Project oxford vision API ocr异常

Posted 2023-04-17

【中文标题】Project oxford vision API ocr异常

【英文标题】：Project oxford vision API ocr exception

【发布时间】：2017-03-24 09:24:27

【问题描述】：

牛津视觉 API 项目出现问题。 project oxford git 中的示例可以正常工作并识别图像上的文本。但是我的代码抛出异常：

引发了“Microsoft.ProjectOxford.Vision.ClientException”类型的异常。 在 Microsoft.ProjectOxford.Vision.VisionServiceClient.HandleException（异常异常） 在 Microsoft.ProjectOxford.Vision.VisionServiceClient.b__39_1[TRequest,TResponse]（异常 e） 在 System.AggregateException.Handle(Func2 predicate) at Microsoft.ProjectOxford.Vision.VisionServiceClient.<SendAsync>d__392.MoveNext() --- 从先前抛出异常的位置结束堆栈跟踪 --- 在 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） 在 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务） 在 Microsoft.ProjectOxford.Vision.VisionServiceClient.d__32.MoveNext() --- 从先前抛出异常的位置结束堆栈跟踪 --- 在 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务任务） 在 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务任务） 在 System.Runtime.CompilerServices.TaskAwaiter1.GetResult() at ..OcrWorker.<UploadAndRecognizeImageAsync>d__15.MoveNext() in ..\\OcrWorker.cs:line 165\r\n --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter1.GetResult() 在 ..OcrWorker.d__14.MoveNext() 在 ..\OcrWorker.cs:127 行

类代码：

public string SubscriptionKey  get; set; 
    public string OcrResultText
    
        get
        
            if (FullOcrResult == null)
            
                FullOcrResult = new StringBuilder();
            
            string response = string.Empty;
            if (OcrDone)
            
                response = FullOcrResult.ToString();
            
            else
            
                response = null;
            
            return response;
        
    
    private bool OcrDone = true;
    public bool IsOcrDone  get  return OcrDone;  
    private StringBuilder FullOcrResult;

    public OcrWorker(string appKey)
    
        SubscriptionKey = appKey;
        FullOcrResult = new StringBuilder();
    

    public string DoWorkSync(List<Bitmap> images)
    
        if (OcrDone)
        
            List<IterationItem> iteartionItems = new List<IterationItem>();
            int i = 0;
            OcrDone = false;
            foreach (var image in images)
            
                IterationItem ocrIterationItem = new IterationItem();
                try
                
                    Task<IterationItem> o = DoWorkForIterationAsync(image, i);
                    o.Wait();
                    ocrIterationItem = o.Result;
                
                catch (Exception ex)
                
                    var a = ex.GetBaseException();
                
                iteartionItems.Add(ocrIterationItem);
                i++;
            
            GetOcrResultFromIterations(iteartionItems);
            OcrDone = true;
        
        return OcrResultText;
    

    public void WriteResultToFile(string path)
    
        if (OcrDone)
        
            if (File.Exists(path))
            
                File.Delete(path);
            
            File.AppendAllText(path, OcrResultText);
        
    

    private void GetOcrResultFromIterations(List<IterationItem> iterationResults)
    
        iterationResults = iterationResults.OrderBy(item => item.Number).ToList();
        foreach (var iterationItem in iterationResults)
        
            var results = iterationItem.OcrResult;
            FullOcrResult.AppendLine();
            foreach (var item in results.Regions)
            
                foreach (var line in item.Lines)
                
                    foreach (var word in line.Words)
                    
                        FullOcrResult.Append(word.Text);
                        FullOcrResult.Append(" ");
                    
                    FullOcrResult.AppendLine();
                
                FullOcrResult.AppendLine();
            
        
    

    /// <summary>
    /// Perform the work for this scenario
    /// </summary>
    /// <param name="imageUri">The URI of the image to run against the scenario</param>
    /// <param name="upload">Upload the image to Project Oxford if [true]; submit the Uri as a remote url if [false];</param>
    /// <returns></returns>
    private async Task<IterationItem> DoWorkForIterationAsync(Bitmap image, int iterationNumber)
    
        var _status = "Performing OCR...";

        //
        // Upload an image
        //
        OcrResults ocrResult = await UploadAndRecognizeImageAsync(image, RecognizeLanguage.ShortCode);
        _status = "OCR Done";

        //
        // Log analysis result in the log window
        //
        return new IterationItem()
        
            Number = iterationNumber,
            OcrResult = ocrResult
        ;
    

    /// <summary>
    /// Uploads the image to Project Oxford and performs OCR
    /// </summary>
    /// <param name="imageFilePath">The image file path.</param>
    /// <param name="language">The language code to recognize for</param>
    /// <returns></returns>
    private async Task<OcrResults> UploadAndRecognizeImageAsync(Bitmap image, string language)
    
        // -----------------------------------------------------------------------
        // KEY SAMPLE CODE STARTS HERE
        // -----------------------------------------------------------------------

        //
        // Create Project Oxford Vision API Service client
        //
        VisionServiceClient VisionServiceClient = new VisionServiceClient(SubscriptionKey);
        Log("VisionServiceClient is created");

        using (Stream imageMemoryStream = new MemoryStream())
        
            image.Save(imageMemoryStream, ImageFormat.Bmp);
            //
            // Upload an image and perform OCR
            //
            Log("Calling VisionServiceClient.RecognizeTextAsync()...");
            OcrResults ocrResult = await VisionServiceClient.RecognizeTextAsync(imageMemoryStream, language);
            return ocrResult;
        

        // -----------------------------------------------------------------------
        // KEY SAMPLE CODE ENDS HERE
        // -----------------------------------------------------------------------
    

    //get ocred text
    class IterationItem
    
        public int Number  get; set; 
        public OcrResults OcrResult  get; set; 
    
    public static class RecognizeLanguage
    
        public static string ShortCode  get  return "en";  
        public static string LongName  get  return "English";  
    

有没有人遇到同样的问题，我该如何解决？

【问题讨论】：

解决了！对于正确的工作，您应该使用：UploadAndRecognizeImageAsync 方法中的 File.OpenRead(imageFilePath) 而不是：创建 MemoryStream 并将位图复制到它所以不要将内存流传递给 SDK 的 RecognizeTextAsync 方法

FileStream 解决方案很好，但如果您希望 MemoryStream 出于任何原因工作（例如，您需要在调用 OCR 之前裁剪或操作图像），您需要做的就是'rewind ' 首先通过调用imageMemoryStream.Position = 0 流。否则，您在 MemoryStream 上的“读取”指针位于image.Save() 之后。

【参考方案1】：

解决了！对于正确的工作，您应该使用 imageMemoryStream.Seek(0, SeekOrigin.Begin);从图像复制流后