* milena/mln/world/binary_2d/subsample.hh: Many fixes.
Conflicts:
milena/ChangeLog
milena/mln/world/binary_2d/subsample.hh
---
milena/ChangeLog | 12 +++++++-
milena/mln/world/binary_2d/subsample.hh | 51 ++++++++++++++++++++++---------
2 files changed, 47 insertions(+), 16 deletions(-)
diff --git a/milena/ChangeLog b/milena/ChangeLog
index 9572039..22bee5f 100644
--- a/milena/ChangeLog
+++ b/milena/ChangeLog
@@ -1,4 +1,3 @@
-<<<<<<< HEAD
2013-09-02 Roland Levillain <roland(a)lrde.epita.fr>
Add parentheses around complex operands of operator `|'.
@@ -4770,6 +4769,17 @@
* mln/geom/crop.hh,
* mln/geom/crop_without_localization.hh: New.
+2013-09-05 Edwin Carlinet <carlinet(a)lrde.epita.fr>
+
+ Fix some shortcomings in binary subsampling. This function used to
+ memory leak and makes an unnecessary heap memory
+ allocation. Moreover, it makes some unnecessary assumptions about
+ the domain of the image (only worked for 2D images with a domain
+ starting at (0,0)).
+
+ * milena/mln/world/binary_2d/subsample.hh: Many fixes.
+
+
2012-06-05 Edwin Carlinet <carlinet(a)lrde.epita.fr>
Fix issues with loading ascii ppm.
diff --git a/milena/mln/world/binary_2d/subsample.hh
b/milena/mln/world/binary_2d/subsample.hh
index 3ea041a..f6baf6c 100644
--- a/milena/mln/world/binary_2d/subsample.hh
+++ b/milena/mln/world/binary_2d/subsample.hh
@@ -50,7 +50,18 @@ namespace mln
namespace binary_2d
{
- /// Subsample a Boolean image.
+ /// \brief Subsample a Boolean image.
+ ///
+ /// Subsample a binary image by a factor \p n and return a gray
+ /// level image by averaging.
+ ///
+ /// \[
+ /// out(p) = \frac{1}{n^2} \sum_{\epsilon=1}^n input(n.(p+pmin) +
+ /// \langle \epsilon, 1\rangle )
+ /// \]
+ ///
+ /// Note that even if the input image does not have its origin
+ /// at (0,0), the output image does so.
///
/// \param[in] input A binary image.
/// \param[in] n Linear subsampling coefficient.
@@ -75,31 +86,41 @@ namespace mln
if (n == 0)
return data::convert(int_u8(), input);
- const bool** ptr = new const bool*[n];
+
const unsigned nrows = input.nrows() / n;
const unsigned ncols = input.ncols() / n;
- image2d<int_u8> output(nrows, ncols);
-
- const unsigned delta_row = input.delta_offset(down);
- for (unsigned row = 0; row < nrows; ++row)
+ algebra::vec<2, unsigned int> vmin;
+ algebra::vec<2, unsigned int> vmax;
+ vmin[0] = 0;
+ vmin[1] = 0;
+ vmax[0] = nrows - 1;
+ vmax[1] = ncols - 1;
+ point2d pmin(vmin);
+ point2d pmax(vmax);
+
+ image2d<int_u8> output(box<point2d>(pmin, pmax));
+ dpoint2d dp_row(1, 0);
+ const unsigned delta_row = input.delta_index(dp_row);
+
+ const bool* origin = &input(input.domain().pmin());
+ const bool* line_ptr = origin;
+ for (unsigned row = 0; row < nrows; ++row, line_ptr += delta_row * n)
{
- ptr[0] = & input(point2d(n * row, 0));
- for (unsigned i = 1; i < n; ++i)
- ptr[i] = ptr[i - 1] + delta_row;
- for (unsigned col = 0; col < ncols; ++col)
+ const bool* ptr = line_ptr;
+ for (unsigned col = 0; col < ncols; ++col, ptr += n)
{
unsigned count = 0;
for (unsigned i = 0; i < n; ++i)
- for (unsigned j = 0; j < n; ++j, ++(ptr[i]))
- if (*(ptr[i]))
+ for (unsigned j = 0; j < n; ++j)
+ {
+ if (ptr[delta_row * i + j])
++count;
- output(point2d(row, col)) = count * mln_max(int_u8) / n / n;
+ }
+ output.at_(row, col) = count * 255 / n / n;
}
}
- delete[] ptr;
-
return output;
}
--
1.7.10.4
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