Get Vision Sensor intrinsic and extrinsic parameters

[ayushpatel14]

I have a scene with some aruco markers on it, I wish to estimate its pose for which vision_sensors intrinsic and extrinsic parameters are required. I can get focal distance and resolution of the sensor from object properties but can't use them directly since focal distance needs to be in 'pixel' (that too for 2 axes i.e fx and fy). Also, I am not sure if there is distortion in the vision_sensor(currently hardcoded the values to 0).
The required values are focal length, optical centres in x,y(in pixels) and the distortion coefficients.
How can I get the parameters of vision_sensor?

[coppelia]

Hello,

Focal length only makes sense with optical camera. OpenGl uses the angle of view. There can be an horizontal and vertical angle of view, since an image does not have to be quadratic, but can be rectangular.
Have a look at this topic for additional details.

Cheers

[ayushpatel14]

Hello,

1. How do I find the horizontal and vertical FOV? Can I use this formula to calculate the focal length in pixels?

''you have a right-angle triangle, with half the FOV as one of the angles (a), and half your image size as the opposite side (A). To calculate the focal length F, use tan(a) = A/F,
which gives F = A/tan(a)''
https://photo.stackexchange.com/questio ... ze-and-fov

2. What does this 'focaldist' denote?
https://drive.google.com/file/d/1TgPxqf ... sp=sharing

thanks

[coppelia]

Check the second link I previously mentioned. That link also links to another topic. There you have it.

focaldist in the extension string is used by the POV-Ray rendering plugin.

Cheers