* feat: move gcgraph to detail

* chore: puts gcgraph cv::detail namespace

* Fix perpendicular decision of RotatedRect::RotatedRect

Error estimation is based on #12455.

* Fix abs to std::fabs and atan to std::atan

* add new chessboard detector

The chessboar detector is based on the paper.
Accurate Detection and Localization of Checkerboard Corners for
Calibration Alexander Duda, Udo Frese
British Machine Vision Conference, o.A., 2018.

It utilizes point symmetry of checkerboard corners in combination with a
localized Radon transform approximated by box filters to achieve high
performance even on large images. Here, tests have shown that the
ability to localize checkerboard corners is close to the theoretical
limit of 1/100 of a pixel while being considerably less sensitive
to image noise than standard methods.

* chessboard: add reference to bibtex file

* chessboard: add dependency to opencv_flann

* fix: test chesscorners. It is valid to return an empty list

In case no chessboard was detected it should be valid for the detector
to return an empty list.

For simplifcation, it should be allowed to return any number of corners
if they are flagged as not found.

* fix: opencv.bib remove empty lines

* fix: doc findChessboardCorners replace cvSize with cv::Size

* chessboard tests: factor out logic selecting detector

* chessboard: add unit test for findChessboardCorners2

This is includes a new chessboard generator which supports subpix
corners with high accuracy by wrapping an optimal chessboard using
wrapPerspective.

* fix: chessboard unit test - overwrite of default parameter flag of findCirclesGrid

* chessboard: remove trailing whitespace

* chessboard: fix debug drawing

* chessboard: fix some issues during code review

* chessboard: normalize asymmetric chessboard

* chessboard: fix float double warning

* remove trailing whitespace

* chessboards: fix compiler warnings

* chessboards: fix compiler warnings

* checkerboard: some performance improvements

* chessboard: remove NULL macros for language bindinges from internal headers

* chessboard: shorten license terms

* chessboard: remove unused internal method

* chessboard: set helper functions to static

* chessboard: fix normalizePoints1D using unshifted points

* chessboard: remove wrongly copied text

* chessboard: use CV_CheckTypeEQ macro

* chessboard: comment all NaN checks

* chessboard: use consistent color conversion

* chessboard: use CheckChannelEQ macro

* chessboard: assume gray color image for internal methods

* chessboard: use std::swap

* chessboard: use Mat.dataend

* chessboard: fix compiler warnings

* chessboard: replace some checks witch CV_CHECK macro

* chessboard: fix comparison function for partial sort

* chessboard: small cleanup

* chessboard: use short license header

* chessboard: rename findChessboard2 to findChessboardSB

* chessboard: fix type in unit test

When cross compiling with clang, the internal C++ headers are not found
when adding sysroot to -isystem, that is redundant anyway because it
will look for headers insider --sysroot path with same quality as it
would do with -isystem otherwise

Fixes errors like

FAILED: 3rdparty/openexr/CMakeFiles/IlmImf.dir/Iex/IexBaseExc.cpp.o
....
In file included from
TOPDIR/build/tmp/work/cortexa7t2hf-neon-vfpv4-bec-linux-musleabi/opencv/3.4.3+gitAUTOINC+b38c50b3_1f6d6f0626_bdb7bb85f3_34e4206aef_fccf7cd6a4-r0/git/3rdparty/openexr/Iex/IexBaseExc.cpp:43:
In file included from
TOPDIR/build/tmp/work/cortexa7t2hf-neon-vfpv4-bec-linux-musleabi/opencv/3.4.3+gitAUTOINC+b38c50b3_1f6d6f0626_bdb7bb85f3_34e4206aef_fccf7cd6a4-r0/git/3rdparty/openexr/Iex/IexBaseExc.h:48:
In file included from
TOPDIR/build/tmp/work/cortexa7t2hf-neon-vfpv4-bec-linux-musleabi/opencv/3.4.3+gitAUTOINC+b38c50b3_1f6d6f0626_bdb7bb85f3_34e4206aef_fccf7cd6a4-r0/recipe-sysroot/usr/lib//arm-bec-linux-musleabi/8.2.0/../../../include/c++/8.2.0/string:52:
In file included from
TOPDIR/build/tmp/work/cortexa7t2hf-neon-vfpv4-bec-linux-musleabi/opencv/3.4.3+gitAUTOINC+b38c50b3_1f6d6f0626_bdb7bb85f3_34e4206aef_fccf7cd6a4-r0/recipe-sysroot/usr/lib//arm-bec-linux-musleabi/8.2.0/../../../include/c++/8.2.0/bits/basic_string.h:6391:
In file included from
TOPDIR/build/tmp/work/cortexa7t2hf-neon-vfpv4-bec-linux-musleabi/opencv/3.4.3+gitAUTOINC+b38c50b3_1f6d6f0626_bdb7bb85f3_34e4206aef_fccf7cd6a4-r0/recipe-sysroot/usr/lib//arm-bec-linux-musleabi/8.2.0/../../../include/c++/8.2.0/ext/string_conversions.h:41:
TOPDIR/build/tmp/work/cortexa7t2hf-neon-vfpv4-bec-linux-musleabi/opencv/3.4.3+gitAUTOINC+b38c50b3_1f6d6f0626_bdb7bb85f3_34e4206aef_fccf7cd6a4-r0/recipe-sysroot/usr/lib//arm-bec-linux-musleabi/8.2.0/../../../include/c++/8.2.0/cstdlib:75:15:
fatal error: 'stdlib.h' file not found
              ^~~~~~~~~~
1 error generated.
Signed-off-by: Khem Raj <raj.khem@gmail.com>

Feature/region layer batch mode (#12249)

* Add batch mode for Darknet networks.

Swap variables in test_darknet.

Adapt reorg layer to batch mode.

Adapt region layer.

Add OpenCL implementation.

Remove trailing whitespace.

Bugifx reorg opencl implementation.

Fix bug in OpenCL reorg.

Fix modulo bug.

Fix bug.

Reorg openCL.

Restore reorg layer opencl code.

OpenCl fix.

Work on openCL reorg.

Remove whitespace.

Fix openCL region layer implementation.

Fix bug.

Fix softmax region opencl bug.

Fix opencl bug.

Fix openCL bug.

Update aff_trans.cpp

When the fullAffine parameter is set to false, the estimateRigidTransform function maybe return empty, then the _localAffineEstimate function will be called, but the bug in it will result in incorrect results.

core(libva): support YV12 too

Added to CPU path only.
OpenCL code path still expects NV12 only (according to Intel OpenCL extension)

cmake: allow to specify own libva paths

via CMake:
- `-DVA_LIBRARIES=/opt/intel/mediasdk/lib64/libva.so.2\;/opt/intel/mediasdk/lib64/libva-drm.so.2`

android: NDK17 support

tested with NDK 17b (17.1.4828580)

Enable more deep learning tests using Intel's Inference Engine backend

ts: don't pass NULL for std::string() constructor

openvino: use 2018R3 defines

experimental version++

OpenCV version++

OpenCV 3.4.3

OpenCV version '-openvino'

openvino: use 2018R3 defines

Fixed windows build with InferenceEngine

dnn: fix variance setting bug for PriorBoxLayer

- The size of second channel should be size[2] of output tensor,
- The Scalar should be {variance[0], variance[0], variance[0], variance[0]}
  for _variance.size() == 1 case.
Signed-off-by: Wu Zhiwen <zhiwen.wu@intel.com>

Fix lifetime of networks which are loaded from Model Optimizer IRs

Adds a small note describing BUILD_opencv_world (#12332)

* Added a mall note describing BUILD_opencv_world cmake option to the Installation in Windows tutorial.

* Made slight changes in BUILD_opencv_world documentation.

* Update windows_install.markdown

improved grammar

Update opengl_interop.cpp

resolves #12307

java: fix LIST_GET macro

fix typo

Added option to fail on missing testdata

Fixed that object_detection.py does not work in python3.

cleanup: IPP Async (IPP_A)

except header file with conversion routines (will be removed in OpenCV 4.0)

imgcodecs: add null pointer check

Include preprocessing nodes to object detection TensorFlow networks (#12211)

* Include preprocessing nodes to object detection TensorFlow networks

* Enable more fusion

* faster_rcnn_resnet50_coco_2018_01_28 test

countNonZero function reworked to use wide universal intrinsics instead of SSE2 intrinsics

resolve #5788

imgcodecs(webp): multiple fixes

- don't reallocate passed 'img' (test fixed - must use IMREAD_UNCHANGED / IMREAD_ANYCOLOR)
- avoid memory DDOS
- avoid reading of whole file during header processing
- avoid data access after allocated buffer during header processing (missing checks)
- use WebPFree() to free allocated buffers (libwebp >= 0.5.0)
- drop unused & undefined `.close()` method
- added checks for channels >= 5 in encoder

ml: fix adjusting K in KNearest (#12358)

dnn(perf): fix and merge Convolution tests

- OpenCL tests didn't run any OpenCL kernels
- use real configuration from existed models (the first 100 cases)
- batch size = 1

dnn(test): use dnnBackendsAndTargets() param generator

Bit-exact resize reworked to use wide intrinsics (#12038)

* Bit-exact resize reworked to use wide intrinsics

* Reworked bit-exact resize row data loading

* Added bit-exact resize row data loaders for SIMD256 and SIMD512

* Fixed type punned pointer dereferencing warning

* Reworked loading of source data for SIMD256 and SIMD512 bit-exact resize

Bit-exact GaussianBlur reworked to use wide intrinsics (#12073)

* Bit-exact GaussianBlur reworked to use wide intrinsics

* Added v_mul_hi universal intrinsic

* Removed custom SSE2 branch from bit-exact GaussianBlur

* Removed loop unrolling for gaussianBlur horizontal smoothing

doc: fix English gramma in tutorial out-of-focus-deblur filter (#12214)

* doc: fix English gramma in tutorial out-of-focus-deblur filter

* Update out_of_focus_deblur_filter.markdown

slightly modified one sentence

doc: add new tutorial motion deblur filter (#12215)

* doc: add new tutorial motion deblur filter

* Update motion_deblur_filter.markdown

a few minor changes

Replace Slice layer to Crop in Faster-RCNN networks from Caffe

js: use generated list of OpenCV headers

- replaces hand-written list

imgcodecs(webp): use safe cast to size_t on Win32

* Put Version status back to -dev.

follow the common codestyle

Exclude some target engines.

Refactor formulas.

Refactor code.

* Remove unused variable.

* Remove inference engine check for yolov2.

* Alter darknet batch tests to test with two different images.

* Add yolov3 second image GT.

* Fix bug.

* Fix bug.

* Add second test.

* Remove comment.

* Add NMS on network level.

* Add helper files to dev.

* syntax fix.

* Fix OD sample.

Fix sample dnn object detection.

Fix NMS boxes bug.

remove trailing whitespace.

Remove debug function.

Change thresholds for opencl tests.

* Adapt score diff and iou diff.

* Alter iouDiffs.

* Add debug messages.

* Adapt iouDiff.

* Fix tests

find innercircle of contour by using pointPolygonTest: (#12206)