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Unified Diff: webrtc/modules/video_processing/util/noise_estimation.cc

Issue 1822333003: External denoiser based on noise estimation and moving object detection. (Closed) Base URL: https://chromium.googlesource.com/external/webrtc.git@master
Patch Set: Created 4 years, 9 months ago
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Index: webrtc/modules/video_processing/util/noise_estimation.cc
diff --git a/webrtc/modules/video_processing/util/noise_estimation.cc b/webrtc/modules/video_processing/util/noise_estimation.cc
new file mode 100644
index 0000000000000000000000000000000000000000..87beac38ae582e265fe35c0541aaf2c15b729179
--- /dev/null
+++ b/webrtc/modules/video_processing/util/noise_estimation.cc
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2016 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/util/noise_estimation.h"
+
+namespace webrtc {
+
+void NoiseEstimation::Init(int width, int height, CpuType cpu_type) {
+ int mb_cols = width >> 4;
+ int mb_rows = height >> 4;
+ consec_low_var_.reset(new uint32_t[mb_cols * mb_rows]());
+ width_ = width;
+ height_ = height;
+ mb_cols_ = width_ >> 4;
+ mb_rows_ = height_ >> 4;
+ cpu_type_ = cpu_type;
+}
+
+void NoiseEstimation::GetNoise(int mb_index, uint32_t var, uint32_t luma) {
+ consec_low_var_[mb_index]++;
+ num_static_block_++;
+ if (consec_low_var_[mb_index] >= kConsecLowVarFrame &&
+ (luma >> 8) < kAverageLumaMax && (luma >> 8) > kAverageLumaMin) {
+ // Normalized var by the average luma value, this gives more weight to
+ // darker blocks.
+ int nor_var = var / (luma >> 12);
+ noise_var_ +=
+ nor_var > kBlockSelectionVarMax ? kBlockSelectionVarMax : nor_var;
+ num_noisy_block_++;
+ }
+}
+
+void NoiseEstimation::ResetConsecLowVar(int mb_index) {
+ consec_low_var_[mb_index] = 0;
+}
+
+void NoiseEstimation::UpdateNoiseLevel() {
+ // TODO(jackychen): Tune a threshold for numb_noisy_block > T to make the
+ // condition more reasonable.
+ // No enough samples implies the motion of the camera or too many moving
+ // objects in the frame.
+ if (num_static_block_ < (0.65 * mb_cols_ * mb_rows_) || !num_noisy_block_) {
+ noise_var_ = 0;
+ noise_var_accum_ = 0;
+ num_static_block_ = 0;
+ num_noisy_block_ = 0;
+#if DISPLAY
+ printf("Not enough samples.\n");
+#endif
+ return;
+ } else {
+ // Normalized by the number of noisy blocks.
+ noise_var_ /= num_noisy_block_;
+ // Get the percentage of static blocks.
+ percent_static_block_ =
+ static_cast<double>(num_static_block_) / (mb_cols_ * mb_rows_);
+#if DISPLAY
+ printf("%d %d fraction = %.3f\n", num_static_block_, mb_cols_ * mb_rows_,
+ percent_static_block_);
+#endif
+ num_noisy_block_ = 0;
+ num_static_block_ = 0;
+ }
+ // For the first frame just update the value with current noise_var_,
+ // otherwise, use the averaging window.
+ if (noise_var_accum_ == 0) {
+ noise_var_accum_ = noise_var_;
+ } else {
+ noise_var_accum_ = (noise_var_accum_ * 15 + noise_var_) / 16;
+ }
+ // Reset noise_var_ for the next frame.
+ noise_var_ = 0;
+#if DISPLAY
+ printf("noise_var_accum_ = %.1f, noise_var_ = %d.\n", noise_var_accum_,
+ noise_var_);
+#endif
+}
+
+uint8_t NoiseEstimation::GetNoiseLevel() {
+ int noise_thr = cpu_type_ ? kNoiseThreshold : kNoiseThresholdNeon;
+ UpdateNoiseLevel();
+ if (noise_var_accum_ > noise_thr) {
+ return 1;
+ }
+ return 0;
+}
+
+} // namespace webrtc
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