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Camera2 调整亮度

  1. 拍摄时调整预览亮度

使用seekbar 调整拍摄时 亮度,找了很久 最后 在 stakeOverflow中找到调整亮度的方法 其中 exposureAdjustment  的 取值范围: - 1 至 1

private double exposureAdjustment = 0.0;
public void setExposure() {
Range<Integer> range1 = characteristics.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 (mPreviewBuilder != null) {
mPreviewBuilder.set(CaptureRequest.CONTROL_AE_EXPOSURE_COMPENSATION, (int) newCalculatedValue);
updatePreview();
}
}
}

  2. 调整初始预览的亮度

ps: 部分设备Camera2预览亮度正常,部分很灰暗,调整FPS就可以,
但需要注意的是,有些低级的设备,虽然能获取到支持的 FPS_RANGES,但是当切到最大帧率时,会很灰暗,
网上流传的代码,通常是FPS小于10的忽略,但是这个FPS合适的值要看个人测试设备,有必要调整一下设定FPS的筛选条件
//自动对焦
previewBuilder.set(CaptureRequest.CONTROL_AF_MODE,CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);
previewBuilder.set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, getFPSRange());
// 对焦触发器设置为空闲状态
previewBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CaptureRequest.CONTROL_AF_TRIGGER_IDLE);


private Range<Integer> getFPSRange() {
    CameraManager mCameraManager = (CameraManager) context.getSystemService(Context.CAMERA_SERVICE);
    CameraCharacteristics chars = null;
    try {
        chars = mCameraManager.getCameraCharacteristics(mCameraManager.getCameraIdList()[0]);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
    Range<Integer>[] ranges = chars.get(CameraCharacteristics.CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES);

    Range<Integer> result = null;

    if (getAndroidVersion() < 26 && ranges.length > 0) {
            // 版本低于8.0,使用中间的帧率
            result = ranges[ranges.length / 2];
            return result;
        }
    for (Range<Integer> range : ranges) {
        //帧率不能太低,大于10
        if (range.getLower() <  10)
            continue;
        if (result==null)
            result = range;
            //FPS下限小于15,弱光时能保证足够曝光时间,提高亮度。range范围跨度越大越好,光源足够时FPS较高,预览更流畅,光源不够时FPS较低,亮度更好。
        else if (range.getLower()<=15 && (range.getUpper()-range.getLower())>(result.getUpper()-result.getLower()))
            result = range;
    }
    return null == result ? ranges[0] : result;
}
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posted @ 2021-02-23 09:02  人间春风意  阅读(914)  评论(0)    收藏  举报