findCirclesGrid fails (sometimes) (Bug #3277)

Added by Nikolas Engelhard over 11 years ago. Updated over 11 years ago.

Status:Done Start date:2013-09-20
Priority:Normal Due date:
Assignee:Vladislav Vinogradov % Done:

0%
Category:calibration, 3d
Target version:3.0-alpha
Affected version:branch 'master' (2.9) Operating System:Linux
Difficulty: HW Platform:x64
Pull request:https://github.com/Itseez/opencv/pull/1497

Description

I can reproduce a assertion error when trying to find the Marker on the attached imag using OpenCV 2.9.0.0.
Code:

Mat bw = imread("fail.png",cv::IMREAD_GRAYSCALE);
        vector<cv::Point2f> pointBuf;
        bool grid_visible = cv::findCirclesGrid(bw, cv::Size(4,11), pointBuf, cv::CALIB_CB_ASYMMETRIC_GRID);

Error:

OpenCV Error: Assertion failed (scn m.cols || scn + 1 m.cols) in transform, file /home/magazino/opencv/modules/core/src/matmul.cpp, line 1748
terminate called after throwing an instance of 'cv::Exception'
what(): /home/magazino/opencv/modules/core/src/matmul.cpp:1748: error: (-215) scn m.cols || scn + 1 m.cols in function transform

This error is only triggered if the angle between the plane normal and the viewing direction of the camera is large. If the camera looks perpendicular to the marker normal, the marker
is correctly recognized.

Associated revisions

Revision e675684c
Added by Vladislav Vinogradov over 11 years ago

fix bug #3277 (findCirclesGrid failures):

findHomagraphy can return empty Mat in master branch

Revision 148e64d4
Added by Maksim Shabunin over 10 years ago

Merge pull request #3277 from a-wi:CMake_FFMPEG_config_v3

History

#1
Updated by Daniil Osokin over 11 years ago

Hi, Nicolas! Is this happen with your image only or not (please, attach fail.png)? Could you please clarify how it can be reproducibly?

  • Category set to calibration, 3d
  • Assignee set to Nikolas Engelhard
  • Target version set to 2.4.7

#2
Updated by Nikolas Engelhard over 11 years ago

Oh, sorry, here is one image which triggers the assertion: http://postimg.org/image/9s4xcy2rh/88de9f7c/

The code works however for this (very similar) image: http://postimg.org/image/5n44lia01/aa0739be/

It can be reproduced, by just reading the image and trying to detect the marker:

        rgb = imread("fail_pattern.png",cv::IMREAD_GRAYSCALE);
        vector<cv::Point2f> pointBuf;
        assert(rgb.type() == CV_8UC1);
        grid_visible = cv::findCirclesGrid(rgb, cv::Size(4,11), pointBuf, cv::CALIB_CB_ASYMMETRIC_GRID);

#3
Updated by Vladislav Vinogradov over 11 years ago

Hello, Nicolas!

Thanks for your report!

I was able to reproduce the issue and submitted patch with fix.

  • Assignee changed from Nikolas Engelhard to Vladislav Vinogradov
  • Pull request set to https://github.com/Itseez/opencv/pull/1497
  • Target version changed from 2.4.7 to 3.0-alpha
  • Status changed from New to Open

#4
Updated by Vladislav Vinogradov over 11 years ago

The pull request was merged.

  • Status changed from Open to Done

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