# Suramya's Blog: Welcome to my crazy life…

## August 27, 2020

### Optimizing the making of peanut butter and banana sandwich using computer vision and machine learning

Filed under: Computer Related,Computer Software,Tech Related — Suramya @ 12:42 AM

The current Pandemic is forcing people to stay at home depriving them of activities that kept them occupied in the past so people are getting a bit stir-crazy & bored of staying at home. Its worse for developers/engineers as you never know what will come out from the depths of a bored programmer’s mind. Case in point is the effort spent by Ethan Rosenthal in writing Machine Learning/Computer Vision code to Optimizing the coverage of the banana slices on his peanut butter & Banana sandwich so that there is the same amount of banana in every mouthful. The whole exercise took him a few months to complete and he is quite proud of the results.

It’s really quite simple. You take a picture of your banana and bread, pass the image through a deep learning model to locate said items, do some nonlinear curve fitting to the banana, transform to polar coordinates and “slice” the banana along the fitted curve, turn those slices into elliptical polygons, and feed the polygons and bread “box” into a 2D nesting algorithm
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If you were a machine learning model (or my wife), then you would tell me to just cut long rectangular strips along the long axis of the banana, but I’m not a sociopath. If life were simple, then the banana slices would be perfect circles of equal diameter, and we could coast along looking up optimal configurations on packomania. But alas, life is not simple. We’re in the middle of a global pandemic, and banana slices are elliptical with varying size.

The problem of fitting arbitrary polygons (sliced circular banana pieces) in a box (the bread piece) is NP-hard so the ideal solution is practically uncomputable and Rosenthal’s solution is a good approximation of the optimal solution in a reasonable time frame. The final solution is available as a command-line package called “nannernest” which takes a photo of the bread piece & banana as its argument and returns the an optimal slice-and-arrange pattern for the given combination.

Sample output created by nannernest

Check out the code & the full writeup on the project if you are interested. Even though the application is silly it’s a good writeup on using Machine Learning & Computer Vision for a project.

Source: Boing Boing

– Suramya

## 1 Comment »

1. Loved this! Thanks for sharing.

Comment by Ankush — September 9, 2020 @ 12:38 AM