Skip to content

Improve Background function descriptions in SimdLib.hpp #816

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ermig1979 merged 1 commit into from
Aug 4, 2026
Merged

Improve Background function descriptions in SimdLib.hpp #816

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 11 additions & 0 deletions docs/2026.html
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,17 @@ <h5>Removing</h5>
<li>Separate support of SVE extension (ARM/ARM64 platform).</li>
</ul>

<h4>Documentation</h4>
<h5>Improving</h5>
<ul>
<li>Improved description of function Simd::BackgroundGrowRangeSlow.</li>
<li>Improved description of function Simd::BackgroundGrowRangeFast.</li>
<li>Improved description of function Simd::BackgroundIncrementCount.</li>
<li>Improved description of function Simd::BackgroundAdjustRange.</li>
<li>Improved description of function Simd::BackgroundShiftRange.</li>
<li>Improved description of function Simd::BackgroundInitMask.</li>
</ul>

<a href="#HOME">Home</a>
<hr/>
<h3 id="R164">August 3, 2026 (version 7.2.164)</h3>
Expand Down
61 changes: 33 additions & 28 deletions src/Simd/SimdLib.hpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -479,11 +479,11 @@ namespace Simd

\fn void BackgroundGrowRangeSlow(const View<A>& value, View<A>& lo, View<A>& hi)

\short Performs background update (initial grow, slow mode).
\short Performs slow expansion of background range.

All images must have the same width, height and format (8-bit gray).

For every point:
For every point, range bounds are moved by one step toward current value:
\verbatim
lo[i] -= value[i] < lo[i] ? 1 : 0;
hi[i] += value[i] > hi[i] ? 1 : 0;
Expand All @@ -508,11 +508,11 @@ namespace Simd

\fn void BackgroundGrowRangeFast(const View<A>& value, View<A>& lo, View<A>& hi)

\short Performs background update (initial grow, fast mode).
\short Performs fast expansion of background range.

All images must have the same width, height and format (8-bit gray).

For every point:
For every point, range bounds are expanded to include current value:
\verbatim
lo[i] = value[i] < lo[i] ? value[i] : lo[i];
hi[i] = value[i] > hi[i] ? value[i] : hi[i];
Expand All @@ -537,11 +537,11 @@ namespace Simd

\fn void BackgroundIncrementCount(const View<A>& value, const View<A>& loValue, const View<A>& hiValue, View<A>& loCount, View<A>& hiCount)

\short Performs collection of background statistic.
\short Collects background out-of-range statistics.

All images must have the same width, height and format (8-bit gray).

Updates background statistic counters for every point:
For every point, counters are incremented with saturation to 255:
\verbatim
loCount[i] += (value[i] < loValue[i] && loCount[i] < 255) ? 1 : 0;
hiCount[i] += (value[i] > hiValue[i] && hiCount[i] < 255) ? 1 : 0;
Expand Down Expand Up @@ -570,11 +570,11 @@ namespace Simd

\fn void BackgroundAdjustRange(View<A>& loCount, View<A>& loValue, View<A>& hiCount, View<A>& hiValue, uint8_t threshold)

\short Performs adjustment of background range.
\short Adjusts background range using collected counters.

All images must have the same width, height and format (8-bit gray).

Adjusts background range for every point:
For every point:
\verbatim
loValue[i] -= (loCount[i] > threshold && loValue[i] > 0) ? 1 : 0;
loValue[i] += (loCount[i] < threshold && loValue[i] < 255) ? 1 : 0;
Expand Down Expand Up @@ -606,21 +606,21 @@ namespace Simd

\fn void BackgroundAdjustRange(View<A>& loCount, View<A>& loValue, View<A>& hiCount, View<A>& hiValue, uint8_t threshold, const View<A>& mask)

\short Performs adjustment of background range with using adjust range mask.
\short Adjusts background range using collected counters and a mask.

All images must have the same width, height and format (8-bit gray).

Adjusts background range for every point:
For every point:
\verbatim
if(mask[i])
{
loValue[i] -= (loCount[i] > threshold && loValue[i] > 0) ? 1 : 0;
loValue[i] += (loCount[i] < threshold && loValue[i] < 255) ? 1 : 0;
loCount[i] = 0;
hiValue[i] += (hiCount[i] > threshold && hiValue[i] < 255) ? 1 : 0;
hiValue[i] -= (hiCount[i] < threshold && hiValue[i] > 0) ? 1 : 0;
hiCount[i] = 0;
}
loCount[i] = 0;
hiCount[i] = 0;
\endverbatim

This function is used for background updating in motion detection algorithm.
Expand All @@ -647,21 +647,23 @@ namespace Simd

\fn void BackgroundShiftRange(const View<A>& value, View<A>& lo, View<A>& hi)

\short Shifts background range.
\short Shifts background range to include current value.

All images must have the same width, height and format (8-bit gray).

For every point:
\verbatim
if (value[i] > hi[i])
add = value[i] - hi[i];
sub = lo[i] - value[i];
if(add > 0)
{
lo[i] = min(lo[i] + value[i] - hi[i], 255);
hi[i] = value[i];
lo[i] = min(lo[i] + add, 255);
hi[i] = min(hi[i] + add, 255);
}
if (lo[i] > value[i])
if(sub > 0)
{
lo[i] = value[i];
hi[i] = max(hi[i] - lo[i] + value[i], 0);
lo[i] = max(lo[i] - sub, 0);
hi[i] = max(hi[i] - sub, 0);
}
\endverbatim

Expand All @@ -684,23 +686,25 @@ namespace Simd

\fn void BackgroundShiftRange(const View<A>& value, View<A>& lo, View<A>& hi, const View<A>& mask);

\short Shifts background range with using shift range mask.
\short Shifts background range to include current value using a mask.

All images must have the same width, height and format (8-bit gray).

For every point:
\verbatim
if(mask[i])
{
if (value[i] > hi[i])
add = value[i] - hi[i];
sub = lo[i] - value[i];
if(add > 0)
{
lo[i] = min(lo[i] + value[i] - hi[i], 255);
hi[i] = value[i];
lo[i] = min(lo[i] + add, 255);
hi[i] = min(hi[i] + add, 255);
}
if (lo[i] > value[i])
if(sub > 0)
{
lo[i] = value[i];
hi[i] = max(hi[i] - lo[i] + value[i], 0);
lo[i] = max(lo[i] - sub, 0);
hi[i] = max(hi[i] - sub, 0);
}
}
\endverbatim
Expand All @@ -726,15 +730,16 @@ namespace Simd

\fn void BackgroundInitMask(const View<A>& src, uint8_t index, uint8_t value, View<A>& dst);

\short Creates background update mask.
\short Initializes background update mask by selected source index.

All images must have the same width, height and format (8-bit gray).

For every point:
\verbatim
if(mask[i] == index)
if(src[i] == index)
dst[i] = value;
\endverbatim
Otherwise dst[i] is left unchanged.

This function is used for background updating in motion detection algorithm.

Expand Down