diff --git a/src/libmv/simple_pipeline/camera_intrinsics.cc b/src/libmv/simple_pipeline/camera_intrinsics.cc
index f9888ff..110a16d 100644
--- a/src/libmv/simple_pipeline/camera_intrinsics.cc
+++ b/src/libmv/simple_pipeline/camera_intrinsics.cc
@@ -23,7 +23,32 @@
 
 namespace libmv {
 
-struct Offset { signed char ix,iy; unsigned char fx,fy; };
+struct Offset {
+  signed char ix, iy;
+  unsigned char fx,fy;
+};
+
+struct Grid {
+  struct Offset *offset;
+  int width, height;
+};
+
+static struct Grid *copyGrid(struct Grid *from)
+{
+  struct Grid *to = NULL;
+
+  if (from) {
+    to = new Grid;
+
+    to->width = from->width;
+    to->height = from->height;
+
+    to->offset = new Offset[to->width*to->height];
+    memcpy(to->offset, from->offset, sizeof(struct Offset)*to->width*to->height);
+  }
+
+  return to;
+}
 
 CameraIntrinsics::CameraIntrinsics()
     : K_(Mat3::Identity()),
@@ -37,9 +62,22 @@ CameraIntrinsics::CameraIntrinsics()
       distort_(0),
       undistort_(0) {}
 
+CameraIntrinsics::CameraIntrinsics(const CameraIntrinsics &from)
+    : K_(from.K_),
+      image_width_(from.image_width_),
+      image_height_(from.image_height_),
+      k1_(from.k1_),
+      k2_(from.k2_),
+      k3_(from.k3_),
+      p1_(from.p1_),
+      p2_(from.p2_)
+{
+  distort_ = copyGrid(from.distort_);
+  undistort_ = copyGrid(from.undistort_);
+}
+
 CameraIntrinsics::~CameraIntrinsics() {
-  if(distort_) delete[] distort_;
-  if(undistort_) delete[] undistort_;
+  FreeLookupGrid();
 }
 
 /// Set the entire calibration matrix at once.
@@ -146,11 +184,17 @@ void CameraIntrinsics::InvertIntrinsics(double image_x,
 
 // TODO(MatthiasF): downsample lookup
 template<typename WarpFunction>
-void CameraIntrinsics::ComputeLookupGrid(Offset* grid, int width, int height) {
+void CameraIntrinsics::ComputeLookupGrid(Grid* grid, int width, int height) {
+  double aspx = (double)width / image_width_;
+  double aspy = (double)height / image_height_;
+
   for (int y = 0; y < height; y++) {
     for (int x = 0; x < width; x++) {
+      double src_x = x / aspx, src_y = y / aspy;
       double warp_x, warp_y;
-      WarpFunction(this,x,y,&warp_x,&warp_y);
+      WarpFunction(this,src_x,src_y,&warp_x,&warp_y);
+      warp_x = warp_x*aspx;
+      warp_y = warp_y*aspy;
       int ix = int(warp_x), iy = int(warp_y);
       int fx = round((warp_x-ix)*256), fy = round((warp_y-iy)*256);
       if(fx == 256) { fx=0; ix++; }
@@ -162,10 +206,10 @@ void CameraIntrinsics::ComputeLookupGrid(Offset* grid, int width, int height) {
       if( iy >= height-2 ) iy = height-2;
       if ( ix-x > -128 && ix-x < 128 && iy-y > -128 && iy-y < 128 ) {
         Offset offset = { ix-x, iy-y, fx, fy };
-        grid[y*width+x] = offset;
+        grid->offset[y*width+x] = offset;
       } else {
         Offset offset = { 0, 0, 0, 0 };
-        grid[y*width+x] = offset;
+        grid->offset[y*width+x] = offset;
       }
     }
   }
@@ -173,11 +217,11 @@ void CameraIntrinsics::ComputeLookupGrid(Offset* grid, int width, int height) {
 
 // TODO(MatthiasF): cubic B-Spline image sampling, bilinear lookup
 template<typename T,int N>
-static void Warp(const Offset* grid, const T* src, T* dst,
+static void Warp(const Grid* grid, const T* src, T* dst,
                  int width, int height) {
   for (int y = 0; y < height; y++) {
     for (int x = 0; x < width; x++) {
-      Offset offset = grid[y*width+x];
+      Offset offset = grid->offset[y*width+x];
       const T* s = &src[((y+offset.iy)*width+(x+offset.ix))*N];
       for (int i = 0; i < N; i++) {
         dst[(y*width+x)*N+i] = ((s[        i] * (256-offset.fx) + s[        N+i] * offset.fx) * (256-offset.fy)
@@ -188,8 +232,17 @@ static void Warp(const Offset* grid, const T* src, T* dst,
 }
 
 void CameraIntrinsics::FreeLookupGrid() {
-  if(distort_) delete distort_, distort_=0;
-  if(undistort_) delete undistort_, undistort_=0;
+  if(distort_) {
+    delete distort_->offset;
+    delete distort_;
+    distort_ = NULL;
+  }
+
+  if(undistort_) {
+    delete undistort_->offset;
+    delete undistort_;
+    undistort_ = NULL;
+  }
 }
 
 // FIXME: C++ templates limitations makes thing complicated, but maybe there is a simpler method.
@@ -211,11 +264,50 @@ struct InvertIntrinsicsFunction {
   }
 };
 
-void CameraIntrinsics::Distort(const float* src, float* dst, int width, int height, int channels) {
-  if(!distort_) {
-    distort_ = new Offset[width*height];
-    ComputeLookupGrid<InvertIntrinsicsFunction>(distort_,width,height);
+void CameraIntrinsics::CheckDistortLookupGrid(int width, int height)
+{
+  if(distort_) {
+    if(distort_->width != width || distort_->height != height) {
+      delete [] distort_->offset;
+      distort_->offset = NULL;
+    }
+  } else {
+    distort_ = new Grid;
+    distort_->offset = NULL;
+  }
+
+  if(!distort_->offset) {
+      distort_->offset = new Offset[width*height];
+      ComputeLookupGrid<InvertIntrinsicsFunction>(distort_,width,height);
   }
+
+  distort_->width = width;
+  distort_->height = height;
+}
+
+void CameraIntrinsics::CheckUndistortLookupGrid(int width, int height)
+{
+  if(undistort_) {
+    if(undistort_->width != width || undistort_->height != height) {
+      delete [] undistort_->offset;
+      undistort_->offset = NULL;
+    }
+  } else {
+    undistort_ = new Grid;
+    undistort_->offset = NULL;
+  }
+
+  if(!undistort_->offset) {
+      undistort_->offset = new Offset[width*height];
+      ComputeLookupGrid<ApplyIntrinsicsFunction>(undistort_,width,height);
+  }
+
+  undistort_->width = width;
+  undistort_->height = height;
+}
+
+void CameraIntrinsics::Distort(const float* src, float* dst, int width, int height, int channels) {
+  CheckDistortLookupGrid(width, height);
        if(channels==1) Warp<float,1>(distort_,src,dst,width,height);
   else if(channels==2) Warp<float,2>(distort_,src,dst,width,height);
   else if(channels==3) Warp<float,3>(distort_,src,dst,width,height);
@@ -224,10 +316,7 @@ void CameraIntrinsics::Distort(const float* src, float* dst, int width, int heig
 }
 
 void CameraIntrinsics::Distort(const unsigned char* src, unsigned char* dst, int width, int height, int channels) {
-  if(!distort_) {
-    distort_ = new Offset[width*height];
-    ComputeLookupGrid<InvertIntrinsicsFunction>(distort_,width,height);
-  }
+  CheckDistortLookupGrid(width, height);
        if(channels==1) Warp<unsigned char,1>(distort_,src,dst,width,height);
   else if(channels==2) Warp<unsigned char,2>(distort_,src,dst,width,height);
   else if(channels==3) Warp<unsigned char,3>(distort_,src,dst,width,height);
@@ -236,10 +325,7 @@ void CameraIntrinsics::Distort(const unsigned char* src, unsigned char* dst, int
 }
 
 void CameraIntrinsics::Undistort(const float* src, float* dst, int width, int height, int channels) {
-  if(!undistort_) {
-    undistort_ = new Offset[width*height];
-    ComputeLookupGrid<ApplyIntrinsicsFunction>(undistort_,width,height);
-  }
+  CheckUndistortLookupGrid(width, height);
        if(channels==1) Warp<float,1>(undistort_,src,dst,width,height);
   else if(channels==2) Warp<float,2>(undistort_,src,dst,width,height);
   else if(channels==3) Warp<float,3>(undistort_,src,dst,width,height);
@@ -248,10 +334,7 @@ void CameraIntrinsics::Undistort(const float* src, float* dst, int width, int he
 }
 
 void CameraIntrinsics::Undistort(const unsigned char* src, unsigned char* dst, int width, int height, int channels) {
-  if(!undistort_) {
-    undistort_ = new Offset[width*height];
-    ComputeLookupGrid<ApplyIntrinsicsFunction>(undistort_,width,height);
-  }
+  CheckUndistortLookupGrid(width, height);
        if(channels==1) Warp<unsigned char,1>(undistort_,src,dst,width,height);
   else if(channels==2) Warp<unsigned char,2>(undistort_,src,dst,width,height);
   else if(channels==3) Warp<unsigned char,3>(undistort_,src,dst,width,height);
diff --git a/src/libmv/simple_pipeline/camera_intrinsics.h b/src/libmv/simple_pipeline/camera_intrinsics.h
index 29bc8a1..f525571 100644
--- a/src/libmv/simple_pipeline/camera_intrinsics.h
+++ b/src/libmv/simple_pipeline/camera_intrinsics.h
@@ -26,11 +26,12 @@ typedef Eigen::Matrix<double, 3, 3> Mat3;
 
 namespace libmv {
 
-struct Offset;
+struct Grid;
 
 class CameraIntrinsics {
  public:
   CameraIntrinsics();
+  CameraIntrinsics(const CameraIntrinsics &from);
   ~CameraIntrinsics();
 
   const Mat3 &K()                 const { return K_;            }
@@ -123,7 +124,9 @@ class CameraIntrinsics {
                  int width, int height, int channels);
 
  private:
-  template<typename WarpFunction> void ComputeLookupGrid(Offset* grid, int width, int height);
+  template<typename WarpFunction> void ComputeLookupGrid(struct Grid* grid, int width, int height);
+  void CheckUndistortLookupGrid(int width, int height);
+  void CheckDistortLookupGrid(int width, int height);
   void FreeLookupGrid();
 
   // The traditional intrinsics matrix from x = K[R|t]X.
@@ -140,8 +143,8 @@ class CameraIntrinsics {
   // independent of image size.
   double k1_, k2_, k3_, p1_, p2_;
 
-  Offset* distort_;
-  Offset* undistort_;
+  struct Grid *distort_;
+  struct Grid *undistort_;
 };
 
 }  // namespace libmv