How to use PHP to implement image recognition and text extraction functions

How to use PHP to implement image recognition and text extraction functions

Abstract:

Nowadays, image recognition and text extraction are widely used in many fields Applications ranging from security monitoring systems to automated document processing are inseparable from these two functions. This article will introduce how to use PHP to implement image recognition and text extraction functions, and provide sample code.

Introduction:

Image recognition is a technology that uses computer algorithms and models to identify and classify images. Text extraction is to extract identifiable text from images through image processing technology. These two functions can be combined to achieve automatic recognition and extraction of text in images.

Steps:

1. Preparation

First, make sure that your PHP environment has installed relevant extensions, including GD library and Tesseract OCR library and related PHP extensions. The GD library is used for image processing and the Tesseract OCR library is used for text recognition.

2. Image recognition

To perform image recognition, we first need to load the image into the program. PHP provides imagecreatefromjpeg, imagecreatefrompng, imagecreatefromgif and other functions to load images in different formats.

Sample code:

<?php
// 加载 JPEG 图像
$image = imagecreatefromjpeg('image.jpg');

// 进行图像处理和识别操作

// 释放图像资源
imagedestroy($image);
?>

After loading the image, we can use various functions provided by the GD library to process the image, such as adjusting brightness, contrast, cropping, rotating, etc. After the image is processed, the image recognition algorithm can be called to identify the image.

3. Text extraction

To perform text extraction, we need to use the Tesseract OCR library. In PHP, this can be achieved through the tesseract-ocr/tesseract extension.

First, make sure that the Tesseract OCR library has been installed correctly and the correct path is configured in the system environment variables.

Sample code:

<?php
// 加载图像
$image = imagecreatefromjpeg('image.jpg');

// 将图像保存为临时文件
$tempImagePath = 'temp.jpg';
imagejpeg($image, $tempImagePath);

// 执行文字提取操作
$tesseractPath = 'tesseract';
$command = $tesseractPath . ' ' . $tempImagePath . ' output';

shell_exec($command);

// 读取输出文件中的文字内容
$outputFile = 'output.txt';
$text = file_get_contents($outputFile);
echo $text;

// 删除临时文件
unlink($tempImagePath);
unlink($outputFile);

// 释放图像资源
imagedestroy($image);
?>

In the sample code, we first save the image as a temporary file, and then use the shell_exec function to execute the tesseract command for text extraction. The content in the output file is the recognition to the text. Finally, the text content in the output file is read and printed.

Conclusion:

This article introduces how to use PHP to implement image recognition and text extraction functions, and provides relevant sample code. Through image recognition and text extraction, we can implement automated image processing and text recognition in various application scenarios, improving work efficiency and accuracy.

Reference link:

1. PHP GD extension document: https://www.php.net/manual/zh/book.image.php
2. Tesseract OCR ：https://github.com/tesseract-ocr/tesseract

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