The purpose of this change is to avoid the cost of supporting many
versions of OpenCV.

It was found that enabling multithreading for these functions did not
significantly improve performance compared to the single-threaded
equivalents.

Multithreading is only enabled in the OpenCV HAL. The multithreaded API
is likely to change and therefore is not supported for direct use.

Igor Podgainoi authored Jun 26, 2024 and Mark Horvath committed Jul 08, 2024

Sigma is the common notation for standard deviation. With this change
the standard deviation of the filter used for blurring can be set.

Igor Podgainoi authored Jun 25, 2024 and Igor Podgainoi committed Jun 25, 2024

Add a new entry to the changelog and fix excessive spacing in the
doc/opencv.md file.

Experiments have shown that although there's little scope for optimizing
such simple operations, the KleidiCV implementations are marginally
faster than OpenCV.

Don't enable 32-bit operations in HAL because OpenCV requires that these
do not saturate, unlike the KleidiCV implementations.