| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| nedhorning | "It's worth testing but those cards you link to look promising. From my experience it's the bright target that is more of a problem than the dark ta..." | Read more » | over 5 years ago | |||
| nedhorning | "Hi Jeff - I wasn't sure if you mean varying over time or over the surface. Over time both will vary but from my experience they seem fairly stable ..." | Read more » | over 5 years ago | |||
| nedhorning | "For the most part I am not able to reliably and accurately validate NDVI calculations. To validate results you would need to have targets with know..." | Read more » | about 6 years ago | |||
| nedhorning | "Setting up and running an integrating sphere is within your reach for a 12 week course as long as the equipment is working and you have access to s..." | Read more » | about 6 years ago | |||
| nedhorning | "Hi dannysmith - I’m glad to hear the note was useful to get you started. I find it helpful to plot both red and blue channel regressions but I expe..." | Read more » | about 6 years ago | |||
| nedhorning | "Hi Suman - Using Analyze => Measure should work. It's not uncommon to have high pixel values for bright targets. In fact if the exposure isn't s..." | Read more » | almost 7 years ago | |||
| nedhorning | "Hi Suman - The values from 0 - 1 have been scaled from the original image. The reason I do this is that some image pixel values range from 0 - 255 ..." | Read more » | almost 7 years ago | |||
| nedhorning | "Hi Suman, I do not have a peer reviewed manuscript about this work so suggest citing this web page using a style appropriate for websites or blogs...." | Read more » | almost 7 years ago | |||
| nedhorning | "Hi sujayj - I uploaded files with the target descriptions and reflectance information to my Google Drive: https://drive.google.com/drive/folders/0B..." | Read more » | almost 7 years ago | |||
| nedhorning | "Hi jenjimah, Testing any of these and reporting back would be worthwhile from my perspective. One word of caution is that these are very bright re..." | Read more » | about 7 years ago | |||
| nedhorning | "The CSV file for the R script is different form the table in the "Improved DIY NIR camera calibration" post. The CSV file has the reflectance value..." | Read more » | about 7 years ago | |||
| nedhorning | "Hi Jeff - This should be the image. Let me know if this is ok or if I need to post it some other way Ned " | Read more » | over 7 years ago | |||
| nedhorning | "Hi kaushalsingh – The three target reflectance values you note seem like a good choice to me. At this point I do not have study material in additi..." | Read more » | over 7 years ago | |||
| nedhorning | "Hi kaushalsingh – Ait seems as if you are trying to calibrate the image using a reference target before you calculate NDVI? If that assumption is a..." | Read more » | over 7 years ago | |||
| nedhorning | "Hi - Using 440nm seem reasonable but I'd probably increase the NIR value to 760nm or beyond or something like that since the peak is probably beyon..." | Read more » | over 7 years ago | |||
| nedhorning | "Hi David - This is an interesting project. The reflection of the glass should affect the results as long as the reflection is not in the area of yo..." | Read more » | almost 8 years ago | |||
| nedhorning | "The current version of the plugin only outputs index (NDVI and DVI) images. The plugin only calibrates two bands, a visible and a NIR band and two ..." | Read more » | over 8 years ago | |||
| nedhorning | "Hi Jacob, To check for aperture you could try another EXIF reader. Maybe "max aperture" is the same as "aperture" but I have no idea. When working ..." | Read more » | over 8 years ago | |||
| nedhorning | "I haven't seen reflectance curves for the "standard" white balance cards that include the NIR region of the spectrum. My guess is they would differ..." | Read more » | over 8 years ago | |||
| nedhorning | "Unfortunately those values would only work if you had the same materials that I used. To get the reflectance values you would either need to fine s..." | Read more » | over 8 years ago | |||
| nedhorning | "Hi aldehyde - Did you look at the user guide on Github: https://github.com/nedhorning/PhotoMonitoringPlugin that should have information about crea..." | Read more » | over 8 years ago | |||
| nedhorning | "Mathew - Have you been able to find a reflectance plot for those paints? I looked but didn't see it. Other paints I was looking at a couple years a..." | Read more » | over 8 years ago | |||
| nedhorning | "HI Agustin - I put the images on my server here: https://resources.cbc.amnh.org/cbccloudstorage/public.php?service=files&t=12385a3a09a4879fcffc..." | Read more » | over 8 years ago | |||
| nedhorning | "The panel order is not important as long as it's predictable and known. The "ideal" targets would probably be a few gray patches from bright to dar..." | Read more » | over 8 years ago |