3-Minute Face Detection Cooking on macOS X

Overview

I’m planning to build a toy that uses a Raspberry Pi so that when it decides you’re a family member, it says “Welcome home, master,” and when you’re not family, it says “I’m calling the cops.”

As a preliminary step to a preliminary step, let’s try detecting a face in a still image.

By the way, face detection and face recognition mean completely different things.

• Face detection … detecting the part of an image that is a face.
• Face recognition … determining that a face belongs to a specific person.

For setting up the environment, please refer to my previous article.

MacOSX に Python2, Python3 仮想環境構築 - 長生村本郷Engineers'Blog

以下に移行しました。 kenzo0107.github.io

Environment

• MacOSX 10.11.5
• Python 3

Installing CV2

• Install cv2 with homebrew

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$ brew tap homebrew/science
$ brew install opencv3 --with-python3

• Use Python 3

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$ source ~/py3env/bin/active
(py3env)$

• Copy cv2.so into pip’s site-packages

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(py3env)$ cd ~/py3env/lib/python3.4/site-packages
(py3env)$ cp /usr/local/Cellar/opencv3/3.1.0_3/lib/python3.4/site-packages/cv2.so .

• Verify the cv2 import

If the version is displayed, it worked.

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(py3env)$ python -c 'import cv2; print(cv2.__version__)'
3.1.0

Installing the Script

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(py3env)$ cd ~/py3env
(py3env)$ git clone https://gist.github.com/kenzo0107/5d174797a5a222295b5a39f6fa435777
(py3env)$ cp ./5d174797a5a222295b5a39f6fa435777/trimming.py .

Running the Script

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(py3env)$ python trimming.py <img_path>

• Before

• After

The leather pants got recognized as a face too…

but for now, it basically works.

Key Points of This Script

• To improve the accuracy of the detection count, we tune the parameters of the following detectMultiScale method in the script.

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facerect = cascade.detectMultiScale(image_gray, scaleFactor=1.02, minNeighbors=3, minSize=(7,7))

And there we have it: the very first step is done ♪