| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| Claytonb | "@everydayduffy -For the above comparison I used the calibration option in Pix4D pro. It consisted of drawing a region of interest on the image of t..." | Read more » | almost 8 years ago | |||
| everydayduffy | "Thanks @Claytonb for this really interesting post. Could you detail a bit more about how you calibrated your images with reflectance targets please? " | Read more » | almost 8 years ago | |||
| warren | "I really liked this note too! I'm interested in how this dataset could be used as a "test set" for software development as well. There are a range ..." | Read more » | almost 8 years ago | |||
| Claytonb | "Hi Alex, I would recommend contacting Charlie Langlois at Labsphere- clanglois@labsphere.com They can make affordable($300 range)targets that are s..." | Read more » | almost 8 years ago | |||
| admaltais | "Hi Claytonb, Really interesting analysis. I currently use a Canon S110 modified by Sensfly for NDVI and I wondered if there could be a big differen..." | Read more » | almost 8 years ago | |||
| nedhorning | "Here are a couple links that should help you get started: https://publiclab.org/wiki/infragram https://publiclab.org/notes/mlamadrid/12-08-2015/pho..." | Read more » | about 8 years ago | |||
| ino | "hello, I have a infrared-visible camera, how i get the NDVI image? " | Read more » | about 8 years ago | |||
| bortek | "Thanks Clayton. I am on it now. :) " | Read more » | about 8 years ago | |||
| Claytonb | "@bortek -the blue in the NDVI image is related to the value of the color LUT I applied to the image during processing. I did that to help me to see..." | Read more » | about 8 years ago | |||
| bortek | "@Claytonb - I am planning to start with a single camera and do some initial testing and learning before I go over to two cameras. Yes the focusing..." | Read more » | about 8 years ago | |||
| Claytonb | "Here is a similar scene with the Event38 at about the same height. This is with f/4, exp 1/1250, ISO 100 " | Read more » | about 8 years ago | |||
| Claytonb | "@bortek -I am assuming that the noise is partly due to the filter thickness and light requirement. I believe the Event38 filter is 0.5mm thick and ..." | Read more » | about 8 years ago | |||
| bortek | "This is really interesting. I have read Ned's article too and it is clearly better contrast when using red filter versus blue. I have just receive..." | Read more » | about 8 years ago | |||
| Jogomez74 | "Cfastie and Agustin If we try to change de index co-dominium? I mean 0 to 1. And the equation of NDVI index must be.. NDVI 1= (1/2)(NDVI+1) = (1/2)..." | Read more » | over 8 years ago | |||
| nedhorning | "Chris - Thanks for pointing that out. I typically clip the values so anything greater than 1 becomes 1 and anything less than -1 become -1. " | Read more » | almost 9 years ago | |||
| cfastie | "It looks like the computed index will no longer be between -1 and +1 if you adjust the red value that way. Do you then have to rescale the index so..." | Read more » | almost 9 years ago | |||
| nedhorning | "Hi Agustin - Your second equation is one option. Another is: (blue- (red-blue0.8)) /(blue+(red-blue0.8)) You can play around with the factor I add..." | Read more » | almost 9 years ago | |||
| agustin_castellano | "Sorry is should be (blue- (red-blue)) /(blue+(red-blue)) ?? To extract the nir data in the red chanel. Regards. " | Read more » | almost 9 years ago | |||
| agustin_castellano | "Could something like this (blue- (red-blue)) /(blue-(red-blue)) ?? To extract the nir data in the red chanel. Regards. " | Read more » | almost 9 years ago | |||
| nedhorning | "Hi Agustin, The formula you wrote is what I use. I typically use the PhotoMonitoring plugin which can be found here: https://github.com/nedhorning..." | Read more » | almost 9 years ago | |||
| agustin_castellano | "Hi Ned thanks for your research! Is great this information. i have two doubts. First if i use a red filter how should be the formula (blue - red) ..." | Read more » | almost 9 years ago | |||
| Tbtouaki | "Hi Sorry for the trouble but how did you proceed to calibrate individual bands to reflectance before calculating NDVI? Did you use "dark object sub..." | Read more » | about 9 years ago | |||
| bwarzak | "Ned, Our company is supposed to be writing an article for Vision System Design magazine regarding uses for dual band filters. I realize that the r..." | Read more » | about 9 years ago | |||
| Thorsten | "I had no problems with using lens filters so far. But it would be interesting if there is some reason to better replace the IR Filter instead. " | Read more » | about 9 years ago |