Fix pixelwise_masks support when the ratio is on in the coco reader

[JanuszL]

• when the ratio option is on the pixelwise_masks calculation
  uses relative coordinates instead of the real one which leads
  to creating a 1-pixel map in the corner of the tensor. This PR
  fixes the math.
• adds relevant test

Category:

Bug fix (non-breaking change which fixes an issue)

Description:

• when the ratio option is on the pixelwise_masks calculation
  uses relative coordinates instead of the real one which leads
  to creating a 1-pixel map in the corner of the tensor. This PR
  fixes the math.
• adds relevant test
• relates to COCO Reader pixelwise_masks Emtpy Output #5404

Additional information:

Affected modules and functionalities:

• coco reader

Key points relevant for the review:

Tests:

• Existing tests apply
• New tests added
  • Python tests
    • test_coco.test_coco_pix_mask_ratio
  • GTests
  • Benchmark
  • Other
• N/A

Checklist

Documentation

• Existing documentation applies
• Documentation updated
  • Docstring
  • Doxygen
  • RST
  • Jupyter
  • Other
• N/A

DALI team only

Requirements

• Implements new requirements
• Affects existing requirements
• N/A

REQ IDs: N/A

JIRA TASK: N/A

[JanuszL]

!build

[dali-automaton]

CI MESSAGE: [13938873]: BUILD STARTED

[5had3z]

I think it would be more efficient to not have normalized points in the first place (since mask and points are exclusive anyway) and change condition here to be something along the lines of if (ratio && !spec_.GetArgument<bool>("pixelwise_masks"))

[dali-automaton]

CI MESSAGE: [13938873]: BUILD PASSED