Freetargets

Camera optimization

Accuracy

The detection of the shot takes place in the image of the canvas captured by the camera. Whenever possible, the screen section should correspond to the aspect ratio of the monitor on which the training session is running. It is advantageous if the resolution of the displayed training unit (monitor) corresponds to the aspect ratio of the projector.

Example

  • The monitor has a resolution of 1280 x 720 pixels (aspect ratio 16:9)
  • The area of the canvas marked with the mouse and cut out is 640 x 360 pixels (aspect ratio 16:9)

If the aspect ratio is the same, in our example 16:9, then the detected shot will be scaled and rendered correctly on the monitor

Distortion

The screen should be filmed centrally from the middle whenever possible. Only then will you get a rectangular image of the screen

The more oblique the camera captures the screen, the greater the parallax distortion of the image. The pink colored area now corresponds to the size of the error, which is drawn into these corners. The result is then reflected in an offset of the real hit and its detection

Correction

Admittedly, equalizing the parallax distortion, i.e. turning the irregular square of the camera image back into a uniform rectangle, sounds tempting. Unfortunately, however, this is a bad idea. Since every single frame of the camera has to be rectified, the number of frames per second decreases and the system consumes computing power, which is then missing from the training sessions. The error persists, the camera image now looks optically better, the rectification fills the missing corners with optically similar pixels, but these have no shot detection since they do not come from the camera. We do not do “eyewashing”, if there is an error, you should see it and also be able to correct it. All measures which create a nice picture only reduce the performance and have no positive effect on the accuracy.