Improves performance a bit. 2.2x on P9 and 2 - 3x on coffee lake
x86-64.

* Adding support for vectorized masking for uchar/ushort.

* Fixing bug where mask was zeroing the dst. Improved the way to calculate
the mask and tweaked for further performance improvements.

* Fixing mask comparison test.

* Restricting to one channel.

* Adding support for 3 channels, switch old approach to start using HAL's
v_select.

* New v_reverse HAL intrinsic for reversing the ordering of a vector

* Fix conflict.

* Try to resolve conflict again.

* Try one more time.

* Add _MM_SHUFFLE. Remove non-vectorize code in SSE2. Fix copy and paste issue with NEON.

* Change v_uint16x8 SSE2 version to use shuffles

- IPP/SSE4.2 works well

- before main() launch

VTK_MAJOR_VERSION not found unless header is included

pylint 1.8.3

…mple

The usage function states that the default for match_conf is
0.65 if the default SURF feature finder is used, and 0.3 for
orbs. Indeed, if --feature orbs is used, match_conf is set
to 0.3f. This is a NOP, because the real default is also set
to 0.3f. Change it to 0.65f when SURF is in play.

…ing_surf_default

Fixing bug with comparison of v_int64x2 or v_uint64x2

* Casting v_uint64x2 to v_float64x2 and comparing does NOT work in all cases.  Rewrite using epi64 instructions - faster too.

* Fix bad merge.

* Fix equal comparsion for non-SSE4.1. Add test cases for v_int64x2 comparisons.

* Try to fix merge conflict.

* Only test v_int64x2 comparisons if CV_SIMD_64F

* Fix compiler warning.

I think it would help to change all 3 of the the input file arguments to be "positional" for consistency with the other tutorials. This also simplifies the command line input to run this tutorial by reducing typing, and helpfully prints the "usage" info if any of the 3 required inputs are missing.

I'm new to OpenCV and working through the tutorials. I kept getting runtime errors with this one until I realized that the arguments weren't positional, and I was missing the "--input1", "--input2, "--input3" flags preceding the filenames. All of the previous tutorials had required filenames as positional arguments and didn't require this.

The original code would require each input to be specified like this:
./compareHist_Demo --input1 filename1 --input2 filename2 --input3 filename3 

But with this change, the above command is simplified to:
./compareHist_Demo  filename1 filename2 filename3

This avoids a confusing runtime error to make things simpler for newcomers like me :)