CODEWITHSUNDEEP
image-processingcameracomputer-visionprojectioncamera-calibration
Kozolovska
Kozolovska

Reputation: 1119

Calibration of stationary video camera

I have a problem in which i have a stationary video camera in a room and several videos from it, i need to transform the image coordinates into world coordinates.

What i know: 1. all the measurements of the room. 2. 16 image coordinates and their respected world coordinates.

The problem i encounter: At first i thought i just need to create a geometric transformation (According to http://xenia.media.mit.edu/~cwren/interpolator/), but i have a problem since the edge of the room are distorted in the image, and i cant calibrate the camera because i can't get a hold of the room or the camera.

Is there anyway i can overcome those difficulties and measure the distance in the room with some accuracy?

Thanks

Upvotes: 1

Views: 125

Answers (1)

sansuiso
sansuiso

Reputation: 9379

You can calibrate the distortion of the camera by extracting first the edges of your room and then finding the best set of distortion parameters (that will minimize edge distortion). There are few works that implement this approach though:

  • you can find a skeleton of distortion estimation procedure in R. Szeliski's book, but without an implementation;
  • alternatively, you can find a method + implementation (+ an online demo where you can upload your images) on IPOL.

Regarding the perspective distortion, after removing the lens distortion just proceed with the link that you have found by applying this method to the image of the four corners of the room floor. This will give you the mapping between an image pixel and a ground pixel (and thus the object world coordinate, assuning you only want the X-Y coordinates). If you need the height measurement, then you need to find an object with a known height in your images to calibrate it too.

Upvotes: 1

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