Added manual file path selection option for coco

[shardulmahamulkar]

Closes #465

Summary

The Streamlit app auto-detects image directories and annotation files based on a fixed COCO folder convention (images/{split}/ + annotations/instances_{split}.json). When users have datasets organised differently, the app failed silently with a generic error and no guidance.

This PR adds an optional "Use manual paths" checkbox in the sidebar (COCO mode only) that lets users override auto-detection by specifying the image directory and annotation file directly.

Changes

perceptionmetrics/utils/gui.py
Added
browse_file(filetypes=None)
A cross-platform native file-picker dialog (Windows / WSL / macOS / Linux via zenity or kdialog), analogous to the existing
browse_folder()
.
app.py
Imports
browse_file
alongside
browse_folder
.

Dataset Viewer (tabs/dataset_viewer.py)

• Added session state keys:
  • manual_img_dir
  • manual_ann_file
  • manual_paths_enabled
• Introduced a "Use manual paths" checkbox for COCO datasets.
  • When enabled:
    • Displays inputs for Image Directory and Annotation File (.json), each with a browse option.
    • Overrides automatic dataset path detection.
  • When disabled:
    • Clears manual path state to ensure default auto-detection is used.
• Moved manual path handling logic to the beginning of dataset_viewer_tab():
  • Allows bypassing dataset_path validation when valid manual paths are provided.
• Updated cache key logic:
  • Uses manual_{img_dir}_{ann_file}_{split} when manual paths are active to prevent stale cache usage.
• Improved error handling:
  • Displays actual exception messages (FileNotFoundError and generic exceptions).
  • Includes expected COCO directory structure in a formatted code block for clarity.

---

Evaluator (tabs/evaluator.py)

• Added the same manual path handling logic as in the dataset viewer.
• Hoisted manual path checks to ensure consistent behavior.
• Updated cache key logic to match dataset viewer implementation.
• Relaxed dataset loading condition:
  • Now allows loading when either:
    • manual paths are provided, OR
    • a valid dataset_path directory exists
      .
      Error messages updated with expected structure hints.

Expected COCO Structure (auto-detection)

dataset_root/
├── images/
│   ├── train/       # or train2017, train2, etc.
│   ├── val/
│   └── test/
└── annotations/
    ├── instances_train.json
    ├── instances_val.json
    └── instances_test.json

Testing

• Default behaviour unchanged : leave checkbox unticked, point to a standard COCO dataset → loads correctly in Dataset Viewer and Evaluator.
• Checkbox reveals inputs : tick "Use manual paths" → Image Directory and Annotation File fields + Browse buttons appear.
• Browse buttons work : folder picker opens for Image Directory;
  .json
• File picker opens for Annotation File.
• Manual override works : fill in non-standard paths → dataset loads correctly.
• Uncheck clears override :untick checkbox → manual path fields disappear and auto-detection resumes on next load.
• Helpful errors : with bad paths, error shows the actual exception + expected folder structure.
• No dataset_path required : manual paths work even if the Dataset Folder field is left empty.
• Existing tests pass : pytest tests/

Update: YOLO Manual Path Selection

The YOLO mode currently does not correctly detect datasets when using manual path selection. Additionally, Streamlit caching is causing inconsistent behavior in some cases.

I am actively working on resolving these issues.

In the meantime, please feel free to review the current changes and let me know if there are any suggestions or improvements.

[shardulmahamulkar]

Updated: YOLO manual path selection is now implemented in the latest commit (4c96108). Both COCO and YOLO manual paths are working. Ready for review.