[Fix] Fix bbox area calculation in inference tracking (#1194)

[pallgeuer]

Motivation

Fix the calculation of bounding box area (#1194).

Modification

• Corrected the way result['area'] is calculated

Checklist

Before PR:

• I have read and followed the workflow indicated in the CONTRIBUTING.md to create this PR.
• Pre-commit or linting tools indicated in CONTRIBUTING.md are used to fix the potential lint issues.
• Bug fixes are covered by unit tests, the case that causes the bug should be added in the unit tests.
• New functionalities are covered by complete unit tests. If not, please add more unit tests to ensure correctness.
• The documentation has been modified accordingly, including docstring or example tutorials.

After PR:

• CLA has been signed and all committers have signed the CLA in this PR.

[CLAassistant]

All committers have signed the CLA.

[jin-s13]

Thanks for your contribution! Could you please sign the CLA?

[codecov]

Codecov Report

Merging #1197 (a0110f5) into master (a2643bd) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1197   +/-   ##
=======================================
  Coverage   82.49%   82.49%           
=======================================
  Files         204      204           
  Lines       16144    16144           
  Branches     2886     2886           
=======================================
  Hits        13318    13318           
  Misses       2096     2096           
  Partials      730      730           

Flag	Coverage Δ
unittests	82.43% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmpose/apis/inference_tracking.py	59.34% <100.00%> (ø)

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[pallgeuer]

I have signed the CLA

[yaqi0510]

pallgeuer，您好！您在MMPose项目中给我们提的PR非常重要，感谢您付出私人时间帮助改进开源项目，相信很多开发者会从你的PR中受益。
我们非常期待与您继续合作，OpenMMLab专门成立了贡献者组织MMSIG，为贡献者们提供开源证书、荣誉体系和专享好礼，可通过添加微信：openmmlabwx 联系我们（请备注mmsig+GitHub id），由衷希望您能加入！

Hi @pallgeuer ！First of all, we want to express our gratitude for your significant PR in the MMPose project. Your contribution is highly appreciated, and we are grateful for your efforts in helping improve this open-source project during your personal time. We believe that many developers will benefit from your PR.

We would also like to invite you to join our Special Interest Group (SIG) private channel on Discord, where you can share your experiences, ideas, and build connections with like-minded peers. To join the SIG channel, simply message moderator— OpenMMLab on Discord or briefly share your open-source contributions in the #introductions channel and we will assist you. Look forward to seeing you there! Join us ：https://discord.gg/raweFPmdzG

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Thank you again for your contribution❤

[OpenMMLab-Assistant-004]

Hi @pallgeuer ！First of all, we want to express our gratitude for your significant PR in the mmpose project. Your contribution is highly appreciated, and we are grateful for your efforts in helping improve this open-source project during your personal time. We believe that many developers will benefit from your PR.

We would also like to invite you to join our Special Interest Group (SIG) private channel on Discord, where you can share your experiences, ideas, and build connections with like-minded peers. To join the SIG channel, simply message moderator— OpenMMLab on Discord or briefly share your open-source contributions in the #introductions channel and we will assist you. Look forward to seeing you there! Join us ：https://discord.gg/raweFPmdzG

If you have WeChat，welcome to join our community on WeChat. You can add our assistant ：openmmlabwx. Please add "mmsig + Github ID" as a remark when adding friends：）
Thank you again for your contribution❤