nir
nir


Author Comment Last activity Moderation
Corymbia "Thank you both, I really appreciate your help. My tiles were far from perfect, but from next week on I will be able to test with six Spectralon sa..." | Read more » almost 4 years ago
cfastie "Subtracting the blue channel from the red channel is a good first step for correcting for contamination of the red channel with NIR. With one parti..." | Read more » almost 4 years ago
nedhorning "It's good you discovered that. Yesterday I started to write about the need to subtract the blue band (NIR) from the red band (red + NIR) so you get..." | Read more » almost 4 years ago
Corymbia "Hi, I have some trouble previewing my processed DNG images in Matlab, but the channel values are similar to the ones in your image. Since the red c..." | Read more » almost 4 years ago
nedhorning "I used this following dcraw command: dcraw -D -W -4 Image1.ORF to create this image which has been scaled to 16-bit integers: https://drive.googl..." | Read more » almost 4 years ago
nedhorning " I have to run out now but will try to make time to check this in the morning. It's also possible it's due to the nature of the filter and after ca..." | Read more » almost 4 years ago
Corymbia "Sure, I've just uploaded ORF files for all three images to the google drive (link at the end of my post). Unfortunately I couldn't find any inform..." | Read more » almost 4 years ago
nedhorning "Can you post one of your RAW images? I looked at Image1.dng and that shows the Bayer pattern so it needs to go through a debayer process to create ..." | Read more » almost 4 years ago
Corymbia "How do you make sure the white balancing step is omitted? I tried that myself (see table 3 and figure 5 in my note), but the resulting NDVI values ..." | Read more » almost 4 years ago
nedhorning "I use RAW pixel values for calibration analysis and since white balance doesn't impact RAW values I don't usually worry about it. If you want to us..." | Read more » almost 4 years ago
Corymbia "Thanks, I will try! One more problem I noticed yesterday was that (at least when I set the white balance on a red/white surface) the red channel g..." | Read more » almost 4 years ago
nedhorning "The calibration coefficients are, in the simplest case, the slope and y-intercept of the linear regression line for wavelength (based on calibratio..." | Read more » almost 4 years ago
Corymbia "Thanks for the advice. How are the calibration coefficients calculated? I need to take photos of >50 trees in a glasshouse, so even within one s..." | Read more » almost 4 years ago
nedhorning " If you're using them for calibration you should be fine taking photos of the targets every so often. The calibration coefficients shouldn't change..." | Read more » almost 4 years ago
Corymbia "I realised that my tiles may be too shiny and grabbed some matt paint samples (pieces of matt paper) from a local store. They’re small and light, m..." | Read more » almost 4 years ago
nedhorning "I just read over Rob Sumner's RAW guide and see Adobe DNG Converter is free. It also looks like he did some pretty rigorous tests so my previous co..." | Read more » almost 4 years ago
nedhorning "The tables look great. Before the end of the week I'll try to compare your converted image with on that I run through dcraw to see if they are simi..." | Read more » almost 4 years ago
Corymbia " Hi Ned, Thanks for your comment, it was mainly your notes that inspired my camera conversion :) I (hope I) fixed the tables by inserting print sc..." | Read more » almost 4 years ago
nedhorning " Hi Corymbia – It’s nice to see some new work in this area. I see that you used the Adobe DNG converter. You might want to look into that to under..." | Read more » almost 4 years ago
Anice " Thank you so much Chris! This information is very helpful. I plan on researching about the spectral sensitivity of my camera (Canon SX230 HS) and ..." | Read more » about 4 years ago
cfastie "You are correct that both red and NIR pass through the red filter (Rosco Fire # 19) and both are captured in the red channel of the photograph. It ..." | Read more » about 4 years ago
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 » about 4 years ago
warren "ah, good point. I guess both are relevant. We could distribute them in a dark envelope or folder, perhaps.  Yes, i also wondered about this -- bot..." | Read more » about 4 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 » about 4 years ago