diff --git a/src/image_handler.cpp b/src/image_handler.cpp
index cb98426..8664922 100644
--- a/src/image_handler.cpp
+++ b/src/image_handler.cpp
@@ -14,6 +14,34 @@ namespace msckf_vio {
 namespace image_handler {
 
 
+cv::Point2f pinholeDownProject(const cv::Point2f& p_in, const cv::Vec4d& intrinsics)
+{
+  return cv::Point2f(p_in.x * intrinsics[0] + intrinsics[2], p_in.y * intrinsics[1] + intrinsics[3]);
+}
+
+cv::Point2f pinholeUpProject(const cv::Point2f& p_in, const cv::Vec4d& intrinsics)
+{
+  return cv::Point2f((p_in.x - intrinsics[2])/intrinsics[0], (p_in.y - intrinsics[3])/intrinsics[1]);
+}
+
+void undistortImage(
+  cv::InputArray src,
+  cv::OutputArray dst,
+  const std::string& distortion_model,
+  const cv::Vec4d& intrinsics,
+  const cv::Vec4d& distortion_coeffs)
+{
+
+  const cv::Matx33d K(intrinsics[0], 0.0, intrinsics[2],
+                      0.0, intrinsics[1], intrinsics[3],
+                      0.0, 0.0, 1.0);
+
+  if (distortion_model == "pre-equidistant")
+      cv::fisheye::undistortImage(src, dst, K, distortion_coeffs, K);
+  else if (distortion_model == "equidistant")
+      src.copyTo(dst);
+}
+
 void undistortPoint(
     const cv::Point2f& pt_in,
     const cv::Vec4d& intrinsics,
@@ -42,10 +70,36 @@ void undistortPoint(
   if (distortion_model == "radtan") {
     cv::undistortPoints(pts_in, pts_out, K, distortion_coeffs,
                         rectification_matrix, K_new);
-  } else if (distortion_model == "equidistant") {
+  } 
+  // equidistant
+  else if (distortion_model == "equidistant") {
     cv::fisheye::undistortPoints(pts_in, pts_out, K, distortion_coeffs,
                                  rectification_matrix, K_new);
-  } else {
+  }
+  // fov
+  else if (distortion_model == "fov") {
+    for(int i = 0; i < pts_in.size(); i++)
+    {
+      float omega = distortion_coeffs[0];
+      float rd = sqrt(pts_in[i].x * pts_in[i].x + pts_in[i].y * pts_in[i].y);
+      float ru = tan(rd * omega)/(2 * tan(omega / 2));
+
+      cv::Point2f newPoint(
+              ((pts_in[i].x - intrinsics[2]) / intrinsics[0]) * (ru / rd),
+              ((pts_in[i].y - intrinsics[3]) / intrinsics[1]) * (ru / rd));
+
+      pts_out.push_back(newPoint);
+    }
+   }
+  else if (distortion_model == "pre-equidistant")
+  {
+    std::vector<cv::Point2f> temp_pts_out;
+    for(int i = 0; i < pts_in.size(); i++)
+      temp_pts_out.push_back(pinholeUpProject(pts_in[i], intrinsics));
+
+    pts_out = temp_pts_out;
+  } 
+   else {
     ROS_WARN_ONCE("The model %s is unrecognized, use radtan instead...",
                   distortion_model.c_str());
     cv::undistortPoints(pts_in, pts_out, K, distortion_coeffs,
@@ -79,10 +133,35 @@ void undistortPoints(
   if (distortion_model == "radtan") {
     cv::undistortPoints(pts_in, pts_out, K, distortion_coeffs,
                         rectification_matrix, K_new);
-  } else if (distortion_model == "equidistant") {
+  } 
+  else if (distortion_model == "equidistant") {
     cv::fisheye::undistortPoints(pts_in, pts_out, K, distortion_coeffs,
                                  rectification_matrix, K_new);
-  } else {
+  } 
+  else if (distortion_model == "fov") {
+    for(int i = 0; i < pts_in.size(); i++)
+    {
+      float omega = distortion_coeffs[0];
+      float rd = sqrt(pts_in[i].x * pts_in[i].x + pts_in[i].y * pts_in[i].y);
+      float ru = tan(rd * omega)/(2 * tan(omega / 2));
+
+      cv::Point2f newPoint(
+              ((pts_in[i].x - intrinsics[2]) / intrinsics[0]) * (ru / rd),
+              ((pts_in[i].y - intrinsics[3]) / intrinsics[1]) * (ru / rd));
+
+      pts_out.push_back(newPoint);
+    }
+  }
+  else if (distortion_model == "pre-equidistant")
+  {
+    std::vector<cv::Point2f> temp_pts_out;
+    for(int i = 0; i < pts_in.size(); i++)
+      temp_pts_out.push_back(pinholeUpProject(pts_in[i], intrinsics));
+
+    pts_out = temp_pts_out;
+
+  }  
+  else {
     ROS_WARN_ONCE("The model %s is unrecognized, use radtan instead...",
                   distortion_model.c_str());
     cv::undistortPoints(pts_in, pts_out, K, distortion_coeffs,
@@ -110,7 +189,31 @@ std::vector<cv::Point2f> distortPoints(
                       distortion_coeffs, pts_out);
   } else if (distortion_model == "equidistant") {
     cv::fisheye::distortPoints(pts_in, pts_out, K, distortion_coeffs);
-  } else {
+  }
+  else if (distortion_model == "fov") {
+    for(int i = 0; i < pts_in.size(); i++)
+    {
+      // based on 'straight lines have to be straight'
+      float ru = sqrt(pts_in[i].x * pts_in[i].x + pts_in[i].y * pts_in[i].y);
+      float omega = distortion_coeffs[0];
+      float rd = 1 / (omega)*atan(2*ru*tan(omega / 2));
+      
+      cv::Point2f newPoint(
+              pts_in[i].x * (rd/ru) * intrinsics[0] + intrinsics[2],
+              pts_in[i].y * (rd/ru) * intrinsics[1] + intrinsics[3]);
+
+      pts_out.push_back(newPoint);
+    }
+  }
+  else if (distortion_model == "pre-equidistant")
+  {
+    std::vector<cv::Point2f> temp_pts_out;
+    for(int i = 0; i < pts_in.size(); i++)
+      temp_pts_out.push_back(pinholeDownProject(pts_in[i], intrinsics));
+
+    pts_out = temp_pts_out;
+  }   
+   else {
     ROS_WARN_ONCE("The model %s is unrecognized, using radtan instead...",
                   distortion_model.c_str());
     std::vector<cv::Point3f> homogenous_pts;
@@ -143,7 +246,31 @@ cv::Point2f distortPoint(
                       distortion_coeffs, pts_out);
   } else if (distortion_model == "equidistant") {
     cv::fisheye::distortPoints(pts_in, pts_out, K, distortion_coeffs);
-  } else {
+  }
+  else if (distortion_model == "fov") {
+    for(int i = 0; i < pts_in.size(); i++)
+    {
+      // based on 'straight lines have to be straight'
+      float ru = sqrt(pts_in[i].x * pts_in[i].x + pts_in[i].y * pts_in[i].y);
+      float omega = distortion_coeffs[0];
+      float rd = 1 / (omega)*atan(2*ru*tan(omega / 2));
+      
+      cv::Point2f newPoint(
+              pts_in[i].x * (rd/ru) * intrinsics[0] + intrinsics[2],
+              pts_in[i].y * (rd/ru) * intrinsics[1] + intrinsics[3]);
+
+      pts_out.push_back(newPoint);
+    }
+  }
+  else if (distortion_model == "pre-equidistant")
+  {
+    std::vector<cv::Point2f> temp_pts_out;
+    for(int i = 0; i < pts_in.size(); i++)
+      pts_out.push_back(pinholeDownProject(pts_in[i], intrinsics));
+
+    pts_out = temp_pts_out;
+  }    
+   else {
     ROS_WARN_ONCE("The model %s is unrecognized, using radtan instead...",
                   distortion_model.c_str());
     std::vector<cv::Point3f> homogenous_pts;
@@ -155,5 +282,5 @@ cv::Point2f distortPoint(
   return pts_out[0];
 }
 
-	} // namespace image_handler
-} // namespace msckf_vio
\ No newline at end of file
+  } // namespace image_handler
+} // namespace msckf_vio
diff --git a/src/image_processor.cpp b/src/image_processor.cpp
index d35bb16..0e690b7 100644
--- a/src/image_processor.cpp
+++ b/src/image_processor.cpp
@@ -219,6 +219,12 @@ void ImageProcessor::stereoCallback(
   cam1_curr_img_ptr = cv_bridge::toCvShare(cam1_img,
       sensor_msgs::image_encodings::MONO8);
 
+
+  image_handler::undistortImage(cam0_curr_img_ptr->image, cam0_curr_img_ptr->image, cam0.distortion_model, cam0.intrinsics, cam0.distortion_coeffs);
+  image_handler::undistortImage(cam1_curr_img_ptr->image, cam1_curr_img_ptr->image, cam1.distortion_model, cam1.intrinsics, cam1.distortion_coeffs);
+
+
+
   // Build the image pyramids once since they're used at multiple places
   createImagePyramids();