CODEWITHSUNDEEP
opencvcameracalibration
AnnaB
AnnaB

Reputation: 35

Why resizing an image in OpenCv decreases the reprojection error of a camera calibration?

I'm using OpenCv to calibrate a camera. Firstly, I was using the original resolution, but then I realize that if I resize the image (downsample) I could get a lower reprojection error. Why this happens?

Upvotes: 3

Views: 697

Answers (1)

Adrian Schneider
Adrian Schneider

Reputation: 1507

The reprojection error is the average error of the projected 3d points on the 2d image plane. Thus, its unit is given in pixel.

The consequence of downsampling your image is a downsampled reprojection error. The actual error is still the same, but the 'pixel unit' does not correspond anymore to the same spatial distance on the image sensor.

In order to receive comparable reprojection error values, one can express the error as a distance on the sensor.

Hope that answer helped you.

Upvotes: 4

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