Monitoring marine life in the past was widely dependent on physical estimates, but video cameras aided in setting up a system that allows for photographic estimations. Models and calibrations can be done for underwater video cameras to enable investigation, analysis and assessment of most marine life species, including deep sea species such as reef fish. Modeling and calibrating underwater video cameras requires accuracy and precision because of the various errors that occur, such as lens distortions or effects of refraction.
Instructions
1. Obtain and assemble the equipment you need and ensure they are in good working condition. Check the number of lenses present in the underwater video camera and their breadth. Confirm the compatibility of the camera's lens to the water in which you want to place the camera because some underwater cameras work in fresh water while others can work in both fresh and salt water.
2. Employ the direct linear transformation analysis in your calibration. Place a box of 50cm by 50cm with a cellophane aperture of approximately 5cm by 5cm in a water tank. Ensure the box is calibrated in grid squares of 5cm by 5cm on the outside marked clearly in checked black and white. Compare the underwater camera lens to the grids on the box to counter the lens distortion that may occur. Use the grids also to correct refraction and scale errors of 3D photography that may arise from the underwater camera. Set the principal point position and principle distance the same for all the underwater video cameras you are using.
3. Use an open, light aluminum structure for the control frame. Roll the camera with respect to the frame at different angles. Ensure that the underwater video camera is able to take the video from the various angles clearly so you get a collection of different views of the images of the marine life. Set each underwater camera at a particular angle to capture multiple images from the various angles and also enable you to work out from the various photogrammetric networks.
4. Use 3D control frames to approximate the coordinates and use these coordinates in the calibration of the underwater camera. Apply relative orientation to the different underwater cameras to counter geometrical problems that may arise from different angle positions of the camera or focus points. Connect the stopwatch to the underwater camera and set it to time from when the camera reaches its required position to take the video. Set the stopwatch in line with the underwater video camera's inbuilt timer. Make sure that you time all the cameras in use and immerse them at the same time to reduce timing errors.
Tags: underwater video, underwater camera, video cameras, from various, marine life, underwater video camera