First;

- Check the reflectance value in each green and NIR bands for the areas of urban green space.

- Calculate NDVI using (NIR - Red)/(Red +NIR)

- Classify the urban space area based on their NDVI value appeared in the vegetation index.

 You can read the following suggested article:

 https://www.researchgate.net/publication/248349395_Comparison_of_various_data_fusion_for_surface_features_extraction_using_IRS_PAN_and_LISS-III_data

 or

Master thesis

https://www.researchgate.net/publication/317304715_Subsurface_information_deduced_from_remote_sensing_and_resistivity_data?_iepl%5BviewId%5D=JXt2WoFpEpDcHNgXVXNl9iZB&_iepl%5BprofilePublicationItemVariant%5D=default&_iepl%5Bcontexts%5D%5B0%5D=prfpi&_iepl%5BtargetEntityId%5D=PB%3A317304715&_iepl%5BinteractionType%5D=publicationTitle

Article Comparison of various data fusion for surface features extra...

Thesis Subsurface information deduced from remote sensing and resis...

Thank you so much. Very helpful

Hello Zydi

You can use fish eyes photos too  in order to count  the foliage percentage of the  sky view factor (SVF) .

You can see;

Conference Paper Influence of trees on the air temperature in outdoor spaces ...