Intrinsics for iOS devices and the Structure Sensor + Depth -> Point Cloud info


#1

Consolidating information about IR and Color camera intrinsics discussed in various forum posts. Also linking to threads discussing calculation of point cloud data from depth frames.

Depth / Infrared Intrinsics for the Structure Sensor:
Focal Length in Pixels = 285.25 for QVGA, 570.5 VGA
Principal Point = (160, 120) for QVGA, (320, 240) for VGA
Distortion K1 = -0.024 (K2 = 0)

Color Intrinsics assuming VGA resolution:
iPad Air 1
Focal length in pixels = 582
Center = 320x240
K1, K1 Distortion = 0.124, -0.214

iPad Air 2
Focal length in pixels = 578
Center = 320x240
K1, K1 Distortion = 0.126, -0.236

For 2592x1936:
Multiply Focal length and Center by 4.05 to go from VGA to 2592x1936.

Forum threads on Point Cloud from Frames

@9gel’s awesome contribution:


Take an static image and then measuring the distance
How should you build a single Point Cloud dataset from multiple frames of depth data?
Retrieve / update calibration parameters with SDK
Scan resolution question
Generating Point Cloud for analysis
#2

Hi Jim

Is there a known set of Color Intrinsics for iPhone 6s.

Thanks


#3

Here you go:

iPhone 6s
Focal length in pixels = 540
Center = 320, 240
K1, K1 Distortion = 0.100, -0.172

-Jim


#4

Works like a charm. Thank you Jim


#5

Hello @jim_selikoff, Do you have the focal length, aperture, and sensorAspectRatio for an early 2016 iPadPro’s rear camera? The model number is MLMV2ZP/A.

I have spent lots of time on the web looking for a clear anwser… Hopefully you can help me too :).


#6

This could help you out with a couple of things, like focal length: https://developer.apple.com/documentation/avfoundation/avcameracalibrationdata

Aperture: https://developer.apple.com/documentation/avfoundation/avcapturedevice/1624589-lensaperture

Basic camera information: https://developer.apple.com/library/archive/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/Cameras/Cameras.html


#7

Hi @anthony.monaco, I found the aperture information with the above links. But, still missing are focal length and sensor aspect ratio.Maybe they mentioned in other terms??


#8

Hi Paul,

Maybe ARCamera.intrinsics and ARCamera.cameraResolution could help?

https://developer.apple.com/documentation/arkit/arcamera/2875730-intrinsics

Best regards,

Jim


#9

Hi, I wonder what is the intrinsic for structure core? is it the same?