add non-fixed path option to coco's instances_val2017.json

[malashinroman]

Very small fix without which I have an error at the end of each training session
[Errno 2] No such file or directory: '../datasets/coco/annotations/instances_val2017.json

🤖 Generated by Copilot at 123b23d

Summary

🛠️🗂️🐛

The pull request improves the annotation file handling for the COCO validation dataset in val.py. It adds a fallback option to look for the file in the annotations subfolder if it is not found in the image folder.

annotation path
not always where expected
try annotations

Walkthrough

• Add a fallback option for the COCO annotation file path (link in val.py)

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced flexibility in locating annotation files for COCO dataset evaluation.

📊 Key Changes

• Added a check to determine if the default COCO annotation file path exists.
• If the default path is not found, the code now looks for the annotation file within a directory specified in the dataset configuration.

🎯 Purpose & Impact

• Purpose: The change ensures that the evaluation script can adapt to different file structures, making it easier for users to use custom paths for their datasets without manual code modifications.
• Impact: Users with non-standard dataset installations can now run evaluations without encountering file not found errors, streamlining the validation process of object detection models trained with YOLOv5. 🔄💡

[github-actions]

👋 Hello @malashinroman, thank you for submitting a YOLOv5 🚀 PR! To allow your work to be integrated as seamlessly as possible, we advise you to:

• ✅ Verify your PR is up-to-date with ultralytics/yolov5 master branch. If your PR is behind you can update your code by clicking the 'Update branch' button or by running git pull and git merge master locally.
• ✅ Verify all YOLOv5 Continuous Integration (CI) checks are passing.
• ✅ Reduce changes to the absolute minimum required for your bug fix or feature addition. "It is not daily increase but daily decrease, hack away the unessential. The closer to the source, the less wastage there is." — Bruce Lee

[glenn-jocher]

@malashinroman thanks for the PR!