Analyze Images with Azure AI Vision

Azure AI Vision is an artificial intelligence capability that enables software systems to interpret visual input by analyzing images. In Microsoft Azure, the Vision Azure AI service provides pre-built models for common computer vision tasks, including analysis of images to suggest captions and tags, detection of common objects and people. You can also use the Azure AI Vision service to remove the background or create a foreground matting of images.

Clone the repository for this course

If you have not already cloned the Azure AI Vision code repository to the environment where you’re working on this lab, follow these steps to do so. Otherwise, open the cloned folder in Visual Studio Code.

  1. Start Visual Studio Code.
  2. Open the palette (SHIFT+CTRL+P) and run a Git: Clone command to clone the https://github.com/MicrosoftLearning/mslearn-ai-vision repository to a local folder (it doesn’t matter which folder).
  3. When the repository has been cloned, open the folder in Visual Studio Code.

  4. Wait while additional files are installed to support the C# code projects in the repo.

    Note: If you are prompted to add required assets to build and debug, select Not Now. If you are prompted with the Message Detected an Azure Function Project in folder, you can safely close that message.

Provision an Azure AI Services resource

If you don’t already have one in your subscription, you’ll need to provision an Azure AI Services resource.

  1. Open the Azure portal at https://portal.azure.com, and sign in using the Microsoft account associated with your Azure subscription.
  2. In the top search bar, search for Azure AI services, select Azure AI Services, and create an Azure AI services multi-service account resource with the following settings:
    • Subscription: Your Azure subscription
    • Resource group: Choose or create a resource group (if you are using a restricted subscription, you may not have permission to create a new resource group - use the one provided)
    • Region: Choose from East US, France Central, Korea Central, North Europe, Southeast Asia, West Europe, West US, or East Asia*
    • Name: Enter a unique name
    • Pricing tier: Standard S0

    *Azure AI Vision 4.0 features are currently only available in these regions.

  3. Select the required checkboxes and create the resource.
  4. Wait for deployment to complete, and then view the deployment details.
  5. When the resource has been deployed, go to it and view its Keys and Endpoint page. You will need the endpoint and one of the keys from this page in the next procedure.

Prepare to use the Azure AI Vision SDK

In this exercise, you’ll complete a partially implemented client application that uses the Azure AI Vision SDK to analyze images.

Note: You can choose to use the SDK for either C# or Python. In the steps below, perform the actions appropriate for your preferred language.

  1. In Visual Studio Code, in the Explorer pane, browse to the Labfiles/01-analyze-images folder and expand the C-Sharp or Python folder depending on your language preference.

  2. Right-click the image-analysis folder and open an integrated terminal. Then install the Azure AI Vision SDK package by running the appropriate command for your language preference:

    C#

     dotnet add package Azure.AI.Vision.ImageAnalysis -v 1.0.0-beta.1

    Note: If you are prompted to install dev kit extensions, you can safely close the message.

    Python

     pip install azure-ai-vision-imageanalysis==1.0.0b1
  3. View the contents of the image-analysis folder, and note that it contains a file for configuration settings:
    • C#: appsettings.json
    • Python: .env

    Open the configuration file and update the configuration values it contains to reflect the endpoint and an authentication key for your Azure AI services resource. Save your changes.

  4. Note that the image-analysis folder contains a code file for the client application:

    • C#: Program.cs
    • Python: image-analysis.py

    Open the code file and at the top, under the existing namespace references, find the comment Import namespaces. Then, under this comment, add the following language-specific code to import the namespaces you will need to use the Azure AI Vision SDK:

    C#

     // Import namespaces
 using Azure.AI.Vision.ImageAnalysis;

    Python

     # import namespaces
 from azure.ai.vision.imageanalysis import ImageAnalysisClient
 from azure.ai.vision.imageanalysis.models import VisualFeatures
 from azure.core.credentials import AzureKeyCredential

View the images you will analyze

In this exercise, you will use the Azure AI Vision service to analyze multiple images.

  1. In Visual Studio Code, expand the image-analysis folder and the images folder it contains.
  2. Select each of the image files in turn to view then in Visual Studio Code.

Analyze an image to suggest a caption

Now you’re ready to use the SDK to call the Vision service and analyze an image.

  1. In the code file for your client application (Program.cs or image-analysis.py), in the Main function, note that the code to load the configuration settings has been provided. Then find the comment Authenticate Azure AI Vision client. Then, under this comment, add the following language-specific code to create and authenticate a Azure AI Vision client object:

C#

// Authenticate Azure AI Vision client
ImageAnalysisClient client = new ImageAnalysisClient(
    new Uri(aiSvcEndpoint),
    new AzureKeyCredential(aiSvcKey));

Python

# Authenticate Azure AI Vision client
cv_client = ImageAnalysisClient(
    endpoint=ai_endpoint,
    credential=AzureKeyCredential(ai_key)
)

  1. In the Main function, under the code you just added, note that the code specifies the path to an image file and then passes the image path to two other functions (AnalyzeImage and BackgroundForeground). These functions are not yet fully implemented.

  2. In the AnalyzeImage function, under the comment Get result with specify features to be retrieved, add the following code:

C#

// Get result with specified features to be retrieved
ImageAnalysisResult result = client.Analyze(
    BinaryData.FromStream(stream),
    VisualFeatures.Caption | 
    VisualFeatures.DenseCaptions |
    VisualFeatures.Objects |
    VisualFeatures.Tags |
    VisualFeatures.People);

Python

# Get result with specified features to be retrieved
result = cv_client.analyze(
    image_data=image_data,
    visual_features=[
        VisualFeatures.CAPTION,
        VisualFeatures.DENSE_CAPTIONS,
        VisualFeatures.TAGS,
        VisualFeatures.OBJECTS,
        VisualFeatures.PEOPLE],
)
  1. In the AnalyzeImage function, under the comment Display analysis results, add the following code (including the comments indicating where you will add more code later.):

C#

// Display analysis results
// Get image captions
if (result.Caption.Text != null)
{
    Console.WriteLine(" Caption:");
    Console.WriteLine($"   \"{result.Caption.Text}\", Confidence {result.Caption.Confidence:0.00}\n");
}

// Get image dense captions
Console.WriteLine(" Dense Captions:");
foreach (DenseCaption denseCaption in result.DenseCaptions.Values)
{
    Console.WriteLine($"   Caption: '{denseCaption.Text}', Confidence: {denseCaption.Confidence:0.00}");
}

// Get image tags


// Get objects in the image


// Get people in the image

Python

# Display analysis results
# Get image captions
if result.caption is not None:
    print("\nCaption:")
    print(" Caption: '{}' (confidence: {:.2f}%)".format(result.caption.text, result.caption.confidence * 100))

# Get image dense captions
if result.dense_captions is not None:
    print("\nDense Captions:")
    for caption in result.dense_captions.list:
        print(" Caption: '{}' (confidence: {:.2f}%)".format(caption.text, caption.confidence * 100))

# Get image tags


# Get objects in the image


# Get people in the image
  1. Save your changes and return to the integrated terminal for the image-analysis folder, and enter the following command to run the program with the argument images/street.jpg:

C#

dotnet run images/street.jpg

Python

python image-analysis.py images/street.jpg
  1. Observe the output, which should include a suggested caption for the street.jpg image.
  2. Run the program again, this time with the argument images/building.jpg to see the caption that gets generated for the building.jpg image.
  3. Repeat the previous step to generate a caption for the images/person.jpg file.

Get suggested tags for an image

It can sometimes be useful to identify relevant tags that provide clues about the contents of an image.

  1. In the AnalyzeImage function, under the comment Get image tags, add the following code:

C#

// Get image tags
if (result.Tags.Values.Count > 0)
{
    Console.WriteLine($"\n Tags:");
    foreach (DetectedTag tag in result.Tags.Values)
    {
        Console.WriteLine($"   '{tag.Name}', Confidence: {tag.Confidence:F2}");
    }
}

Python

# Get image tags
if result.tags is not None:
    print("\nTags:")
    for tag in result.tags.list:
        print(" Tag: '{}' (confidence: {:.2f}%)".format(tag.name, tag.confidence * 100))
  1. Save your changes and run the program once for each of the image files in the images folder, observing that in addition to the image caption, a list of suggested tags is displayed.

Detect and locate objects in an image

Object detection is a specific form of computer vision in which individual objects within an image are identified and their location indicated by a bounding box..

  1. In the AnalyzeImage function, under the comment Get objects in the image, add the following code:

C#

// Get objects in the image
if (result.Objects.Values.Count > 0)
{
    Console.WriteLine(" Objects:");

    // Prepare image for drawing
    stream.Close();
    System.Drawing.Image image = System.Drawing.Image.FromFile(imageFile);
    Graphics graphics = Graphics.FromImage(image);
    Pen pen = new Pen(Color.Cyan, 3);
    Font font = new Font("Arial", 16);
    SolidBrush brush = new SolidBrush(Color.WhiteSmoke);

    foreach (DetectedObject detectedObject in result.Objects.Values)
    {
        Console.WriteLine($"   \"{detectedObject.Tags[0].Name}\"");

        // Draw object bounding box
        var r = detectedObject.BoundingBox;
        Rectangle rect = new Rectangle(r.X, r.Y, r.Width, r.Height);
        graphics.DrawRectangle(pen, rect);
        graphics.DrawString(detectedObject.Tags[0].Name,font,brush,(float)r.X, (float)r.Y);
    }

    // Save annotated image
    String output_file = "objects.jpg";
    image.Save(output_file);
    Console.WriteLine("  Results saved in " + output_file + "\n");
}

Python

# Get objects in the image
if result.objects is not None:
    print("\nObjects in image:")

    # Prepare image for drawing
    image = Image.open(image_filename)
    fig = plt.figure(figsize=(image.width/100, image.height/100))
    plt.axis('off')
    draw = ImageDraw.Draw(image)
    color = 'cyan'

    for detected_object in result.objects.list:
        # Print object name
        print(" {} (confidence: {:.2f}%)".format(detected_object.tags[0].name, detected_object.tags[0].confidence * 100))
        
        # Draw object bounding box
        r = detected_object.bounding_box
        bounding_box = ((r.x, r.y), (r.x + r.width, r.y + r.height)) 
        draw.rectangle(bounding_box, outline=color, width=3)
        plt.annotate(detected_object.tags[0].name,(r.x, r.y), backgroundcolor=color)

    # Save annotated image
    plt.imshow(image)
    plt.tight_layout(pad=0)
    outputfile = 'objects.jpg'
    fig.savefig(outputfile)
    print('  Results saved in', outputfile)
  1. Save your changes and run the program once for each of the image files in the images folder, observing any objects that are detected. After each run, view the objects.jpg file that is generated in the same folder as your code file to see the annotated objects.

Detect and locate people in an image

People detection is a specific form of computer vision in which individual people within an image are identified and their location indicated by a bounding box.

  1. In the AnalyzeImage function, under the comment Get people in the image, add the following code:

C#

// Get people in the image
if (result.People.Values.Count > 0)
{
    Console.WriteLine($" People:");

    // Prepare image for drawing
    System.Drawing.Image image = System.Drawing.Image.FromFile(imageFile);
    Graphics graphics = Graphics.FromImage(image);
    Pen pen = new Pen(Color.Cyan, 3);
    Font font = new Font("Arial", 16);
    SolidBrush brush = new SolidBrush(Color.WhiteSmoke);

    foreach (DetectedPerson person in result.People.Values)
    {
        // Draw object bounding box
        var r = person.BoundingBox;
        Rectangle rect = new Rectangle(r.X, r.Y, r.Width, r.Height);
        graphics.DrawRectangle(pen, rect);
        
        // Return the confidence of the person detected
        //Console.WriteLine($"   Bounding box {person.BoundingBox.ToString()}, Confidence: {person.Confidence:F2}");
    }

    // Save annotated image
    String output_file = "persons.jpg";
    image.Save(output_file);
    Console.WriteLine("  Results saved in " + output_file + "\n");
}

Python

# Get people in the image
if result.people is not None:
    print("\nPeople in image:")

    # Prepare image for drawing
    image = Image.open(image_filename)
    fig = plt.figure(figsize=(image.width/100, image.height/100))
    plt.axis('off')
    draw = ImageDraw.Draw(image)
    color = 'cyan'

    for detected_people in result.people.list:
        # Draw object bounding box
        r = detected_people.bounding_box
        bounding_box = ((r.x, r.y), (r.x + r.width, r.y + r.height))
        draw.rectangle(bounding_box, outline=color, width=3)

        # Return the confidence of the person detected
        #print(" {} (confidence: {:.2f}%)".format(detected_people.bounding_box, detected_people.confidence * 100))
        
    # Save annotated image
    plt.imshow(image)
    plt.tight_layout(pad=0)
    outputfile = 'people.jpg'
    fig.savefig(outputfile)
    print('  Results saved in', outputfile)

  1. (Optional) Uncomment the Console.Writeline command under the Return the confidence of the person detected section to review the confidence level returned that a person was detected at a particular position of the image.

  2. Save your changes and run the program once for each of the image files in the images folder, observing any objects that are detected. After each run, view the objects.jpg file that is generated in the same folder as your code file to see the annotated objects.

Note: In the preceding tasks, you used a single method to analyze the image, and then incrementally added code to parse and display the results. The SDK also provides individual methods for suggesting captions, identifying tags, detecting objects, and so on - meaning that you can use the most appropriate method to return only the information you need, reducing the size of the data payload that needs to be returned. See the .NET SDK documentation or Python SDK documentation for more details.

Remove the background or generate a foreground matte of an image

In some cases, you may need to create remove the background of an image or might want to create a foreground matte of that image. Let’s start with the background removal.

  1. In your code file, find the BackgroundForeground function; and under the comment Remove the background from the image or generate a foreground matte, add the following code:

C#

// Remove the background from the image or generate a foreground matte
Console.WriteLine($" Background removal:");
// Define the API version and mode
string apiVersion = "2023-02-01-preview";
string mode = "backgroundRemoval"; // Can be "foregroundMatting" or "backgroundRemoval"

string url = $"computervision/imageanalysis:segment?api-version={apiVersion}&mode={mode}";

// Make the REST call
using (var client = new HttpClient())
{
    var contentType = new MediaTypeWithQualityHeaderValue("application/json");
    client.BaseAddress = new Uri(endpoint);
    client.DefaultRequestHeaders.Accept.Add(contentType);
    client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", key);

    // You can change the url to use other images in the images folder,
    // such as "building.jpg" or "person.jpg" to see different results.
    var data = new
    {
        url="https://github.com/MicrosoftLearning/mslearn-ai-vision/blob/main/Labfiles/01-analyze-images/Python/image-analysis/images/street.jpg?raw=true"
    };

    var jsonData = JsonSerializer.Serialize(data);
    var contentData = new StringContent(jsonData, Encoding.UTF8, contentType);
    var response = await client.PostAsync(url, contentData);

    if (response.IsSuccessStatusCode) {
        File.WriteAllBytes("background.png", response.Content.ReadAsByteArrayAsync().Result);
        Console.WriteLine("  Results saved in background.png\n");
    }
    else
    {
        Console.WriteLine($"API error: {response.ReasonPhrase} - Check your body url, key, and endpoint.");
    }
}

Python

# Remove the background from the image or generate a foreground matte
print('\nRemoving background from image...')
    
url = "{}computervision/imageanalysis:segment?api-version={}&mode={}".format(endpoint, api_version, mode)

headers= {
    "Ocp-Apim-Subscription-Key": key, 
    "Content-Type": "application/json" 
}

image_url="https://github.com/MicrosoftLearning/mslearn-ai-vision/blob/main/Labfiles/01-analyze-images/Python/image-analysis/{}?raw=true".format(image_file)  

body = {
    "url": image_url,
}
    
response = requests.post(url, headers=headers, json=body)

image=response.content
with open("backgroundForeground.png", "wb") as file:
    file.write(image)
print('  Results saved in backgroundForeground.png \n')
  1. Save your changes and run the program once for each of the image files in the images folder, opening the background.png file that is generated in the same folder as your code file for each image. Notice how the background has been removed from each of the images.

Let’s now generate a foreground matte for our images.

  1. In your code file, find the BackgroundForeground function; and under the comment Define the API version and mode, change the mode variable to be foregroundMatting.

  2. Save your changes and run the program once for each of the image files in the images folder, opening the background.png file that is generated in the same folder as your code file for each image. Notice how a foreground matte has been generated for your images.

Clean up resources

If you’re not using the Azure resources created in this lab for other training modules, you can delete them to avoid incurring further charges. Here’s how:

  1. Open the Azure portal at https://portal.azure.com, and sign in using the Microsoft account associated with your Azure subscription.

  2. In the top search bar, search for Azure AI services multi-service account, and select the Azure AI services multi-service account resource you created in this lab.

  3. On the resource page, select Delete and follow the instructions to delete the resource.

More information

In this exercise, you explored some of the image analysis and manipulation capabilities of the Azure AI Vision service. The service also includes capabilities for detecting objects and people, and other computer vision tasks.

For more information about using the Azure AI Vision service, see the Azure AI Vision documentation.