| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| LaPa | "Hi, could it be a good idea to choose as calibration target the bare soil area that is in each (thousands) photos? Best regards LaPa " | Read more » | over 8 years ago | |||
| warren | "Hi! We just released a Node.js version of the core library here: https://github.com/publiclab/spectral-workbench.js I think it'd be possible to ta..." | Read more » | over 8 years ago | |||
| LaPa | "1) Could be a good idea put the calibration targets of known spectral reflectivity in Greenhouse to include in the photos ? 2) Where can I get the..." | Read more » | over 8 years ago | |||
| cfastie | "NDVI is based solely on color (near infrared is one of the colors). If a camera records different colors for two leaves, the NDVI computed for tho..." | Read more » | over 8 years ago | |||
| LaPa | "Thank a lot all of you for the consideration and the suggestions! Chris, sincerely I didn't understand from your reply if you consider my directio..." | Read more » | over 8 years ago | |||
| liz | "Hi @LaPa, great to see your note! I'm tagging some other raspberry pi developers @rjstatic and @seankmcginnis " | Read more » | over 8 years ago | |||
| cfastie | "Hi LaPa, Your time-lapse videos are impressive. These are excellent teaching videos. You can clearly see that the NDVI values for the foliage of t..." | Read more » | over 8 years ago | |||
| cfastie | "That's a good description of what the Rosco blue filter does. Both the blue and the red channels will have a mixture of visible and NIR light. The ..." | Read more » | over 8 years ago | |||
| Rayishido | "Hi! I was in the filed without internet. I wrote a program that trigger the photo on the second pi when a picture is taken with the first so it is..." | Read more » | over 8 years ago | |||
| cfastie | "other areas (not foliage) showed values between 0.2 and 0.9 and I don't know why, since there is no photosynthesis occuring there. Getting high ND..." | Read more » | almost 9 years ago | |||
| cfastie | "Do you know how well synchronized the photo pairs are? Do you have to start them both taking photos at the same time, or synchronize their clocks? ..." | Read more » | almost 9 years ago | |||
| Rayishido | "I am using 2 raspberry Pis (one camera on each) and I synchronize the shutters using interrupts. I had some strange behavior (one Pi taking more pi..." | Read more » | almost 9 years ago | |||
| cfastie | "The NDVI image in my last comment was made by stretching only the NIR channel. The default is to stretch both NIR and VIS and that usually works we..." | Read more » | almost 9 years ago | |||
| Rayishido | "Hi Chris, to obtain this picture you stretched the histogram of the visible or visible and IR. As far as I understand to make NDVI picture a visib..." | Read more » | almost 9 years ago | |||
| cfastie | "Both NDVI images look good. Both seem to have some biological meaning and both have reasonable NDVI values in areas that are shady which is very go..." | Read more » | almost 9 years ago | |||
| Rayishido | "Hi Chris! You assumed right! :D The pictures was taken with the pi noir and the blue filter and turned off the automatic white balance to set my o..." | Read more » | almost 9 years ago | |||
| cfastie | "Rayishido, I assume the orangish photo was taken with the PiNoir camera with a blue filter. By calibration I think you mean you used the AWB_gains..." | Read more » | almost 9 years ago | |||
| Rayishido | "Hi! Thank you very much for your answers! I have downloaded Fiji and it's plugin and will test as soon as possible. This weekend I am going to mak..." | Read more » | almost 9 years ago | |||
| cfastie | "Hi Rayishido, Nice Pi photos. Claytonb is correct about the shadows. It's a common artifact for dark areas to have very high NDVI values. In your ..." | Read more » | almost 9 years ago | |||
| Claytonb | "@Rayishido -the high NDVI values is a normal occurrence with shadows. You will notice that the NDVI values will change in the shadows depending on ..." | Read more » | almost 9 years ago | |||
| LaPa | "I'm happy for this my first step in NIR and NDVI photograph! Maybe you know but ..... 1) I use not a real camera but a computer board (Raspberry Pi..." | Read more » | almost 9 years ago | |||
| cfastie | "That looks pretty good. With the defaults in the photo monitoring plugin, the plant leaves have an NDVI value around 0.3. We don't know what the ND..." | Read more » | almost 9 years ago | |||
| LaPa | "HI, What do you think about my last test? NoIR modulo cam+blue filter, WBgain red = 0.88 and WBgain blue = 0.57 " | Read more » | almost 9 years ago | |||
| LaPa | "I'll try to get blue > 30 and red < 200 changing the gain. At the moment I do not know how change the exposure. May be I have to read better ..." | Read more » | almost 9 years ago |