Commit 94839c9b authored by Ian Humphrey's avatar Ian Humphrey
Browse files

gradient provides ability to calculate gradients approximately or exactly... 

gradient provides ability to calculate gradients approximately or exactly (default approximate). Fixes #1741.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@6273 41f8697f-d340-4b68-9986-7bafba869bb8
parent 778a019c

isis/src/base/apps/gradient/assets/images/robertsGui.jpg

−26.8 KiB (65.2 KiB)
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isis/src/base/apps/gradient/assets/images/sobelGui.jpg

−27.8 KiB (64.5 KiB)
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isis/src/base/apps/gradient/assets/thumbs/robertsGui.jpg

−25.8 KiB (4.39 KiB)
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isis/src/base/apps/gradient/assets/thumbs/sobelGui.jpg

−26.3 KiB (4.35 KiB)
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isis/src/base/apps/gradient/gradient.cpp

+63 −3
Original line number Diff line number Diff line 
#include <cmath>



#include "Isis.h"

#include "ProcessByBoxcar.h"

#include "SpecialPixel.h"
@@ -6,7 +8,9 @@ using namespace std; 
using namespace Isis;



void robertGradient(Buffer &in, double &v);

void robertGradientApprox(Buffer &in, double &v);

void sobelGradient(Buffer &in, double &v);

void sobelGradientApprox(Buffer &in, double &v);



void IsisMain() {
@@ -20,22 +24,38 @@ void IsisMain() { 
  //  Allocate the output cube

  p.SetOutputCube("TO");



  //  Which computation?

  QString method = ui.GetString("METHOD");



  //  Which gradient?

  QString gradType = ui.GetString("GRADTYPE");



  //  Set boxcar size depending on the gradient type

  if (gradType == "SOBEL") {

    p.SetBoxcarSize(3, 3);

    if (method == "EXACT") {

      p.StartProcess(sobelGradient);

    }

  else if(gradType == "ROBERTS") {

    else { // APPROXIMATE

      p.StartProcess(sobelGradientApprox);

    }

  }



  else { // ROBERTS

    p.SetBoxcarSize(2, 2);

    if (method == "EXACT") {

      p.StartProcess(robertGradient);

    }

    else { // APPROXIMATE

      p.StartProcess(robertGradientApprox);

    }

  }



  p.EndProcess();



}





//  Sobel gradient filter

void sobelGradient(Buffer &in, double &v) {
@@ -49,14 +69,54 @@ void sobelGradient(Buffer &in, double &v) { 
    v = Isis::Null;

    return;

  }

  v = abs((in[0] + 2 * in[1] + in[2]) - (in[6] + 2 * in[7] + in[8])) +

      abs((in[2] + 2 * in[5] + in[8]) - (in[0] + 2 * in[3] + in[6]));

  v = sqrt(

        pow( (in[2] + 2 * in[5] + in[8]) - (in[0] + 2 * in[3] + in[6]), 2 ) +

        pow( (in[0] + 2 * in[1] + in[2]) - (in[6] + 2 * in[7] + in[8]), 2 )

      );



}





//  Sobel approximate gradient filter

void sobelGradientApprox(Buffer &in, double &v) {



  bool specials = false;

  for(int i = 0; i < in.size(); ++i) {

    if(IsSpecial(in[i])) {

      specials = true;

    }

  }

  if(specials) {

    v = Isis::Null;

    return;

  }

  v = abs((in[2] + 2 * in[5] + in[8]) - (in[0] + 2 * in[3] + in[6])) +

      abs((in[0] + 2 * in[1] + in[2]) - (in[6] + 2 * in[7] + in[8])); 

 

}





//   Roberts gradient filter

void robertGradient(Buffer &in, double &v) {



  bool specials = false;

  for(int i = 0; i < in.size(); ++i) {

    if(IsSpecial(in[i])) {

      specials = true;

    }

  }

  if(specials) {

    v = Isis::Null;

    return;

  }

  v = sqrt( pow((in[0] - in[3]), 2) + pow((in[1] - in[2]), 2) );



}





//  Roberts approximate gradient filter

void robertGradientApprox(Buffer &in, double &v) {



  bool specials = false;

  for(int i = 0; i < in.size(); ++i) {

    if(IsSpecial(in[i])) {