在主摄像机中设置一个固定的焦点值(Android )

Question

我正在为我的项目开发一个应用程序，我不希望我的主相机有自动对焦。我希望我的相机有一个特定的焦点值，它可以聚焦在离主相机大约5-10厘米的物体上。

下面是关于如何实现CameraManager的代码：

private String chooseCamera() {
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
      for (final String cameraId : manager.getCameraIdList()) {
        final CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);

        // We don't use a front facing camera in this sample.
        final Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
        if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) {
          continue;
        }

        final StreamConfigurationMap map =
                characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);

        if (map == null) {
          continue;
        }

        // Fallback to camera1 API for internal cameras that don't have full support.
        // This should help with legacy situations where using the camera2 API causes
        // distorted or otherwise broken previews.
        useCamera2API =
                (facing == CameraCharacteristics.LENS_FACING_FRONT)
                        || isHardwareLevelSupported(
                        characteristics);
        LOGGER.i("Camera API lv2?: %s", useCamera2API);

//        manager.setTorchMode(cameraId, true);
        return cameraId;
      }
    } catch (CameraAccessException e) {
      LOGGER.e(e, "Not allowed to access camera");
    }
    return null;
  }

protected void setFragment() {
  String cameraId = chooseCamera();
  Fragment fragment;
  if (useCamera2API) {
     CameraConnectionFragment camera2Fragment =
        CameraConnectionFragment.newInstance(
                      (size, rotation) -> {
                        previewHeight = size.getHeight();
                        previewWidth = size.getWidth();
                        CameraActivity.this.onPreviewSizeChosen(size, rotation);
                      },
                      this,
                      getLayoutId(),
                      getDesiredPreviewFrameSize());

      camera2Fragment.setCamera(cameraId);
      fragment = camera2Fragment;
    } else {
      fragment =
              new LegacyCameraConnectionFragment(this, getLayoutId(), getDesiredPreviewFrameSize());
    }

    getFragmentManager().beginTransaction().replace(R.id.container, fragment).commit();
}

Answer 1

您需要首先使用CaptureRequest.CONTROL_AF_MODE关闭自动焦点，然后使用该请求键CaptureRequest.LENS_FOCUS_DISTANCE设置所需的焦点距离值。

若要了解设备是否支持手动传感器，请查询特征并检查是否支持。https://developer.android.com/reference/android/hardware/camera2/CameraMetadata#REQUEST_AVAILABLE_CAPABILITIES_MANUAL_SENSOR