Archive | Tutorials

How-To: 3 Ways to Compare Histograms using OpenCV and Python

So you’ve extracted color histograms from a set of images… But how are you going to compare them for similarity? You’ll need a distance function to handle that. But which one? How you choose? And how do you compare histograms using Python and OpenCV? Don’t worry, I’ve got you covered. In this blog post I’ll […]

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Announcing “Case Studies: Solving real world problems with computer vision”

I have some big news to announce today… Besides writing a ton of blog posts about computer vision, image processing, and image search engines, I’ve been behind the scenes, working on a second book. And you may be thinking, hey, didn’t you just finish up Practical Python and OpenCV? Yep. I did. Now, don’t get […]

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Building a Pokedex in Python: Comparing Shape Descriptors with OpenCV (Step 6 of 6)

Here we are, the final step of building a real-life Pokedex in Python and OpenCV. This is where it all comes together. We’ll glue all our pieces together and put together an image search engine based on shape features. We explored what it takes to build a Pokedex using computer vision. Then we scraped the web […]

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Building a Pokedex in Python: OpenCV and Perspective Warping (Step 5 of 6)

We’re getting closer to finishing up our real-life Pokedex! In my previous blog post, I showed you how to find a Game Boy screen in an image using Python and OpenCV. This post will show you how to apply warping transformations to obtain a “birds-eye-view” of the Game Boy screen. From there, we will be […]

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Building a Pokedex in Python: Finding the Game Boy Screen (Step 4 of 6)

Quick question. How does a Pokedex work? Well, you simply point it a Pokemon, the Pokedex examines its physical characteristics, and the Pokemon is identified instantly. Looking for the source code to this post? Jump right to the downloads section. In this case, our smartphone camera is our “Pokedex”. We point our smartphone at our […]

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Building a Pokedex in Python: Indexing our Sprites using Shape Descriptors (Step 3 of 6)

So, how is our Pokedex going to “know” what Pokemon is in an image? How are we going to describe each Pokemon? Are we going to characterize the color of the Pokemon? The texture? Or the shape? Well, do you remember playing Who’s that Pokemon as a kid? You were able to identify the Pokemon […]

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