class `StaffFinder_miyao`

Last modified: October 27, 2015

Contents

StaffFinder_miyao
- find_staves

`StaffFinder_miyao`

In module gamera.toolkits.musicstaves.stafffinder_miyao

This staff finding algorithm is a based on a paper by H. Miyao (see below).

The method as described by Miyao:

Find stave candidate points on equally spaced vertical scan lines
Use Dynamic Programming Matching to link stave candidate points
Link points vertically and identify stave groups as connected components
Adjust the edge point positions

Deviations from Miyao's method by Dalitz:

The mismatch penalty in the Dynamic Programming Matching is set to three instead of two
The number of lines per staff system is automatically guessed as the most frequent vertical link runlength
Points on the same vertical scanline with the same staff/line label are melted into a single point

Limitations:

Cannot deal with a varying number of lines per staff as in mixed music and tablature prints

References:

Hidetoshi Miyao: Stave Extraction for Printed Music Scores. in H. Yin et al. (Eds.): IDEAL 2002, LNCS 2412, pp. 562-568, Springer (2002)
Hidetoshi Miyao, Masayuki Okamoto: Stave Extraction for Printed Music Scores Using DP Matching. Journal of Advanced Computational Intelligence and Intelligent Informatics, Vol. 8 No. 2 (2004)
Gina M. Cannarozzi: String Alignment using Dynamic Programming

Note that the first two references are almost identical, with the second somewhat more detailed.

Author:	Christoph Dalitz (after an algorithm by H. Miyao)

`find_staves`

Finds staff lines from a music/tablature image with Miyao's method.

Signature:

find_staves(num_lines=0, scanlines=20, blackness=0.8, tolerance=-1, debug=0)

with

num_lines:

Number of lines within one staff. When zero, the number is automatically detected.

scan_lines:

Number of vertical scan lines for extracting candidate points.

blackness:

Required blackness on the connection line between two candidate points in order to consider them matching.

tolerance:

How much the vertical black runlength of a candidate point may deviate from staffline_height. When negative, this value is set to max([2, staffline_height / 4]).

debug:

When > 0, information about each step is printed to stdout (flushed immediately). When > 1, runtime information is printed. When > 2, the information about some steps is more detailed. When > 3, a number of images is written into the current working directory; the image names have the prefix miyaodebug.

class StaffFinder_miyao

StaffFinder_miyao

find_staves

class `StaffFinder_miyao`

`StaffFinder_miyao`

`find_staves`