Azure Cognitive Service\Computer Visio\OCR - Can I use it into into WebSite C#

Question

I'm trying to use Azure Ocr into my website c#. I added the package Microsoft.Azure.CognitiveServices.Vision.ComputerVision and I wrote code, with key and endpoint of my subscription.

static string subscriptionKey = "mykey";
static string endpoint = "https://myocr.cognitiveservices.azure.com/";

private const string ANALYZE_URL_IMAGE = "https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/printed_text.jpg";

protected void Page_Load(object sender, EventArgs e)
{
    // Create a client
    ComputerVisionClient client = Authenticate(endpoint, subscriptionKey);

    // Analyze an image to get features and other properties.
    AnalyzeImageUrl(client, ANALYZE_URL_IMAGE).Wait();
}

public static ComputerVisionClient Authenticate(string endpoint, string key)
{
    ComputerVisionClient client =
      new ComputerVisionClient(new ApiKeyServiceClientCredentials(key))
      { Endpoint = endpoint };
    return client;
}

public static async Task AnalyzeImageUrl(ComputerVisionClient client, string imageUrl)
{        
    // Read text from URL
    var textHeaders = await client.ReadAsync(imageUrl);
    ...
}

It seems all ok, but at line var textHeaders = await client.ReadAsync(urlFile); website crashes. I don't understand why. No error, it's just stopped.

So I ask: azure ocr can to be use only with console app?

EDIT

The code is ok for ConsoleApp and WebApp but not working for my asp.net WEBSITE. Could be a problem with async?

RajkumarM · Answer

We can use OCR with web app also,I have taken the .net core 3.1 webapp in Visual Studio and installed the dependency of Microsoft.Azure.CognitiveServices.Vision.ComputerVision by selecting the check mark of include prerelease as shown in the below image:

enter image description here

After creating computer vision resource in Azure Portal, copied the key and endpoint from there and used inside the c# code.

using System;
using System.Collections.Generic;
using Microsoft.Azure.CognitiveServices.Vision.ComputerVision;
using Microsoft.Azure.CognitiveServices.Vision.ComputerVision.Models;
using System.Threading.Tasks;
using System.IO;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Threading;
using System.Linq;

namespace ComputerVisionQuickstart
{
    class Program
    {
        // Add your Computer Vision subscription key and endpoint
        static string subscriptionKey = "c1****b********";
        static string endpoint = ".abc.cognitiveservices.azure.com/";

        private const string READ_TEXT_URL_IMAGE = "https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/printed_text.jpg";

        static void Main(string[] args)
        {
          
            Console.WriteLine("Azure Cognitive Services Computer Vision - .NET quickstart example");
            Console.WriteLine();

            ComputerVisionClient client = Authenticate(endpoint, subscriptionKey);

            // Extract text (OCR) from a URL image using the Read API
            ReadFileUrl(client, READ_TEXT_URL_IMAGE).Wait();
        }

       public static ComputerVisionClient Authenticate(string endpoint, string key)
        {
            ComputerVisionClient client =
              new ComputerVisionClient(new ApiKeyServiceClientCredentials(key))
              { Endpoint = endpoint };
            return client;
        }

        public static async Task ReadFileUrl(ComputerVisionClient client, string urlFile)
        {
            Console.WriteLine("----------------------------------------------------------");
            Console.WriteLine("READ FILE FROM URL");
            Console.WriteLine();

            // Read text from URL
            var textHeaders = await client.ReadAsync(urlFile);
            // After the request, get the operation location (operation ID)
            string operationLocation = textHeaders.OperationLocation;
            Thread.Sleep(2000);

            // Retrieve the URI where the extracted text will be stored from the Operation-Location header.
            // We only need the ID and not the full URL
            const int numberOfCharsInOperationId = 36;
            string operationId = operationLocation.Substring(operationLocation.Length - numberOfCharsInOperationId);

            // Extract the text
            ReadOperationResult results;
            Console.WriteLine($"Extracting text from URL file {Path.GetFileName(urlFile)}...");
            Console.WriteLine();
            do
            {
                results = await client.GetReadResultAsync(Guid.Parse(operationId));
            }
            while ((results.Status == OperationStatusCodes.Running ||
                results.Status == OperationStatusCodes.NotStarted));

            // Display the found text.
            Console.WriteLine();
            var textUrlFileResults = results.AnalyzeResult.ReadResults;

            
            foreach (ReadResult page in textUrlFileResults)
            {
                foreach (Line line in page.Lines)
                {
                    Console.WriteLine(line.Text);
                }
            }
            Console.WriteLine();
        }

    }
}

The above code is taken from the Microsoft Document.

I can be able to read the text inside the image successfully as shown in the below screenshot:

enter image description here

Azure Cognitive Service\Computer Visio\OCR - Can I use it into into WebSite C#

1 Answers