Adding the LPIPS metrics

[RebornForPower]

I have add the lpips metrice by referring the https://github.com/xinntao/BasicSR/pull/367

[RebornForPower]

editing the __init__.py and adding the lpips.py file which can be supported by the ymal file to test

[xinntao]

@RebornForPower Thanks for the contribution:-)

As LPIPS takes torch tensors as inputs， we may need to directly pass torch tensors into this metric.

Let me think about it and it may involve the modification to the metric mechanism.

[RebornForPower]

@RebornForPower Thanks for the contribution:-)

As LPIPS takes torch tensors as inputs， we may need to directly pass torch tensors into this metric.

Let me think about it and it may involve the modification to the metric mechanism.

why not process the img into tensor in the calculate function?

[lgtm-com[bot]]

This pull request introduces 1 alert when merging a74fb5751cd002481d78cec4d3a118fc47d42605 into 4d34d071218d0e767096eddefa919200d5239936 - view on LGTM.com

new alerts:

• 1 for Unused local variable

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 10f55c8efd030a7c7a05f9502858b56f2d8c6cb5 into 4d34d071218d0e767096eddefa919200d5239936 - view on LGTM.com

new alerts:

• 1 for Unused local variable

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 556909df827b71d96c525e8a38445c99e7929c4e into 4d34d071218d0e767096eddefa919200d5239936 - view on LGTM.com

new alerts:

• 1 for Unused local variable