Detect human faces using Python
Tags: ai, python
Published: 2023-02-27 05:35:31

_**SOME GENERAL INSIGHTS ABOUT THIS POST**_
This post will cover all of the fundamental knowledge about AI in general as well as the library and language recommended to create a detect human faces application.

**_ARTIFICIAL INTELLIGENCE IN A NUTSHELL_**
Artificial intelligence has made significant advancements in computer vision, or the capacity of computers to comprehend and interpret images and movies, in recent years. Face detection, which is the act of identifying and locating human faces in an image or video, is one typical use of computer vision. This article will discuss how to utilize Python's artificial intelligence library to recognize human faces.

Let's first talk about the idea of artificial intelligence. Artificial intelligence is the capacity of machines to carry out operations that ordinarily require human intelligence, such as comprehending speech, recognize natural language, and forming judgements based on facts. Machine learning is a branch of artificial intelligence that deals with the process of teaching a computer system to make predictions based on data

Using a variety of algorithms, models, and methodologies, machine learning enables a computer to learn and enhance its performance over time. In order to find patterns in the data and create predictions based on those patterns, these algorithms employ statistical techniques.

Image and video analysis can be solved using machine learning, which is a potent technique. Machine learning techniques can be used to recognize faces, track motion, and identify objects in the field of computer vision.

**_SO WHAT IS HUMAN FACE DETECTION?_**

The detection of human faces in an image is a classic machine learning problem that may be solved using a number of well-liked algorithms. The Viola-Jones algorithm, which was created in 2001 by Paul Viola and Michael Jones, is one of the most frequently used algorithms. The eyes, nose, and mouth are among the traits that this programme looks for using a method known as Haar cascades.

**_WHAT IS OPENCV ( PYTHON LIBRARY ) AND WHY SHOULD WE USE IT_**

A well-liked open-source Python package for computer vision and image processing is called OpenCV (Open Source Computer Vision). It provides a variety of capabilities, including as face detection, for image and video analysis.

Pros:

Accuracy: OpenCV's face detection algorithm has been thoroughly tested on a wide range of images and is incredibly accurate.

Performance: For real-time applications, OpenCV offers quick speed thanks to its high level of optimization.

Simple and intuitive API provided by OpenCV makes it simple to use and comprehend.

Cross-platform: OpenCV can be used on Windows, macOS, and Linux as well as other operating systems because it is cross-platform.

Strong developer community: OpenCV has a sizable and active developer community, making it simple to obtain assistance and support.

Cons:

Training: Although OpenCV offers pre-trained models for face identification, it can be difficult to train your own models.

False positives: On occasion, the face identification algorithm in OpenCV may mistakenly recognise non-faces as faces.

Difficult configuration: Setting up OpenCV needs a process that can be challenging for beginners.

Restricted application: The face detection method in OpenCV is only effective on frontal faces; it may not be as effective on side profiles or other positions.

Problems with dependencies: OpenCV needs dependencies like NumPy and Matplotlib, which might complicate installation and configuration.

**_SO WHY PYTHON?_**

Python is a popular programming language used for various applications, including computer vision and image processing. Here are some reasons why Python is a good choice for detecting human faces:

Large number of libraries: Python has a large number of libraries and frameworks for computer vision and image processing, including OpenCV, Dlib, and TensorFlow, which can make it easier to detect human faces.

Easy to read and write: Python has a simple syntax and is easy to read and write, making it easier for developers to create and maintain code for detecting human faces.

Cross-platform compatibility: Python is cross-platform and can run on various operating systems, including Windows, macOS, and Linux, making it accessible for developers on different platforms.

Extensive community support: Python has a large and active community of developers, which means that you can find help and support easily.

Integration with other languages: Python can be integrated with other languages such as C++ and Java, which can help developers optimize performance and increase the speed of the face detection process.

Prototyping: Python is a great language for rapid prototyping, which is important when developing new face detection algorithms or improving existing ones.

Overall, Python is a powerful programming language for detecting human faces, with a large number of libraries, cross-platform compatibility, and a strong community support. These factors make it an excellent choice for developers who want to create robust and accurate face detection systems.

**_OK. HERE IS HOW _**

Install OpenCV: If you haven't already, install the OpenCV library by running the following command in your terminal: `pip install opencv-python.`

Load the image: Use the OpenCV imread() function to load the image into memory. For example: `img = cv2.imread('image.jpg')`.

Convert the image to grayscale: Convert the image to grayscale using the OpenCV` cvtColor()` function. This is necessary because the Viola-Jones algorithm requires grayscale images. For example: `gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY).`

Load the face detection model: Use the OpenCV `CascadeClassifier() `function to load the pre-trained face detection model. For example: `face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml').
`
Detect faces: Use the `detectMultiScale()` method of the face detection model to detect human faces in the grayscale image. This method returns a list of rectangles that represent the bounding boxes of the detected faces. For example: f`aces = face_cascade.detectMultiScale(gray, scaleFactor=1.1, minNeighbors=5).`

Draw bounding boxes: Use the OpenCV rectangle() function to draw a bounding box around each detected face. For example:

```
for (x, y, w, h) in faces:
    cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)
```

Display the image: Use the OpenCV `imshow() `function

**_Other library implementation_**

**Dlib:**


```
import dlib
import cv2

detector = dlib.get_frontal_face_detector()
img = cv2.imread('test_image.jpg')

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

faces = detector(gray)

for face in faces:
    x, y, w, h = face.left(), face.top(), face.right(), face.bottom()
    cv2.rectangle(img, (x, y), (w, h), (255, 0, 0), 2)

cv2.imshow('img', img)
cv2.waitKey()
```


**TensorFlow**

```
import tensorflow as tf
import cv2

model = tf.keras.models.load_model('face_detection_model.h5')
img = cv2.imread('test_image.jpg')

input_data = cv2.resize(img, (224, 224))
input_data = input_data.reshape((1, 224, 224, 3))
input_data = input_data / 255.0

predictions = model.predict(input_data)

for box in predictions[0]:
    x, y, w, h = box
    x *= img.shape[1]
    y *= img.shape[0]
    w *= img.shape[1]
    h *= img.shape[0]
    cv2.rectangle(img, (int(x), int(y)), (int(w), int(h)), (255, 0, 0), 2)

cv2.imshow('img', img)
cv2.waitKey()


```

**Helpful links for further study**
Simple Application: https://www.youtube.com/watch?v=5cg_yggtkso
Deep Applicaton: https://www.youtube.com/watch?v=N_W4EYtsa10

Thanks for reading this post! Hope you find something interest here