Investigation of Satellite Imagery Normalisation for Mosaic Creation in Living England Workflow

About

Natural England awarded a contract to TERRABOTICS LTD for investigating the normalisation of satellite imagery for mosaic creation within the Living England workflow.

The project examined current best practices and potential impacts of image normalisation on Spring and Autumn satellite mosaics used for segmentation and habitat classification.

The existing mosaicking process employs a 'Swiss-cheese' method to create cloud-free mosaics by removing cloudy or shadow pixels and stacking imagery, with the least cloudy image as primary and gaps filled by subsequent images.

Radiometric differences between stacked images due to acquisition timing and ground conditions had not been quantified.

The investigation assessed whether normalising input imagery prior to mosaicking could improve segmentation and aid comparisons of segmentations from different mosaics, potentially enhancing assessments of habitat change over time.

It also considered impacts on habitat classification accuracy, as normalised values affect zonal statistics within segment objects modelled using a random forest classification model.

The contract value was £23,924.