USGS CoastCam at Isla Verde, Puerto Rico: 2018-2019 Intrinsic and Extrinsic Calibration Data

The CoastCam was used to take IO photos. This involves slightly tilting a printed checkerboard with 30-millimeter (mm) squares in various parts of the cameras field of view. An example image can be found in IslaVerdePR_c1_20181106_calibrationIOEO_exampleImagery.zip. There are a total of 58 IO images (IslaVerdePR_c1_20181105_IO.zip) of which 55 were used for the intrinsic calibration. The 55 images were used in step A in the Camera Calibration procedures outlined in Bruder and Brodie (2020). The resultant parameters are stored in a YAML file located in IslaVerdePR_c1_20181105_IO.zip. Image file naming format follows “IslaVerdePR_c1_20181105_###”, 20181105 is the date that the images were taken (YYYYMMDD format) and ### is the original unique ID from the camera.

Extrinsic orientation (EO) calibration ground control points (GCPs) were surveyed with a Trimble R10 survey-grade dual-frequency GNSS receiver set to record raw GNSS observables in Post-Processed Kinematic (PPK) mode. To place the photos taken by the CoastCam into real world coordinates and to rectify them into a planar view, objects within the field of view of the camera must be located. Multiple large square targets painted white and black in opposite quadrants were laid flat on the beach to be visible by the CoastCam. The GNSS receiver was placed on a fixed-height survey rod and set to record observations for one minute at each ground control point at the center of each target (between black and white). After the survey, concurrent GNSS observations were downloaded from the National Geodetic Survey (NGS) Continuously Operating Base Station (CORS), ZSU4, located approximately 2.5 kilometers from the study area. These data were then used to post-process the GNSS measurements using the Trimble Business Center ver. 5.00 software package. The CoastCam took pictures of the position of each target within the camera view (raw JPEG image). The CSV file was used to hand label the raw images to generate annotated images so that the targets could be labeled correctly in Step B of the Camera Calibration steps in Bruder and Brodie (2020). The pixel coordinates of each GCP within the raw images, solved in Step B of Bruder and Brodie (2020), the GNSS positions from the CSV files, and the IO parameters in the IO YAML file were used in Step C of the Camera Calibration steps in Bruder and Brodie (2020) to solve for the EO parameters. The resultant parameters for the EO calibration are stored in a YAML file located in “IslaVerdePR_c1_20181106_EO.zip”.

All intrinsic calibration images were given additional information required by the USGS to the exchangeable image file format (EXIF) and other imagery headers using PyExifTool Python library (https://pypi.org/project/PyExifTool/, version: 0.5.5). All intrinsic photos were given EXIF header information in the directory with all the photos by assigning all the tags in a Python dictionary object to each photo using PyExifTool. The following describes the Python dictionary object with each entry in the dictionary being a tag-value pair: tags = { 'Copyright': 'Public Domain', 'CopyrightNotice': 'Public Domain - please credit U.S. Geological Survey', 'Artist': 'USGS SPCMSC', 'Make': 'FLIR','Model': 'BFLY-PGE-50S5C-C','UserComment': ‘The following nested dictionary contains the cameras intrinsic and extrinsic calibration parameters. Intrinsic camera parameters use the Brown distortion model (Brown, D.C., 1971. "Close-Range Camera Calibration." Photogrammetric Engineering), using the Camera Calibration Toolbox for Matlab by Jean-Yves Bouguet (https://doi.org/10.22002/D1.20164). Extrinsic calibration parameters were computed using the CIRN Quantitative Coastal Imaging Toolbox (Bruder, B. L. and Brodie, K. L., 2020, "CIRN Quantitative Coastal Imaging Toolbox.", SoftwareX 12 (10052), https://doi.org/10.1016/j.softx.2020.100582.)’, 'GPSLatitude': '18.44381759', 'GPSLongitude': '-66.01223722', 'GPSMapDatum': 'EPSG:6318 (NAD83_National_Spatial_Reference_System_2011)', 'GPSLatitudeRef': 'N', 'GPSLongitudeRef': 'W', 'GPSDateStamp': '2018-11-05', 'Credit': 'U.S. Geological Survey', 'Contact': 'gs-g-spcmsc_data_inquiries@usgs.gov', 'UsageTerms': "Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty", 'AttributionURL': 'https://doi.org/10.5066/P13RKCPN', 'ExternalMetadataLink': 'https://www1.usgs.gov/pir/api/identifiers/USGS:e3ad3264-3a27-45ef-b316-311d4499874e', 'Contributor': 'Shawn R. Harrison, Mark L. Buckley, Paco López Mújica, Josh Logan, Olivia Cheriton, T. Shay Viehman, Curt D. Storlazzi, Justin J. Birchler, Margaret L. Palmsten, Eric Swanson, Emily L. Johnson', 'XMP-photoshop:Credit': 'U.S. Geological Survey', 'iptcCore:CreatorWorkEmail': 'gs-g-spcmsc_data_inquiries@usgs.gov','Rights': 'Public Domain', 'Keywords' : "Isla Verde, Puerto Rico, CoastCam, USGS, intrinsic calibration, snapshot, remote sensing, ground control point", 'ImageDescription': 'This image was captured from a stationary mounted camera at Isla Verde, Puerto Rico. Field Activity Number: 2018-670-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-670-FA)', 'Description': 'This image was captured from a stationary mounted camera at Isla Verde, Puerto Rico. Field Activity Number: 2018-670-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-670-FA)'}. If there were errors generating keywords with the Python script, additional keywords were added to the imagery headers for all of the IO images using the following command: 'exiftool -sep ", " -iptc:keywords="Isla Verde, Puerto Rico, CoastCam, USGS, intrinsic calibration" *.jpg'. The UserComment EXIF metadata field was used to store the camera intrinsics and extrinsics in the image metadata. The UserComment has a nested dictionary structure. The highest-level dictionary contains two nested dictionaries as well as a note explaining the structure of the UserComment field. One nested dictionary contains the actual intrinsic and extrinsic data variables. The other nested dictionary contains text descriptions for each of the variables in the dictionary of data variables. To read out the imagery header information to a CSV file the command is: 'exiftool -csv *.jpg > allheaders.csv'. Specific tags may be specified with this command, if preferred.

All extrinsic calibration ground control point images were given additional information required by the USGS to the exchangeable image file format (EXIF) and other imagery headers using PyExifTool Python library (https://pypi.org/project/PyExifTool/, version: 0.5.5). All extrinsic photos were given EXIF header information in the directory with all the photos by assigning all the tags in a Python dictionary object to each photo using PyExifTool. The following describes the Python dictionary object with each entry in the dictionary being a tag-value pair: tags = { 'Copyright': 'Public Domain', 'CopyrightNotice': 'Public Domain - please credit U.S. Geological Survey', 'Artist': 'USGS SPCMSC', 'Make': 'FLIR','Model': 'BFLY-PGE-50S5C-C','UserComment': ‘The following nested dictionary contains the cameras intrinsic and extrinsic calibration parameters. Intrinsic camera parameters use the Brown distortion model (Brown, D.C., 1971. "Close-Range Camera Calibration." Photogrammetric Engineering), using the Camera Calibration Toolbox for Matlab by Jean-Yves Bouguet (https://doi.org/10.22002/D1.20164). Extrinsic calibration parameters were computed using the CIRN Quantitative Coastal Imaging Toolbox (Bruder, B. L. and Brodie, K. L., 2020, "CIRN Quantitative Coastal Imaging Toolbox.", SoftwareX 12 (10052), https://doi.org/10.1016/j.softx.2020.100582.)’, 'GPSLatitude': '18.44381759', 'GPSLongitude': '-66.01223722', 'GPSMapDatum': 'EPSG:6318 (NAD83_National_Spatial_Reference_System_2011)', 'GPSLatitudeRef': 'N', 'GPSLongitudeRef': 'W', 'Credit': 'U.S. Geological Survey', 'Contact': 'gs-g-spcmsc_data_inquiries@usgs.gov', 'UsageTerms': "Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty", 'AttributionURL': 'https://doi.org/10.5066/P13RKCPN', 'ExternalMetadataLink':'https://www1.usgs.gov/pir/api/identifiers/USGS:e3ad3264-3a27-45ef-b316-311d4499874e', 'Contributor': 'Shawn R. Harrison, Mark L. Buckley, Paco López Mújica, Josh Logan, Olivia Cheriton, T. Shay Viehman, Curt D. Storlazzi, Justin J. Birchler, Margaret L. Palmsten, Eric Swanson, Emily L. Johnson', 'XMP-photoshop:Credit': 'U.S. Geological Survey', 'iptcCore:CreatorWorkEmail': 'gs-g-spcmsc_data_inquiries@usgs.gov','Rights': 'Public Domain', 'Keywords' : "Isla Verde, Puerto Rico, CoastCam, USGS, intrinsic calibration, snapshot, remote sensing, ground control point", 'ImageDescription': 'This image was captured from a stationary mounted camera at Isla Verde, Puerto Rico. Field Activity Number: 2018-670-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-670-FA)', 'Description': 'This image was captured from a stationary mounted camera at Isla Verde, Puerto Rico. Field Activity Number: 2018-670-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-670-FA)'}. If there were errors generating keywords with the Python script, additional keywords were added to the imagery headers for all of the IO images using the following command: 'exiftool -sep ", " -iptc:keywords="Isla Verde, Puerto Rico, CoastCam, USGS, extrinsic calibration" *.jpg'. The only tag which can have a different value from image to image is GPSDateStamp. Depending on the date the photo was captured, the value in the GPSDatestamp tag changes. The UserComment EXIF metadata field was used to store the camera intrinsics and extrinsics in the image metadata. The UserComment has a nested dictionary structure. The highest-level dictionary contains two nested dictionaries as well as a note explaining the structure of the UserComment field. One nested dictionary contains the actual intrinsic and extrinsic data variables. The other nested dictionary contains text descriptions for each of the variables in the dictionary of data variables. To read out the imagery header information to a CSV file the command is: 'exiftool -csv *.jpg > allheaders.csv'. Specific tags may be specified with this command, if preferred.