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isp:sample_awb_implementation_in_c [2018/06/14 23:12] – [Helper one-liners] Igor Yefmovisp:sample_awb_implementation_in_c [2022/04/04 23:32] (current) – external edit 127.0.0.1
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   * ''%%S2R::enum HIST_TYPE%%'' - a helper enum used as an index into histogram data arrays   * ''%%S2R::enum HIST_TYPE%%'' - a helper enum used as an index into histogram data arrays
  
-The code below conforms to C++14 standard but it is recommended to use the C++17 toolchain as this is the version the [[code::SUB2r-lib]] is targetting.+The code below conforms to C++17 standard and it is recommended to use the C++17 toolchain as this is the version the [[code::SUB2r-lib]] is targetting.
  
 ====== Helper one-liners ====== ====== Helper one-liners ======
 A few short functions for code readability, put into a local anonymous namespace (effectively making these function ''static'' and making sure we don't pollute/collide with the global namespace). A few short functions for code readability, put into a local anonymous namespace (effectively making these function ''static'' and making sure we don't pollute/collide with the global namespace).
  
-Side note: I'm fully aware of the ''std::clamp()'' template yet using my own ''_box()'' because of type conversions I need. In one case I'm limiting a ''double'' into an ''int'' range, returning an ''int'' result. In the second case the range is specified by ''[#PerPart]]'' values that would otherwise need to be explicitly cast to ''double'' which looked too ugly, TBH.+Side note: I'm fully aware of the ''std::clamp()'' template yet using my own ''_box()'' because of type conversions I need. In one case I'm limiting a ''double'' into an ''int'' range, returning an ''int'' result. In the second case the range is specified by ''[[#PerPart]]'' values that would otherwise need to be explicitly cast to ''double'' which looked too ugly, TBH.
  
 <code c++>namespace{ <code c++>namespace{
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 ===== Constructor AWB::AWB ===== ===== Constructor AWB::AWB =====
  
-A bulk of (quite simplistic) calculations is performed with data in ''_stats'' and the results are stored in the ''m_vars'' struct;+A bulk of (quite simplistic) calculations is performed with data in ''_stats'' and the results are stored in the ''m_vars'' struct:
  
 <code c++>AWB::AWB(IImgSensor * _ov, LumaCalc _alg, const ImgStats & _stats, const PerPart & _satTH) <code c++>AWB::AWB(IImgSensor * _ov, LumaCalc _alg, const ImgStats & _stats, const PerPart & _satTH)
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 // A more generic definition of this special condition is: too much red overexposure relative to // A more generic definition of this special condition is: too much red overexposure relative to
 // green overexposure relative to overall brightness of the picture. The brighter the image the // green overexposure relative to overall brightness of the picture. The brighter the image the
-// more overexposure we can tolerate+// more overexposure we can tolerate, but to a certain point
 bool AWB::_isRedOE() const bool AWB::_isRedOE() const
 { {
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     }else if(m_vars.avgY < 60){     }else if(m_vars.avgY < 60){
         return m_vars.oeR > m_vars.oeG * m_vars.avgY * 3;         return m_vars.oeR > m_vars.oeG * m_vars.avgY * 3;
 +    }else if(m_vars.avgY < 85){
 +        return m_vars.oeR > m_vars.oeG * m_vars.avgY;
     }else{     }else{
-        return m_vars.oeR > m_vars.oeG * m_vars.avgY * 7;+        return m_vars.oeR > m_vars.oeG * 8;
     }     }
 }</code> }</code>
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 <code c++>void AWB::_resetRed() <code c++>void AWB::_resetRed()
 { {
-    const int gainG = m_ov[Val::GAIN_G]; +    const int gainG = m_ov[Val::gain_g]; 
-    const int gainR = m_ov[Val::GAIN_R];+    const int gainR = m_ov[Val::gain_r];
     if(gainR > gainG){     if(gainR > gainG){
         const auto diff = (gainG - gainR) * 5 / 8;  // 62.5% closer to green gain value         const auto diff = (gainG - gainR) * 5 / 8;  // 62.5% closer to green gain value
-        m_ov[Val::GAIN_R] = gainR + diff;+        m_ov[Val::gain_r] = gainR + diff;
     }     }
 }</code> }</code>
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     assert(m_vars.op == Action::correctGains);     assert(m_vars.op == Action::correctGains);
  
-    const auto limit = m_ov.getLimit(Val::GAIN_G); // assume the same limit for all 3 channels +    const auto limit = m_ov.getLimit(Val::gain_g); // assume the same limit for all 3 channels 
-    const double precision = 0.1;+    const double precision = 0.01;
  
     if(abs(m_vars.avgU) > precision){     if(abs(m_vars.avgU) > precision){
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         //m_vars.avgB /= blueAdj;         //m_vars.avgB /= blueAdj;
         const auto gb = m_vars.avgB == 0 ? 0 : m_vars.avgG / m_vars.avgB;         const auto gb = m_vars.avgB == 0 ? 0 : m_vars.avgG / m_vars.avgB;
-        const int gainB = _box(m_ov[Val::GAIN_B] * gb, 10, limit); +        const int gainB = _box(m_ov[Val::gain_b] * gb, 10, limit); 
-        m_ov[Val::GAIN_B] = gainB;+        m_ov[Val::gain_b] = gainB;
     }     }
  
     if(abs(m_vars.avgV) > precision){     if(abs(m_vars.avgV) > precision){
         const auto gr = m_vars.avgR == 0 ? 0 : m_vars.avgG / m_vars.avgR;         const auto gr = m_vars.avgR == 0 ? 0 : m_vars.avgG / m_vars.avgR;
-        const int gainR = _box(m_ov[Val::GAIN_R] * gr, 10, limit); +        const int gainR = _box(m_ov[Val::gain_r] * gr, 10, limit); 
-        m_ov[Val::GAIN_R] = gainR;+        m_ov[Val::gain_r] = gainR;
     }     }
 } }
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 ====== Sample usage ====== ====== Sample usage ======
  
-This is a copy-paste of the code used in [[manual:Aria]] utility for the POC. This code has minimal comments but should be fairly easy to comprehend nonetheless:+This is a copy-paste of the code used in [[manual:Aria]] utility for the POC. This code has minimal comments but should be fairly easy to follow:
  
 <code c++>void ImgAnalyzerDlg::_awbInfo() <code c++>void ImgAnalyzerDlg::_awbInfo()
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 } }
 </code> </code>
 +
 +
 +====== Initial values ======
 +
 +Following are the initial defaults for the variables that affect the process of automatic white balance adjustment:
 +^ Name (as seen in ''%%ImgAnalyzerDlg%%::_awbInfo()'' above) ^ Value ^
 +| ''currTolerance'' | ''15/100'', adjusted automagically based on last frame's stats |
 +

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