How reliable is the camera for the Android2 CameraCharacteristics API for sensor size?

Question

I am trying to get / compute FOV for device cameras using the camera2API my code below).

During my attempt on galaxy S7:

• this sensor size is 3.2 mm x 2.4 mm (using SENSOR_INFO_PHYSICAL_SIZE).
• In this case, my calculated HFOV is 41.7 ° (the given focal length is 4.2 mm), which I proved wrong by experimenting.
• Different specifications indicate the size of the sensor 1 / 2.5 "(5.76 mm x 4.29 mm according to wikipedia ) - which would give me an HFOV of 68.9 °, closer to my experiments.
• the values ​​in CameraCharacteristicsseem wrong.

The same queries and experiments on the Samsung Galaxy A3-2016 are more convincing, the calculated HFOV seems to correspond to the experimental one.

Does anyone have experience or data to exchange information about the reliability of the testimony CameraCharacteristics?

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The code I used to query CameraCharacteristics::

CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraID);
if (characteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_FRONT)
    continue;

int support = characteristics.get(CameraCharacteristics.INFO_SUPPORTED_HARDWARE_LEVEL);
if( support == CameraMetadata.INFO_SUPPORTED_HARDWARE_LEVEL_LEGACY )
    Log.d("mr", "Camera " + cameraID + " has LEGACY Camera2 support");
else if( support == CameraMetadata.INFO_SUPPORTED_HARDWARE_LEVEL_LIMITED )
    Log.d("mr", "Camera " + cameraID + " has LIMITED Camera2 support");
else if( support == CameraMetadata.INFO_SUPPORTED_HARDWARE_LEVEL_FULL )
    Log.d("mr", "Camera " + cameraID + " has FULL Camera2 support");
else
    Log.d("mr", "Camera " + cameraID + " has unknown Camera2 support?!");

// voir http://myandroidarchive.tistory.com/5 pour le query android
// voir http://paulbourke.net/miscellaneous/lens/ pour les maths
// include every focal length supported by the camera device, in ascending order.
float[] focalLengths = characteristics.get(CameraCharacteristics.LENS_INFO_AVAILABLE_FOCAL_LENGTHS);
SizeF sensorSize = characteristics.get(CameraCharacteristics.SENSOR_INFO_PHYSICAL_SIZE);

float w = 0.5f * sensorSize.getWidth();
float h = 0.5f * sensorSize.getHeight();
Log.d("mr", "Camera " + cameraID + " has sensorSize == " + Float.toString(2.0f*w) + ", " + Float.toString(2.0f*h));
for (int focusId=0; focusId<focalLengths.length; focusId++) {
    float focalLength = focalLengths[focusId];
    float horizonalAngle = (float) Math.toDegrees(2 * Math.atan(w / focalLength));
    float verticalAngle = (float) Math.toDegrees(2 * Math.atan(h / focalLength));
    Log.d("mr", "Camera " + cameraID + "/f" + focusId + " has focalLength == " + Float.toString(focalLength));
    Log.d("mr", "  * horizonalAngle == " + Float.toString(horizonalAngle));
    Log.d("mr", "  * verticalAngle == " + Float.toString(verticalAngle));
}

Answer 1

Scanbot developer is here (otherwise I worked with the camera enough).

Camera API , API . , API , ( Android SDK), Google.