Real time tile inspection s/w development (2005)
A real time algorithm (< 300 ms) was needed to check the size of marble tiles on a running belt corridor. Marble colors were also important therefore both geometric and color (radiometric) calibration has been performed prior to operation. Each tile was checked for size and corner orthogonality, then cropped from the image and stored in a data base for further processing.
The algorithm also includes internal self checks for the linear CCD and informs operates when needs cleaning or it should be replaced. A large number of tile failure cases were tested so that the algorithm is fail safe in production mode.
The main geometric algorithm is based in Prewitt edge extraction, thresholding and robust least squares line fitting. Corners are detected as line intersections. Tile dimensioning was checked against design sizes. Final cropping of tile image in a predefined image size for data base storage was performed using projective transformation. Code in C++
Under the I-Stone (NMP priority FP6) project, in collaboration with Zenon S.A.
For further info see publications
The algorithm also includes internal self checks for the linear CCD and informs operates when needs cleaning or it should be replaced. A large number of tile failure cases were tested so that the algorithm is fail safe in production mode.
The main geometric algorithm is based in Prewitt edge extraction, thresholding and robust least squares line fitting. Corners are detected as line intersections. Tile dimensioning was checked against design sizes. Final cropping of tile image in a predefined image size for data base storage was performed using projective transformation. Code in C++
Under the I-Stone (NMP priority FP6) project, in collaboration with Zenon S.A.
For further info see publications
Below you may see original images from the CCD sensor and the detected edges of the tile overlaid in red
