Welcome to the exciting world of PHP-OpenCV! This blog post will guide you through installing and using the PHP extension for OpenCV, a powerful library for computer vision. Though the project is no longer in active development, the existing code can still be incredibly useful.

Requirements

• OpenCV version 4.0.0 or higher
• PHP version 7.0 or higher

Installation

Let’s dive into how you can get PHP-OpenCV up and running. There are two main methods to install PHP-OpenCV:

Method 1: Use OpenCV Docker (Recommended)

If you’re new to OpenCV and want a smooth installation, consider using a Docker image. It’s a quick way to get started, and it only takes up around 300 MB, including opencv_contrib.

bash
docker pull hihozhou/php-opencv

Method 2: Compile and Install the PHP-OpenCV Extension

For those who prefer a more hands-on approach, you can follow these steps:

bash
git clone https://github.com/hihozhou/php-opencv.git
cd php-opencv
phpize
./configure --with-php-config=your php-config path
make
make install

Configuration

After installation, configure the extension by modifying your php.ini file:

ini
extension=your opencv.so path

Using PHP-OpenCV: Examples

Now that you’ve installed OpenCV, let’s look at some practical examples to understand its capabilities better.

Example 1: LBPH Face Recognition

Picture OpenCV as a skilled detective that can recognize faces in a crowded room. Here’s how you can harness that power:

php
use CV\Face\LBPHFaceRecognizer;
use ...;

$src = imread('facePic.jpg');
$gray = cvtColor($src, COLOR_BGR2GRAY);
equalizeHist($gray, $gray);

$faceRecognizer = LBPHFaceRecognizer::create();
// Get $images and $labels for training
$faceRecognizer->train($images, $labels);
$faceLabel = $faceRecognizer->predict($gray);

Example 2: Image Processing

In this scenario, let’s visualize an image of Obama. Think of it as opening a photo album—each image tells a story:

php
use function CV\imread, imshow, waitKey, namedWindow;

$im = imread('Obama.png');
// Load image
namedWindow('This is Obama id card', WINDOW_FULLSCREEN);
imshow('This is Obama id card', $im);
waitKey(0);

Example 3: Drawing Something on an Image

Imagine you’re an artist sketching on a canvas. Here, you’re creating an ellipse on a blank image:

php
use CV\Mat, Scalar, Point, Size;
use function CV\ellipse, imwrite, waitKey;
use const CV\CV_8UC3;

$windowWidth = 600;
$matScalar = new Scalar(0, 0, 0);
$mat = new Mat($windowWidth, $windowWidth, CV_8UC3, $matScalar);
$point = new Point($windowWidth / 2, $windowWidth / 2);
$size = new Size($windowWidth / 4, $windowWidth / 16);
$scalar = new Scalar(255, 129, 0);

for ($i = 0; $i < 360; $i += 45) {
    ellipse($mat, $point, $size, $i, 0, 360, $scalar, 2, 8);
}
imwrite('tests/ellipse.png', $mat);

Troubleshooting

Not everything goes as planned. Here are a few common issues you might encounter:

• PHP-OpenCV not loading: Make sure to double-check the path in your php.ini file. If the extension path is incorrect, PHP won’t be able to find the OpenCV library.
• Image not showing: Ensure the file name and path to the image are correct in your code. Typos can sneak in!
• Compilation errors: Verify your PHP version and OpenCV installation to ensure they meet the specified requirements.

For more insights, updates, or to collaborate on AI development projects, stay connected with fxis.ai.

Wrapping Up

At fxis.ai, we believe that such advancements are crucial for the future of AI, as they enable more comprehensive and effective solutions. Our team is continually exploring new methodologies to push the envelope in artificial intelligence, ensuring that our clients benefit from the latest technological innovations.

With the PHP-OpenCV extension, you're well on your way to creating powerful computer vision applications. Dive in and explore the possibilities!