| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| reversevector | "Since these cheap consumer cameras have a lot of NIR crosstalk, especially with small sensor cameras like the GoPro, would it be better to subtract..." | Read more » | about 7 years ago | |||
| nedhorning | "I do not have any peer-reviewed papers related to this work - sorry. Ned " | Read more » | about 7 years ago | |||
| suman | "Dear Ned, Recently i have been going through your interesting works on Infragram NDVI and calibration. I was wondering if you had a..." | Read more » | about 7 years ago | |||
| sujayj | "Thanks Chris " | Read more » | about 7 years ago | |||
| cfastie | "You can use any filter that blocks most blue and green light (all visible light other than red) and also passes a lot of near infrared light (somew..." | Read more » | about 7 years ago | |||
| cfastie | "Finding inexpensive, do-it-yourself calibration targets is an obstacle to NDVI calibration. You need targets for which the spectral reflectance is ..." | Read more » | about 7 years ago | |||
| J_tanna | "@cfastie sample image is like this, " | Read more » | about 7 years ago | |||
| J_tanna | "@cfastie On an agriculture land, How can we specify the targets for calibration? " | Read more » | about 7 years ago | |||
| cfastie | "Here is my discussion of calibrating NDVI images: https://publiclab.org/notes/cfastie/05-01-2016/calibration-cogitation And Ned's most recent note..." | Read more » | over 7 years ago | |||
| J_tanna | "@cfastie Thank you for your time. I have two more doubts in my mind, 1.) What are the steps that I need to apply for image calibration? 2.) What is..." | Read more » | over 7 years ago | |||
| cfastie | "With a blue filter which blocks only red light, the red channel will capture NIR. Use the red channel for NIR and the blue channel for visible ligh..." | Read more » | over 7 years ago | |||
| cfastie | "With a blue filter which blocks only red light, the red channel will capture NIR. Use the red channel for NIR and the blue channel for visible ligh..." | Read more » | over 7 years ago | |||
| J_tanna | "@cfastie What should be the formula of NDVI for NIR camera as it is blocking red light. " | Read more » | over 7 years ago | |||
| platteferguson | "So my million dollar question do I buy 3 or 4 inspire 2.0 with extra batteries or go for the new Ebee SQ ag drone for 12-15k with the multi spec wi..." | Read more » | over 7 years ago | |||
| dannysmith | "thanks @Claytonb, they seem like the way to go " | Read more » | over 7 years ago | |||
| Claytonb | "@dannysmith -I have been using the Labsphere Permaflect coated targets http://labsphere.com/labsphere-products-solutions/materials-coatings-2/coati..." | Read more » | over 7 years ago | |||
| dannysmith | "@Claytonb - I was just wondering if you could indicate what type of calibration targets you are using? I've been looking at targets produced by lab..." | Read more » | over 7 years ago | |||
| Claytonb | "@Thorsten I have not tried using a chart like the color checker though I have used materials(plastic, felt, paper) in the shade of red on the chart..." | Read more » | over 7 years ago | |||
| Thorsten | "@Claytonb great work as usual! Two questions: Have you tried some reddish colors of calibration targets such as the ColorChecker? http://xriteph..." | Read more » | over 7 years ago | |||
| cfastie | "The spectral response figure came from an article linked in this thread: https://groups.google.com/forum/#!topic/plots-infrared/aJhM30D6bUM That's..." | Read more » | over 7 years ago | |||
| curiousity | "thanks to @cfastie for the interesting charts... How did you take it ? Looking at chart, using just the blue channel as NIR the NIR/VIS sensitivi..." | Read more » | over 7 years ago | |||
| cfastie | "All three Bayer filters (R,G,B) transmit some near IR light. Above: Spectral response of a Canon PowerShot A2200 before (top) and after (bottom)..." | Read more » | over 7 years ago | |||
| curiousity | "You said ...With the red filter we can be fairly confident that the blue channel contains primarily NIR light... But how this happens ? As I know..." | Read more » | over 7 years ago | |||
| Claytonb | "@Artichoke23 - What I have seen in testing is that a red filter will give you much greater contrast and sensitivity in crop vigor. A good example i..." | Read more » | over 7 years ago |