Adding Differential Binarization model from PaddleOCR to Keras3

[gowthamkpr]

This adds the Differntial Binarization model for text detection.

Implemented the architecture based on ResNet50_vd from PaddleOCR and ported the weights.

[mattdangerw]

Let's split this up. Start with ResNetVD backbone?

Some notes...

• Remove the aliases. One ResNetVDBackbone can handle all of these with different presets.
• Conversion scripts as scripts not colabs.
• Follow the local style for backbones as closely as possible. See some comments here Add VGG16 and VGG19 backbone #1737
• Keep models a flat directory. No backbones/xx etc.
• Add some tests.

[divyashreepathihalli]

@gowthamkpr is the PR ready for review?

[divyashreepathihalli]

Thanks for the PR! I have left a reorganization comment.

example for structuring the code - https://github.com/keras-team/keras-hub/tree/master/keras_hub/src/models/sam

[divyashreepathihalli]

rename folder to differential_binarization and file to differential_binarization.py

[divyashreepathihalli]

please create a file differential_binarization_backbone.py and move the diffbin_fpn_model and backbone code into that. You can rename the backbone you are using in this file to image_encoder in the differential_binarization_backbone file. The task model should contain the preprocessor, backbone and the task head.

[divyashreepathihalli]

add test coverage for the losses here