Using PHP to Capture Camera Stream and Perform Emotion Recognition

Camera devices are ubiquitous, and recognizing human emotions via camera has become feasible with AI. This article explains how to operate a camera using PHP and analyze emotions through facial expression parsing.

1. Preparation

First, install the PHP GD library for image processing: sudo apt-get install php7.4-gd Then install the V4L2 utilities:

sudo apt-get install v4l-utils

2. Obtaining Camera Video Stream

Use PHP's shell_exec to run an FFmpeg command that captures a single frame from the camera and saves it as an image, then display it with an <img> tag.

<?php
function getVideoStream() {
    $cmd = "ffmpeg -i /dev/video0 -vf fps=1 -s 1280x720 -f image2 -frames 1 /path/to/image.jpg";
    shell_exec($cmd);
    return "/path/to/image.jpg";
}
$videoStream = getVideoStream();
echo "<img src='$videoStream'>";
?>

3. Emotion Recognition and Facial Parsing

Integrate the open‑source Fer2013 emotion‑recognition model. Pass the captured image path to a Python script that returns the detected emotion.

4. Complete Example

<?php
function getVideoStream() {
    $cmd = "ffmpeg -i /dev/video0 -vf fps=1 -s 1280x720 -f image2 -frames 1 /path/to/image.jpg";
    shell_exec($cmd);
    return "/path/to/image.jpg";
}
function getEmotion($imagePath) {
    $modelPath = "path/to/Fer2013/model.hdf5";
    $cmd = "python3 scripts/emotion_classification.py $modelPath $imagePath";
    $emotion = shell_exec($cmd);
    return $emotion;
}
$videoStream = getVideoStream();
$emotion = getEmotion($videoStream);
echo "<img src='$videoStream'>";
echo "Current emotion: $emotion";
?>

Running this script displays the live camera frame on a web page and prints the inferred emotion.

Conclusion

The guide demonstrates a basic workflow for using PHP to capture camera video, process the image, and perform emotion recognition, providing a starting point for integrating such technology into projects.