Скачать или смотреть Solving the SystemError in OpenCV: Why cv2.imwrite() Fails with Path Variables

Discover how to fix the `SystemError` encountered when saving images with OpenCV's `cv2.imwrite()` function using variable paths.
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This video is based on the question https://stackoverflow.com/q/65322928/ asked by the user 'Sergio García' ( https://stackoverflow.com/u/14792641/ ) and on the answer https://stackoverflow.com/a/66107134/ provided by the user 'Ophir S' ( https://stackoverflow.com/u/7321682/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the SystemError with cv2.imwrite()

Have you ever faced the frustrating error while using OpenCV's cv2.imwrite() function that reads:

[[See Video to Reveal this Text or Code Snippet]]

If you’re working on a Python project where you need to save a NumPy array as an image, you may run into issues when passing the file path as a variable. This guide will break down the problem and the solution in a digestible manner, allowing you to avoid this common error.

The Problem: Error with Path Variables

When trying to save an image, you might use cv2.imwrite() like this:

[[See Video to Reveal this Text or Code Snippet]]

This works perfectly fine. However, when you try to store the file path in a variable, like this:

[[See Video to Reveal this Text or Code Snippet]]

It returns the dreaded error instead. This issue arises from how the OpenCV function handles inputs.

Why Does This Happen?

The root of the problem is that the cv2.imwrite() function does not accept Path objects directly. When you attempt to pass a Path object, the function fails to find the appropriate file location, hence returning a NULL error.

The Solution: Convert Path to String

Fortunately, the solution is simple! Instead of passing a Path object, convert it to a string. Here’s how you can adjust your code to avoid the error:

Step-by-Step Guide

Keep your variable for the path as it is:

[[See Video to Reveal this Text or Code Snippet]]

Convert the path to a string and use it in the cv2.imwrite() function:

[[See Video to Reveal this Text or Code Snippet]]

Example Code

Here is a complete example to demonstrate how to implement this fix:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By simply adding str() around your path variable, you can successfully save your images without encountering the SystemError. Ensuring that you pass the file path as a string will help streamline your image processing tasks with OpenCV.

Next time you work with OpenCV's cv2.imwrite(), remember to convert your path variables! Happy coding!