scholarly journals KLT-IV v1.0: Image velocimetry software for use with fixed and mobile platforms

2020 ◽  
Author(s):  
Matthew T. Perks
Keyword(s):  
River Flow ◽  
High Flow ◽  
Ground Control ◽  
Control Points ◽  
Flow Conditions ◽  
Mobile Platforms ◽  
Differential Gps ◽  
Ground Control Points ◽  
Image Velocimetry

Abstract. Accurately monitoring river flows can be challenging, particularly under high-flow conditions. In recent years, there has been considerable development of remote sensing techniques for the determination of river flow dynamics. Image velocimetry is one particular approach which has been shown to accurately reconstruct surface velocities under a range of hydro-geomorphic conditions. Building on these advances, a new software package, KLT-IV v1.0 has been designed to offer a user-friendly graphical interface for the determination of river flow velocity and river discharge using videos acquired from a variety of fixed and mobile platforms. Platform movement can be accounted for when ground control points and/or stable features are present, or where the platform is equipped with a differential GPS device and inertial measurement unit (IMU) sensor. The application of KLT-IV v1.0 is demonstrated using two case studies at sites in the UK: (i) River Feshie; and (ii) River Coquet. At these sites, footage is acquired from unmanned aerial systems (UAS) and fixed cameras. Using a combination of ground control points (GCPs), and differential GPS and IMU data to account for platform movement, image coordinates are converted to real world distances and displacements. Flow measurements made with a UAS and fixed camera are used to generate a well-defined flow rating curve for the River Feshie. Concurrent measurements made by UAS and fixed camera are shown to deviate by < 4 % under high-flow conditions where maximum velocities exceed 3 m s−1. The acquisition of footage on the River Coquet using a UAS equipped with differential GPS and IMU sensors enabled flow velocities to be precisely reconstructed along a 180 m river reach. In-channel velocities of between 0.2 and 1 m s−1 are produced. Check points indicated that unaccounted for motion in the UAS platform is in the region of 6 cm. These examples are provided to illustrate the potential for KLT-IV to be used for quantifying flow rates using videos collected from fixed, or mobile camera systems.

scholarly journals KLT-IV v1.0: image velocimetry software for use with fixed and mobile platforms

2020 ◽  
Vol 13 (12) ◽  
pp. 6111-6130
Author(s):  
Matthew T. Perks
Keyword(s):  
River Flow ◽  
High Flow ◽  
Ground Control ◽  
Control Points ◽  
Flow Conditions ◽  
Mobile Platforms ◽  
Differential Gps ◽  
Ground Control Points ◽  
Image Velocimetry

Abstract. Accurately monitoring river flows can be challenging, particularly under high-flow conditions. In recent years, there has been considerable development of remote sensing techniques for the determination of river flow dynamics. Image velocimetry is one particular approach which has been shown to accurately reconstruct surface velocities under a range of hydro-geomorphic conditions. Building on these advances, a new software package, KLT-IV v1.0, has been designed to offer a user-friendly graphical interface for the determination of river flow velocity and river discharge using videos acquired from a variety of fixed and mobile platforms. Platform movement can be accounted for when ground control points and/or stable features are present or where the platform is equipped with a differential GPS device and inertial measurement unit (IMU) sensor. The application of KLT-IV v1.0 is demonstrated using two case studies at sites in the UK: (i) river Feshie and (ii) river Coquet. At these sites, footage is acquired from unmanned aerial systems (UASs) and fixed cameras. Using a combination of ground control points (GCPs) and differential GPS and IMU data to account for platform movement, image coordinates are converted to real-world distances and displacements. Flow measurements made with a UAS and fixed camera are used to generate a well-defined flow rating curve for the river Feshie. Concurrent measurements made by UAS and fixed camera are shown to deviate by < 4 % under high-flow conditions where maximum velocities exceed 3 m s−1. The acquisition of footage on the river Coquet using a UAS equipped with differential GPS and IMU sensors enabled flow velocities to be precisely reconstructed along a 180 m river reach. In-channel velocities of between 0.2 and 1 m s−1 are produced. Check points indicated that unaccounted-for motion in the UAS platform is in the region of 6 cm. These examples are provided to illustrate the potential for KLT-IV to be used for quantifying flow rates using videos collected from fixed or mobile camera systems.

scholarly journals Avaliação de Desempenho no Georreferenciamento de Imagens do Sensor HR CCD (High Resolution Charge-Coupled Device) do Satélite CBERS-1

2005 ◽  
Vol 32 (2) ◽  
pp. 81
Author(s):  
RAFAEL PEREIRA ZANARDI ◽  
SILVIA BEATRIZ ALVES ROLIM ◽  
CLÁUDIO BIELENKI JÚNIOR ◽  
CARLOS ALUISIO MESQUITA DE ALMEIDA
Keyword(s):  
High Resolution ◽  
Geometric Transformation ◽  
Ground Control ◽  
Control Points ◽  
Differential Gps ◽  
Charge Coupled Device ◽  
Qualitative And Quantitative ◽  
Ground Control Points ◽  
Sampling Points ◽  
Nearest Neighborhood

In this work it was analyzed the validation of CBERS-1 (China and Brazillian Earth Resourses Satellite) data related to qualitative and quantitative parameters that define the precision of its georeferencing. A topographical survey was carried out for the acquisition of ground control points spatially well distributed in the study area, employing differential GPS, aiming at the georeferencing of the image. Tests with different numbers of sampling points and several methods of Geometric Transformation and Resampling were made during the georeferencing. These results were statistically analyzed to determine the best method to georeference CBERS-1 images. It was verified that the first-degree polinomial transformation with nearest neighborhood resampling presented the best result, showing a precision of 18,52m.

scholarly journals THE PERFORMANCE OF A TIGHT INS/GNSS/PHOTOGRAMMETRIC INTEGRATION SCHEME FOR LAND BASED MMS APPLICATIONS IN GNSS DENIED ENVIRONMENTS

2016 ◽  
Vol XLI-B1 ◽  
pp. 551-557 ◽  
Author(s):  
Chien-Hsun Chu ◽  
Kai-Wei Chiang
Keyword(s):  
Satellite System ◽  
Ground Control ◽  
Integration Scheme ◽  
Control Points ◽  
Mobile Mapping ◽  
Positioning Accuracy ◽  
Variable Position ◽  
Ground Control Points ◽  
Position And Orientation

The early development of mobile mapping system (MMS) was restricted to applications that permitted the determination of the elements of exterior orientation from existing ground control. Mobile mapping refers to a means of collecting geospatial data using mapping sensors that are mounted on a mobile platform. Research works concerning mobile mapping dates back to the late 1980s. This process is mainly driven by the need for highway infrastructure mapping and transportation corridor inventories. In the early nineties, advances in satellite and inertial technology made it possible to think about mobile mapping in a different way. Instead of using ground control points as references for orienting the images in space, the trajectory and attitude of the imager platform could now be determined directly. Cameras, along with navigation and positioning sensors are integrated and mounted on a land vehicle for mapping purposes. Objects of interest can be directly measured and mapped from images that have been georeferenced using navigation and positioning sensors. Direct georeferencing (DG) is the determination of time-variable position and orientation parameters for a mobile digital imager. The most common technologies used for this purpose today are satellite positioning using the Global Navigation Satellite System (GNSS) and inertial navigation using an Inertial Measuring Unit (IMU). Although either technology used along could in principle determine both position and orientation, they are usually integrated in such a way that the IMU is the main orientation sensor, while the GNSS receiver is the main position sensor. However, GNSS signals are obstructed due to limited number of visible satellites in GNSS denied environments such as urban canyon, foliage, tunnel and indoor that cause the GNSS gap or interfered by reflected signals that cause abnormal measurement residuals thus deteriorates the positioning accuracy in GNSS denied environments. This study aims at developing a novel method that uses ground control points to maintain the positioning accuracy of the MMS in GNSS denied environments. At last, this study analyses the performance of proposed method using about 20 check-points through DG process.

scholarly journals RESULTS OF RESEARCHES ON PHOTOGRAMMETRIC CALIBRATION OF THE SONY CYBER-SHOT DSC-RX1RM2 CAMERA

2019 ◽  
Vol XLII-2/W18 ◽  
pp. 73-77
Author(s):  
S. A. Kadnichansky ◽  
M. B. Kurkov ◽  
V. M. Kurkov ◽  
A. G. Chibunichev ◽  
L. K. Trubina
Keyword(s):  
Aerial Survey ◽  
Ground Control ◽  
Test Field ◽  
Control Points ◽  
Aerial Photos ◽  
Ground Control Points ◽  
Operational Test ◽  
Time Accuracy ◽  
Specific Project

Abstract. Results of researches of calibration of the SONY CYBER-SHOT DSC-RX1RM2 camera on the basis of the test field aerial survey are given in article. Researches showed that calibration using aerial survey of a calibration test field provides reliable result with a required accuracy. Recommendations about execution of aerial survey and about creation of an operational test field for photogrammetric calibration of the camera before execution of the specific project are made. When aerial survey is carried out with GNSS determination of coordinates of the perspective centers of aerial photos with RMS of coordinates no more than 0.08 m it is possible to use the self-calibration mode for photogrammetric network block adjustment without ground control points. At the same time accuracy of the end result of photogrammetric processing commensurable with an accuracy, achieved with ground control points, is provided.

scholarly journals THE PERFORMANCE OF A TIGHT INS/GNSS/PHOTOGRAMMETRIC INTEGRATION SCHEME FOR LAND BASED MMS APPLICATIONS IN GNSS DENIED ENVIRONMENTS

2016 ◽  
Vol XLI-B1 ◽  
pp. 551-557
Author(s):  
Chien-Hsun Chu ◽  
Kai-Wei Chiang
Keyword(s):  
Satellite System ◽  
Ground Control ◽  
Integration Scheme ◽  
Control Points ◽  
Mobile Mapping ◽  
Positioning Accuracy ◽  
Variable Position ◽  
Ground Control Points ◽  
Position And Orientation

The early development of mobile mapping system (MMS) was restricted to applications that permitted the determination of the elements of exterior orientation from existing ground control. Mobile mapping refers to a means of collecting geospatial data using mapping sensors that are mounted on a mobile platform. Research works concerning mobile mapping dates back to the late 1980s. This process is mainly driven by the need for highway infrastructure mapping and transportation corridor inventories. In the early nineties, advances in satellite and inertial technology made it possible to think about mobile mapping in a different way. Instead of using ground control points as references for orienting the images in space, the trajectory and attitude of the imager platform could now be determined directly. Cameras, along with navigation and positioning sensors are integrated and mounted on a land vehicle for mapping purposes. Objects of interest can be directly measured and mapped from images that have been georeferenced using navigation and positioning sensors. Direct georeferencing (DG) is the determination of time-variable position and orientation parameters for a mobile digital imager. The most common technologies used for this purpose today are satellite positioning using the Global Navigation Satellite System (GNSS) and inertial navigation using an Inertial Measuring Unit (IMU). Although either technology used along could in principle determine both position and orientation, they are usually integrated in such a way that the IMU is the main orientation sensor, while the GNSS receiver is the main position sensor. However, GNSS signals are obstructed due to limited number of visible satellites in GNSS denied environments such as urban canyon, foliage, tunnel and indoor that cause the GNSS gap or interfered by reflected signals that cause abnormal measurement residuals thus deteriorates the positioning accuracy in GNSS denied environments. This study aims at developing a novel method that uses ground control points to maintain the positioning accuracy of the MMS in GNSS denied environments. At last, this study analyses the performance of proposed method using about 20 check-points through DG process.

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