Image lens distortion correction - image-processing

Question

I am using Aptina 5Mp sensor with Fish-eye lens for capturing an image.
I am using following algorithm to correct lens distortion.
http://www.tannerhelland.com/4743/simple-algorithm-correcting-lens-distortion/
this is not correcting the image properly.
Any help will be appreciated.
//code----
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
#include <stdio.h>
#include <math.h>
using namespace cv;
using namespace std;
// globals
Mat src, dst;
Mat map_x, map_y;
#define REMAP_WINDOW "Remap Circle"
void make_circle_map(float , float , float , float );
int main(int argc, char** argv) {
// load image
src = imread(argv[1], 1);
float qvDepth = atof(argv[2]);
float fixStrength = atof(argv[3]);
float fixZoom = atof(argv[4]);
float lensRadius = atof(argv[5]);
// create destination and the maps
dst.create(src.size(), src.type());
map_x.create(src.size(), CV_32FC1);
map_y.create(src.size(), CV_32FC1);
// create window
// namedWindow(REMAP_WINDOW, CV_WINDOW_AUTOSIZE);
make_circle_map(qvDepth, fixStrength, fixZoom, lensRadius);
remap(src, dst, map_x, map_y, CV_INTER_LINEAR, BORDER_CONSTANT, Scalar(0,0, 0));
//imshow(REMAP_WINDOW, dst);
imwrite("got1.jpg",dst);
// while(27 != waitKey()) {
// just wait
// }
// cvDestroyWindow(REMAP_WINDOW);
return 0;
}
void make_circle_map(float qvDepth, float fixStrength, float fixZoom, float lensRadius ) {
//ApplyLensCorrection(double fixStrength, double fixZoom, double lensRadius, long long edgeHandling, long long superSamplingAmount
cout<<"qvDepth :"<<qvDepth<<" fixStrength :"<<fixStrength<<" fixZoom :"<<fixZoom<<" lensRadius :"<<lensRadius<<endl;
//float qvDepth = 32;//24;
//float fixStrength = 4.5; // has to utilized further
//float fixZoom = 0.5;
//float lensRadius =2;
//Calculate the center of the image
//double midX = 0;
//double midY = 0;
long tWidth = 1944;
long tHeight = 2580;
// the center
double midX = (double)src.cols/2;
double midY = (double)src.rows/2;
//Rotation values
double theta = 0;
double sRadius = 0;
double sRadius2 = 0;
double sDistance = 0;
double radius = 0;
double j = 0;
double k = 0;
//X and Y values, remapped around a center point of (0, 0)
double nX = 0;
double nY = 0;
double QuickVal =0;
float ssX;
float ssY;
//Source X and Y values, which may or may not be used as part of a bilinear interpolation function
double srcX = 0;
double srcY = 0;
sRadius = sqrt(tWidth * tWidth + tHeight * tHeight) / 2;
cout<<"sRadius :"<<sRadius<<endl;
double refDistance = 0;//modified 0 to 2
if (fixStrength == 0)
{
fixStrength = 0.00000001;
}
refDistance = sRadius * 2 / fixStrength;
sRadius = sRadius * (lensRadius / 100);
sRadius2 = sRadius * sRadius;
cout<<"refDistance :"<<refDistance<<" sRadius :"<<sRadius<<" sRadius2 :"<<sRadius2<<endl;
float sampleIndex =1; //has to be changed in future
for (int x = 0; x <= tWidth; x++)
{
QuickVal = x * qvDepth;
for (int y = 0; y <= tHeight; y++)
{
//Remap the coordinates around a center point of (0, 0)
nX = x - midX;
nY = y - midY;
//Offset the pixel amount by the supersampling lookup table
for(int ii = 1; ii<4;ii++){
j = nX + ii;
k = nY + ii;
//Calculate distance automatically
sDistance = (j * j) + (k * k);
//cout<<"nx :"<<nX<<" ny :"<<nY<<" j :"<<j<<" k :"<<k<<" sDistance :"<<sDistance<<" sRadius2 :"<<sRadius2<<endl;
if (sDistance <= sRadius2)
{
sDistance = sqrt(sDistance);
radius = sDistance / refDistance;
if (radius == 0)
{
theta = 1;
}
else
{
theta = atan(radius) / radius;
}
//srcX = midX + theta * j * fixZoom;
//srcY = midY + theta * k * fixZoom;
map_x.at<float>(x,y) = midX + cos(fabs(theta)) * j * fixZoom;
map_y.at<float>(x,y) = midY + sin(fabs(theta)) * k * fixZoom;
}
else
{
map_x.at<float>(x,y) = x + cos(fabs(theta)) ;//* fixZoom;//x;
map_y.at<float>(x,y) = y + sin(fabs(theta)) ;//* fixZoom;//y;
}
}
}
}
}
Image

Answer 1

replace the following line.
map_x.at<float>(x,y) = midX + theta * j * fixZoom;
map_y.at<float>(x,y) = midY + theta * k * fixZoom;
}
else
{
map_x.at<float>(x,y) = x ;//* fixZoom;//x;
map_y.at<float>(x,y) = y ;//* fixZoom;//y;
use argument executable [image name], BBP, correction parameter, zoom parameter, applied ratio.
ex-> ./lensdistortcorrect image.jpg 24 6.2 2.2 100