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Minor tweaks to intensity calculation (code clarity, not function) #34

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Minor tweaks to intensity calculation (code clarity, not function) #34

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d3c625e
Minor cleanup of intensity->color calculation
lauralindzey Jan 27, 2023
55fc01f
Fix use of wrong variable in calculation
lauralindzey Jan 27, 2023
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37 changes: 6 additions & 31 deletions ros/src/sonar_postprocessor_nodelet.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -54,47 +54,22 @@ class SonarPostprocessorNodelet : public nodelet::Nodelet {
out.image.data.reserve(interface.ranges().size() *
interface.azimuths().size());

double logmin, logmax;

for (unsigned int r_idx = 0; r_idx < interface.nRanges(); ++r_idx) {
for (unsigned int a_idx = 0; a_idx < interface.nAzimuth(); ++a_idx) {
sonar_image_proc::AzimuthRangeIndices idx(a_idx, r_idx);

// const uint32_t pix = interface.intensity_uint32(idx);
// const auto range = interface.range(r_idx);

// Avoid log(0)
auto intensity = interface.intensity_uint32(idx);
auto v = log(std::max((uint)1, intensity)) / log(UINT32_MAX);

if ((r_idx == 0) && (a_idx == 0)) {
logmin = v;
logmax = v;
} else {
logmin = std::min(v, logmin);
logmax = std::max(v, logmax);
}
auto vv = log(std::max((uint)1, intensity)) / log(UINT32_MAX);

// The output image will look better if the full range of the colormap
// corresponds to a subset of the range of v.
const float vmax = 1.0, threshold = 0.74;

v = (v - threshold) / (vmax - threshold);
v = std::min(1.0, std::max(0.0, v));
out.image.data.push_back(UINT8_MAX * v);

// Just do the math in float for now
// float i = static_cast<float>(pix)/UINT32_MAX;

// //ROS_INFO_STREAM(a_idx << "," << r_idx << " : " << pix << " => " <<
// i);

// i *= gain_;

// UINT8_MAX * i);
auto color = (vv - threshold) / (vmax - threshold);
color = std::min(1.0, std::max(0.0, color));
out.image.data.push_back(UINT8_MAX * color);
}
}

//
float dr = exp(logmax - logmin);
pubSonarImage_.publish(out);
}

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