Exact Meaning of the parameters given to initialize MSER in OpenCV 2.4.x?

Question

OpenCV reference manual (2.4.x) states that the constructor that initializes MSER requires the following parameters:

delta, min_area, max_area, max_variation, min_d

Answer 1

Matlab has an almost identical function MSER. In Mathworks you can find very well explained what are those parameters for, in my opinion.

I will copy the 2 inputs definitions you ask for (there are no options, in Matlab, for color images):

• _delta. Step size between intensity threshold levels, specified as the comma-separated pair consisting of 'ThresholdDelta' and a numeric value in the range (0,100]. This value is expressed as a percentage of the input data type range used in selecting extremal regions while testing for their stability. Decrease this value to return more regions. Typical values range from 0.8 to 4.

• _max_variation. Maximum area variation between extremal regions at varying intensity thresholds, specified as the comma-separated pair consisting of 'MaxAreaVariation' and a positive scalar value. Increasing this value returns a greater number of regions, but they may be less stable. Stable regions are very similar in size over varying intensity thresholds. Typical values range from 0.1 to 1.0.

However, as penelope says, the original paper is very useful for a more deep understanding of the full process. Also, I give this reference of a very interesting comparison between well-known feature detectors.