Used to extracting the product number from a label

TextExtractor.cs

using System;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Azure.CognitiveServices.Vision.ComputerVision;
using Microsoft.Azure.CognitiveServices.Vision.ComputerVision.Models;

namespace Recognize_TextSdk
{
    public static class TextExtractor
    {
        private const string ApiKey = "9cf7b9ac8b06459096ee343c129eacd3";

        private const string Endpoint = "https://westeurope.api.cognitive.microsoft.com/";

        private static readonly ComputerVisionClient Client;

        static TextExtractor()
        {
            Client = new ComputerVisionClient(new ApiKeyServiceClientCredentials(ApiKey))
            {
                Endpoint = Endpoint
            };
        }

        private static async Task<string> GetTextAsync(string operationLocation)
        {
            var operationId = operationLocation.Substring(operationLocation.LastIndexOf('/') + 1);
            while (true)
            {
                var result = await Client.GetTextOperationResultAsync(operationId);

                if (result.Status == TextOperationStatusCodes.Succeeded)
                {
                    foreach (var line in result.RecognitionResult.Lines)
                    {
                        var lineText = line.Text;
                        if (lineText.Length == 8 && lineText.All(char.IsDigit))
                        {
                            return lineText;
                        }
                    }
                    break;
                }
            }

            throw new Exception("Couldn't find label");
        }

        public static async Task<string> ExtractTextAsync(string image)
        {
            // The SDK uses the 'async' POST/GET pattern. For a regular POST pattern, please see the Recognize-TextHttp sample
            using (var imageStream = File.OpenRead(image))
            {
                // Submit POST request
                var textHeaders = await Client.RecognizeTextInStreamAsync(imageStream, TextRecognitionMode.Printed);

                // Submit GET requests to poll for result
                return await GetTextAsync(textHeaders.OperationLocation);
            }
        }
    }
}