How can I split objects (verso dots and recto dots) in Braille into 2 efferents images ?

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Answer 1

[Image Analyst]

Google told me how to do it.

It said to follow the directions in this paper: http://ieeexplore.ieee.org/abstract/document/5601020/?reload=true

Abstract: This paper presents a new algorithm for Braille cells recognition using image processing technique. Scanned Braille document is composed from three classes of gray-level: (i) background, (ii) recto dots, and (iii) verso dots. We segment the Braille image using a stability thresholding method with a mixture of Beta distributions. To ensure correct detection and extraction of dots composing Braille cells, a grid is formed to contain the Braille dots. We identified a recto dot by a light region that exists above a dark region using the segmented image. In the same way, we identify a verso dot in double sided document by a light region that exists below a dark region. After having recto and verso dots, Braille cells are then recognized based on the standard regrouping of dots. Experimentation showed that Braille cells composing are automatically identified from those grids with excellent accuracy.

[Israa Alqaraleh]

[Israa Alqaraleh]

Im trying to do that depending on the size of the dots ... I still have incorrect results so I need another way for splitting of the 2 types of dots ... when looking for the dots they have 2 shapes of semicircles . the directions of them are right and left .... how can I split these 2 shapes in Matlab ...Which I'm not familiar with ...can you help me

[Image Analyst]

I don't know why you think the area or direction of dots is the way to distinguish them when the paper mentioned a different way. Since the paper method worked and yours didn't why are you still trying your way?

To get the direction of the blobs, you can use regionprops() to get the BoundingBox and Orientation angle. If the angle is between 45 and 135, it's vertical. If the height (from BoundingBox is greater than the width, it's vertical.

See my Image Segmentation Tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862&sort=downloads_desc

[Israa Alqaraleh]

In the link you have a demo for thresholding I searched for a way to threshold the image above to segment it into 3 regions recto dots verso dots and background but I failed ... researchers did that by adaptive thresholding .... do you have a way for that please