Update 'kill_isolated_pixels' to manage images with 'NaN' value.
Update 'kill_isolated_pixels' to manage images with 'NaN' value.

jdhp-sap/data-pipeline-standalone-scripts,jdhp-sap/data-pipeline-standalone-scripts,jdhp-sap/sap-cta-data-pipeline,jdhp-sap/sap-cta-data-pipeline