Hi, Currently I am developing a 3D reconstruction project. Which requires images to be distortion-free (rectilinear) and with known intrinsics. The session I am developing on is a builtInDualWideCamera, with isGeometricDistortionCorrectionEnabled set to false to be able to get the intrinsic matrix of the images, isVirtualDeviceConstituentPhotoDeliveryEnabled set to true and isAutoVirtualDeviceFusionEnabled set to false to get both images and isCameraCalibrationDataDeliveryEnabled set to true to actually get the calibration data. The distortion correction parameters such as lensDistortionLookupTable are used. The 42 coefficients mapping array is used as described in the AVCameraCalibrationData header file. A simple piecewise linear interpolation. There are two questions I would like to get support on: A way to set the calibration parameters in each image. I have an approach that sets the parameters in the kCGImagePropertyExifDictionary -> "UserComment". Is there a better approach to write calibration parameter data into the images? I feel like this is a bit dirty and there might be a better and neat approach. For the ultra-wide angle camera's images, the lensDistortionLookupTable contains several zeros at the end of the array. For example (last 10 elements are zero): "LensDistortionLookupTable":"0.000000000000000,0.000349554029526,0.001385628827848,0.003071037586778,... ,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000,0.000000000000000" The problem comes when the complete array is used to correct the image (including zeros), the end result is a wrapped-like-circle image close to the edges of it which is completely wrong. In contrast, if the LensDistortionLookupTable is used without the last zeros and the new size accommodated the image looks better (although not as rectilinear as if you take the image from the iPhone's camera app), but definitely less distorted. Including zeros (full array): Excluding zeros (array size changed): Am I missing an important point in the usage of the lensDistortionLookupTable where this case is addressed (zeros at the end)? What is the criteria to shrink/exclude elements of the array? Any advice is very much welcome.

Hi everyone, I am wondering under which settings the camera(s) were set by the time they were calibrated. For instance, one aspect that is easy to find is the reference resolution of the images taken when calibrating the intrinsics, this is by retrieving intrinsicMatrixReferenceDimensions. Making sure that the principal point is referenced to the by the time resolution used when the calibration was ongoing. However, recently I saw that there are focusing modes that potentially displace the lens' physical position. Settings like: AutoFocusRangeRestriction: none, near, far setFocusModeLocked: Locks the lens position at the specified value, and sets the focus mode to a locked state. My concern lies the impact this focusing lens displacements have on the intrinsic matrix parameters, if the lens is displaced, these parameters no longer describe the camera since the lens position has changed w.r.t. the lensPosition set when they were calibrated [0-1]. If my understanding is correct the AutoFocusRangeRestriction is just a range freedom the system is allowed to auto-focus and not a specific lens position. Conversely, the setFocusModeLocked does indeed fix the lensPosition to a certain value [0 - 1]. In simple words, what is the focus lensPosition the cameras were set when calibrating them for intrnisics?

Hi everyone, I am wondering under which settings the camera(s) were set by the time they were calibrated. For instance, one aspect that is easy to find is the reference resolution of the images taken when calibrating the intrinsics, this is by retrieving intrinsicMatrixReferenceDimensions. Making sure that the principal point is referenced to the by the time resolution used when the calibration was ongoing. However, recently I saw that there are focusing modes that potentially displace the lens' physical position. Settings like: AutoFocusRangeRestriction: none, near, far setFocusModeLocked: Locks the lens position at the specified value, and sets the focus mode to a locked state. My concern lies the impact this focusing lens displacements can have on the intrinsic matrix parameters, like these parameters no longer describe the camera since the lens position has changed. In simple words, what is the focus 'mode'/'range' the cameras were set when calibrating them for intrnisics?

Hi everyone, I am working on a 3D reconstruction project. Recently I have been able to retrieve the intrinsics from the two cameras on the back of my iPhone. One consideration is that I want this app to run regardless if there is no LiDAR, but at least two cameras on the back. IF there is a LiDAR that is something I have considered to work later on the course of the project. I am using a AVCaptureSession with the two cameras AVCaptureDevice: builtInWideAngleCamera builtInUltraWideCamera The intrinsic matrices seem to be correct. However, the when I retrieve the extrinsics, e.g., builtInWideAngleCamera w.r.t. builtInUltraWideCamera the matrix I get looks like this: Extrinsic Matrix (Ultra-Wide to Wide): [0.9999968, 0.0008149305, -0.0023960583, 0.0] [-0.0008256607, 0.9999896, -0.0044807075, 0.0] [0.002392382, 0.0044826716, 0.99998707, 0.0]. [-14.277955, -8.135408e-10, -0.3359985, 0.0] The extrinsic matrix of the form: [R | t], seems to be correct for the rotational part, but the translational vector is ALL ZEROS. Which suggests that the cameras are physically overlapped as well the last element not being 1 (homogeneous coordinates). Has anyone encountered this 'issue' before? Is there a flaw in my reasoning or something I might be missing? Any comments are very much appreciated.