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Comments

Author Comment Last activity Moderation
nedhorning "Hi - I actually thought I posted this a few days ago but for some reason I guess it didn't work. Now when I post it I see that the comments are int..." | Read more » over 6 years ago
nedhorning "Hi Jeff - I'm not sure what math you are looking for. For the gamma correction I use: The first step is to remove the effect of the gamma correcti..." | Read more » over 6 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 » over 6 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 » over 6 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 » over 6 years ago
nedhorning "Ok - That site was taken off line last year I think - sorry. " | Read more » over 6 years ago
nedhorning "Hi Dj - Can you let me know which link you refer to? I have a few scripts that mostly deal with image classification and regression at https://bitb..." | Read more » over 6 years ago
nedhorning "Hi Nanfeng, I'm not certain why the results look the way they do but I have a feeling that it could be a result of doing pixel-by-pixel comparison..." | Read more » over 6 years ago
nedhorning "Hi Grayson, This looks really nice - a great little setup. I think you made good choices: using two sensors close together with a (relatively) narr..." | Read more » over 6 years ago
nedhorning "The value of camera calibration depends on what you're doing. If you're just looking for relative differences across an image calibration isn't all..." | Read more » over 6 years ago
nedhorning "You could try using VisualSFM(http://ccwu.me/vsfm/). I played around with that a couple years ago and remember seeing video of someone who created ..." | over 6 years ago
nedhorning "For what it's worth the software to make mosaics out of oblique images will correct the image geometry but it is unlikely going to correct the pixe..." | over 6 years ago
nedhorning "I wouldn't say the time of day doesn't matter but it is more important to be consistent. You are imaging at an oblique angle (from a pole?) so you ..." | over 6 years ago
nedhorning "Hi - Different sensor, target, illumination geometries will tend to give different NDVI values of the same vegetation. The difference in impact bet..." | over 6 years ago
nedhorning "I don't have experience with lens mounted filters but you might get some feedback if you post your question on the plots-infrared list at http://pu..." | Read more » over 6 years ago
nedhorning "Hi Giovanni - You should be able to use the photo monitoring plugin to process images from different cameras even if the cameras have different se..." | Read more » over 6 years ago
nedhorning "Hi manattta - Keep in mind that white balance and calibration are two different processes. White balance is used to adjust the in-camera processing..." | Read more » over 6 years ago
nedhorning "Hi - Using a field spectroradiometer for getting reflectance values of targets is a good idea. It would probably be best if you can take reflectanc..." | Read more » almost 7 years ago
nedhorning "Good stuff. From my perspective NDVI is good for mapping vegetation and can provide some indication of overall health and is good at differentiatin..." | Read more » almost 7 years ago
nedhorning "Hi Scott - Using public lab aerial photography for counting wildlife is a sensible idea. In your example image the resolution is probably your most..." | Read more » almost 7 years ago
nedhorning "Hi Johan, Although a shift in the red edge could indicate heavy metal stress it could also indicate a host of other types of stress. Monitoring th..." | Read more » almost 7 years ago
nedhorning "Interesting - My guess is that the preset white balance is responsible for the nice looking images. It would be interesting to record some RAW imag..." | Read more » almost 7 years ago
nedhorning "At this time it is not possible to use geo-reference data. If there is sufficient interest in that functionality I could try to add it but it's not..." | Read more » about 7 years ago
nedhorning "Hi Alan, That sounds good. The first thing your son will realize is that I'm not a very talented programmer. I'm traveling until early next week b..." | Read more » about 7 years ago