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