Loading...

Table of Content

    20 June 2018, Volume 47 Issue 6
    Photogrammetry and Deep Learning
    GONG Jianya, JI Shunping
    2018, 47(6):  693-704.  doi:10.11947/j.AGCS.2018.20170640
    Asbtract ( )   HTML   PDF (4176KB) ( )  
    References | Related Articles | Metrics
    Deep learning has become popular and the mainstream in types of researches related to learning,and has shown its impact on photogrammetry.According to the definition of photogrammetry,a subject that researches shapes,locations,sizes,characteristics and inter-relationships of real objects from optical images,photogrammetry considers two aspects,geometry and semantics.From the two aspects,we review the history of deep learning and discuss its current applications on photogrammetry,and forecast the future development of photogrammetry.In geometry,the deep convolutional neural network (CNN) has been widely applied in stereo matching,SLAM and 3D reconstruction,and has made some effect but needs more improvement.In semantics,conventional empirical and handcrafted methods have failed to extract the semantic information accurately and failed to produce types of “semantic thematic map” as 4D productions (DEM,DOM,DLG,DRG) of photogrammetry,which causes the semantic part of photogrammetry be ignored for a long time.The powerful generalization capacity,ability to fit any functions and stability under types of situations of deep leaning is making the automated production of thematic maps possible.We review the achievements that have been obtained in road network extraction,building detection and crop classification,etc.,and forecast that producing high-accuracy semantic thematic maps directly from optical images will become reality and these maps will become a type of standard products of photogrammetry.At last,we introduce two current researches related to geometry and semantics respectively.One is stereo matching of aerial images based on deep learning and transfer learning; the other is fine crop classification from satellite special-temporal images based on 3D CNN.
    A Preliminary Study on the Theory of Polar Coordinates Digital Photogrammetry and the Coordinate System of Spatial Information
    YAN Lei, CHEN Rui, SUN Yanbiao
    2018, 47(6):  705-721.  doi:10.11947/j.AGCS.2018.20170636
    Asbtract ( )   HTML   PDF (3723KB) ( )  
    References | Related Articles | Metrics
    The diversity of means of obtaining space information and the tight constraints of the strict mathematical rules of data processing are the new contradictions associated with the development of the new aeronautics and astronautics technology.For example,push broom,variable angle swing staring,zoom imaging,aerial platform attitude,large angle flight,high overlap and short baseline effect,which bring severe challenges to convergence,efficiency,accuracy and anti-interference.Based on the principle of the bionic machine parallax angle and the essence of pyramidal projection of the aerial space platform to the surface,the mathematical expression of polar coordinates is introduced.This paper has explored the solution to the causes of the high resolution image sparsity ill conditioned singularity and nonconvergence,built a set of mathematical models for the polar coordinates processing of the parallax angular vector,and formed the polar information theory of spatial information initially.This method has been improved in the range of accuracy,efficiency and anti-interference order of magnitude in close-range photogrammetry and the free net bundle adjustment model,and publish open source code in the world more than three years,which has a good reaction.The effectiveness is verified in the aero photogrammetry and absolute network adjustment model experiment,and the performance is better than the Descartes coordinate processing method.Finally,the high-order solution characteristics of various applications and spaceflight platforms are given,which is expected to lay the foundation for the construction of the new polar coordinates system for aerospace multi-scale all attitude spatial information (acquisition organization management storage processing application).
    Smart Photogrammetric and Remote Sensing Image Processing for Optical Very High Resolution Images-Examples from the CRC-AGIP Lab at UNB
    Yun ZHANG
    2018, 47(6):  722-729.  doi:10.11947/j.AGCS.2018.20180011
    Asbtract ( )   HTML   PDF (18074KB) ( )  
    References | Related Articles | Metrics
    This paper introduces some of the image processing techniques developed in the Canada Research Chair in Advanced Geomatics Image Processing Laboratory (CRC-AGIP Lab) and in the Department of Geodesy and Geomatics Engineering (GGE) at the University of New Brunswick (UNB),Canada.The techniques were developed by innovatively utilizing the characteristics of the available very high resolution remote sensing optical images to solve important problems or create new applications in photogrammetry and remote sensing.The techniques to be introduced are:automated image fusion (UNB-PanSharp),satellite image online mapping,street view technology,moving vehicle detection using single set satellite imagery,supervised image segmentation,image matching in smooth areas,and change detection using images from different viewing angles.
    Research on Key Technologies of Precise InSAR Surveying and Mapping Application Using Automatic SAR Imaging
    TANG Xinming, LI Tao, GAO Xiaoming, CHEN Qianfu, ZHANG Xiang
    2018, 47(6):  730-740.  doi:10.11947/j.AGCS.2018.20170621
    Asbtract ( )   HTML   PDF (6486KB) ( )  
    References | Related Articles | Metrics
    Precise InSAR is a new intelligent photogrammetric technology using the automatic imaging and processing means.It becomes the most efficient satellite-surveying-and-mapping (SASM) way that uses interferometric phase to create global digital elevation model (DEM) with high-precision.In this paper,we proposed the systematic InSAR technologies applied in SASM.Three key technologies are proposed.They are calibration technology,data processing technology and the post-processing technologies.Firstly,we need to calibrate the geometric and interferometric parameters including azimuth time delay,range time delay,atmospheric delay as well as baseline errors.Secondly,we have to use the calibrated parameters to create precise DEM.One of the important procedures in data processing is the phase constant determination.Finally,we improve the quality of DEM by jointly using block-adjustment method,long-and-short baseline combination method as well as descending-and-ascending data merge method.We use 6 TanDEM-X data that covers Shanxi to carry out the experiment.The root-mean-square error of final DEM is 5.07 m in the mountainous regions.And the area with low coherence is 0.8 km2.The accuracy meets the accuracy of China domestic SASM standard at 1∶50 000 and even the 1∶25 000 measurement scales.
    Instantaneous 3D Mapping Method Based on Mobile LiDAR
    ZHANG Aiwu, GONG Huili, Jiaguo QI, HU Shaoxing, XIAO Yang
    2018, 47(6):  741-747.  doi:10.11947/j.AGCS.2018.20180068
    Asbtract ( )   HTML   PDF (2273KB) ( )  
    References | Related Articles | Metrics
    An instantaneous three-dimensional mapping method was presented for mobile LiDAR.This method has been applied to indoor,outdoor and other environments.As the new intelligent method of digital photogrammetry based on machine vision,it solved the basic problem of self-localization and simultaneous mapping of mobile LiDAR without GPS and high precision IMU.As results,the differences between the method and the traditional method were analyzed;the self-calibration method of bore-sight angle errors were studied;Effective feature extraction algorithm by planeness and incremental mapping strategy were proposed;and an optimal adjustment algorithm was modeled.Finally,the method was testified by three different environmental mapping experiments.The results show that the method is applicable in many kinds of environments,no matter of structured or unstructured environments,indoor,outdoor or woodland,and horizontal mapping or vertical mapping.Requiring no data post-processing,the method can do instantaneous mapping.
    Normal Physics Model of Aerial Remote Sensing Platform and Systemic Accuracy Assessment Variable Baseline-height Ratio
    YAN Lei, LI Yingcheng, ZHAO Shihu, YUAN Xiuxiao, SONG Yan, ZHONG Yubiao, XUE Qingsheng
    2018, 47(6):  748-759.  doi:10.11947/j.AGCS.2018.20170632
    Asbtract ( )   HTML   PDF (2063KB) ( )  
    References | Related Articles | Metrics
    Accuracy is a key factor in high-resolution remote sensing and photogrammetry.The factors that affect accuracy are imaging system errors and data processing errors.Because of the complexity of aerial camera system errors,this paper focuses on the design of digital aerial camera system,to reduce the system error and provide data procession fundamentally.There are many kinds of digital aerial camera system at present,but lacking a unified physical model,which causes the system to be built in multi-camera and multi-rigid model.Such system is complex,costly,and difficult to describe,and is easily affected by factors such as vibration and temperature,so the installed accuracy can only reach millimeter level.For this reason,this paper proposes the unified physical structure of digital aerial camera,which imitates the theory of out-of-field multi-CCD,in-field multi-CCD,and once-imaging and twice-imaging digital camera systems.Considering this,the spatial-temporal representation of the variable baseline-height ratio is established.From the variable baseline-height ratio,we can link the opto-mechanical spatial parameters with the elevation accuracy,so that to achieve connection between the surface elevation with opto-mechanical structural parameter; further designing the twice-imaging digital camera prototype system and the wideband limb imaging spectrometer,which provides prototype for transformation from the current multi-rigid,one-time imaging aerial camera to single rigid structure.Our research has laid a theoretical foundation and prototype references for the construction and industrialization of digital aerial system.
    Stream-computing Based High Accuracy On-board Real-time Cloud Detection for High Resolution Optical Satellite Imagery
    WANG Mi, ZHANG Zhiqi, DONG Zhipeng, JIN Shuying, Hongbo SU
    2018, 47(6):  760-769.  doi:10.11947/j.AGCS.2018.20170618
    Asbtract ( )   HTML   PDF (1939KB) ( )  
    References | Related Articles | Metrics
    This paper focuses on the time efficiency for machine vision and intelligent photogrammetry,especially high accuracy on-board real-time cloud detection method.With the development of technology,the data acquisition ability is growing continuously and the volume of raw data is increasing explosively.Meanwhile,because of the higher requirement of data accuracy,the computation load is also become heavier.This situation makes time efficiency extremely important.Moreover,the cloud cover rate of optical satellite imagery is up to approximately 50%,which is seriously restricting the applications of on-board intelligent photogrammetry services.To meet the on-board cloud detection requirements and offer valid input data to subsequent processing,this paper presents a stream-computing based high accuracy on-board real-time cloud detection solution which follows the “bottom-up” understanding strategy of machine vision and uses multiple embedded GPU with significant potential to be applied on-board.Without external memory,the data parallel pipeline system based on multiple processing modules of this solution could afford the “stream-in,processing,stream-out” real-time stream computing.In experiments,images of GF-2 satellite are used to validate the accuracy and performance of this approach,and the experimental results show that this solution could not only bring up cloud detection accuracy,but also match the on-board real-time processing requirements.
    Progress and Applications of Visual SLAM
    DI Kaichang, WAN Wenhui, ZHAO Hongying, LIU Zhaoqin, WANG Runzhi, ZHANG Feizhou
    2018, 47(6):  770-779.  doi:10.11947/j.AGCS.2018.20170652
    Asbtract ( )   HTML   PDF (2946KB) ( )  
    References | Related Articles | Metrics
    Visual SLAM provides mapping and self-localization results of a robot in an unknown environment based on visual sensor,which has the advantages of small volume,low power consumption,and richness of information acquisition.Visual SLAM is critical and significant in supporting of robots’ automated and intelligent applications.This paper presents the key techniques of visual SLAM,summarizes the current status of visual SLAM research,and analyzes the new trends of visual SLAM research and development.Finally,status and prospect of visual SLAM application in restricted environments,such as deep space,indoor scene and so on,are discussed.
    A Variational Approach for Automatic Man-made Object Detection from Remote Sensing Images
    HU Xiangyun, GONG Xiaoya, ZHANG Mi
    2018, 47(6):  780-789.  doi:10.11947/j.AGCS.2018.20170642
    Asbtract ( )   HTML   PDF (6637KB) ( )  
    References | Related Articles | Metrics
    Man-made object detection is important for object detection from remote sensing images.In this paper we propose a variational approach for man-made object detection which formulates the man-made object detection problem as a problem of variational energy optimization.In this method,an image is firstly segmented into superpixels,and the saliency map by combining image features such as texture,color and gradient is computed.In second step,we construct an energy function with saliency,area,edge,texture and intensity variance constrains.The energy function is solved via variational method to obtain the foreground,which is the detected man-made objects.The proposed approach on several remote sensing images is evaluated and compared with the C-V model,MRF model and deep learning based semantic segmentation.Experimental results show that the proposed approach can effectively detect man-made objects on remote sensing images with low false alarm and false negatives rates.The comparison and analysis with deep learning based method are also presented.
    Dense High-definition Image Matching Strategy Based on Scale Distribution of Feature and Geometric Constraint
    ZHAO Hongrui, LU Shenghan
    2018, 47(6):  790-798.  doi:10.11947/j.AGCS.2018.20170630
    Asbtract ( )   HTML   PDF (3565KB) ( )  
    References | Related Articles | Metrics
    This paper mainly expounds the basic issue three about the intelligent photogrammetry based on machine vision:the intelligent and fast matching process among high-definition images.Image feature matching,as a fundamental data processing procedure,plays an important role in the computational efficiency of computing the digital photogrammetry coordinate space.There are challenges for image feature match including high computational expense due to high-resolution data and similar feature interference.Concerning these problems,the mathematical nature of the invariant feature of image scale was studied,and the geometric model of multi-view camera was used to derive and verify the scale distribution of image feature points.The information interaction process of the scale component in the feature extraction and the matching process was determined.Through the equal-scale feature matching,the calculation amount in the image matching process was reduced and the effective information was retained,which greatly reduced the time of the initial distance matching progress among 105 points in 1 second.On this basis,combining the feature scale distribution and the geometric constraint,the improved feature matching algorithm was used to reduce the matching search range under the limited time and the computational scale.Fast and dense matching achieves through the feature index and the partition parallel processing.Using intel i7-4720HQ and NVIDIA GTX970M,the experiment shows that the feature matching method based on the scale distribution feature has a great advantage in improving the speed and accuracy of automatic image matching and matches thousands of points in less than one second.It provides a new idea for the fast and high precision processing of digital images,which can not only meet the accuracy of digital photogrammetry but greatly improve the efficiency of production.
    Research on 3D Target Pose Tracking and Modeling
    SHANG Yang, SUN Xiaoliang, ZHANG Yueqiang, LI You, YU Qifeng
    2018, 47(6):  799-808.  doi:10.11947/j.AGCS.2018.20170626
    Asbtract ( )   HTML   PDF (1973KB) ( )  
    References | Related Articles | Metrics
    This paper tackles imaging system pose tracking and model refinement,one of the fundamental work for 3D photogrammetry.The researches belong to the videometrics,an interdiscipline which combines computer vision,digital image processing,photogrammetry and optical measurement.Related works are summarized briefly in this paper.We study the problems of pose tracking for target with 3D model.For the target with accurate 3D model,line model based pose tracking methods are proposed for target with rich line features.Experimental results indicate that the proposed methods track the target pose accurately.Normal distance iterative reweighted least squares and distance image iterative least squares methods are proposed to process more general targets.This paper adopts bound adjustment to tackle pose tracking in image sequence for target with inaccurate 3D line model.The proposed method optimizes model line parameters and pose parameters simultaneously.The model line orientation,position and mean angle error,mean position error of pose are 0.3°,3.5 mm and 0.12°,20.1 mm in simulation experiments of satellite pose tracking.Line features are used to track target pose with unknown 3D model through image sequence.The model line parameters and pose parameters are optimized under the framework of SFM.In simulation experiments,the reconstructed line orientation,position error and mean angle error,mean position error of pose are 0.4°,7.5 mm and 0.16°,23.5 mm.
    Micro Lens Mono-channel Light Field 3D Direct Imaging Method Based on Bionic Vision and 3-3 Dimensional Information Transformation Foundation
    ZHAO Shoujiang, ZHAO Hongying, YANG Peng, ZHAO Haimeng, Anand ASUNDI, YAN Lei
    2018, 47(6):  809-815.  doi:10.11947/j.AGCS.2018.20170628
    Asbtract ( )   HTML   PDF (5079KB) ( )  
    References | Related Articles | Metrics
    This paper is the third part of the three dimensional digital photogrammetry intelligent conformation under the machine vision parameter:the direct 3D imaging mechanism of the light field and the 3D intelligent conformation benchmark of digital photogrammetry.In this paper,the moving object’s capture takes 3-3-2 information processing as the starting point,the basic principle of using biological compound eye three-dimensional imaging,however,because the traditional bionic vision by the hardware constraints,this paper obtained the theory based on bionic compound eye 3-3-2 information,the use of a new generation of micro lens array light field camera technology,put forward a method of extracting depth information of the scene to single light field images,and its application to absolute depth measurement.The light field image an important characteristic is that the intensity and direction of different light information recording into the camera,this paper proposes the use of light information for multi depth focusing,the focusing points in different levels of cost calculation,determine the object image plane,finally construct the depth map object point based on the location of the imaging plane.Compared with the traditional light depth estimation,the depth map obtained by this method can greatly improve the resolution,and does not depend on the number of micro lens in the light field.In order to verify the effectiveness of the proposed method,this paper will compare the depth calculation using the algorithm proposed in this paper and the existing depth information algorithm.
    3D Reconstruction of High-reflective and Textureless Targets Based on Multispectral Polarization and Machine Vision
    HAO Jinglei, ZHAO Yongqiang, ZHAO Haimeng, Peter BREZANY, SUN Jiayu
    2018, 47(6):  816-824.  doi:10.11947/j.AGCS.2018.20170624
    Asbtract ( )   HTML   PDF (2057KB) ( )  
    References | Related Articles | Metrics
    With the rapid development of photogrammetry and machine vision technology,a higher universality of three-dimensional reconstruction is required.For high-reflective and non-metal targets with smooth surface or extreme simple texture,a large area of data void may appear on the reconstruction surface since the traditional 3D reconstruction methods depend on texture and reflective characteristics.To solve this problem,a 3D reconstruction method based on multispectral polarization imaging is proposed in this paper,which integrates photogrammetry and machine vision and achieves accurate reconstruction by obtaining accurate multispectral polarization characteristics of targets.The proposed method does not rely on the texture information on the surface,and it can solve the problem of joint estimating refractive index and zenith angle simultaneously,which cannot be achieved only by Fresnel theory.Due to straylights and diffuse reflection light have different polarization and spectral characteristics at different wavelengths,we can remove the highlight to improve the reconstruction accuracy.The 3D reconstruction method based on multiband polarization imaging is the guiding progress of 3D reconstruction after the fusion of photogrammetry and machine vision,which has a wider application range.
    Hash Map Method of 3D Point Cloud Data for Real-time Organizing
    ZHENG Shunyi, HE Yuan, XU Gang, WANG Chen, ZHU Fengbo
    2018, 47(6):  825-832.  doi:10.11947/j.AGCS.2018.20170619
    Asbtract ( )   HTML   PDF (1633KB) ( )  
    References | Related Articles | Metrics
    In this paper,one of the key elements of intelligent data processing in digital photogrammetry is discussed based on machine vision:efficient management technology of massive point cloud,an improved algorithm for hash mapping 3D data on GPU is proposed.The algorithm can efficiently perform dynamic insertion,update and indexing of data without the limitation of data scale.We applied the algorithm to TSDF (truncated signed distance field) algorithm for point cloud fusion,which can reduce the noise of single frame and the data registration error between different frames in a very efficient way.Currently,most of the data structures of point cloud fusion algorithms are regular or hierarchical grid data structures,so the object bounding boxes should be specified in advance.Moreover,the hierarchical data structure is complex and hard to parallelization.Therefore,the requirements of dynamic scalability,updating and indexing data of real-time 3D reconstruction cannot be satisfied.This paper exploited hash map to manage 3D data.At the same time,the current active region could be estimated with sensor motion to exchange data between host and GPU,keeping low memory utilization of GPU.In the experiments on different levels of graphics cards(GTX960,GTX1050,GTX1060),the algorithm can satisfy the real-time frame rate requirements(60 fps,2.11×105 points per frame),so it meets the requirement of efficient management of 3D point cloud data in three-dimensional imaging.
    Splitting and Merging Based Multi-model Fitting for Point Cloud Segmentation
    ZHANG Liangpei, ZHANG Yun, CHEN Zhenzhong, XIAO Peipei, LUO Bin
    2018, 47(6):  833-843.  doi:10.11947/j.AGCS.2018.20180131
    Asbtract ( )   HTML   PDF (2281KB) ( )  
    References | Related Articles | Metrics
    This paper deals with the massive point cloud segmentation processing technology on the basis of machine vision,which is the second essential factor for the intelligent data processing of three dimensional conformation in digital photogrammetry.In this paper,multi-model fitting method is used to segment the point cloud according to the spatial distribution and spatial geometric structure of point clouds by fitting the point cloud into different geometric primitives models.Because point cloud usually possesses large amount of 3D points,which are uneven distributed over various complex structures,this paper proposes a point cloud segmentation method based on multi-model fitting.Firstly,the pre-segmentation of point cloud is conducted by using the clustering method based on density distribution.And then the follow fitting and segmentation are carried out by using the multi-model fitting method based on split and merging.For the plane and the arc surface,this paper uses different fitting methods,and finally realizing the indoor dense point cloud segmentation.The experimental results show that this method can achieve the automatic segmentation of the point cloud without setting the number of models in advance.Compared with the existing point cloud segmentation methods,this method has obvious advantages in segmentation effect and time cost,and can achieve higher segmentation accuracy.After processed by method proposed in this paper,the point cloud even with large-scale and complex structures can often be segmented into 3D geometric elements with finer and accurate model parameters,which can give rise to an accurate 3D conformation.
    Satellite Image Matching Method Based on Deep Convolution Neural Network
    FAN Dazhao, DONG Yang, ZHANG Yongsheng
    2018, 47(6):  844-853.  doi:10.11947/j.AGCS.2018.20170627
    Asbtract ( )   HTML   PDF (15310KB) ( )  
    References | Related Articles | Metrics
    This article focuses on the first aspect of the album of deep learning: the deep convolution method.The traditional matching point extraction algorithm usually uses the manually-designed feature descriptor and the shortest distance between them to match as the matching criterion.The matching result is easy to fall into the local extreme value,which causes the missing of the partial matching point.Aiming at this problem,we introduce a two-channel deep convolution neural network based on spatial scale convolution,and performs matching pattern learning between images to realize the satellite image matching based on deep convolution neural network.The experimental results show that the method can extract the richer matching point in the case of heterogeneous,multi-temporal and multi-resolution satellite images,compared with the traditional matching method.And the accuracy of the final matching results can be maintained at above 90%.
    A Multi-source DEM Fusion Method Based on Elevation Difference Fitting Neural Network
    SHEN Huanfeng, LIU Lu, YUE Linwei, LI Xinghua, ZHANG Liangpei
    2018, 47(6):  854-863.  doi:10.11947/j.AGCS.2018.20180135
    Asbtract ( )   HTML   PDF (6785KB) ( )  
    References | Related Articles | Metrics
    This paper focuses on machine learning in intelligent photogrammetry:the elevation difference fitting neural network method.The limitations of observation technologies and processing methods lead to the lack of global high-accuracy seamless DEMs,which further restrict DEMs’ application in the fields of hydrology,geology,meteorology,military and other applications.In this paper,we propose a multi-source DEM fusion method using the neural network model trained based on elevation difference.The proposed method is employed to generate a high-quality seamless DEM dataset blending SRTM1,ASTER GDEM v2,and ICESat GLAS.At first,the ICESat GLAS data were filtered according to the relevant parameters and the elevation differences with DEMs.The threshold of elevation difference adaptively varied with terrain slope to remove the abnormal points effectively.The neural network was then applied to learn the error distribution of ASTER GDEM v2,using the ICESat GLAS data as the control points.We constructed the network input composed of slope information,latitude and longitude coordinates,while the elevation difference of ICESat GLAS and ASTER GDEM v2 were set as the target output.The corrected ASTER GDEM v2 results can be obtained by adding the predicted output to the original elevation values.At last,the corrected ASTER GDEM v2 values were utilized to fill the voids of SRTM1,where the vertical bias between the datasets were dealt with TIN delta surface method to blend the seamless DEM.Randomly selected data were used for actual experiments,and the proposed model was evaluated by comparing with other methods and DEM datasets through quantitative evaluation and visual discrimination.Experiment results show that the proposed method has lower value of RMSE than compared methods both in void or the whole area,which can effectively overcome the influence of outliers in ASTER GDEM v2,and generate seamless DEM.
    High Precision Building Detection from Aerial Imagery Using a U-Net Like Convolutional Architecture
    WU Guangming, CHEN Qi, Ryosuke SHIBASAKI, GUO Zhiling, SHAO Xiaowei, XU Yongwei
    2018, 47(6):  864-872.  doi:10.11947/j.AGCS.2018.20170651
    Asbtract ( )   HTML   PDF (9802KB) ( )  
    References | Related Articles | Metrics
    Automatic identification of the building target and precise acquisition of its vector contour has been an urgent task which is at the same time facing huge challenges.In recent years,due to its ability of automatically extracting high-dimensional abstract features with extremely high complexity,convolutional neural network (CNN) have made considerable improvement in this research area,and strongly enhanced the classification accuracy and generalization capability of the state-of-art building detection methods.However,the pooling layers in a classic CNN model actually considerably reduce the spatial resolution of the input image,the building detection results generated from the top layer of CNN often have coarse edges,which poses big challenges for extracting accurate building contour.In order to tackle this problem,an improved fully convolutional network based on U-Net is proposed.First,the structure of U-Net is adopted to detect accurate building edge by using a bottom-up refinement process.Then,by predicting results in both top and bottom layers with the feature pyramid,a twofold constraint strategy is proposed to further improve the detection accuracy.Experiments on aerial imagery datasets covering 30 square kilometers and over 28 000 buildings demonstrate that proposed method performs well for different areas.The accuracy values in the form of average IoU and Kappa are 83.7% and 89.5%,respectively;which are higher than the classic U-Net model,and significantly outperforms the classic full convolutional network model and the AdaBoost model trained with low-level features.
    Salient Object Detection from Multi-spectral Remote Sensing Images with Deep Residual Network
    DAI Yuchao, ZHANG Jing, Fatih PORIKLI, HE Mingyi
    2018, 47(6):  873-881.  doi:10.11947/j.AGCS.2018.20170633
    Asbtract ( )   HTML   PDF (10212KB) ( )  
    References | Related Articles | Metrics
    This paper focuses on intelligent photogrammetry deep learning:deep residual method.Salient object detection aims at identifying the visually interesting object regions that are consistent with human perception.Multispectral remote sensing images provide rich radiometric information in revealing the physical properties of the observed objects,therefore promise a great potential in salient object detection tasks.Conventional salient object detection methods often employ handcrafted features to predict saliency by evaluating the pixel-wise or superpixel-wise similarity.With the recent emergence of deep learning based approaches,in particular,fully convolutional neural networks,there has been profound progress in visual saliency detection.However,this success has not been extended to multispectral remote sensing images,and existing multispectral salient object detection methods are still mainly based on handcrafted features,essentially due to the difficulties in image acquisition and labeling.In this paper,we propose a novel deep residual network based on a top-down model,which is trained in an end-to-end manner to tackle the above issues in multispectral salient object detection.Our model effectively exploits the saliency cues at different levels of the deep residual network.To overcome the limited availability of remote sensing images in training of our deep residual network,we also introduce a new spectral image reconstruction model that can generate multispectral images from RGB images.Our extensive experimental evaluations using both multispectral and RGB salient object detection datasets demonstrate a significant performance improvement of more than 10% compared with the state-of-the-art methods.
    Machine Vision Special Issue: Building Match Graph Using Deep Convolution Feature for Structure from Motion
    WAN Jie, Alper YILMAZ
    2018, 47(6):  882-891.  doi:10.11947/j.AGCS.2018.20180040
    Asbtract ( )   HTML   PDF (2457KB) ( )  
    References | Related Articles | Metrics
    Image matching in an unordered image dataset is quite time-consuming for structure from motion (SfM) due to image matching by comparing features and large number of matches between all image pairs. To reduce matching times, deep convolution feature (DCF) is proposed to create image match graph in this paper. Firstly, the convolutional feature map of an image is extracted using the VGG-16 convolutional neural network trained on ImageNet. Then, the sum pooling is used to process the feature map. Finally, the vector is normalized and used to represent the image. The similarities between an image and all other images is calculated by calculating the distances between these feature vectors. Thus, the match graph is constructed by selecting the top 10 images with highest similarities. The experiment results showed that the proposed DCF can create the match graph effectively, find the potential image pairs. On the Urban and South Building datasets, the results of the SfM reconstruction based on the match graph created by the proposed DCF are almost the same as those of the exhaustive matching, but the number of matches are reduced by 97.4% and 92.1%, respectively. At the same time, the match graph created by the proposed DCF is obviously better than the match graph crated by the DBoW3 in the most advanced SLAM system.
    Research on Application of Remote Sensing Tupu-take Monitoring of Meteorological Disaster for Example
    YE Sijing
    2018, 47(6):  892-892.  doi:10.11947/j.AGCS.2018.20170535
    Asbtract ( )   HTML   PDF (744KB) ( )  
    Related Articles | Metrics