samples/risp4ml/isp_stages/dg.c

#include "samples/risp4ml/common/utils.h"
#include "samples/risp4ml/isp_stages/dg.h"

static const uint16_t kDgFractional = kRawPipelineFraction;
static const uint16_t kDgUnityGain = 1 << kDgFractional;
static DgParams dg_params = {
    .enable = true,
    .gains = {kDgUnityGain, kDgUnityGain, kDgUnityGain, kDgUnityGain}};

void set_dg_params(DgParams* params) { dg_params = *params; }

void dg_process(Image* input, Image* output) {
  if (!dg_params.enable) {
    *output = *input;
    return;
  }

  uint16_t height = input->height;
  uint16_t width = input->width;

  for (uint16_t y = 0; y < height; ++y) {
    const pixel_type_t* in_line = image_row(input, 0, y);
    pixel_type_t* out_line = image_row(output, 0, y);

    for (uint16_t x = 0; x < width; ++x) {
      BayerIndex bayer_index = GetBayerIndex(kBayerType, x, y);
      uint16_t input_val = in_line[x];
      // + (1 << (kDgFractional -1)) adds 0.5 for more accurate rounding
      uint32_t scaled_pixel =
          input_val * dg_params.gains[bayer_index] + (1 << (kDgFractional - 1));

      out_line[x] = (pixel_type_t)Clamp(scaled_pixel >> kDgFractional, 0,
                                        kRawPipelineMaxVal);
    }
  }
}