Did you also take a reading of this panel while on the ground before flight? If so, you can use Empirical Line Calibration:
http://www.harrisgeospati...cal_line_calibration

Hi Mari - what difference would there be between capturing the panel during the flight and capturing it from the ground prior to the flight? This is a pushbroom UAV sensor so it would be difficult to capture the panel while the UAV is on the ground. It seems like I could use ELM with the panel image taken during flight, correct?

I guess I was thinking it was more of an atmospheric correction, where you need field and image spectra to calculate gains and offsets, but it does not sound like the case here.

A straight calibration would mean you get a mean spectrum of your panel to divide into your data cube. So you could draw an ROI over your panel and then calculate stats on the ROI, which will show you the basic stats and 'mean' spectrum. Leave this dialog open. Go to Spectral Math and enter the equation:

float(s1)/s2
where s1 will be mapped to your hyperspectral data cube (I used float in case it is stored as integers and you need to promote the data type)
and s2 is mapped to the plotted mean spectrum from your panel

The result should be floating point, "top-of-the-sensor" reflectance.

Perfect, thanks Mari!

Hi!

I tried to use spectral math for this type of calibration, exactly like you describe with the ROI. It works for small images, but an error occurs when I apply the correction to my larger images (+/- 1 GB image size).

I guess my memory might have run out, causing the calculation to fail?

Thanks!

What is the error message? Spectral math should be a tiled process so it will work on smaller 'tiles' of data to reduce memory usage. If you have set your tile size to a large value, then it could be a problem.

This is the error message:

File Spectra Math: an error has occurred during processing

Error: "WRITEU: Error encountered writing to file. Unit: 101
File:D:\..."

The result may be invalid.

WRITEU errors typically mean the output directory does not have adequate space, it has permissions issues, or if it is an external drive, intermittent connection issues causing the writing of data to be interrupted. It is not memory related.