如何使用camera2 API获取从对象到Android设备的距离 [英] How to get the distance from an object to android device using camera2 API

问题描述

我想使用android camera2 API获取从对象到android设备的距离.在CaptureCallback中，通过result.get(CaptureResult.LENS_FOCUS_DISTANCE)获取值，并同时检查LENS_STATE, CONTROL_AF_MODE, CONTROL_AF_STATE.它们是"STATIONARY"，CONTINUOUS_PICTURE和PASSIVE_FOCUSED.我认为焦点距离应该是有效的，并且从对象到Android设备的距离应该为1/focus_distance.但实际上，计算出的值与实际距离完全不同.它出什么问题了? LENS_FOCUS_DISTANCE是距离估计的正确值吗?有人知道吗?

I want to get the distance from an object to android device using android camera2 API. In CaptureCallback, I get the value by result.get(CaptureResult.LENS_FOCUS_DISTANCE) and check LENS_STATE, CONTROL_AF_MODE, CONTROL_AF_STATE at the same time. They are "STATIONARY", CONTINUOUS_PICTURE and PASSIVE_FOCUSED. I think the focus distance should be valid and the distance from an object to android device should be 1/focus_distance. But in fact the calculated value is totally different from the actual distance. What's wrong with it? Is LENS_FOCUS_DISTANCE the correct value for distance estimation? Anyone have idea?

final CameraCaptureSession.CaptureCallback captureCallbackListener = new CameraCaptureSession.CaptureCallback() {
    @Override
    public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
        super.onCaptureCompleted(session, request, result);
        Log.e(TAG, String.format("captureCallbackListener %s-%f", lensStateToString(result.get(CaptureResult.LENS_STATE)), result.get(CaptureResult.LENS_FOCUS_DISTANCE) ));
        Log.e(TAG, String.format("AF mode %s-%s", ctlAfModeToString(result.get(CaptureResult.CONTROL_AF_MODE)), ctlAfStateToString(result.get(CaptureResult.CONTROL_AF_STATE)) ));
    }
};

推荐答案

请检查

Please check the value of CameraCharacteristics.LENS_INFO_FOCUS_DISTANCE_CALIBRATION. If it's UNCALIBRATED or APPROXIMATE, then the value of LENS_FOCUS_DISTANCE will likely not be close to reality.

即使使用校准"，物体越远，误差就越大-对于相机而言，超过超焦距(最多几米)的所有物体都开始无法精确测量到的距离.

And even with CALIBRATED, the farther objects are, the more error there will be - to the camera, everything past the hyperfocal distance (a few meters at best) starts being impossible to accurately measure distance to.

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