Identify Paragraphs

I’m learning computer vision and I’m using the Opencv and Python to write algorithms in this field of computer science. This field is very interisting because it envolves computer science and math. It is necessary to have good ideas to solve the problems.

Here, I will show my first algorithm in computer vision. It is to identifies paragraphs in a text image. It consider that the image have a white background and that the characters have a black color.

This algorithm have two main ideas: First, it removes blank lines and columns before finding the text. After this, it calculate the number of blank lines between no blank lines. The minimum and the maximum number of blank lines is computed. Though that the number of blank lines between two no blank lines is greather or equal 90%(maximum - minimum), we consider that we found a new paragraph.

Below, you can see the image with text to input in the algorithm:

Text extract from python's doc

And in the image below is possible to see the image with the identified paragraphs:

Identified paragraphs

You can download the algorithm and get more details in the repository: https://github.com/joaojunior/identify_paragraphs_in_image

Resources in Operational Research

I write a list of operational research resource. In this list have many name of books, events, groups, solvers and teachers. I publish this list here: awesome-operational_research. It is a github’s repository and you can help to update :-)

I write based on the list, wrote by Avelino, about resources for go programming language.

You can also read this in Medium.

Callbacks in Cplex

I will try to use LazyConstraintCallback to implement a Branch and Cut algorithm with CPLEX, but when I implemented and run this algorithm, it is very slow if I compare with version that don’t use callbacks in Cplex. It is because ControlCallback(LazyConstraintCallback is a ControlCallback) switch Cplex to sequential mode by default and turn off dynamic search. I write this post, because I don’t find this information in Cplex’s documentation, I only found this information in this technical forum.

You can also read this in Medium.