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Diffstat (limited to 'tests/validation/reference/EqualizeHistogram.cpp')
-rw-r--r-- | tests/validation/reference/EqualizeHistogram.cpp | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/tests/validation/reference/EqualizeHistogram.cpp b/tests/validation/reference/EqualizeHistogram.cpp new file mode 100644 index 0000000000..0e966cd0b4 --- /dev/null +++ b/tests/validation/reference/EqualizeHistogram.cpp @@ -0,0 +1,90 @@ +/* + * Copyright (c) 2017-2018 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 "EqualizeHistogram.h" + +namespace arm_compute +{ +namespace test +{ +namespace validation +{ +namespace reference +{ +template <typename T> +SimpleTensor<T> equalize_histogram(const SimpleTensor<T> &src) +{ + const size_t num_bins = 256; // 0-255 inclusive + + std::vector<T> lut(num_bins); + std::vector<uint32_t> hist(num_bins); + std::vector<uint32_t> cd(num_bins); // cumulative distribution + + SimpleTensor<T> dst(src.shape(), src.data_type()); + + // Create the histogram + for(int element_idx = 0; element_idx < src.num_elements(); ++element_idx) + { + hist[src[element_idx]]++; + } + + // Calculate cumulative distribution + std::partial_sum(hist.begin(), hist.end(), cd.begin()); + + // Get the number of pixels that have the lowest non-zero value + const uint32_t cd_min = *std::find_if(hist.begin(), hist.end(), [](const uint32_t &x) + { + return x > 0; + }); + + const size_t total_num_pixels = cd.back(); + + // Single color - create linear distribution + if(total_num_pixels == cd_min) + { + std::iota(lut.begin(), lut.end(), 0); + } + else + { + const float diff = total_num_pixels - 1; + + for(size_t i = 0; i < num_bins; ++i) + { + lut[i] = lround((cd[i] - cd_min) / diff * 255.f); + } + } + + // Fill output tensor with equalized values + for(int i = 0; i < src.num_elements(); ++i) + { + dst[i] = lut[src[i]]; + } + + return dst; +} + +template SimpleTensor<uint8_t> equalize_histogram(const SimpleTensor<uint8_t> &src); +} // namespace reference +} // namespace validation +} // namespace test +} // namespace arm_compute |