Comments

Author Comment Last activity Moderation
nedhorning "Hi Roolark - This sound like an interesting project. I hope you keep us posted with your progress. I think there is a lot of value in pairing Land..." | Read more » over 10 years ago
nedhorning "Thanks for the suggestion. Maybe a teflon sheet is the way to go although I don't have any experience with these. Some of the thin sheets seem tran..." | Read more » over 10 years ago
nedhorning "I have been making some progress toward standardized calibration targets. Does anyone viewing this know of a source for inexpensive paints/coatings..." | Read more » over 10 years ago
nedhorning "Hi Thorsten, Glad to hear you're making progress. When you run the plugin are you specifying that the channel from the visible image to use for th..." | Read more » over 10 years ago
nedhorning "Hi Hagit, I don't have any research notes related to community mapping. Most of my involvement is peripheral, providing input into methods and hel..." | Read more » over 10 years ago
nedhorning "Hi Hagit, I enjoyed viewing your video and reading this note. I haven't put much thought into a generic work flow. From my limited experience the ..." | Read more » over 10 years ago
nedhorning "Nice work. I'm looking into using VisualSFM to create orthorectified images. They recently added some new geo-referencing features but I haven't ha..." | Read more » over 10 years ago
nedhorning "Is this your conclusion or do we have to test lots of other materials that commonly show up in the NDVI images we take? I have looked at a lot of..." | Read more » over 10 years ago
nedhorning "Chris, So many questions... I think more testing is necessary but I'll take a shot at answering each question. I'd like to hear what other folks th..." | Read more » over 10 years ago
nedhorning "If you use a dual-camera setup I suggest using an unmodified camera and a NIR-pass (visible cutoff) filter for the other camera. Some people use un..." | Read more » over 10 years ago
nedhorning "Hi Thorsten, Sorry for the confusion. Some of the non-linearity between the response of the red and blue filter should be explained in the post I d..." | Read more » over 10 years ago
nedhorning "One drawback of using the red filter is that the red part of the bayer filter passes more NIR than the blue or green parts. I'm looking into ways t..." | Read more » over 10 years ago
nedhorning "I'm curious why you need at least 3 bands for automated classification. I don't have a specific classification task in mind. In general I'm working..." | Read more » over 10 years ago
nedhorning "That's a good observation. The hotspot in these test images would tend to be toward the bottom around the shadow from Chris' head since that's wher..." | Read more » over 10 years ago
nedhorning "If it's sunny tomorrow I'll be out with the wood, tar paper and other things. With a little luck I'll have a research note before the end of the we..." | Read more » over 10 years ago
nedhorning "I got a 3" x 3" Wratten 25A gel filter on ebay for $10. There's a lot left over if you want to try it. " | Read more » over 10 years ago
nedhorning "Chris - It's interesting that you find that the Canon Powershots don't record much NIR in the blue channel. I found just the opposite - that the bl..." | Read more » over 10 years ago
nedhorning "Thanks for your comments. I am rethinking the idea that a blue filter is sensitive to chlorophyll absorption. Blue wavelengths have similar reflect..." | Read more » over 10 years ago
nedhorning "Thanks for the comments Chris. I would be a little cautious drawing more than very broad conclusions at this point. The reflectance values for the ..." | Read more » over 10 years ago
nedhorning "You could try to use some of these for calibration using Landsat imagery to estimate NDVI. " | Read more » over 10 years ago
nedhorning "Thanks for the comments Chris. I might have overstated the influence that different shutter speed, aperture and ISO could affect NDVI but I expect ..." | Read more » over 10 years ago
nedhorning "I have not used the non-pro version but it should perform equally well as far as the stitching goes but my understanding is that it won't handle co..." | Read more » over 10 years ago
nedhorning "The big mosaic was a combination of three different missions. Two were geotagged using GPS coordinates and the third was just images without any co..." | Read more » over 10 years ago
nedhorning "There are gel and glass NIR-block filters that you can buy that do a pretty good job at blocking visible light. There might also be some other free..." | Read more » over 10 years ago