Eliminating aliasing vertical lines.
Reduce the cross-fading factor to eliminate the aliasing vertical lines.
Also, fix an issues in blending: skipping cross-fading when the
cross-fading width is 0.
Bug: 5446629
Change-Id: Id5fed50824a2b93d80ad464864e4e74a656acb82
diff --git a/jni/feature_mos/src/mosaic/Blend.cpp b/jni/feature_mos/src/mosaic/Blend.cpp
index 1f3d93c..18972ee 100644
--- a/jni/feature_mos/src/mosaic/Blend.cpp
+++ b/jni/feature_mos/src/mosaic/Blend.cpp
@@ -416,40 +416,49 @@
// the two component images,
int tw = STRIP_CROSS_FADE_WIDTH * width;
- for(int y = 0; y < imgMos.Y.height; y++)
+ // Proceed with the image index calculation for cross-fading
+ // only if the cross-fading width is larger than 0
+ if (tw > 0)
{
- for(int x = tw; x < imgMos.Y.width - tw + 1; )
+ for(int y = 0; y < imgMos.Y.height; y++)
{
- // Determine where the seam is...
- if (imgMos.Y.ptr[y][x] != imgMos.Y.ptr[y][x+1] &&
- imgMos.Y.ptr[y][x] != 255 &&
- imgMos.Y.ptr[y][x+1] != 255)
+ // Since we compare two adjecant pixels to determine
+ // whether there is a seam, the termination condition of x
+ // is set to imgMos.Y.width - tw, so that x+1 below
+ // won't exceed the imgMos' boundary.
+ for(int x = tw; x < imgMos.Y.width - tw; )
{
- // Find the image indices on both sides of the seam
- unsigned char idx1 = imgMos.Y.ptr[y][x];
- unsigned char idx2 = imgMos.Y.ptr[y][x+1];
-
- for (int o = tw; o >= 0; o--)
+ // Determine where the seam is...
+ if (imgMos.Y.ptr[y][x] != imgMos.Y.ptr[y][x+1] &&
+ imgMos.Y.ptr[y][x] != 255 &&
+ imgMos.Y.ptr[y][x+1] != 255)
{
- // Set the image index to use for cross-fading
- imgMos.V.ptr[y][x - o] = idx2;
- // Set the intensity weights to use for cross-fading
- imgMos.U.ptr[y][x - o] = 50 + (99 - 50) * o / tw;
- }
+ // Find the image indices on both sides of the seam
+ unsigned char idx1 = imgMos.Y.ptr[y][x];
+ unsigned char idx2 = imgMos.Y.ptr[y][x+1];
- for (int o = 1; o <= tw; o++)
+ for (int o = tw; o >= 0; o--)
+ {
+ // Set the image index to use for cross-fading
+ imgMos.V.ptr[y][x - o] = idx2;
+ // Set the intensity weights to use for cross-fading
+ imgMos.U.ptr[y][x - o] = 50 + (99 - 50) * o / tw;
+ }
+
+ for (int o = 1; o <= tw; o++)
+ {
+ // Set the image index to use for cross-fading
+ imgMos.V.ptr[y][x + o] = idx1;
+ // Set the intensity weights to use for cross-fading
+ imgMos.U.ptr[y][x + o] = imgMos.U.ptr[y][x - o];
+ }
+
+ x += (tw + 1);
+ }
+ else
{
- // Set the image index to use for cross-fading
- imgMos.V.ptr[y][x + o] = idx1;
- // Set the intensity weights to use for cross-fading
- imgMos.U.ptr[y][x + o] = imgMos.U.ptr[y][x - o];
+ x++;
}
-
- x += (tw + 1);
- }
- else
- {
- x++;
}
}
}
@@ -460,40 +469,49 @@
// the two component images,
int tw = STRIP_CROSS_FADE_WIDTH * height;
- for(int x = 0; x < imgMos.Y.width; x++)
+ // Proceed with the image index calculation for cross-fading
+ // only if the cross-fading width is larger than 0
+ if (tw > 0)
{
- for(int y = tw; y < imgMos.Y.height - tw + 1; )
+ for(int x = 0; x < imgMos.Y.width; x++)
{
- // Determine where the seam is...
- if (imgMos.Y.ptr[y][x] != imgMos.Y.ptr[y+1][x] &&
- imgMos.Y.ptr[y][x] != 255 &&
- imgMos.Y.ptr[y+1][x] != 255)
+ // Since we compare two adjecant pixels to determine
+ // whether there is a seam, the termination condition of y
+ // is set to imgMos.Y.height - tw, so that y+1 below
+ // won't exceed the imgMos' boundary.
+ for(int y = tw; y < imgMos.Y.height - tw; )
{
- // Find the image indices on both sides of the seam
- unsigned char idx1 = imgMos.Y.ptr[y][x];
- unsigned char idx2 = imgMos.Y.ptr[y+1][x];
-
- for (int o = tw; o >= 0; o--)
+ // Determine where the seam is...
+ if (imgMos.Y.ptr[y][x] != imgMos.Y.ptr[y+1][x] &&
+ imgMos.Y.ptr[y][x] != 255 &&
+ imgMos.Y.ptr[y+1][x] != 255)
{
- // Set the image index to use for cross-fading
- imgMos.V.ptr[y - o][x] = idx2;
- // Set the intensity weights to use for cross-fading
- imgMos.U.ptr[y - o][x] = 50 + (99 - 50) * o / tw;
- }
+ // Find the image indices on both sides of the seam
+ unsigned char idx1 = imgMos.Y.ptr[y][x];
+ unsigned char idx2 = imgMos.Y.ptr[y+1][x];
- for (int o = 1; o <= tw; o++)
+ for (int o = tw; o >= 0; o--)
+ {
+ // Set the image index to use for cross-fading
+ imgMos.V.ptr[y - o][x] = idx2;
+ // Set the intensity weights to use for cross-fading
+ imgMos.U.ptr[y - o][x] = 50 + (99 - 50) * o / tw;
+ }
+
+ for (int o = 1; o <= tw; o++)
+ {
+ // Set the image index to use for cross-fading
+ imgMos.V.ptr[y + o][x] = idx1;
+ // Set the intensity weights to use for cross-fading
+ imgMos.U.ptr[y + o][x] = imgMos.U.ptr[y - o][x];
+ }
+
+ y += (tw + 1);
+ }
+ else
{
- // Set the image index to use for cross-fading
- imgMos.V.ptr[y + o][x] = idx1;
- // Set the intensity weights to use for cross-fading
- imgMos.U.ptr[y + o][x] = imgMos.U.ptr[y - o][x];
+ y++;
}
-
- y += (tw + 1);
- }
- else
- {
- y++;
}
}
}
diff --git a/jni/feature_mos/src/mosaic/Blend.h b/jni/feature_mos/src/mosaic/Blend.h
index a5bc05b..80bb577 100644
--- a/jni/feature_mos/src/mosaic/Blend.h
+++ b/jni/feature_mos/src/mosaic/Blend.h
@@ -42,7 +42,7 @@
// This threshold determines the number of pixels on either side of the strip
// to cross-fade using the images contributing to each seam. This threshold
// is specified as a fraction of the input image frame width.
-const float STRIP_CROSS_FADE_WIDTH = 0.02;
+const float STRIP_CROSS_FADE_WIDTH = 0.002;
/**
* Class for pyramid blending a mosaic.
*/
