Tutorial: Find similar images from previous searches using an image insights token

The Visual Search client library enables you to find images online from previous searches that return an ImageInsightsToken. This application gets an ImageInsightsToken and uses the token in a subsequent search. It then sends the ImageInsightsToken to Bing and returns results that include Bing Search URLs and URLs of similar images found online.

The full source code for this tutorial can be found with additional error handling and annotations on GitHub.

Prerequisites

• Any edition of Visual Studio 2019.
• If you are using Linux/MacOS, you can run this application using Mono.
• The NuGet Visual Search and Image Search packages.
  • From the Solution Explorer in Visual Studio, right-click on your project and select Manage NuGet Packages from the menu. Install the Microsoft.Azure.CognitiveServices.Search.CustomSearch package, and the Microsoft.Azure.CognitiveServices.Search.ImageSearch package. Installing the NuGet packages also installs the following:
    • Microsoft.Rest.ClientRuntime
    • Microsoft.Rest.ClientRuntime.Azure
    • Newtonsoft.Json

Create an Azure resource

Start using the Bing Visual Search API by creating one of the following Azure resources:

Bing Search v7 resource

• Available through the Azure portal until you delete the resource.
• Select the S9 pricing tier.

Multi-service resource

• Available through the Azure portal until you delete the resource.
• Use the same key and endpoint for your applications, across multiple Azure AI services.

Get the ImageInsightsToken from the Bing Image Search client library

This application uses an ImageInsightsToken obtained through the Bing Image Search client library. In a new C# console application, create a client to call the API using ImageSearchClient(). Then use SearchAsync() with your query:

var client = new ImageSearchClient(new Microsoft.Azure.CognitiveServices.Search.ImageSearch.ApiKeyServiceClientCredentials(subKey));
var imageResults = client.Images.SearchAsync(query: "canadian rockies").Result;
Console.WriteLine("Search images for query \"canadian rockies\"");

Store the first search result using imageResults.Value.First(), and then store the image insight's ImageInsightsToken.

String insightTok = "None";
if (imageResults.Value.Count > 0)
{
    var firstImageResult = imageResults.Value.First();
    insightTok = firstImageResult.ImageInsightsToken;
}
else
{
    insightTok = "None found";
    Console.WriteLine("Couldn't find image results!");
}

This ImageInsightsToken is sent to Bing Visual Search in a request.

Add the ImageInsightsToken to a Visual Search request

Specify the ImageInsightsToken for a Visual Search request by creating an ImageInfo object from the ImageInsightsToken contained in responses from Bing Visual Search.

ImageInfo ImageInfo = new ImageInfo(imageInsightsToken: insightsTok);

Use Bing Visual Search to find images from an ImageInsightsToken

The VisualSearchRequest object contains information about the image in ImageInfo to be searched. The VisualSearchMethodAsync() method gets the results. You don't have to provide an image binary, as the image is represented by the token.

VisualSearchRequest VisualSearchRequest = new VisualSearchRequest(ImageInfo);

var visualSearchResults = client.Images.VisualSearchMethodAsync(knowledgeRequest: VisualSearchRequest).Result;

Iterate through the Visual Search results

Visual Search results are ImageTag objects. Each tag contains a list of ImageAction objects. Each ImageAction contains a Data field, which is a list of values that depend on the type of action. You can iterate through the ImageTag objects in visualSearchResults.Tags, for instance, and get the ImageAction tag within it. The sample below prints the details of PagesIncluding actions:

if (visualSearchResults.Tags.Count > 0)
{
    // List of tags
    foreach (ImageTag t in visualSearchResults.Tags)
    {
        foreach (ImageAction i in t.Actions)
        {
            Console.WriteLine("\r\n" + "ActionType: " + i.ActionType + " WebSearchURL: " + i.WebSearchUrl);

            if (i.ActionType == "PagesIncluding")
            {
                foreach (ImageObject o in (i as ImageModuleAction).Data.Value)
                {
                    Console.WriteLine("ContentURL: " + o.ContentUrl);
                }
            }
        }
    }
}

PagesIncluding ActionTypes

Getting the actual image URLs from action types requires a cast that reads an ActionType as ImageModuleAction, which contains a Data element with a list of values. Each value is the URL of an image. The following casts the PagesIncluding action type to ImageModuleAction and reads the values:

    if (i.ActionType == "PagesIncluding")
    {
        foreach(ImageObject o in (i as ImageModuleAction).Data.Value)
        {
            Console.WriteLine("ContentURL: " + o.ContentUrl);
        }
    }

For more information about these data types, see Images - Visual Search.

Returned URLs

The complete application returns the following URLs:

As shown above, the TopicResults and ImageResults types contain queries for related images. The URLs link to Bing search results.

Next steps