Hello,

For my thesis completion:

I’m trying to calculate the color of a lab reference mineral with the summary parameters formulations as Viviano et al. (2014) did in this figure (9):

 

 

For that, I used the relevant summary parameters formulations described in Viviano et al. (2014), table 2, and section 4. But first, to check that my calculations are correctly implemented (using Matlab), I tried to calculate them on an IF_TER cube to reproduce the same browse product as I would get if I opened it by the pre-calculated summary parameters bands in the SU_TER cube (as was shown originally in the data processing pipeline by Seelos et al. 2011).

Unfortunately, it wasn’t a matching result. What could be the problem?

 

I appreciate any help you can provide.

Nathan

Nathan: Hard for me to evaluate what is wrong. If you are willing, send me the Matlab code for one or more of your spectral index calculations and I will try and replicate your steps.

Ray Arvidson

Hello Ray,

Thank you so much for your reply.

Attaching my Matlab `browse_product()` code (just change from `.txt` to `.m`) and a spectral library. Please run it and just follow the GUI instructions. I recommend using the default settings for the first time by hitting ‘Enter’ (and clicking on ‘OK’ in stretch parameters choose) through the process.

The core function of the summary parameters calculations is inside the main code under the function name `calc_summary_parameters()`, which calls `calc_summary_parameter()` with its nested helper functions for each parameter name.

I try to reproduce the work of Wray et al. (2010) with the FRT00009326 scene and bassanite mineral.

Also, I’ve uploaded these files to my GitHub repo.

 

Thanks a lot,

Nathan

Sulfates and Sulfite.txt browse_product.txt

Hi Nathan,

I will follow your step to see if we can have the same result. Meanwhile would you please post your result in the forum?

 

Thanks,

 

Feng Zhou

Hello Feng,

Thank you for your reply. Yes, of course.

As mentioned, I used the FRT00009326 scene.

When I load the custom browse product of the pre-calculated summary parameters of SINDEX2, D2300, BD1900_2 (stretch: [0.003, 0.020], [0.010, 0.038], [0.028, 0.058], respectively), by loading from the SU_TER cube – I get this (as should be):

 

But when I am calculating these summary parameters with IF_TER cube by myself with the relevant algebra, I get different values in each parameter matrix (band), which get me this:

 

Thanks,

Nathan

Hi Nathan,

 

I am unable to run your Matlab code. I got some errors. One error is:

I use CAT function to compute these summary parameters from IF_TER and then compare to the SU_TER. I also got the similar results like yours. I wonder if it is caused by calculation rounding error.

 

Thanks,

Feng

Hi Feng,

The error is because you need to install Matlab’s Image Processing Toolbox Hyperspectral Imaging Library to use some functions such as enviinfo()and hypercube().

Interesting. Please, update me if you get any explanation for this problem.

 

Thanks,

Nathan

Hi Nathan,

 

We are contacting the creator of the SU_TER products to see if there is any additional steps involved. We will let you know once we get answers.

 

Thanks,

 

Feng

Thank you for reaching out to the creator, Feng.
I truly appreciate your help and am eagerly waiting for the update.
Looking forward to hearing from you soon.

Best regards,
Nathan

Hi Nathan,

 

We emailed the question to the data producer one week ago but didn't get his response. On the other hand, we think your result and code are correct. We did get the same result as yours through different method. There is some difference between SU TER and summary parameters from IF TER. I suggest you can continue your way for the further steps.

 

Thanks,

Feng

Hi Feng,

Thank you for following up on this topic and for confirming the accuracy of my results. I appreciate your efforts.

Thank you,
Nathan