如何在 Android 上的 Camera2 API 中设置“CONTROL_AE_EXPOSURE_COMPENSATION”？

Question

我目前正在开发 Androids Camera 2 API，我目前的问题是，我无法设置“CONTROL_AE_EXPOSURE_COMPENSATION”。

我的代码：

-1.0

public void setExposure(double exposureAdjustment) {
    Range<Integer> range1 = mCameraCharacteristics.get(CameraCharacteristics.CONTROL_AE_COMPENSATION_RANGE);
    int minExposure = range1.getLower();
    int maxExposure = range1.getUpper();

    float newCalculatedValue = 0;
    if (exposureAdjustment >= 0) {
        newCalculatedValue = (float) (minExposure * exposureAdjustment);
    } else {
        newCalculatedValue = (float) (maxExposure * -1 * exposureAdjustment);
    }

    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_EXPOSURE_COMPENSATION, (int) newCalculatedValue);
}

不幸的是，它不起作用。

Answer 1

我找到了一个适合我的解决方案。其中exposureAdjustment 参数介于 -1 到 +1 之间。

public void setExposure(double exposureAdjustment) {
    Range<Integer> range1 = mCameraCharacteristics.get(CameraCharacteristics.CONTROL_AE_COMPENSATION_RANGE);

    int minExposure = range1.getLower();
    int maxExposure = range1.getUpper();

    if (minExposure != 0 || maxExposure != 0) {
        float newCalculatedValue = 0;
        if (exposureAdjustment >= 0) {
            newCalculatedValue = (float) (minExposure * exposureAdjustment);
        } else {
            newCalculatedValue = (float) (maxExposure * -1 * exposureAdjustment);
        }

        if (mPreviewRequestBuilder != null) {
            try {
                CaptureRequest captureRequest = mPreviewRequestBuilder.build();
                mCaptureSession.setRepeatingRequest(captureRequest, camera2FocusMeteringManager.mCaptureCallbackListener, mBackgroundHandler);
                mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_EXPOSURE_COMPENSATION, (int) newCalculatedValue);
                mCaptureSession.capture(captureRequest, camera2FocusMeteringManager.mCaptureCallbackListener, mBackgroundHandler);
            } catch (CameraAccessException e) {
            }
        }
    }
}

我通过我的mPreviewRequestBuilder（捕获请求的构建器）为每次曝光调整构建一个新的CaptureRequest。

Here 你可以找到完整的 Camera2 示例。