Airborne Oblique Imaging: Towards the Hybrid Era

2019 ◽  
Vol 31 (1) ◽  
pp. 21-28
Author(s):  
Isabella Toschi

Abstract If the use of oblique aerial camera systems is steadily growing for 3D capture of urban areas, their combination with a LiDAR unit seems to have all the potential to lead the airborne mapping sector a step forward. To fully exploit the complementary sensor behaviour, a new perspective should be adopted that looks beyond the traditional data processing chains and extends them towards an hybrid data processing concept. Assisted tie point matching, integrated sensor orientation and augmented 3D reconstruction are the keystones of a rigorous hybrid workflow for hybrid sensors. They should all rely on a deep understanding of the different properties of active and passive 3D imaging, and of the uncertainty components in their measurements. The paper will focus on the most recent answers to these issues, that open new opportunities for boosting the quality of the geospatial products w.r.t completeness, geometric quality, object detection and processing efficiency

2021 ◽  
Vol 237 ◽  
pp. 110810
Author(s):  
Chenli Wang ◽  
Jun Jiang ◽  
Thomas Roth ◽  
Cuong Nguyen ◽  
Yuhong Liu ◽  
...  

2011 ◽  
Vol 59 (2) ◽  
pp. 137-140 ◽  
Author(s):  
S. Szczepański ◽  
M. Wöjcikowski ◽  
B. Pankiewicz ◽  
M. KŁosowski ◽  
R. Żaglewski

FPGA and ASIC implementation of the algorithm for traffic monitoring in urban areas This paper describes the idea and the implementation of the image detection algorithm, that can be used in integrated sensor networks for environment and traffic monitoring in urban areas. The algorithm is dedicated to the extraction of moving vehicles from real-time camera images for the evaluation of traffic parameters, such as the number of vehicles, their direction of movement and their approximate speed. The authors, apart from the careful selection of particular steps of the algorithm towards hardware implementation, also proposed novel improvements, resulting in increasing the robustness and the efficiency. A single, stationary, monochrome camera is used, simple shadow and highlight elimination is performed. The occlusions are not taken into account, due to placing the camera at a location high above the road. The algorithm is designed and implemented in pipelined hardware, therefore high frame-rate efficiency has been achieved. The algorithm has been implemented and tested in FPGA and ASIC.


Author(s):  
Elhamh Yahya Hussein Al- alawi, Suad Said Ali Aldaghaishi, A

  This study aims to design a new theoretical framework to help the Holy Quran memorizers not only to memories the verses but also to retain them. This design goes in accordance with the new perspective of data processing which points to the fact that profound data processing has a great impact on remembering the verses through three major ways: Keyword Method as a code for the word to be remembered, Colour as a way to recall information as evident by a number of research studies and Story Strategy as a way to enable recalling of verses by linking the words to be remembered with an innovative story with reference to the science of event; Surat Al Hadid as an example. In order to prove the effectiveness of this proposal, a descriptive analysis and semi experimental study was conducted on a sample of Holy Quran Circle students ‘Halaqah’. 80 male and female students were divided into four groups, two experimental groups and two controlled groups. The findings of the study have demonstrated positive effect of the proposed model in ease of memorizing verses of the Holy Quran. The results show that there is a significant difference between male and female in goodness of their hafiz for favor of male group.    


2015 ◽  
Vol 13 (03) ◽  
Author(s):  
Debbie Deborah. S. Mokolinug ◽  
Novi S. Budiarso

Breakthroughs related to the application of Information Technology in taxation activity continues to be done in order to facilitate, improve and optimize the service to taxpayers. There are many factors that influence the success of applied information technology. It is associated with a recent study also analyzes the success of information technology established by the Directorate General of Taxation (DGT) is an e-SPT This study was conducted to verify the success of e-SPT system used by employers taxable. The purpose of this study was to determine the effect of practicality, ease of calculation, the ease of reporting and reliability of e-tax return on tax data processing efficiency. The analytical method used is multiple regression analysis. The results showed that the practicality and ease of calculation significantly affect the efficiency of data processing tax on taxable employers in Tomohon while reporting the ease and convenience of e-SPT does not significantly affect the efficiency of data processing tax on taxable employers in Tomohon


Author(s):  
C. Cortes ◽  
M. Shahbazi ◽  
P. Ménard

<p><strong>Abstract.</strong> In the last decade, applications of unmanned aerial vehicles (UAVs), as remote-sensing platforms, have extensively been investigated for fine-scale mapping, modeling and monitoring of the environment. In few recent years, integration of 3D laser scanners and cameras onboard UAVs has also received considerable attention as these two sensors provide complementary spatial/spectral information of the environment. Since lidar performs range and bearing measurements in its body-frame, precise GNSS/INS data are required to directly geo-reference the lidar measurements in an object-fixed coordinate system. However, such data comes at the price of tactical-grade inertial navigation sensors enabled with dual-frequency RTK-GNSS receivers, which also necessitates having access to a base station and proper post-processing software. Therefore, such UAV systems equipped with lidar and camera (UAV-LiCam Systems) are too expensive to be accessible to a wide range of users. Hence, new solutions must be developed to eliminate the need for costly navigation sensors. In this paper, a two-fold solution is proposed based on an in-house developed, low-cost system: 1) a multi-sensor self-calibration approach for calibrating the Li-Cam system based on planar and cylindrical multi-directional features; 2) an integrated sensor orientation method for georeferencing based on unscented particle filtering which compensates for time-variant IMU errors and eliminates the need for GNSS measurements.</p>


Author(s):  
M. Rehak ◽  
J. Skaloud

Mapping with Micro Aerial Vehicles (MAVs whose weight does not exceed 5&amp;thinsp;kg) is gaining importance in applications such as corridor mapping, road and pipeline inspections, or mapping of large areas with homogeneous surface structure, e.g. forest or agricultural fields. In these challenging scenarios, integrated sensor orientation (ISO) improves effectiveness and accuracy. Furthermore, in block geometry configurations, this mode of operation allows mapping without ground control points (GCPs). Accurate camera positions are traditionally determined by carrier-phase GNSS (Global Navigation Satellite System) positioning. However, such mode of positioning has strong requirements on receiver’s and antenna’s performance. In this article, we present a mapping project in which we employ a single-frequency, low-cost (<&amp;thinsp;$100) GNSS receiver on a MAV. The performance of the low-cost receiver is assessed by comparing its trajectory with a reference trajectory obtained by a survey-grade, multi-frequency GNSS receiver. In addition, the camera positions derived from these two trajectories are used as observations in bundle adjustment (BA) projects and mapping accuracy is evaluated at check points (ChP). Several BA scenarios are considered with absolute and relative aerial position control. Additionally, the presented experiments show the possibility of BA to determine a camera-antenna spatial offset, so-called lever-arm.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2783 ◽  
Author(s):  
Yilin Zhou ◽  
Ewelina Rupnik ◽  
Paul-Henri Faure ◽  
Marc Pierrot-Deseilligny

With the development of unmanned aerial vehicles (UAVs) and global navigation satellite system (GNSS), the accurate camera positions at exposure can be known and the GNSS-assisted bundle block adjustment (BBA) approach is possible for integrated sensor orientation (ISO). This study employed ISO approach for camera pose determination with the objective of investigating the impact of a good sensor pre-calibration on a poor acquisition geometry. Within the presented works, several flights were conducted on a dike by a small UAV embedded with a metric camera and a GNSS receiver. The multi-lever-arm estimation within the BBA procedure makes it possible to merge image blocks of different configurations such as nadir and oblique images without physical constraints on camera and GNSS antenna positions. The merged image block achieves a better accuracy and the sensor self-calibrated well. The issued sensor calibration is then applied to a less preferable acquisition configuration and the accuracy is significantly improved. For a corridor acquisition scene of about 600 m , a centimetric accuracy is reached with one GCP. With the provided sensor pre-calibration, an accuracy of 3.9 c m is achieved without any GCP.


2021 ◽  
Author(s):  
Hongjie Zheng ◽  
Hanyu Chang ◽  
Yongqiang Yuan ◽  
Qingyun Wang ◽  
Yuhao Li ◽  
...  

&lt;p&gt;Global navigation satellite systems (GNSS) have been playing an indispensable role in providing positioning, navigation and timing (PNT) services to global users. Over the past few years, GNSS have been rapidly developed with abundant networks, modern constellations, and multi-frequency observations. To take full advantages of multi-constellation and multi-frequency GNSS, several new mathematic models have been developed such as multi-frequency ambiguity resolution (AR) and the uncombined data processing with raw observations. In addition, new GNSS products including the uncalibrated phase delay (UPD), the observable signal bias (OSB), and the integer recovery clock (IRC) have been generated and provided by analysis centers to support advanced GNSS applications.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; However, the increasing number of GNSS observations raises a great challenge to the fast generation of multi-constellation and multi-frequency products. In this study, we proposed an efficient solution to realize the fast updating of multi-GNSS real-time products by making full use of the advanced computing techniques. Firstly, instead of the traditional vector operations, the &amp;#8220;level-3 operations&amp;#8221; (matrix by matrix) of Basic Liner Algebra Subprograms (BLAS) is used as much as possible in the Least Square (LSQ) processing, which can improve the efficiency due to the central processing unit (CPU) optimization and faster memory data transmission. Furthermore, most steps of multi-GNSS data processing are transformed from serial mode to parallel mode to take advantage of the multi-core CPU architecture and graphics processing unit (GPU) computing resources. Moreover, we choose the OpenBLAS library for matrix computation as it has good performances in parallel environment.&lt;/p&gt;&lt;p&gt;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160;&amp;#160; The proposed method is then validated on a 3.30 GHz AMD CPU with 6 cores. The result demonstrates that the proposed method can substantially improve the processing efficiency for multi-GNSS product generation. For the precise orbit determination (POD) solution with 150 ground stations and 128 satellites (GPS/BDS/Galileo/GLONASS/QZSS) in ionosphere-free (IF) mode, the processing time can be shortened from 50 to 10 minutes, which can guarantee the hourly updating of multi-GNSS ultra-rapid orbit products. The processing time of uncombined POD can also be reduced by about 80%. Meanwhile, the multi-GNSS real-time clock products can be easily generated in 5 seconds or even higher sampling rate. In addition, the processing efficiency of UPD and OSB products can also be increased by 4-6 times.&lt;/p&gt;


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