topic Re: Intensity Return from Lidar in Data Management Questions

Intensity Return from Lidar

AmitMhalas — Thu, 14 Jul 2011 09:46:39 GMT

I have Lidar data (for England) in .img (Imagine Image format) and just has elevation information. Can anyone tell me if its possible to obtain intensity return information from it?

I am looking to extract features from Lidar data especially houses.

Re: Intensity Return from Lidar

JeffreyEvans — Thu, 14 Jul 2011 16:20:33 GMT

Intensity is the 8-bit reflective intensity of the photons returning to the sensor. As such this is an independent attribute and cannot be derived from the elevation information. There has been some success using mathematical morphological operators or Wavelets to extract features in lidar derived all-return height images.

Re: Intensity Return from Lidar

AmitMhalas — Sun, 17 Jul 2011 12:23:57 GMT

Intensity is the 8-bit reflective intensity of the photons returning to the sensor. As such this is an independent attribute and cannot be derived from the elevation information. There has been some success using mathematical morphological operators or Wavelets to extract features in lidar derived all-return height images.

Thanks Jeff.

Re: Intensity Return from Lidar

GordonSumerling — Sun, 17 Jul 2011 21:39:59 GMT

If you have the raw LAS files then intensity is an attribute that can be extracted against each return in the file. Much like the classification values or return values. However, if you have an .img file then the Lidar has already gone through processing and the intensity is no longer available. You simly have the DEM or DSM from the original Lidar. You will need to go back to the original Lidar files to obtain the intensity values.