无法让 Camera2 API 触摸以专注于工作

Question

我无法在 Camera2 API 上获得对焦以正常工作。触摸时，我似乎只集中了一秒钟，然后变得非常模糊。手机是 Nexus 5X。这是我的触摸对焦代码。

private void refocus(MotionEvent event, View view){

    //Handler for autofocus callback
    CameraCaptureSession.CaptureCallback captureCallbackHandler = new CameraCaptureSession.CaptureCallback() {
        @Override
        public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
            super.onCaptureCompleted(session, request, result);

            if (request.getTag() == "FOCUS_TAG") {
                //the focus trigger is complete -
                //resume repeating (preview surface will get frames), clear AF trigger
                previewRequest.set(CaptureRequest.CONTROL_AF_TRIGGER, null);
                try{
                    mSession.setRepeatingRequest(previewRequest.build(), null, null);}
                catch (Exception e){

                }
            }
        }

        @Override
        public void onCaptureFailed(CameraCaptureSession session, CaptureRequest request, CaptureFailure failure) {
            super.onCaptureFailed(session, request, failure);
            Log.e(TAG, "Manual AF failure: " + failure); }
    };

    try {
        final Rect sensorArraySize = manager.getCameraCharacteristics(mCameraDevice.getId()).get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);

        //Find area size
        int x = (int)(event.getX()/(float)view.getWidth() * (float)sensorArraySize.width());
        int y = (int)(event.getY()/(float)view.getHeight() * (float)sensorArraySize.height());
        final int halfTouchWidth  = 150; //(int)motionEvent.getTouchMajor(); //TODO: this doesn't represent actual touch size in pixel. Values range in [3, 10]...
        final int halfTouchHeight = 150; //(int)motionEvent.getTouchMinor();
        MeteringRectangle rect = new MeteringRectangle(Math.max(x - halfTouchWidth,  0),
                Math.max(y - halfTouchHeight, 0),
                halfTouchWidth  * 2,
                halfTouchHeight * 2,
                MeteringRectangle.METERING_WEIGHT_MAX - 1);
        mSession.stopRepeating();
        transparentLayer.drawFeedback(rect);

        //Cancel requests
        previewRequest.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);
        previewRequest.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_OFF);
        mSession.capture(previewRequest.build(), captureCallbackHandler, null);

        //Now add a new AF trigger with focus region
        if (isMeteringAreaAFSupported()) {
            previewRequest.set(CaptureRequest.CONTROL_AF_REGIONS, new MeteringRectangle[]{rect});
        }
        previewRequest.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
        previewRequest.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO);
        previewRequest.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);
        previewRequest.setTag("FOCUS_TAG"); //we'll capture this later for resuming the preview

        //then we ask for a single request (not repeating!)
        mSession.capture(previewRequest.build(), captureCallbackHandler, null);

    }catch (Exception e){
        e.printStackTrace();
    }

}

还有另一个辅助函数：

private boolean isMeteringAreaAFSupported() {
    try {
        return manager.getCameraCharacteristics(mCameraDevice.getId()).get(CameraCharacteristics.CONTROL_MAX_REGIONS_AF) >= 1;
    }catch (Exception e){
        return false;
    }
}

焦点工作了片刻，然后重新启动或变得完全模糊的可能原因是什么？我找不到任何有用的解决方案。

谢谢大家！

Answer 1

我会尝试在 onCaptureCompleted 中将 AF_TRIGGER 设置为 IDLE - 完全删除它并不是完全指定的。

除此之外，我不清楚您如何将屏幕触摸坐标转换为测光区域的相机active array coordinates。看起来你假设坐标是相同的，这是不正确的。这不应该导致模糊，但会导致您专注于与您想象的不同的区域。

您需要正确缩放 x 和 y（基于当前的crop region，它定义了使用数字缩放时的可见视野，以及活动阵列矩形）