Quickstart: Analyze a remote image using the REST API and PHP in Computer Vision

In this quickstart, you analyze a remotely stored image to extract visual features by using Computer Vision's REST API. With the Analyze Image method, you can extract visual features based on image content.

If you don't have an Azure subscription, create a free account before you begin.

Prerequisites

  • You must have PHP installed.
  • You must have Pear installed.
  • You must have a subscription key for Computer Vision. To get a subscription key, see Obtaining Subscription Keys.

Create and run the sample

To create and run the sample, do the following steps:

  1. Install the PHP5 HTTP_Request2 package.

    1. Open a command prompt window as an administrator.
    2. Run the following command:

      pear install HTTP_Request2
      
    3. After the package is successfully installed, close the command prompt window.

  2. Copy the following code into a text editor.

  3. Make the following changes in code where needed:
    1. Replace the value of subscriptionKey with your subscription key.
    2. Replace the value of uriBase with the endpoint URL for the Analyze Image method from the Azure region where you obtained your subscription keys, if necessary.
    3. Optionally, replace the value of imageUrl with the URL of a different image that you want to analyze.
    4. Optionally, replace the value of the language request parameter with a different language.
  4. Save the code as a file with a .php extension. For example, analyze-image.php.
  5. Open a browser window with PHP support.
  6. Drag and drop the file into the browser window.
<html>
<head>
    <title>Analyze Image Sample</title>
</head>
<body>
<?php
// Replace <Subscription Key> with a valid subscription key.
$ocpApimSubscriptionKey = '<Subscription Key>';

// You must use the same location in your REST call as you used to obtain
// your subscription keys. For example, if you obtained your subscription keys
// from westus, replace "westcentralus" in the URL below with "westus".
$uriBase = 'https://westcentralus.api.cognitive.microsoft.com/vision/v2.0/';

$imageUrl = 'http://upload.wikimedia.org/wikipedia/commons/3/3c/Shaki_waterfall.jpg';

require_once 'HTTP/Request2.php';

$request = new Http_Request2($uriBase . '/analyze');
$url = $request->getUrl();

$headers = array(
    // Request headers
    'Content-Type' => 'application/json',
    'Ocp-Apim-Subscription-Key' => $ocpApimSubscriptionKey
);
$request->setHeader($headers);

$parameters = array(
    // Request parameters
    'visualFeatures' => 'Categories,Description',
    'details' => '',
    'language' => 'en'
);
$url->setQueryVariables($parameters);

$request->setMethod(HTTP_Request2::METHOD_POST);

// Request body parameters
$body = json_encode(array('url' => $imageUrl));

// Request body
$request->setBody($body);

try
{
    $response = $request->send();
    echo "<pre>" .
        json_encode(json_decode($response->getBody()), JSON_PRETTY_PRINT) . "</pre>";
}
catch (HttpException $ex)
{
    echo "<pre>" . $ex . "</pre>";
}
?>
</body>
</html>

Examine the response

A successful response is returned in JSON. The sample website parses and displays a successful response in the browser window, similar to the following example:

{
  "categories": [
    {
      "name": "outdoor_water",
      "score": 0.9921875,
      "detail": {
        "landmarks": []
      }
    }
  ],
  "description": {
    "tags": [
      "nature",
      "water",
      "waterfall",
      "outdoor",
      "rock",
      "mountain",
      "rocky",
      "grass",
      "hill",
      "covered",
      "hillside",
      "standing",
      "side",
      "group",
      "walking",
      "white",
      "man",
      "large",
      "snow",
      "grazing",
      "forest",
      "slope",
      "herd",
      "river",
      "giraffe",
      "field"
    ],
    "captions": [
      {
        "text": "a large waterfall over a rocky cliff",
        "confidence": 0.916458423253597
      }
    ]
  },
  "requestId": "ebf5a1bc-3ba2-4c56-99b4-bbd20ba28705",
  "metadata": {
    "height": 959,
    "width": 1280,
    "format": "Jpeg"
  }
}

Clean up resources

When no longer needed, delete the file, and then uninstall the PHP5 HTTP_Request2 package. To uninstall the package, do the following steps:

  1. Open a command prompt window as an administrator.
  2. Run the following command:

    pear uninstall HTTP_Request2
    
  3. After the package is successfully uninstalled, close the command prompt window.

Next steps

Explore the Computer Vision API used to analyze an image, detect celebrities and landmarks, create a thumbnail, and extract printed and handwritten text. To rapidly experiment with the Computer Vision API, try the Open API testing console.