[Camera]: Proposal to expose Intrinsic parameters like Focal Length and Principal Points in Flutter

[smoothumut]

We are going to develop a mobile app that is going to take photos. But the app is supposed to get camera's intrinsic parameters like focal length and principal points in order to help us to calibrate and process the images we take. If it is already available, I will be really appreciated if you point it out, But if not available, it would be great to have that info in order to go deep in photography with flutter for our case and other use cases.

[iapicca]

@smoothumut
some info are already available (see example)

  double _minAvailableExposureOffset = 0.0;
  double _maxAvailableExposureOffset = 0.0;
  double _currentExposureOffset = 0.0;
// 
  double _minAvailableZoom = 1.0;
  double _maxAvailableZoom = 1.0;
  double _currentScale = 1.0;

but it would be nice if more of the api would be exposed

[darshankawar]

Related to #31225

[dgmouris]

I would love to see a simple way to get focal distance and sensor height as well.

Thanks folks for your hard work on this package:)

[etozzato]

Yesterday I started messing with the camera and camera_platform_interface plugin and exposing lensAperture was a breeze (low hanging fruit!) - we are also looking at exposing a few new parameters and the depth map;

We'll probably create a new plugin that extends the existing, since the first concern is to maintain compatibility with the core plugins!

Ping me if you want to join forces!

[etozzato]

I have been pinged about the previous comment! Depth is done.
I've made enormous progress on the iOS front, almost nothing on the android side :(
This could be useful snippet - it assumes that depth capture is supported and enabled and that we have the color capture in scope as uiimage

  AVDepthData *depthData = [photo depthData];
  if (depthData != nil) {
    @try {
      // intrinsicMatrix
      AVCameraCalibrationData *calibrationData = [depthData cameraCalibrationData];
      CGFloat pixelSize = [calibrationData pixelSize];
      matrix_float3x3 intrinsicMatrix = [calibrationData intrinsicMatrix];
      CGSize referenceDimensions = [calibrationData intrinsicMatrixReferenceDimensions];
      CGFloat photoWidth = uiimage.size.width;
      CGFloat photoHeight = uiimage.size.height;
      CGFloat ratio = referenceDimensions.height / photoWidth;

      CGFloat fx = intrinsicMatrix.columns[1][1] / ratio;
      CGFloat fy = intrinsicMatrix.columns[0][0] / ratio;
      CGFloat cx = photoWidth - intrinsicMatrix.columns[2][1] / ratio;
      CGFloat cy = intrinsicMatrix.columns[2][0] / ratio;

It has been a painful but fun trial & error adventure, I hope we'll be able to release the final work as a camera++ plugin early next year!