/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/video_processing/brightness_detection.h"
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#include <math.h>
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#include "webrtc/modules/video_processing/include/video_processing.h"
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namespace webrtc {
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VPMBrightnessDetection::VPMBrightnessDetection() {
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Reset();
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}
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VPMBrightnessDetection::~VPMBrightnessDetection() {}
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void VPMBrightnessDetection::Reset() {
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frame_cnt_bright_ = 0;
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frame_cnt_dark_ = 0;
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}
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int32_t VPMBrightnessDetection::ProcessFrame(
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const VideoFrame& frame,
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const VideoProcessing::FrameStats& stats) {
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if (frame.IsZeroSize()) {
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return VPM_PARAMETER_ERROR;
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}
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int width = frame.width();
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int height = frame.height();
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if (!VideoProcessing::ValidFrameStats(stats)) {
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return VPM_PARAMETER_ERROR;
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}
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const uint8_t frame_cnt_alarm = 2;
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// Get proportion in lowest bins.
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uint8_t low_th = 20;
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float prop_low = 0;
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for (uint32_t i = 0; i < low_th; i++) {
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prop_low += stats.hist[i];
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}
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prop_low /= stats.num_pixels;
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// Get proportion in highest bins.
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unsigned char high_th = 230;
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float prop_high = 0;
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for (uint32_t i = high_th; i < 256; i++) {
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prop_high += stats.hist[i];
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}
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prop_high /= stats.num_pixels;
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if (prop_high < 0.4) {
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if (stats.mean < 90 || stats.mean > 170) {
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// Standard deviation of Y
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const uint8_t* buffer = frame.buffer(kYPlane);
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float std_y = 0;
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for (int h = 0; h < height; h += (1 << stats.sub_sampling_factor)) {
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int row = h * width;
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for (int w = 0; w < width; w += (1 << stats.sub_sampling_factor)) {
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std_y +=
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(buffer[w + row] - stats.mean) * (buffer[w + row] - stats.mean);
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}
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}
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std_y = sqrt(std_y / stats.num_pixels);
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// Get percentiles.
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uint32_t sum = 0;
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uint32_t median_y = 140;
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uint32_t perc05 = 0;
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uint32_t perc95 = 255;
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float pos_perc05 = stats.num_pixels * 0.05f;
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float pos_median = stats.num_pixels * 0.5f;
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float posPerc95 = stats.num_pixels * 0.95f;
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for (uint32_t i = 0; i < 256; i++) {
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sum += stats.hist[i];
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if (sum < pos_perc05)
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perc05 = i; // 5th perc.
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if (sum < pos_median)
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median_y = i; // 50th perc.
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if (sum < posPerc95)
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perc95 = i; // 95th perc.
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else
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break;
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}
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// Check if image is too dark
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if ((std_y < 55) && (perc05 < 50)) {
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if (median_y < 60 || stats.mean < 80 || perc95 < 130 ||
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prop_low > 0.20) {
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frame_cnt_dark_++;
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} else {
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frame_cnt_dark_ = 0;
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}
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} else {
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frame_cnt_dark_ = 0;
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}
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// Check if image is too bright
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if ((std_y < 52) && (perc95 > 200) && (median_y > 160)) {
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if (median_y > 185 || stats.mean > 185 || perc05 > 140 ||
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prop_high > 0.25) {
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frame_cnt_bright_++;
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} else {
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frame_cnt_bright_ = 0;
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}
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} else {
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frame_cnt_bright_ = 0;
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}
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} else {
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frame_cnt_dark_ = 0;
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frame_cnt_bright_ = 0;
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}
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} else {
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frame_cnt_bright_++;
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frame_cnt_dark_ = 0;
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}
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if (frame_cnt_dark_ > frame_cnt_alarm) {
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return VideoProcessing::kDarkWarning;
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} else if (frame_cnt_bright_ > frame_cnt_alarm) {
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return VideoProcessing::kBrightWarning;
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} else {
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return VideoProcessing::kNoWarning;
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}
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}
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} // namespace webrtc
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