COMPMID-344 Updated doxygen
Change-Id: I32f7b84daa560e460b77216add529c8fa8b327ae
diff --git a/src/runtime/CL/functions/CLEqualizeHistogram.cpp b/src/runtime/CL/functions/CLEqualizeHistogram.cpp
new file mode 100644
index 0000000..3b182d3
--- /dev/null
+++ b/src/runtime/CL/functions/CLEqualizeHistogram.cpp
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2016, 2017 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "arm_compute/runtime/CL/functions/CLEqualizeHistogram.h"
+
+#include "arm_compute/core/CL/ICLDistribution1D.h"
+#include "arm_compute/core/CL/ICLLut.h"
+#include "arm_compute/core/CL/OpenCL.h"
+#include "arm_compute/core/Types.h"
+#include "arm_compute/runtime/CL/CLScheduler.h"
+
+#include <algorithm>
+#include <cmath>
+#include <cstddef>
+#include <numeric>
+
+using namespace arm_compute;
+
+namespace
+{
+void calculate_cum_dist_and_lut(CLDistribution1D &dist, CLDistribution1D &cum_dist, CLLut &lut)
+{
+ dist.map(true);
+ cum_dist.map(true);
+ lut.map(true);
+
+ const uint32_t *dist_ptr = dist.buffer();
+ uint32_t *cum_dist_ptr = cum_dist.buffer();
+ uint8_t *lut_ptr = lut.buffer();
+
+ ARM_COMPUTE_ERROR_ON(dist_ptr == nullptr);
+ ARM_COMPUTE_ERROR_ON(cum_dist_ptr == nullptr);
+ ARM_COMPUTE_ERROR_ON(lut_ptr == nullptr);
+
+ // Calculate cumulative distribution
+ std::partial_sum(dist_ptr, dist_ptr + 256, cum_dist_ptr);
+
+ // Get the number of pixels that have the lowest value in the input image
+ const uint32_t num_lowest_pixels = *std::find_if(dist_ptr, dist_ptr + 256, [](const uint32_t &v)
+ {
+ return v > 0;
+ });
+ const size_t image_size = cum_dist_ptr[255];
+
+ if(image_size == num_lowest_pixels)
+ {
+ std::iota(lut_ptr, lut_ptr + 256, 0);
+ }
+ else
+ {
+ const float diff = image_size - num_lowest_pixels;
+
+ for(size_t i = 0; i < 256; ++i)
+ {
+ lut_ptr[i] = lround((cum_dist_ptr[i] - num_lowest_pixels) / diff * 255.f);
+ }
+ }
+
+ dist.unmap();
+ cum_dist.unmap();
+ lut.unmap();
+}
+} // namespace
+
+CLEqualizeHistogram::CLEqualizeHistogram()
+ : _histogram_kernel(), _border_histogram_kernel(), _map_histogram_kernel(), _hist(nr_bins, 0, max_range), _cum_dist(nr_bins, 0, max_range), _cd_lut(nr_bins, DataType::U8)
+{
+}
+
+void CLEqualizeHistogram::configure(const ICLImage *input, ICLImage *output)
+{
+ _histogram_kernel.configure(input, &_hist);
+ _border_histogram_kernel.configure(input, &_hist);
+ _map_histogram_kernel.configure(input, &_cd_lut, output);
+}
+
+void CLEqualizeHistogram::run()
+{
+ // Calculate histogram of input.
+ CLScheduler::get().enqueue(_histogram_kernel, false);
+
+ // Calculate remaining pixels when image is not multiple of the elements of histogram kernel
+ CLScheduler::get().enqueue(_border_histogram_kernel, false);
+
+ // Calculate cumulative distribution of histogram and create LUT.
+ calculate_cum_dist_and_lut(_hist, _cum_dist, _cd_lut);
+
+ // Map input to output using created LUT.
+ CLScheduler::get().enqueue(_map_histogram_kernel);
+}