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3624d0b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 | #include "preprocess.hpp"
#include <algorithm>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <stdexcept>
#include <omp.h>
namespace rclane {
void normalize_bgr_to_nchw(
const std::uint8_t* bgr,
int source_width,
int source_height,
std::vector<float>& destination
) {
constexpr int output_width = 800;
constexpr int output_height = 320;
constexpr float mean[3]{0.485F, 0.456F, 0.406F};
constexpr float standard_deviation[3]{0.229F, 0.224F, 0.225F};
if (bgr == nullptr || source_width <= 0 || source_height <= 0) {
throw std::invalid_argument("invalid BGR source image");
}
const std::size_t plane = static_cast<std::size_t>(
output_width * output_height
);
destination.resize(plane * 3);
constexpr int coefficient_scale = 1 << 11;
const double scale_x = static_cast<double>(source_width)
/ static_cast<double>(output_width);
const double scale_y = static_cast<double>(source_height)
/ static_cast<double>(output_height);
#pragma omp parallel for schedule(static)
for (int output_y = 0; output_y < output_height; ++output_y) {
const float source_y = static_cast<float>(
(static_cast<double>(output_y) + 0.5) * scale_y - 0.5
);
int y0 = static_cast<int>(std::floor(source_y));
float wy = source_y - static_cast<float>(y0);
if (y0 < 0) {
y0 = 0;
wy = 0.0F;
}
int y1 = std::min(y0 + 1, source_height - 1);
if (y0 >= source_height - 1) {
y0 = source_height - 1;
y1 = y0;
wy = 0.0F;
}
const int beta1 = static_cast<int>(std::nearbyint(
wy * static_cast<float>(coefficient_scale)
));
const int beta0 = static_cast<int>(std::nearbyint(
(1.0F - wy) * static_cast<float>(coefficient_scale)
));
for (int output_x = 0; output_x < output_width; ++output_x) {
const float source_x = static_cast<float>(
(static_cast<double>(output_x) + 0.5) * scale_x - 0.5
);
int x0 = static_cast<int>(std::floor(source_x));
float wx = source_x - static_cast<float>(x0);
if (x0 < 0) {
x0 = 0;
wx = 0.0F;
}
int x1 = std::min(x0 + 1, source_width - 1);
if (x0 >= source_width - 1) {
x0 = source_width - 1;
x1 = x0;
wx = 0.0F;
}
const int alpha1 = static_cast<int>(std::nearbyint(
wx * static_cast<float>(coefficient_scale)
));
const int alpha0 = static_cast<int>(std::nearbyint(
(1.0F - wx) * static_cast<float>(coefficient_scale)
));
const std::size_t output = static_cast<std::size_t>(
output_y * output_width + output_x
);
const std::size_t top_left = static_cast<std::size_t>(
(y0 * source_width + x0) * 3
);
const std::size_t top_right = static_cast<std::size_t>(
(y0 * source_width + x1) * 3
);
const std::size_t bottom_left = static_cast<std::size_t>(
(y1 * source_width + x0) * 3
);
const std::size_t bottom_right = static_cast<std::size_t>(
(y1 * source_width + x1) * 3
);
for (int rgb_channel = 0; rgb_channel < 3; ++rgb_channel) {
const int bgr_channel = 2 - rgb_channel;
const int top = static_cast<int>(bgr[top_left + bgr_channel]) * alpha0
+ static_cast<int>(bgr[top_right + bgr_channel]) * alpha1;
const int bottom = static_cast<int>(bgr[bottom_left + bgr_channel]) * alpha0
+ static_cast<int>(bgr[bottom_right + bgr_channel]) * alpha1;
// Match OpenCV 4.11's Apache-licensed VResizeLinear<8u>; see
// cpp/THIRD_PARTY_NOTICES.md. Its
// fixed-point shifts intentionally happen before accumulation.
const int pixel_integer = (
((beta0 * (top >> 4)) >> 16)
+ ((beta1 * (bottom >> 4)) >> 16) + 2
) >> 2;
const float pixel = static_cast<float>(
std::clamp(pixel_integer, 0, 255)
);
destination[static_cast<std::size_t>(rgb_channel) * plane + output]
= (pixel * (1.0F / 255.0F) - mean[rgb_channel])
/ standard_deviation[rgb_channel];
}
}
}
}
} // namespace rclane
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