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Merge pull request #28804 from asmorkalov:as/calib_boards_migration

Migrated chessboard and circles grid detectors to objdetect #28804
  
OpenCV Contrib: https://github.com/opencv/opencv_contrib/pull/4125
OpenCV Extra: https://github.com/opencv/opencv_extra/pull/1375

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
This commit is contained in:
Alexander Smorkalov
2026-05-27 16:06:51 +03:00
committed by GitHub
parent dafe7cef97
commit e19b0ebc5c
41 changed files with 880 additions and 456 deletions
@@ -45,6 +45,7 @@
#define OPENCV_OBJDETECT_HPP
#include "opencv2/core.hpp"
#include "opencv2/features.hpp"
#include "opencv2/objdetect/aruco_detector.hpp"
#include "opencv2/objdetect/graphical_code_detector.hpp"
#include "opencv2/objdetect/mcc_checker_detector.hpp"
@@ -316,6 +317,269 @@ public:
CV_WRAP void setArucoParameters(const aruco::DetectorParameters& params);
};
enum { CALIB_CB_ADAPTIVE_THRESH = 1,
CALIB_CB_NORMALIZE_IMAGE = 2,
CALIB_CB_FILTER_QUADS = 4,
CALIB_CB_FAST_CHECK = 8,
CALIB_CB_EXHAUSTIVE = 16,
CALIB_CB_ACCURACY = 32,
CALIB_CB_LARGER = 64,
CALIB_CB_MARKER = 128,
CALIB_CB_PLAIN = 256
};
enum { CALIB_CB_SYMMETRIC_GRID = 1,
CALIB_CB_ASYMMETRIC_GRID = 2,
CALIB_CB_CLUSTERING = 4
};
/** @brief Finds the positions of internal corners of the chessboard.
@param image Source chessboard view. It must be an 8-bit grayscale or color image.
@param patternSize Number of inner corners per a chessboard row and column
( patternSize = cv::Size(points_per_row,points_per_column) = cv::Size(columns,rows) ).
@param corners Output array of detected corners.
@param flags Various operation flags that can be zero or a combination of the following values:
- @ref CALIB_CB_ADAPTIVE_THRESH Use adaptive thresholding to convert the image to black
and white, rather than a fixed threshold level (computed from the average image brightness).
- @ref CALIB_CB_NORMALIZE_IMAGE Normalize the image gamma with equalizeHist before
applying fixed or adaptive thresholding.
- @ref CALIB_CB_FILTER_QUADS Use additional criteria (like contour area, perimeter,
square-like shape) to filter out false quads extracted at the contour retrieval stage.
- @ref CALIB_CB_FAST_CHECK Run a fast check on the image that looks for chessboard corners,
and shortcut the call if none is found. This can drastically speed up the call in the
degenerate condition when no chessboard is observed.
- @ref CALIB_CB_PLAIN All other flags are ignored. The input image is taken as is.
No image processing is done to improve to find the checkerboard. This has the effect of speeding up the
execution of the function but could lead to not recognizing the checkerboard if the image
is not previously binarized in the appropriate manner.
The function attempts to determine whether the input image is a view of the chessboard pattern and
locate the internal chessboard corners. The function returns a non-zero value if all of the corners
are found and they are placed in a certain order (row by row, left to right in every row).
Otherwise, if the function fails to find all the corners or reorder them, it returns 0. For example,
a regular chessboard has 8 x 8 squares and 7 x 7 internal corners, that is, points where the black
squares touch each other. The detected coordinates are approximate, and to determine their positions
more accurately, the function calls #cornerSubPix. You also may use the function #cornerSubPix with
different parameters if returned coordinates are not accurate enough.
Sample usage of detecting and drawing chessboard corners: :
@code
Size patternsize(8,6); //interior number of corners
Mat gray = ....; //source image
vector<Point2f> corners; //this will be filled by the detected corners
//CALIB_CB_FAST_CHECK saves a lot of time on images
//that do not contain any chessboard corners
bool patternfound = findChessboardCorners(gray, patternsize, corners,
CALIB_CB_ADAPTIVE_THRESH + CALIB_CB_NORMALIZE_IMAGE
+ CALIB_CB_FAST_CHECK);
if(patternfound)
cornerSubPix(gray, corners, Size(11, 11), Size(-1, -1),
TermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 30, 0.1));
drawChessboardCorners(img, patternsize, Mat(corners), patternfound);
@endcode
@note The function requires white space (like a square-thick border, the wider the better) around
the board to make the detection more robust in various environments. Otherwise, if there is no
border and the background is dark, the outer black squares cannot be segmented properly and so the
square grouping and ordering algorithm fails.
Use the `generate_pattern.py` Python script (@ref tutorial_camera_calibration_pattern)
to create the desired checkerboard pattern.
*/
CV_EXPORTS_W bool findChessboardCorners( InputArray image, Size patternSize, OutputArray corners,
int flags = CALIB_CB_ADAPTIVE_THRESH + CALIB_CB_NORMALIZE_IMAGE );
/*
Checks whether the image contains chessboard of the specific size or not.
If yes, nonzero value is returned.
*/
CV_EXPORTS_W bool checkChessboard(InputArray img, Size size);
/** @brief Finds the positions of internal corners of the chessboard using a sector based approach.
@param image Source chessboard view. It must be an 8-bit grayscale or color image.
@param patternSize Number of inner corners per a chessboard row and column
( patternSize = cv::Size(points_per_row,points_per_column) = cv::Size(columns,rows) ).
@param corners Output array of detected corners.
@param flags Various operation flags that can be zero or a combination of the following values:
- @ref CALIB_CB_NORMALIZE_IMAGE Normalize the image gamma with equalizeHist before detection.
- @ref CALIB_CB_EXHAUSTIVE Run an exhaustive search to improve detection rate.
- @ref CALIB_CB_ACCURACY Up sample input image to improve sub-pixel accuracy due to aliasing effects.
- @ref CALIB_CB_LARGER The detected pattern is allowed to be larger than patternSize (see description).
- @ref CALIB_CB_MARKER The detected pattern must have a marker (see description).
This should be used if an accurate camera calibration is required.
@param meta Optional output array of detected corners (CV_8UC1 and size = cv::Size(columns,rows)).
Each entry stands for one corner of the pattern and can have one of the following values:
- 0 = no meta data attached
- 1 = left-top corner of a black cell
- 2 = left-top corner of a white cell
- 3 = left-top corner of a black cell with a white marker dot
- 4 = left-top corner of a white cell with a black marker dot (pattern origin in case of markers otherwise first corner)
The function is analog to #findChessboardCorners but uses a localized radon
transformation approximated by box filters being more robust to all sort of
noise, faster on larger images and is able to directly return the sub-pixel
position of the internal chessboard corners. The Method is based on the paper
@cite duda2018 "Accurate Detection and Localization of Checkerboard Corners for
Calibration" demonstrating that the returned sub-pixel positions are more
accurate than the one returned by cornerSubPix allowing a precise camera
calibration for demanding applications.
In the case, the flags @ref CALIB_CB_LARGER or @ref CALIB_CB_MARKER are given,
the result can be recovered from the optional meta array. Both flags are
helpful to use calibration patterns exceeding the field of view of the camera.
These oversized patterns allow more accurate calibrations as corners can be
utilized, which are as close as possible to the image borders. For a
consistent coordinate system across all images, the optional marker (see image
below) can be used to move the origin of the board to the location where the
black circle is located.
@note The function requires a white boarder with roughly the same width as one
of the checkerboard fields around the whole board to improve the detection in
various environments. In addition, because of the localized radon
transformation it is beneficial to use round corners for the field corners
which are located on the outside of the board. The following figure illustrates
a sample checkerboard optimized for the detection. However, any other checkerboard
can be used as well.
Use the `generate_pattern.py` Python script (@ref tutorial_camera_calibration_pattern)
to create the corresponding checkerboard pattern:
\image html pics/checkerboard_radon.png width=60%
*/
CV_EXPORTS_AS(findChessboardCornersSBWithMeta)
bool findChessboardCornersSB(InputArray image,Size patternSize, OutputArray corners,
int flags,OutputArray meta);
/** @overload */
CV_EXPORTS_W inline
bool findChessboardCornersSB(InputArray image, Size patternSize, OutputArray corners,
int flags = 0)
{
return findChessboardCornersSB(image, patternSize, corners, flags, noArray());
}
/** @brief Estimates the sharpness of a detected chessboard.
Image sharpness, as well as brightness, are a critical parameter for accuracte
camera calibration. For accessing these parameters for filtering out
problematic calibraiton images, this method calculates edge profiles by traveling from
black to white chessboard cell centers. Based on this, the number of pixels is
calculated required to transit from black to white. This width of the
transition area is a good indication of how sharp the chessboard is imaged
and should be below ~3.0 pixels.
@param image Gray image used to find chessboard corners
@param patternSize Size of a found chessboard pattern
@param corners Corners found by #findChessboardCornersSB
@param rise_distance Rise distance 0.8 means 10% ... 90% of the final signal strength
@param vertical By default edge responses for horizontal lines are calculated
@param sharpness Optional output array with a sharpness value for calculated edge responses (see description)
The optional sharpness array is of type CV_32FC1 and has for each calculated
profile one row with the following five entries:
* 0 = x coordinate of the underlying edge in the image
* 1 = y coordinate of the underlying edge in the image
* 2 = width of the transition area (sharpness)
* 3 = signal strength in the black cell (min brightness)
* 4 = signal strength in the white cell (max brightness)
@return Scalar(average sharpness, average min brightness, average max brightness,0)
*/
CV_EXPORTS_W Scalar estimateChessboardSharpness(InputArray image, Size patternSize, InputArray corners,
float rise_distance=0.8F,bool vertical=false,
OutputArray sharpness=noArray());
//! finds subpixel-accurate positions of the chessboard corners
CV_EXPORTS_W bool find4QuadCornerSubpix( InputArray img, InputOutputArray corners, Size region_size );
/** @brief Renders the detected chessboard corners.
@param image Destination image. It must be an 8-bit color image.
@param patternSize Number of inner corners per a chessboard row and column
(patternSize = cv::Size(points_per_row,points_per_column)).
@param corners Array of detected corners, the output of #findChessboardCorners.
@param patternWasFound Parameter indicating whether the complete board was found or not. The
return value of #findChessboardCorners should be passed here.
The function draws individual chessboard corners detected either as red circles if the board was not
found, or as colored corners connected with lines if the board was found.
*/
CV_EXPORTS_W void drawChessboardCorners( InputOutputArray image, Size patternSize,
InputArray corners, bool patternWasFound );
struct CV_EXPORTS_W_SIMPLE CirclesGridFinderParameters
{
CV_WRAP CirclesGridFinderParameters();
CV_PROP_RW cv::Size2f densityNeighborhoodSize;
CV_PROP_RW float minDensity;
CV_PROP_RW int kmeansAttempts;
CV_PROP_RW int minDistanceToAddKeypoint;
CV_PROP_RW int keypointScale;
CV_PROP_RW float minGraphConfidence;
CV_PROP_RW float vertexGain;
CV_PROP_RW float vertexPenalty;
CV_PROP_RW float existingVertexGain;
CV_PROP_RW float edgeGain;
CV_PROP_RW float edgePenalty;
CV_PROP_RW float convexHullFactor;
CV_PROP_RW float minRNGEdgeSwitchDist;
enum GridType
{
SYMMETRIC_GRID, ASYMMETRIC_GRID
};
CV_PROP_RW GridType gridType;
CV_PROP_RW float squareSize; //!< Distance between two adjacent points. Used by CALIB_CB_CLUSTERING.
CV_PROP_RW float maxRectifiedDistance; //!< Max deviation from prediction. Used by CALIB_CB_CLUSTERING.
};
/** @brief Finds centers in the grid of circles.
@param image grid view of input circles; it must be an 8-bit grayscale or color image.
@param patternSize number of circles per row and column
( patternSize = Size(points_per_row, points_per_column) ).
@param centers output array of detected centers.
@param flags various operation flags that can be one of the following values:
- @ref CALIB_CB_SYMMETRIC_GRID uses symmetric pattern of circles.
- @ref CALIB_CB_ASYMMETRIC_GRID uses asymmetric pattern of circles.
- @ref CALIB_CB_CLUSTERING uses a special algorithm for grid detection. It is more robust to
perspective distortions but much more sensitive to background clutter.
@param blobDetector feature detector that finds blobs like dark circles on light background.
If `blobDetector` is NULL then `image` represents Point2f array of candidates.
@param parameters struct for finding circles in a grid pattern.
The function attempts to determine whether the input image contains a grid of circles. If it is, the
function locates centers of the circles. The function returns a non-zero value if all of the centers
have been found and they have been placed in a certain order (row by row, left to right in every
row). Otherwise, if the function fails to find all the corners or reorder them, it returns 0.
Sample usage of detecting and drawing the centers of circles: :
@code
Size patternsize(7,7); //number of centers
Mat gray = ...; //source image
vector<Point2f> centers; //this will be filled by the detected centers
bool patternfound = findCirclesGrid(gray, patternsize, centers);
drawChessboardCorners(img, patternsize, Mat(centers), patternfound);
@endcode
@note The function requires white space (like a square-thick border, the wider the better) around
the board to make the detection more robust in various environments.
*/
CV_EXPORTS_W bool findCirclesGrid( InputArray image, Size patternSize,
OutputArray centers, int flags,
const Ptr<FeatureDetector> &blobDetector,
const CirclesGridFinderParameters& parameters);
/** @overload */
CV_EXPORTS_W bool findCirclesGrid( InputArray image, Size patternSize,
OutputArray centers, int flags = CALIB_CB_SYMMETRIC_GRID,
const Ptr<FeatureDetector> &blobDetector = cv::SimpleBlobDetector::create());
//! @}
}