无法使Camera2 API正常工作 [英] Cannot get Camera2 API touch to focus to work

问题描述

我无法集中精力在Camera2 API上正常工作.在触摸时，我似乎只专注了一秒钟，然后变得非常模糊.手机是Nexus 5X.这是我的触摸重点代码.

I'm unable to get the touch to focus to work properly on Camera2 API. On touching I just seem to focus for a second and then it becomes extremely blurred. The phone is a Nexus 5X. Here is my code for touch to focus.

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();
    }

}

还具有另一个帮助功能:

Also have another helper function:

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

聚焦工作一小会儿，然后重新启动，或者变得完全模糊，可能是什么原因?我找不到能帮助您的解决方案.

What could be the possible reason for the focus working for a brief second, and then restarting, or getting completely blurry? There is no solution that I can find which is helpful.

谢谢！

推荐答案

我会尝试在onCaptureCompleted中将AF_TRIGGER设置为IDLE-完全删除它的方法并不完全明确.

I would try setting AF_TRIGGER to IDLE in onCaptureCompleted - removing it entirely isn't totally well-specified.

除此之外，我不清楚您如何将屏幕触摸坐标转换为相机有效区域坐标(针对测光区域).您似乎在假设坐标是相同的，这是不正确的.那不会引起模糊，但是会导致您将注意力集中在与您想像的区域不同的地方.

Beyond that, it's not clear to me how you're converting from the screen touch coordinates to the camera active array coordinates for the metering regions. It looks like you're assuming the coordinates are identical, which isn't true. That shouldn't cause blurriness, but will cause you to focus on a different area than you think.

您需要正确缩放x和y(基于当前裁剪区域，它定义了使用数字缩放时的可见视野，以及活动数组矩形)

You need to scale the x and y correctly (based on the current crop region which defines the visible field of view when using digital zoom, and the active array rectangle)

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