Tips & tricks for text detection from images using Google Vision API in PHP

Tips & tricks for text detection from images using Google Vision API in PHP

In this tutorial, I will let you know how to get content of images with Google Vision API.

Google Vision API can easily detect and extract text from an image. There are two annotation features (TEXT_DETECTION, DOCUMENT_TEXT_DETECTION) that perform Optical Character Recognition and return the extracted text, if any.

In order to use Google Vision API, you will have to create new project or select an existing project and enable the Vision API.

Example

<!DOCTYPE html>
<html>
<head>
	<title>Tips & tricks for text detection from images using Google Vision API</title>
</head>
<body>

	<form enctype="multipart/form-data" action="" method="POST">
		Choose an image to upload: <input name="image" type="file" /><br />
		<input type="submit" value="Upload Document" />
	</form>

<?php

$url = "https://vision.googleapis.com/v1/images:annotate?key={api_key}";
$detection_type = "TEXT_DETECTION";
$image_validation = array('image/jpeg','image/png','image/gif');

if($_FILES){

	// validate uploaded file for allowed mime type
	if(in_array($_FILES['image']['type'],$image_validation)){	    	

		// base64 encode image
    	$image = file_get_contents($_FILES['image']['tmp_name']);
		$image_base64 = base64_encode($image);

		$json_request ='{
			  	"requests": [
					{
					"image": {
					    "content":"' . $image_base64. '"
					  },
					  "features": [
					      {
					      	"type": "' .$detection_type. '",
					      	"maxResults": 200
					      }
					  ]
					}
				]
			}';

		$curl = curl_init();
		curl_setopt($curl, CURLOPT_URL, $url);
		curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
		curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
		curl_setopt($curl, CURLOPT_HTTPHEADER, array("Content-type: application/json"));
		curl_setopt($curl, CURLOPT_POST, true);
		curl_setopt($curl, CURLOPT_POSTFIELDS, $json_request);
		$json_response = curl_exec($curl);
		$status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
		curl_close($curl);

		// verify if we got a correct response
		if ( $status != 200 ) {
			die("Something when wrong. Status code: $status" );
		}
		
		// create an image identifier for the uploaded file
		switch($_FILES['image']['type']){
			case 'image/jpeg':
				$im = imagecreatefromjpeg($_FILES['image']['tmp_name']);
				break;
			case 'image/png':
				$im = imagecreatefrompng($_FILES['image']['tmp_name']);
				break;
			case 'image/gif':
				$im = imagecreatefromgif($_FILES['image']['tmp_name']);
				break;
		}

		// transform the json response to an associative array
		$response = json_decode($json_response, true);			
		// display the first text annotation
		echo'<pre>';
		print_r($response['responses'][0]['textAnnotations'][0]['description']);
		echo'</pre>';
	
    }
    else{
    	echo 'File type not allowed';
    }

	}
?>

</body>
</html>


We are using cURL request to detect text from uploaded image using Google Vision API because everything is encapsulated in a RESTful API.

Share This Blog

Comment

Do you want to get our quality service for your business?