Identify and remove text from graph

2 views (last 30 days)
I'm in the process of designing a semi-automatic graph digitizer that can convert screenshots of a graph into a CSV file with the data.
I'm running into an issue when certain graphs contain characters and text boxes in the graph space, as in the example images below:
After removing the gridlines and producing a binary image "curve" (that's supposed to contain just the curve), my current code uses
[y, x] = find(curve)
to determine the x and y position of points on the curve. However, if there is any text on the graph, the code thinks it's part of the data curve and finds points in its location. As in the above examples, the code "finds" datapoints where the 'Conditions' and '3C96' text is located.
My question is: Is there any way to automatically detect and mask over this text, perhaps using OCR? Or is automating it a lost cause, and I should instead manually crop out any text initially?

Accepted Answer

Image Analyst
Image Analyst on 23 Jul 2021
Edited: Image Analyst on 23 Jul 2021
If the graphs are digital images, you can simply use bwareafilt() in the Image Processing Toolbox to take either the largest blob, or blobs within a certain size range. You might need to add some code options to handle cases where grid lines can be solid or dashed, whether text is in boxes or not, or whether you want the gridlines to remain in the output image or not.
By the way, there are File Exchange entries already:
Image Analyst
Image Analyst on 28 Jul 2021
If you have a consistent type of graph you're dealing with then it's possible to do it automatically. If however the graphs are wildly different, then developing an automatic solution may be more trouble than it's worth and it's best just to have user-assisted processing.

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by