially at large scaling factors.To preserve the accuracy of depth discontinuity,a novel joint bilateral depth super-resolution with intensity guidance method is proposed.Particularly,the fast local intensity classification is exploited to estimate depth coefficients in joint bilateral up-sampling for depth maps,so as to eliminate depth discontinuity edge misalignment.Additionally,the proposed method is accelerated on graphic processing units(GPUs)to meet the requirement of realtime application.Experiments demonstrate that our method can preserve the accuracy of depth discontinuity edges after super resolution,leveraging the visual quality of synthesized image in 3D image warping.展开更多
The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion.In this study,three structurally intact soil samples were collected from the steppe of Inner Mongolia Auton...The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion.In this study,three structurally intact soil samples were collected from the steppe of Inner Mongolia Autonomous Region,China and placed in a wind tunnel where they were subjected to six different wind speeds(10,15,17,20,25,and 30 m/s)to simulate wind erosion in the wind tunnel.After each test,the soil surfaces were scanned by a 3D laser scanner to create a high-resolution Digital Elevation Model(DEM),and the changes in wind erosion mass and microtopography were quantified.Based on this,we performed further analysis of wind erosion-controlling factors.The study results showed that the average measurement error between the 3D laser scanning method and weighing method was 6.23%for the three undisturbed soil samples.With increasing wind speed,the microtopography on the undisturbed soil surface first became smooth,and then fine stripes and pits gradually developed.In the initial stage of wind erosion processes,the ability of the soil to resist wind erosion was mainly affected by the soil hardness.In the late stage of wind erosion processes,the degree of soil erosion was mainly affected by soil organic matter and CaCO_(3)content.The results of this study are expected to provide a theoretical basis for soil wind erosion control and promote the application of 3D laser scanners in wind erosion monitoring.展开更多
This paper analyzes the technical characteristic of three-dimensional display technology (3DTV) system and some core technologies yet to be solved. It points out the ways to solve these problems and presents an effe...This paper analyzes the technical characteristic of three-dimensional display technology (3DTV) system and some core technologies yet to be solved. It points out the ways to solve these problems and presents an effective solution for thediscomfort of watching the three-dimensional TV.展开更多
To reduce the computational complexity and storage cost caused by wedge segmentation algorithm,a scheme of simplifying wedge matching is proposed.It takes advantage of the correlation of the wedge separation line of d...To reduce the computational complexity and storage cost caused by wedge segmentation algorithm,a scheme of simplifying wedge matching is proposed.It takes advantage of the correlation of the wedge separation line of depth map and the direction of intra-prediction for 3D high-efficiency video coding(3D-HEVC).According to the difference of wedge segmentation between adjacent edge and opposite edge,a set only including 104×4 wedgelet templates is given.By expanding of the wedge wave of a certain minimum unit,a simple separation line acquisition method for different size of depth block is put forward.Furthermore,based on the array processor(DPR-CODEC)developed by project team,an efficient parallel scheme of the improved wedge segmentation mode prediction is introduced.By the scheme,prediction unit(PU)size can be changed randomly from 4×4 to 8×8,16×16,and 32×32,which is more in line with the needs of the HEVC standard.Veri-fied with test sequence in HTM16.1 and the Xilinx virtex-6 field programmable gate array(FPGA)respectively,the experiment results show that the proposed methods save 99.2%of the storage space and 63.94%of the encoding time,the serial/parallel acceleration ratio of each template reaches 1.84 in average.The coding performance,storage and resource consumption are considered for both.展开更多
Depth estimation is an active research area with the developing of stereo vision in recent years. It is one of the key technologies to resolve the large data of stereo vision communication. Now depth estimation still ...Depth estimation is an active research area with the developing of stereo vision in recent years. It is one of the key technologies to resolve the large data of stereo vision communication. Now depth estimation still has some problems, such as occlusion, fuzzy edge, real-time processing, etc. Many algorithms have been proposed base on software, however the performance of the computer configurations limits the software processing speed. The other resolution is hardware design and the great developments of the digital signal processor (DSP), and application specific integrated circuit (ASIC) and field programmable gate array (FPGA) provide the opportunity of flexible applications. In this work, by analyzing the procedures of depth estimation, the proper algorithms which can be used in hardware design to execute real-time depth estimation are proposed. The different methods of calibration, matching and post-processing are analyzed based on the hardware design requirements. At last some tests for the algorithm have been analyzed. The results show that the algorithms proposed for hardware design can provide credited depth map for further view synthesis and are suitable for hardware design.展开更多
基金The National Natural Science Foundation of China under contract No. 42076078China–Mozambique Joint Cruise under contract No. GASI-01-DLJHJ-CM。
文摘Mozambique's continental margin in East Africa was formed during the break-off stage of the east and west Gondwana lands. Studying the geological structure and division of continent-ocean boundary(COB) in Mozambique's continental margin is considered of great significance to rebuild Gondwana land and understand its movement mode. Along these lines, in this work, the initial Moho was fit using the known Moho depth from reflection seismic profiles, and a 3D multi-point constrained gravity inversion was carried out. Thus, highaccuracy Moho depth and crustal thickness in the study area were acquired. According to the crustal structure distribution based on the inversion results, the continental crust at the narrowest position of the Mozambique Channel was detected. According to the analysis of the crustal thickness, the Mozambique ridge is generally oceanic crust and the COB of the whole Mozambique continental margin is divided.
文摘A new method creating depth information for 2D/3D conversion was proposed. The distance between objects is determined by the distances between objects and light source position which is estimated by the analysis of the image. The estimated lighting value is used to normalize the image. A threshold value is determined by some weighted operation between the original image and the normalized image. By applying the threshold value to the original image, background area is removed. Depth information of interested area is calculated from the lighting changes. The final 3D images converted with the proposed method are used to verify its effectiveness.
基金supported by National Nature Science Foundation of China[61302123]
文摘An approach to the direct measure of stereoscopic (3D) videos with different accelerations was presented, using electroen- cephalography (EEG). In the study, subjects viewed 1-sec-long video clips with a stone ap- proaching straightforward and were required to perceive whether they were able to catch the outline of stone. Peak amplitude of each part was extracted from PO3 electrode located at the occipital region corresponding visual processing and cognition. Three components were conspicuously observed in the periods: 650-800 ms, 800-900 ms and 1150-1250 ms, which were called N310, N480 and N810 in this paper. N310 related to the perception to the initial stage of movement. Movement in- depth could be immediately perceived when initial speed was not less than 3 m/s. N480 related to the perception to acceleration/decel- eration. N810 related to the perception to the point a movement was about to vanish. Sub- jects couldn't perceive the outline with the fi- nal speed more than 3 rn/s. For 3 m/s, subjects were in a dilemma to judge with the detecting rate 54%. Together, component analysis com- bined with behavioral results, it was supposed that 3 m/s to be the threshold to completely perceive the outline.
基金National Natural Science Foundation of China(61732016).
文摘Three-dimensional(3D)modeling is an important topic in computer graphics and computer vision.In recent years,the introduction of consumer-grade depth cameras has resulted in profound advances in 3D modeling.Starting with the basic data structure,this survey reviews the latest developments of 3D modeling based on depth cameras,including research works on camera tracking,3D object and scene reconstruction,and high-quality texture reconstruction.We also discuss the future work and possible solutions for 3D modeling based on the depth camera.
基金The National Natural Science Foundation of China under contract No.42076235the Fundamental Research Funds for the Central Universities under contract No.2042022kf0018.
文摘The snow depth on sea ice is an extremely critical part of the cryosphere.Monitoring and understanding changes of snow depth on Antarctic sea ice is beneficial for research on sea ice and global climate change.The Microwave Radiation Imager(MWRI)sensor aboard the Chinese FengYun-3D(FY-3D)satellite has great potential for obtaining information of the spatial and temporal distribution of snow depth on the sea ice.By comparing in-situ snow depth measurements during the 35th Chinese Antarctic Research Expedition(CHINARE-35),we took advantage of the combination of multiple gradient ratio(GR(36V,10V)and GR(36V,18V))derived from the measured brightness temperature of FY-3D MWRI to estimate the snow depth.This method could simultaneously introduce the advantages of high and low GR in the snow depth retrieval model and perform well in both deep and shallow snow layers.Based on this,we constructed a novel model to retrieve the FY-3D MWRI snow depth on Antarctic sea ice.The new model validated by the ship-based observational snow depth data from CHINARE-35 and the snow depth measured by snow buoys from the Alfred Wegener Institute(AWI)suggest that the model proposed in this study performs better than traditional models,with root mean square deviations(RMSDs)of 8.59 cm and 7.71 cm,respectively.A comparison with the snow depth measured from Operation IceBridge(OIB)project indicates that FY-3D MWRI snow depth was more accurate than the released snow depth product from the U.S.National Snow and Ice Data Center(NSIDC)and the National Tibetan Plateau Data Center(NTPDC).The spatial distribution of the snow depth from FY-3D MWRI agrees basically with that from ICESat-2;this demonstrates its reliability for estimating Antarctic snow depth,and thus has great potential for understanding snow depth variations on Antarctic sea ice in the context of global climate change.
基金supported by the National Natural Science Foundation of China(Grant No.60832003)Key Laboratory of Advanced Display and System Application(Shanghai University),Ministry of Education,China(Grant No.P200902)the Key Project of Science and Technology Commission of Shanghai Municipality(Grant No.10510500500)
文摘Depth maps are used for synthesis virtual view in free-viewpoint television (FTV) systems. When depth maps are derived using existing depth estimation methods, the depth distortions will cause undesirable artifacts in the synthesized views. To solve this problem, a 3D video quality model base depth maps (D-3DV) for virtual view synthesis and depth map coding in the FTV applications is proposed. First, the relationships between distortions in coded depth map and rendered view are derived. Then, a precisely 3DV quality model based depth characteristics is develop for the synthesized virtual views. Finally, based on D-3DV model, a multilateral filtering is applied as a pre-processed filter to reduce rendering artifacts. The experimental results evaluated by objective and subjective methods indicate that the proposed D-3DV model can reduce bit-rate of depth coding and achieve better rendering quality.
文摘Holoscopic 3D imaging is a true 3D imaging system mimics fly’s eye technique to acquire a true 3D optical model of a real scene. To reconstruct the 3D image computationally, an efficient implementation of an Auto-Feature-Edge (AFE) descriptor algorithm is required that provides an individual feature detector for integration of 3D information to locate objects in the scene. The AFE descriptor plays a key role in simplifying the detection of both edge-based and region-based objects. The detector is based on a Multi-Quantize Adaptive Local Histogram Analysis (MQALHA) algorithm. This is distinctive for each Feature-Edge (FE) block i.e. the large contrast changes (gradients) in FE are easier to localise. The novelty of this work lies in generating a free-noise 3D-Map (3DM) according to a correlation analysis of region contours. This automatically combines the exploitation of the available depth estimation technique with edge-based feature shape recognition technique. The application area consists of two varied domains, which prove the efficiency and robustness of the approach: a) extracting a set of setting feature-edges, for both tracking and mapping process for 3D depthmap estimation, and b) separation and recognition of focus objects in the scene. Experimental results show that the proposed 3DM technique is performed efficiently compared to the state-of-the-art algorithms.
文摘Prestack depth migration for seismic reflection data is commonly used tool for imaging complex geological structures such as salt domes, faults, thrust belts, and stratigraphic structures. Phase shift plus interpolation (PSPI) algorithm is a useful tool to directly solve a wave equation and the results have natural properties of the wave equation. Amplitude and phase characteristics, in particular, are better preserved. The PSPI algorithm is widely used in hydrocarbon exploration because of its simplicity, efficiency, and reduced efforts for computation. However, meaningful depth image of 3D subsurface requires parallel computing to handle heavy computing time and great amount of input data. We implemented a parallelized version of 3D PSPI for prestack depth migration using Open-Multi-Processing (Open MP) library. We verified its performance through applications to 3D SEG/EAGE salt model with a small scale Linux cluster. Phase-shift was performed in the vertical and horizontal directions, respectively, and then interpolated at each node. This gave a single image gather according to shot gather. After summation of each single image gather, we got a 3D stacked image in the depth domain. The numerical model example shows good agree- ment with the original geological model.
基金supported by the National Natural Science Foundation of China(61773272,61976191)the Six Talent Peaks Project of Jiangsu Province,China(XYDXX-053)Suzhou Research Project of Technical Innovation,Jiangsu,China(SYG201711)。
文摘Hand gesture recognition is a popular topic in computer vision and makes human-computer interaction more flexible and convenient.The representation of hand gestures is critical for recognition.In this paper,we propose a new method to measure the similarity between hand gestures and exploit it for hand gesture recognition.The depth maps of hand gestures captured via the Kinect sensors are used in our method,where the 3D hand shapes can be segmented from the cluttered backgrounds.To extract the pattern of salient 3D shape features,we propose a new descriptor-3D Shape Context,for 3D hand gesture representation.The 3D Shape Context information of each 3D point is obtained in multiple scales because both local shape context and global shape distribution are necessary for recognition.The description of all the 3D points constructs the hand gesture representation,and hand gesture recognition is explored via dynamic time warping algorithm.Extensive experiments are conducted on multiple benchmark datasets.The experimental results verify that the proposed method is robust to noise,articulated variations,and rigid transformations.Our method outperforms state-of-the-art methods in the comparisons of accuracy and efficiency.
基金Supported by the National Natural Science Foundation of China(No.61834005,61772417,61802304,61602377,61874087,61634004)the Shaanxi Province Key R&D Plan(No.2020JM-525,2021GY-029,2021KW-16)。
文摘After the extension of depth modeling mode 4(DMM-4)in 3D high efficiency video coding(3D-HEVC),the computational complexity increases sharply,which causes the real-time performance of video coding to be impacted.To reduce the computational complexity of DMM-4,a simplified hardware-friendly contour prediction algorithm is proposed in this paper.Based on the similarity between texture and depth map,the proposed algorithm directly codes depth blocks to calculate edge regions to reduce the number of reference blocks.Through the verification of the test sequence on HTM16.1,the proposed algorithm coding time is reduced by 9.42%compared with the original algorithm.To avoid the time consuming of serial coding on HTM,a parallelization design of the proposed algorithm based on reconfigurable array processor(DPR-CODEC)is proposed.The parallelization design reduces the storage access time,configuration time and saves the storage cost.Verified with the Xilinx Virtex 6 FPGA,experimental results show that parallelization design is capable of processing HD 1080p at a speed above 30 frames per second.Compared with the related work,the scheme reduces the LUTs by 42.3%,the REG by 85.5%and the hardware resources by 66.7%.The data loading speedup ratio of parallel scheme can reach 3.4539.On average,the different sized templates serial/parallel speedup ratio of encoding time can reach 2.446.
基金supported by the National Natural Science Foundation of China (11704314 and 11474230)the Fundamental Research Funds for the Central Universities (3102016QD056) for financial support
文摘We present the design of micro-helix metamaterial supporting high sound absorption characteristic by 3D printing. The sample structure which is fabricated out of polylactide (PLA) material, many micro-helix are arranged by periodic arrays on XY plane. Experiment measurement results show that different geometrical dimensions of helix vestibule and cavity depth have a great effect on sound absorption coefficient. Physical mechanism depends on the friction and viscosity between the air and the helix vestibule. This work shows great potential of micro-structure metamaterial in noise control applications require light weight and large rigid of sound absorption.
文摘This paper presents a method for hand gesture recognition based on 3D point cloud. Digital image processing technology is used in this research. Based on the 3D point from depth camera, the system firstly extracts some raw data of the hand. After the data segmentation and preprocessing, three kinds of appearance features are extracted, including the number of stretched fingers, the angles between fingers and the gesture region’s area distribution feature. Based on these features, the system implements the identification of the gestures by using decision tree method. The results of experiment demonstrate that the proposed method is pretty efficient to recognize common gestures with a high accuracy.
文摘Background Depth sensor is an essential element in virtual and augmented reality devices to digitalize users'environment in real time.The current popular technologies include the stereo,structured light,and Time-of-Flight(ToF).The stereo and structured light method require a baseline separation between multiple sensors for depth sensing,and both suffer from a limited measurement range.The ToF depth sensors have the largest depth range but the lowest depth map resolution.To overcome these problems,we propose a co-axial depth map sensor which is potentially more compact and cost-effective than conventional structured light depth cameras.Meanwhile,it can extend the depth range while maintaining a high depth map resolution.Also,it provides a high-resolution 2 D image along with the 3 D depth map.Methods This depth sensor is constructed with a projection path and an imaging path.Those two paths are combined by a beamsplitter for a co-axial design.In the projection path,a cylindrical lens is inserted to add extra power in one direction which creates an astigmatic pattern.For depth measurement,the astigmatic pattern is projected onto the test scene,and then the depth information can be calculated from the contrast change of the reflected pattern image in two orthogonal directions.To extend the depth measurement range,we use an electronically focus tunable lens at the system stop and tune the power to implement an extended depth range without compromising depth resolution.Results In the depth measurement simulation,we project a resolution target onto a white screen which is moving along the optical axis and then tune the focus tunable lens power for three depth measurement subranges,namely,near,middle and far.In each sub-range,as the test screen moves away from the depth sensor,the horizontal contrast keeps increasing while the vertical contrast keeps decreasing in the reflected image.Therefore,the depth information can be obtained by computing the contrast ratio between features in orthogonal directions.Conclusions The proposed depth map sensor could implement depth measurement for an extended depth range with a co-axial design.
基金Supported by the National Natural Science Foundation of China(61572058)
文摘Depth discontinuity edge affects the visual quality of synthesized images in 3D image warping.However,it suffers from accuracy degradation when up-sampled from low-resolution depth maps,especially at large scaling factors.To preserve the accuracy of depth discontinuity,a novel joint bilateral depth super-resolution with intensity guidance method is proposed.Particularly,the fast local intensity classification is exploited to estimate depth coefficients in joint bilateral up-sampling for depth maps,so as to eliminate depth discontinuity edge misalignment.Additionally,the proposed method is accelerated on graphic processing units(GPUs)to meet the requirement of realtime application.Experiments demonstrate that our method can preserve the accuracy of depth discontinuity edges after super resolution,leveraging the visual quality of synthesized image in 3D image warping.
基金supported by National Natural Science Foundation of China(41871010)The Second Comprehensive Scientific Expedition to the Qinghai-Tibet Plateau of China(2019QZKK0906)。
文摘The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion.In this study,three structurally intact soil samples were collected from the steppe of Inner Mongolia Autonomous Region,China and placed in a wind tunnel where they were subjected to six different wind speeds(10,15,17,20,25,and 30 m/s)to simulate wind erosion in the wind tunnel.After each test,the soil surfaces were scanned by a 3D laser scanner to create a high-resolution Digital Elevation Model(DEM),and the changes in wind erosion mass and microtopography were quantified.Based on this,we performed further analysis of wind erosion-controlling factors.The study results showed that the average measurement error between the 3D laser scanning method and weighing method was 6.23%for the three undisturbed soil samples.With increasing wind speed,the microtopography on the undisturbed soil surface first became smooth,and then fine stripes and pits gradually developed.In the initial stage of wind erosion processes,the ability of the soil to resist wind erosion was mainly affected by the soil hardness.In the late stage of wind erosion processes,the degree of soil erosion was mainly affected by soil organic matter and CaCO_(3)content.The results of this study are expected to provide a theoretical basis for soil wind erosion control and promote the application of 3D laser scanners in wind erosion monitoring.
基金supported by the National Natural Science Foundation of China(Grant No.60832003)the Science and Technology Commission of Shanghai Municipality(Grant No.10510500500)the Key Laboratory of Advanced Display and System Applications(Shanghai University),Ministry of Education,China(Grant No.P200801)
文摘This paper analyzes the technical characteristic of three-dimensional display technology (3DTV) system and some core technologies yet to be solved. It points out the ways to solve these problems and presents an effective solution for thediscomfort of watching the three-dimensional TV.
基金the National Natural Science Foundation of China(No.61834005,61772417,61802304,61602377,61874087,61634004)Shaanxi International Science and Technology Cooperation Program(No.2018KW-006).
文摘To reduce the computational complexity and storage cost caused by wedge segmentation algorithm,a scheme of simplifying wedge matching is proposed.It takes advantage of the correlation of the wedge separation line of depth map and the direction of intra-prediction for 3D high-efficiency video coding(3D-HEVC).According to the difference of wedge segmentation between adjacent edge and opposite edge,a set only including 104×4 wedgelet templates is given.By expanding of the wedge wave of a certain minimum unit,a simple separation line acquisition method for different size of depth block is put forward.Furthermore,based on the array processor(DPR-CODEC)developed by project team,an efficient parallel scheme of the improved wedge segmentation mode prediction is introduced.By the scheme,prediction unit(PU)size can be changed randomly from 4×4 to 8×8,16×16,and 32×32,which is more in line with the needs of the HEVC standard.Veri-fied with test sequence in HTM16.1 and the Xilinx virtex-6 field programmable gate array(FPGA)respectively,the experiment results show that the proposed methods save 99.2%of the storage space and 63.94%of the encoding time,the serial/parallel acceleration ratio of each template reaches 1.84 in average.The coding performance,storage and resource consumption are considered for both.
基金supported by the National Natural Science Foundation of China(Grant Nos.60832003)the Key Laboratory of Advanced Display and System Applications(Shanghai University),Ministry of Education,China(Grant No.P200801)the Science and Technology Commission of Shanghai Municipality(Grant No.10510500500)
文摘Depth estimation is an active research area with the developing of stereo vision in recent years. It is one of the key technologies to resolve the large data of stereo vision communication. Now depth estimation still has some problems, such as occlusion, fuzzy edge, real-time processing, etc. Many algorithms have been proposed base on software, however the performance of the computer configurations limits the software processing speed. The other resolution is hardware design and the great developments of the digital signal processor (DSP), and application specific integrated circuit (ASIC) and field programmable gate array (FPGA) provide the opportunity of flexible applications. In this work, by analyzing the procedures of depth estimation, the proper algorithms which can be used in hardware design to execute real-time depth estimation are proposed. The different methods of calibration, matching and post-processing are analyzed based on the hardware design requirements. At last some tests for the algorithm have been analyzed. The results show that the algorithms proposed for hardware design can provide credited depth map for further view synthesis and are suitable for hardware design.