Photogramerty Appliation for Water Resources

Photogramerty Appliation for Water Resources

1. Chukka Vinay Kumar 23CE61R06 Hydraulics and Water Resources Engineering INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR Enhanced River Flow Analysis Using Fudaa -LSPIV : Techniques and Applications

2. Objectives 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 2 To utilize Fudaa -LSPIV for accurate and efficient measurement of surface flow velocities in riverine and open channel environments. To enhance hydrological modeling and flood management by applying Fudaa -LSPIV’s advanced image processing capabilities.

3. Introduction Fudaa -LSPIV is a powerful software tool that enables researchers and engineers to analyze image sequences of flowing water to compute surface velocity fields and discharges. By leveraging the Large-Scale Particle Image Velocimetry (LSPIV) technique, Fudaa -LSPIV provides a robust and versatile method for quantifying complex flow dynamics across a range of aquatic environments, from rivers and canals to estuaries and coastal regions. The software utilizes advanced image processing algorithms to track the movement of natural or artificial particles on the water surface over time. 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 3

4. Advantages of Fudaa -LSPIV 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 4 Non-Intrusive Fudaa-LSPIV is a non-invasive technique that allows for the measurement of surface flow dynamics without interfering with the natural flow conditions. High Spatial Resolution The software can provide high-resolution velocity data across the entire field of view, enabling a detailed analysis of complex flow patterns. Rapid Measurements Fudaa-LSPIV can generate instantaneous velocity fields from image sequences, allowing for the rapid assessment of evolving flow conditions. Cost-Effective Compared to traditional in-situ measurement techniques, Fudaa-LSPIV offers a more cost-effective solution for flow monitoring and characterization.

5. Methodology 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 5 Source Images and Stabilization Orthorectification 3 LSPIV analysis 4 Post-processing 5 Discharge

6. Source Images and Stabilization The Fudaa -LSPIV workflow begins with importing a sequence of images that capture the flow of interest. Users can either provide a pre-recorded video file or a series of individual images, ensuring the necessary temporal resolution to track the movement of flow features. Import Image Sequence 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 7

7. Source Images and Stabilization Once the image sequence is loaded, Fudaa -LSPIV automatically synchronizes the frames, establishing a consistent time interval between each image. This temporal information is crucial for the subsequent velocity computations, as it allows the software to quantify the displacement of flow features over time. Temporal Synchronization 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 8

8. Source Images and Stabilization It will consider the marked area as flowing area. Stabilization done for the banks of canal. Stabilization 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 9

9. Orthorectification New ones menu brings you to the GUI for positioning reference points. Enter the terrain coordinates (real X, real Y and real Z) of the first point, then click on the pixel of the image locating the GRP, the image coordinates I and J are then filled. It is possible to zoom to better see a point. Repeat the operation for all reference points (at least 4 for 2D orthorectification, at least 6 for 3D orthorectification ). Reference Points 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 11

10. Orthorectification The study area is defined by a rectangle whose position of the corners in the real coordinate system ( Xmin , Xmax , Ymin , Ymax ) is indicated. This framework makes it possible to reduce the orthorectification to the area of ​​interest and thus limit the calculation times. The resolution, in meters per pixel, corresponds to the size of a pixel in the orthorectified image. Transformation Parameters 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 12

11. Orthorectification Transform images menu starts the orthorectification of all selected images. Orthorectified images are stored in the img_transf folder The cache folder contains the same .gif images, which are smaller in size. Transformation of All Images 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 13

12. LSPIV Analyis Define menu launches the interface for the Grid outline. The outline of the grid is a quadrilateral defined by its four corners thanks to clicks on the orthoimage. The density of the grid is defined by a spacing pitch on the opposite segments of the quadrilateral. Grid Points 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 15

13. LSPIV Analyis Interrogation Area (IA) size, in meters or in pixels (linked units). This area must be large enough to incorporate tracers, but small enough to be representative of the flow (velocity gradients in an AI must be negligible). Search Area (SA) size in meters or pixels (linked units). The search area is a rectangle defined around the center of the interrogation area. It corresponds to the zone in which the patterns are searched on the successive images. Calculation of Instantaneous Results 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 16

14. LSPIV Analyis Calculation of instantaneous results menu launches the statistical analysis of plotter displacements for all image pairs in the sequence. An "instantaneous" velocity field (at the step of the time interval between two images) is obtained for all consecutive image pairs. Thus, for N selected images, we obtain N-1 velocity fields, stored in the vel_raw folder. 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 17 R Velocities R Velocitiy Isosurfaces

15. Post-processing The Velocity ​​tab allows you to filter on standard values ​​or or components. To use this filter, select the Filter velocities check box and enter the minimum and maximum values ​​for the different filters. By fixing a maximum bound at 0.98, we will avoid artifices if the calculation grid overflows the flow and encroaches on static areas (bank, edge image). The default correlation thresholds are set as 0.4 (min) and 0.98 (max).   Filtering Instant Results 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 19

16. Post-processing Filtered Instant Results 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 20 F Velocities F Velocity Isosurfaces

17. Post-processing We select the filtered velocity fields to be averaged (a priori, all the filtered results are selected) and the validation button is used to calculate the averaged velocity field on all the image pairs of the sequence. Averaging the Results 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 21

18. Post-processing Filtered average instantaneous results 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 22 A Velocities A Velocity Isosurfaces

19. Discharge A profile is indicated on a straight line, preferably perpendicular to the discharge. First, enter the Z coordinate in the real coordinate system of the edge on the left bank of the transect, then click on the corresponding point in the orthorectified image. Repeat for all points of the bathymetric transect. The first two points indicated define the orientation of the bathymetric profile. Transacts 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 24

20. Discharge The Interpolation space step of the bathymetry (m) interpolates a bathymetric transect that is not sufficiently sampled. Since discharge is calculated using velocities at known bathymetry points, the transect should have about 20 points in the wet zone. The Velocity ​​searching radius (m) indicates the area around the known bathymetry point in which the calculated LSPIV velocities (Average Area Velocity) will be averaged to assign a surface velocity value. The Velocity ​​coefficient is the ratio of the velocity averaged over the depth to the surface velocity. Transacts Parameters 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 25

21. Discharge Calculation of the discharge menu starts the discharge calculation for the bathymetric transects present. At the end of the calculation, the results window opens. It allows you to see the calculated parameters for all transects and compare each result to the average of all transects. Discharge Calculation 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 26

22. Conclusions 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 27 The velocity coefficient (Vel. coef.) remained consistent across all transects at 0.850, indicating uniform calibration and application of the software settings. The total flow rate (Total Q) displayed minor variations across the transects, ranging from 0.007 m³/s to 0.009 m³/s, with an average of 0.007 m³/s. These minor differences reflect slight fluctuations in flow conditions, but the average remains within an acceptable range. The wetted area showed minor deviations with gaps ranging from -3.9% to +8.3%. Similarly, the average velocity (Ave. vel.) had slight variations, with the gap ranging from -16.3% to +13.8%. Despite these variations, the overall average velocity gap was 0.0%, demonstrating the software’s capability to accurately measure flow velocities. The ratio of measured flow rate to total flow rate (Measured Q / Total Q) was consistently at 100% for all transects, confirming the accuracy and reliability of Fudaa -LSPIV in capturing the flow measurements.

23. 15-10-2024 Enhanced River Flow Analysis Using Fudaa-LSPIV : Techniques and Applications 28 Thank You