Hough transform troubleshooting

Hi,
I'm trying to implement Hough transform on DM642EVM. I'm using gradient information found earlier during edge detection.

However, when run the program, I always get the the value of maxvalu to be 1. So it will always inform me that the there is a line, even when there
isn't any. Help please.
Thanks,
Hanief

void simpleHT(
  unsigned char * edgeMap,    //input data from edge detection
  //unsigned char * restrict l_data,
  double * directionalMap,      //edge direction data from edge detection
  double * abspace,                //accumulator
  int i_cols,                                //columns = image width
  int i_rows                                //rows = image height
  ) {
  int scanRows = 0; int scanCols = 0; //int scanMaxVal = 0;
  int maxvalu = 0;
  int size = i_cols * i_rows;
  int rho, rhoNorm;
  int theta, tanTheta, denom;
  int TAN_TOO_BIG = 263; // tan(89.7821)
  int x1, y1;
  int xMax, yMax;
  memset(abspace, 0, size * sizeof(double));

/* perform Hough transform */
rhoNorm = (i_cols-1) / 865.33231;             //width=i_cols=720

for (scanRows = 0; scanRows < i_rows; scanRows++) {     //scanRows=y
  for (scanCols = 0; scanCols < i_cols; scanCols++) {           //scanCols=x
    if (edgeMap[scanCols + scanRows * i_cols] == 255) {      //if pixel (x, y) is an edge
      theta = (directionalMap[scanCols + scanRows * i_cols]);  //find theta
      tanTheta = tan (theta);
      if (tanTheta > TAN_TOO_BIG) {              //find rho
        // rho = x * cos(theta) + y * sin(theta)
        rho = scanRows; // y * sin (90)
      }
      else {
        denom = tanTheta * tanTheta + 1.0;
        y1 = (scanRows - scanCols * tanTheta) / denom;
        x1 = (scanCols * tanTheta * tanTheta - scanRows * tanTheta) / denom;
        rho = sqrt (x1 * x1 + y1 * y1);
      }
      if (abspace[scanCols + scanRows * i_cols] < 255)          //increment accumulator
  abspace[scanCols + scanRows * i_cols] +=1 ;
  }
  }
}

/* determine peak in Hough space and (theta, rho) coords */
for (scanRows = 0; scanRows < i_rows; scanRows++) {
  for (scanCols = 0; scanCols < i_cols; scanCols++) {
    if (abspace[scanCols + scanRows * i_cols] > maxvalu) {
      maxvalu = abspace[scanCols + scanRows * i_cols];           //find highest value in accumulator
      xMax = scanCols;
      yMax = scanRows;
    }
  }
}

/* inform user of result */
if (maxvalu > 0) {
  rho = xMax / rhoNorm;
  theta = yMax * PI / i_rows;
  puts ("Line located with parameters:\n");
  //printf ("\tpolar coords: (%5.2f, %5.2f) (rho [pixels], theta [radians])\n", rho, theta);
  //printf ("\tpolar coords: (%d,%d)\n", rho, theta);
  //printf ("Peak located at: (%d,%d)\n", xMax, yMax);

  //l_data[xMax + yMax * i_cols] = 255;     //this variable not used
}
else
  puts ("No line found.\n");

}