English
English
Image processing refers to the technique of performing various operations on digital images to improve their quality, reduce noise, or convert the color space from one to another, such as from RGB to CMYK.
Image processing technology is widely used in e-commerce for product image optimization, photo editing software, social media platforms, and more. Common operations include resizing, cropping, rotating, watermarking, and applying filters.
GD is the most commonly used image processing library in PHP, available for PHP 5.0 and above. It offers a variety of functions for modifying images, such as resizing, cropping, merging, and also supports image format conversion and basic color operations.
Here is an example demonstrating how to resize an image to 150x150 using the GD library:
$src = imagecreatefromjpeg('image.jpg');
$dst = imagecreatetruecolor(150, 150);
imagecopyresampled($dst, $src, 0, 0, 0, 0, 150, 150, imagesx($src), imagesy($src));
header('Content-type: image/jpeg');
imagejpeg($dst);
imagedestroy($src);
imagedestroy($dst);
In this example, we use imagecreatefromjpeg() to create the original image resource, imagecreatetruecolor() to create the target image, imagecopyresampled() to perform high-quality resizing, and finally imagejpeg() to output the result.
Image recognition is the process of automatically extracting and interpreting the information contained in digital images. This process involves using a series of algorithms and models for object detection and classification.
Deep learning mimics the structure of the human brain’s neural networks for learning, with convolutional neural networks (CNN) being the core model for handling grid-like data, such as images, sounds, and sequential data, widely used in image recognition.
Tesseract is an open-source OCR (Optical Character Recognition) engine developed by Google, capable of recognizing text in multiple languages.
Here is an example of how to use Imagick and TesseractOCR to recognize text in an image with PHP:
$image = new \Imagick('image.png');
$image->setImageFormat('jpeg');
$image->writeImage('image.jpg');
$tesseract = new \TesseractOCR('image.jpg');
$tesseract->setTempDir('/tmp');
$text = $tesseract->recognize();
echo $text;
In the code, Imagick is used to convert the PNG image to JPEG format, and TesseractOCR is used to extract text from the image. Note that the TesseractOCR library must be installed before using it.
This article introduced the key technologies for image processing and image recognition in PHP, focusing on the image operations provided by the GD library and the OCR text recognition with Tesseract. Mastering these techniques will greatly enhance the efficiency and quality of image-related functionalities in development.
