Cahvor fix (#490)

* Removed tolerance check from optical shift addition

* Updated changelog

CHANGELOG.md

@@ -35,6 +35,9 @@ release.
 
 ## [Unreleased]
 
+### Fixed
+- Fixed CAHVOR model optical shifts by removing tolerance check [#488](https://github.com/DOI-USGS/usgscsm/issues/488)
+
 ## [2.0.1] - 2024-01-23
 
 ### Changed
@@ -51,4 +54,4 @@ release.
 - Updated ALE submodule [#470](https://github.com/DOI-USGS/usgscsm/pull/470)
 
 ### Fixed
-- Fixed issue with radial distortion computation [#464](https://github.com/DOI-USGS/usgscsm/pull/464)
\ No newline at end of file
+- Fixed issue with radial distortion computation [#464](https://github.com/DOI-USGS/usgscsm/pull/464)

src/Distortion.cpp

@@ -328,16 +328,13 @@ void removeDistortion(double dx, double dy, double &ux, double &uy,
       double shiftedDy = dy - opticalDistCoeffs[4];
       double rr = shiftedDx * shiftedDx + shiftedDy * shiftedDy;
 
-      if (rr > tolerance)
-      {
-        double dr = opticalDistCoeffs[0] +
-                    (rr * (opticalDistCoeffs[1] + rr * opticalDistCoeffs[2]));
+      double dr = opticalDistCoeffs[0] +
+                  (rr * (opticalDistCoeffs[1] + rr * opticalDistCoeffs[2]));
 
-        ux = shiftedDx * (1.0 - dr);
-        uy = shiftedDy * (1.0 - dr);
-        ux += opticalDistCoeffs[3];
-        uy += opticalDistCoeffs[4];
-      }
+      ux = shiftedDx * (1.0 - dr);
+      uy = shiftedDy * (1.0 - dr);
+      ux += opticalDistCoeffs[3];
+      uy += opticalDistCoeffs[4];
     }
     break;
     
@@ -587,51 +584,48 @@ void applyDistortion(double ux, double uy, double &dx, double &dy,
       double shiftedUx = ux - opticalDistCoeffs[3];
       double shiftedUy = uy - opticalDistCoeffs[4];
       double rp2 = (ux * ux) + (uy * uy);
+      double rp = sqrt(rp2);
+      // Compute first fractional distortion using rp
+      double drOverR =
+          opticalDistCoeffs[0] +
+          (rp2 * (opticalDistCoeffs[1] + (rp2 * opticalDistCoeffs[2])));
 
-      if (rp2 > tolerance)
+      // Compute first distorted point estimate, r
+      double r = rp + (drOverR * rp);
+      double r_prev, r2_prev;
+      int iteration = 0;
+
+      do
       {
-        double rp = sqrt(rp2);
-        // Compute first fractional distortion using rp
-        double drOverR =
-            opticalDistCoeffs[0] +
-            (rp2 * (opticalDistCoeffs[1] + (rp2 * opticalDistCoeffs[2])));
-
-        // Compute first distorted point estimate, r
-        double r = rp + (drOverR * rp);
-        double r_prev, r2_prev;
-        int iteration = 0;
-
-        do
+        // Don't get in an end-less loop.  This algorithm should
+        // converge quickly.  If not then we are probably way outside
+        // of the focal plane.  Just set the distorted position to the
+        // undistorted position. Also, make sure the focal plane is less
+        // than 1km, it is unreasonable for it to grow larger than that.
+        if (iteration >= 20 || r > 1E9)
         {
-          // Don't get in an end-less loop.  This algorithm should
-          // converge quickly.  If not then we are probably way outside
-          // of the focal plane.  Just set the distorted position to the
-          // undistorted position. Also, make sure the focal plane is less
-          // than 1km, it is unreasonable for it to grow larger than that.
-          if (iteration >= 20 || r > 1E9)
-          {
-            drOverR = 0.0;
-            break;
-          }
-
-          r_prev = r;
-          r2_prev = r * r;
-
-          // Compute new fractional distortion:
-          drOverR = opticalDistCoeffs[0] +
-                    (r2_prev *
-                     (opticalDistCoeffs[1] + (r2_prev * opticalDistCoeffs[2])));
-
-          // Compute new estimate of r
-          r = rp + (drOverR * r_prev);
-          iteration++;
-        } while (fabs(r - r_prev) > desiredPrecision);
-
-        dx = shiftedUx / (1.0 - drOverR);
-        dy = shiftedUy / (1.0 - drOverR);
-        dx += opticalDistCoeffs[3];
-        dy += opticalDistCoeffs[4];
-      }
+          drOverR = 0.0;
+          break;
+        }
+
+        r_prev = r;
+        r2_prev = r * r;
+
+        // Compute new fractional distortion:
+        drOverR = opticalDistCoeffs[0] +
+                  (r2_prev *
+                    (opticalDistCoeffs[1] + (r2_prev * opticalDistCoeffs[2])));
+
+        // Compute new estimate of r
+        r = rp + (drOverR * r_prev);
+        iteration++;
+      } while (fabs(r - r_prev) > desiredPrecision);
+
+      dx = shiftedUx / (1.0 - drOverR);
+      dy = shiftedUy / (1.0 - drOverR);
+      dx += opticalDistCoeffs[3];
+      dy += opticalDistCoeffs[4];
+    
     }
     break;