Question

我正在将相机应用程序从camera1迁移到camera2。我在Motorola G5和Samsung Galaxy S4上遇到了一个奇怪的问题，它们的闪光灯模式处于开启状态，每次我点击预览视图进行手动对焦时，闪光灯都会闪光。

有人遇到同样的问题吗？这是我用于点击聚焦功能的代码：

        val focusAreaTouch = calculateFocusArea(pointOfInterestX, pointOfInterestY, sensorArraySize)

        //cancel any existing AF trigger
        previewRequestBuilder?.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL)
        previewRequestBuilder?.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_OFF)

        try {
            captureSession?.capture(previewRequestBuilder?.build(), captureCallback, null)
        }catch (ex: Exception) {
            Log.e(TAG, "Tap To Focus -> Failed to cancel any existing AF trigger.", ex)
        }

        Log.e(TAG, "AF Regions: " + previewRequestBuilder?.get(CaptureRequest.CONTROL_AF_REGIONS)?.first()?.rect)

        //Then we add a new AF trigger with focus region
        previewRequestBuilder?.set(CaptureRequest.CONTROL_AF_REGIONS, arrayOf(focusAreaTouch))

        previewRequestBuilder?.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO)
        previewRequestBuilder?.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO)
        previewRequestBuilder?.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START)

这是我检查AE状态的方法：

private fun process(result: CaptureResult) {
    when (state) {
        CameraState.STATE_LOCKING -> {
            val af = result.get(CaptureResult.CONTROL_AF_STATE) ?: return
            if (af == CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED
                    || af == CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED
                    || af == CaptureResult.CONTROL_AF_STATE_PASSIVE_FOCUSED) {
                val ae = result.get(CaptureResult.CONTROL_AE_STATE)
                if (ae == null || ae == CaptureResult.CONTROL_AE_STATE_CONVERGED) {
                    state = CameraState.STATE_CAPTURING
                    onReady()
                } else {
                    state = CameraState.STATE_LOCKED
                    onPreCaptureRequired()
                }
            }
        }
        CameraState.STATE_PRECAPTURE -> {
            val ae = result.get(CaptureResult.CONTROL_AE_STATE)
            if (ae == null || ae == CaptureResult.CONTROL_AE_STATE_PRECAPTURE ||
                    ae == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED ||
                    ae == CaptureResult.CONTROL_AE_STATE_CONVERGED) {
                state = CameraState.STATE_WAITING
            }
        }
        CameraState.STATE_WAITING -> {
            val ae = result.get(CaptureResult.CONTROL_AE_STATE)
            if (ae == null || ae != CaptureResult.CONTROL_AE_STATE_PRECAPTURE) {
                state = CameraState.STATE_CAPTURING
                onReady()
            }
        }
    }
}

Answer 1

原因是如果您还设置了自动曝光，则自动曝光算法会根据需要根据当前的光照条件适当地调整曝光，从而触发闪光灯。

要解决此问题，请为预览和照片捕获会话分别处理Flash配置。使用下一个功能配置您的请求构建器。

调用 setFlash（）时有4个地方。请注意，该方法仅设置给定的构建器Flash配置，您仍然需要将构建器传递给目标会话。对于预览会话，将作为重复请求。

在最初配置预览时，将 isPreviewSession 设置为 True ，因此诸如点击聚焦之类的操作不会触发Flash。
拍照时，就在用户按下快门按钮时，使用 isPreviewSession 设置配置预览请求构建器 设为 False 。将其设置为 False 意味着这次 Preview构建器实际上将具有所需的目标Flash配置，因此 Capture Session Callback （捕获会话回调）知道何时焦点， AE等使用目标闪光灯配置收敛 AE算法可能需要。
然后，在融合并准备开始捕获会话时，致电再次 setFlash 传递了从 cameraDevice。 createCaptureRequest（CameraDevice.TEMPLATE_STILL_CAPTURE），再次将 isPreviewSession 设置为 False 。
最后，当捕获结束时，在通知的回调中关于捕获完成，必须再次重新配置预览请求构建器 但这一次将 isPreviewSession 设置为 True ，因此闪光灯状态再次设置为“关闭”。

static final int FLASH_MODE_OFF = 0;
static final int FLASH_MODE_AUTO = 1;
static final int FLASH_MODE_ON = 2;
static final int FLASH_MODE_TORCH = 3;


public void setFlash(@NonNull final CaptureRequest.Builder builder, 
                             final boolean isPreviewSession, final int flashMode)
{
    if (isPreviewSession == true)
    {
        // For preview session

        builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON);

        if (flashMode == FLASH_MODE_TORCH)
        {
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_TORCH);
        }
        else
        {
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
        }
    }
    else
    {
        // For capture session

        if (flashMode == FLASH_MODE_OFF)
        {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
        }
        else if (flashMode == FLASH_MODE_AUTO)
        {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_AUTO_FLASH);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
        }
        else if (flashMode == FLASH_MODE_ON)
        {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON_ALWAYS_FLASH);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_SINGLE);
        }
        else if (flashMode == FLASH_MODE_TORCH)
        {
            builder.set(CaptureRequest.CONTROL_AE_MODE, CameraMetadata.CONTROL_AE_MODE_ON);
            builder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_TORCH);
        }
    }
}

闪光灯问题

1 个答案: