Error: There is a significant difference between the Initial and Optimized Focal Length

Error

Sometimes the optimized focal length differs considerably from the initial value (e.g. more than 5%).

 

Description

The software calibrates the camera for every project. The calibration is done in the first step 1. Initial project processing.

The reason is that the interior camera parameters can vary with temperature, shocks, altitude between each flight, etc.

 

Cause

The software can read from the EXIF data the focal length and the number of pixels from the sensor (pixel*pixel), but it can not always read the correct pixel size to calculate the sensor size (mm*mm). This is why the software supposes that the sensor size is 36*24 mm. It supposes that the images have the 35 mm equivalent senor size. Starting with initial value the focal length that is read at the EXIF or given by the user, it recalculates the most appropriate one for the 36*24 mm sensor size.

 

Solution

1. Edit the camera model using the optimized focal length as it is calculated and process again: 202560059
2. If still fails, search (on Internet or ask your camera manufacturer) the real sensor size of the camera. Edit the camera model using the real sensor size and process again: 202560169.

 

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