android - 如何计算arcore中的视野？

Question

在使用 arcore 时，是否有可用于访问相机视野(“FoV”、“视角”)的属性或方法？

根据一些实验，FoV 似乎通常约为 60 度，但据推测这会因设备硬件而异。

如果不能直接访问，有没有办法从任何相机对象属性计算 FoV 角度，例如 View 矩阵？

Answer 1

ARCore 库 v1.8.0 不返回 FoV 值。相反，您可以使用 Camera 参数计算它:

val frame = session.update()
val camera = frame.camera
val imageIntrinsics = camera.imageIntrinsics

val focalLength = imageIntrinsics.focalLength[0]
val size = imageIntrinsics.imageDimensions
val w = size[0]
val h = size[1]

val fovW = Math.toDegrees(2 * Math.atan(w / (focalLength * 2.0)))
val fovH = Math.toDegrees(2 * Math.atan(h / (focalLength * 2.0)))

另一种使用 Camera2 API 的解决方案:

val cameraId = session.cameraConfig.cameraId

val cameraManager = context.getSystemService(Context.CAMERA_SERVICE) as CameraManager
val characteristics = cameraManager.getCameraCharacteristics(cameraId)

val maxFocus = characteristics.get(CameraCharacteristics.LENS_INFO_AVAILABLE_FOCAL_LENGTHS)
val size = characteristics.get(CameraCharacteristics.SENSOR_INFO_PHYSICAL_SIZE)
val w = size.width
val h = size.height

val fovW = Math.toDegrees(2 * Math.atan(w / (maxFocus[0] * 2.0)))
val fovH = Math.toDegrees(2 * Math.atan(h / (maxFocus[0] * 2.0)))