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Merge pull request #29034 from rmsalinas:fix-arucodictionary

objdetect(aruco): fix maxCorrectionBits in predefined dictionaries #29034

This PR fixes the bugs in the creation of some dictionaries and standarizes its construction.

## Bugs
1. **DICT_ARUCO_MIP_36h12_DATA** was incorrectly assigned `maxCorrectionBits=12`, which is the intermarker distance. This was causing a high rate of false positives during detection, which is a significant problem.
2. **APRILTAG** dictionaries were incorrectly created with `maxCorrectionBits=0`, making it impossible to do error correction.

## Solution
Given a intermarker distance X, the correct `maxCorrectionBits = X/2 - 1`. Thus, standardize the construction of Dictionaries as such.
This commit is contained in:
Rafael Muñoz Salinas
2026-05-19 08:18:29 +02:00
committed by GitHub
parent 6b40aa6637
commit 8c8b266b74
@@ -266,36 +266,42 @@ Mat Dictionary::getBitsFromByteList(const Mat &byteList, int markerSize, int rot
Dictionary getPredefinedDictionary(PredefinedDictionaryType name) {
// The maximum number of bits that can be corrected is theoretically (d-1)/2,
// where d is the minimum Hamming distance between any two codes in the dictionary.
// However, we use a more conservative limit (d/2)-1 to reduce the probability
// of false positives during detection. This formula is equivalent to the
// theoretical limit for even distances and stricter for odd distances.
// DictionaryData constructors calls
// moved out of globals so construted on first use, which allows lazy-loading of opencv dll
static const Dictionary DICT_ARUCO_DATA = Dictionary(Mat(1024, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_ARUCO_BYTES), 5, 0);
static const Dictionary DICT_ARUCO_DATA = Dictionary(Mat(1024, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_ARUCO_BYTES), 5, (3-1)/2);
static const Dictionary DICT_4X4_50_DATA = Dictionary(Mat(50, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, 1);
static const Dictionary DICT_4X4_100_DATA = Dictionary(Mat(100, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, 1);
static const Dictionary DICT_4X4_250_DATA = Dictionary(Mat(250, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, 1);
static const Dictionary DICT_4X4_1000_DATA = Dictionary(Mat(1000, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, 0);
static const Dictionary DICT_4X4_50_DATA = Dictionary(Mat(50, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, (4-1)/2);
static const Dictionary DICT_4X4_100_DATA = Dictionary(Mat(100, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, (3-1)/2);
static const Dictionary DICT_4X4_250_DATA = Dictionary(Mat(250, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, (3-1)/2);
static const Dictionary DICT_4X4_1000_DATA = Dictionary(Mat(1000, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_4X4_1000_BYTES), 4, (2-1)/2);
static const Dictionary DICT_5X5_50_DATA = Dictionary(Mat(50, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, 3);
static const Dictionary DICT_5X5_100_DATA = Dictionary(Mat(100, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, 3);
static const Dictionary DICT_5X5_250_DATA = Dictionary(Mat(250, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, 2);
static const Dictionary DICT_5X5_1000_DATA = Dictionary(Mat(1000, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, 2);
static const Dictionary DICT_5X5_50_DATA = Dictionary(Mat(50, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, (8-1)/2);
static const Dictionary DICT_5X5_100_DATA = Dictionary(Mat(100, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, (7-1)/2);
static const Dictionary DICT_5X5_250_DATA = Dictionary(Mat(250, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, (6-1)/2);
static const Dictionary DICT_5X5_1000_DATA = Dictionary(Mat(1000, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_5X5_1000_BYTES), 5, (5-1)/2);
static const Dictionary DICT_6X6_50_DATA = Dictionary(Mat(50, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, 6);
static const Dictionary DICT_6X6_100_DATA = Dictionary(Mat(100, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, 5);
static const Dictionary DICT_6X6_250_DATA = Dictionary(Mat(250, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, 5);
static const Dictionary DICT_6X6_1000_DATA = Dictionary(Mat(1000, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, 4);
static const Dictionary DICT_6X6_50_DATA = Dictionary(Mat(50, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, (13-1)/2);
static const Dictionary DICT_6X6_100_DATA = Dictionary(Mat(100, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, (12-1)/2);
static const Dictionary DICT_6X6_250_DATA = Dictionary(Mat(250, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, (11-1)/2);
static const Dictionary DICT_6X6_1000_DATA = Dictionary(Mat(1000, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_6X6_1000_BYTES), 6, (9-1)/2);
static const Dictionary DICT_7X7_50_DATA = Dictionary(Mat(50, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, 9);
static const Dictionary DICT_7X7_100_DATA = Dictionary(Mat(100, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, 8);
static const Dictionary DICT_7X7_250_DATA = Dictionary(Mat(250, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, 8);
static const Dictionary DICT_7X7_1000_DATA = Dictionary(Mat(1000, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, 6);
static const Dictionary DICT_7X7_50_DATA = Dictionary(Mat(50, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, (19-1)/2);
static const Dictionary DICT_7X7_100_DATA = Dictionary(Mat(100, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, (18-1)/2);
static const Dictionary DICT_7X7_250_DATA = Dictionary(Mat(250, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, (17-1)/2);
static const Dictionary DICT_7X7_1000_DATA = Dictionary(Mat(1000, (7 * 7 + 7) / 8, CV_8UC4, (uchar*)DICT_7X7_1000_BYTES), 7, (14-1)/2);
static const Dictionary DICT_APRILTAG_16h5_DATA = Dictionary(Mat(30, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_16h5_BYTES), 4, 0);
static const Dictionary DICT_APRILTAG_25h9_DATA = Dictionary(Mat(35, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_25h9_BYTES), 5, 0);
static const Dictionary DICT_APRILTAG_36h10_DATA = Dictionary(Mat(2320, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_36h10_BYTES), 6, 0);
static const Dictionary DICT_APRILTAG_36h11_DATA = Dictionary(Mat(587, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_36h11_BYTES), 6, 0);
static const Dictionary DICT_APRILTAG_16h5_DATA = Dictionary(Mat(30, (4 * 4 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_16h5_BYTES), 4, (5-1)/2);
static const Dictionary DICT_APRILTAG_25h9_DATA = Dictionary(Mat(35, (5 * 5 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_25h9_BYTES), 5, (9-1)/2);
static const Dictionary DICT_APRILTAG_36h10_DATA = Dictionary(Mat(2320, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_36h10_BYTES), 6, (10-1)/2);
static const Dictionary DICT_APRILTAG_36h11_DATA = Dictionary(Mat(587, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_APRILTAG_36h11_BYTES), 6, (11-1)/2);
static const Dictionary DICT_ARUCO_MIP_36h12_DATA = Dictionary(Mat(250, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_ARUCO_MIP_36h12_BYTES), 6, 12);
static const Dictionary DICT_ARUCO_MIP_36h12_DATA = Dictionary(Mat(250, (6 * 6 + 7) / 8, CV_8UC4, (uchar*)DICT_ARUCO_MIP_36h12_BYTES), 6, (12-1)/2);
switch(name) {