Pixel density refers to the number of pixels in a given area. It plays a big role in determining the detail of information obtained and the total area covered by the camera. The pixel density of an image depends on several factors:
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Camera resolution
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Aspect ratio
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Instantaneous field of view (IFOV)
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Distance from camera to object
How to Calculate Pixel Density
Example Scenario:
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Image size of Rayfin Mk2 with 12.3MP sensor is 4056 x 3040 pixels
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FOV in water is min 81° diagonal, 71° horizontal, 57° vertical. 4:3 aspect ratio
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The distance between camera and object is 2m
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Using the formula below we can find the area covered
Width of image = 2 * distance * tan(FOV / 2)
Image width = 2 * 2000mm * tan(71/2) = 2850mm
Image height = 2 * 2000mm * tan(57/2) = 2170mm
Divide the vertical pixels by the coverage:
2850mm / 4056 pixels = 0.70mm/pixel
