2. Workflow

The application is a series of linear MATLAB m-scripts that can be run in different ‘processing sequences’ (Figure 1) depending on the collection mechanism (hovering UAS vs fixed land-based single (multi) -camera stations). Scripts work with multiple processing sequences to emphasize commonalities between processing steps between collection techniques as well as reduce replicative code. Sections of the processing sequence are characterized by their functionality.

Scripts are run sequentially as inferred by the alphanumeric prefixes in the filenames and Figure 1. Each script represents a key photogrammetric processing step or decision point, (e.g. what GCPs to use) and saves intermediate products (e.g. extrinsics, etc) for input into the next script. The intermediate products allow the user flexibility in processing and an ease of exploring processing decisions (e.g. changing coordinate systems or grid resolutions) without having to restart the entire end-to-end processing. Metadata such as GCP projection errors are saved in the output mat-files as well.

In addition to the demonstrative scripts in the main repository directory, there is a X_CoreFunctions folder that contains sub-functions that execute fundamental photogrammetry processes (e.g. plotting rectified images, undistorting images). These functions can also be used independently of the demonstrative scripts making them easily adaptable to a user’s needs.

The remaining folders in the main directory contain demonstration data for UAS (X_UASDemoData) and mulit-camera land-based stations (X_FixedMultiCamDemoData). The processing sequences for each demo are highlighted in Figure 1. The demo scripts prefixed (A0-G2) are pre-populated to process the UASDemoData end-to-end. The FixedMultiCamDemoData path starts at D_gridGenExampleRect since geometry solutions are already provided, and requires users to uncomment blocks of code to execute. Scripts prefixed D, G1-G2 are also pre-populated for FixedMultiCamDemoData but these inputs are commented out. Both demos are demonstrated in Section 3. Sections 3 and 4 outline each processing script as well required inputs, outputs, and dependent functions. Example output is from demonstration data.

Figure 1: Introduction to Quantitative Coastal Imaging Toolbox repository and workflow. White boxes represents characterizations, yellow boxes represent folders, and orange boxes represent scripts.