-215 opencv assertion_error ai_generated true

cv::error: (-215:Assertion failed) !_dictionary.empty() in function 'detectMarkers'

ID: opencv/aruco-dictionary-not-found

Also available as: JSON · Markdown · 中文
92%Fix Rate
86%Confidence
1Evidence
2024-01-05First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
4.6.0 active — — —
4.8.1 active — — —
4.9.0 active — — —

Root Cause

The ArUco dictionary object passed to cv::aruco::detectMarkers is empty or not properly initialized, often due to an invalid dictionary ID or failed creation.

generic

中文

传递给 cv::aruco::detectMarkers 的 ArUco 字典对象为空或未正确初始化，通常是由于无效的字典 ID 或创建失败。

Official Documentation

https://docs.opencv.org/4.x/d5/dae/tutorial_aruco_detection.html

Workarounds

  1. 95% success Use a predefined dictionary: cv::aruco::Dictionary dictionary = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250); 
    Use a predefined dictionary: cv::aruco::Dictionary dictionary = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);
  2. 90% success Check dictionary availability before use: if (dictionary.empty()) { /* fallback */ } 
    Check dictionary availability before use: if (dictionary.empty()) { /* fallback */ }

中文步骤

  1. 使用预定义字典：cv::aruco::Dictionary dictionary = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);
  2. 在使用前检查字典是否为空：if (dictionary.empty()) { /* 回退 */ }

Dead Ends

Common approaches that don't work:

  1. 80% fail

    The dictionary object may be empty if not populated with marker images; detectMarkers requires a non-empty dictionary with predefined markers.

  2. 85% fail

    If the dictionary ID is not available in the OpenCV build, the constructor returns an empty dictionary, causing the assertion.