NullReferenceException Thrown in OMR Processing

Aspose.OMR Product Family
1

I am encountering a NullReferenceException while processing an OMR file using the TemplateProcessor.Recognize() method. The file exists at the specified location, but the exception is still thrown.

Error Details:

  • Exception: System.NullReferenceException: Object reference not set to an instance of an object
  • Code Snippet:
TemplateProcessor templateProcessor = omrEngine.GetTemplateProcessor("D:\\Veera\\HelloOMR\\wwwroot\\A50MRGenerated\\QueSetUpRaw.omr");
var x = templateProcessor.Recognize(Path.Combine("D:\\Veera\\HelloOMR\\wwwroot\\A50Uploads", fileName));
RecognitionResult recognitionResult = x;
  • Observation:
    • The file does exist at the specified location.
    • The exception occurs at Recognize() method.
    • The templateProcessor object might be null.

Attached Screenshot:

I have attached a screenshot showing the error message and code context for reference.

Can you please help me troubleshoot this issue? Let me know if any additional information is required.

image.png (61.3 KB)

2

@StanlyIGX

The NullReferenceException you are encountering while using the TemplateProcessor.Recognize() method may be due to the templateProcessor object being null. This can happen if the GetTemplateProcessor method fails to retrieve the template correctly. Here are some steps to troubleshoot the issue:

  1. Check Template Path: Ensure that the path you are providing to GetTemplateProcessor is correct and that the template file exists at that location. You can add a check to confirm that the template path is valid before calling the method.

  2. Verify Template File: Make sure that the template file (QueSetUpRaw.omr) is not corrupted and is compatible with the OMR engine you are using.

  3. Handle Null Case: Before calling the Recognize() method, check if templateProcessor is null. If it is, log an appropriate message or throw an exception to handle this case gracefully.

Here’s an example of how you might modify your code to include these checks:

string templatePath = "D:\\Veera\\HelloOMR\\wwwroot\\A50MRGenerated\\QueSetUpRaw.omr";
TemplateProcessor templateProcessor = omrEngine.GetTemplateProcessor(templatePath);

if (templateProcessor == null)
{
    throw new InvalidOperationException("TemplateProcessor could not be created. Please check the template path and file.");
}

var x = templateProcessor.Recognize(Path.Combine("D:\\Veera\\HelloOMR\\wwwroot\\A50Uploads", fileName));
RecognitionResult recognitionResult = x;

By implementing these checks, you can better diagnose the source of the NullReferenceException and ensure that your application handles such cases more robustly. If the issue persists, consider reviewing the documentation or examples related to the OMR processing to ensure that all prerequisites are met.

If you need further assistance, feel free to provide additional details or context regarding your implementation.

Sources:
[1]: Aspose.OMR Recognize Example

3

Getting same issue. while using your shared idea. Kindly refer below image

image.png (60.2 KB)

4

Hello, @StanlyIGX

Can you share additional details regarding this issue - .omr file and scan image?
We will investigate a solution for this issue.

5

Find an attachment(.omr file and scan image)

issue.zip (1007.6 KB)

6

I have tested provided samples using a VS project below. I also have attached a result of recognition in result.csv.
Please check sample project and tell if issue persist in this test project.
ConsoleApp1.zip (1.7 KB)

Thank you.

7

I noticed a discrepancy between the image I shared and the text in the file you provided. The correct details from my image are:

  • Name: VEERAMANIKANDAN M
  • Reg. No.: 0612002

However, the file I received contains:

  • Name: veerubdnsumhdmn mll
  • Reg. No.: 2672002

Please check and correct the details as needed. Let me know if you need any further information.

8

Unfortunately, at the current moment, recognition of the provided image does not provide a 100% correct result.

We are working on improving character recognition of ML based Handwriting plugin. Current implementation is performing better with images at higher resolution, bigger symbol cells and more distinct letters.

I can recommend using a scan of the template with at least 2000x2000 px and dpi of 300 and setting test_input cell size to extralarge:

?text_input=name
	cell_size=extralarge