| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| cfastie | "A custom white balance setting is easy to do using the msetup program. Just try different numbers for R, G, and B until you get what you like. Firs..." | Read more » | almost 9 years ago | |||
| cfastie | "A good focal length for mapping is probably around 35 to 40mm (35 mm equiv.). That is what the old A495 had (37.6 mm). More typical small PowerShot..." | Read more » | almost 9 years ago | |||
| cfastie | "That looks like a good way to avoid passing the rubber bands out of the bottle top, especially if the shaft could slide easily so the camera can be..." | Read more » | almost 9 years ago | |||
| cfastie | "Ned, So the displayed graphs with two points are not meaningless (I found them to be helpful), but the R² values are not useful because they are a..." | Read more » | almost 9 years ago | |||
| cfastie | "The gadget is designed to measure soil compaction as described in the research note from which the photo was borrowed. " | Read more » | almost 9 years ago | |||
| cfastie | "LaPa, yes that would be very useful. It would also be useful if someone could do that with a red filter on the NoIR. Blue should be exaggerated whe..." | Read more » | almost 9 years ago | |||
| cfastie | "A couple of comments ago I included NDVI images from infragram.org and Fiji that are essentially the same. This sort of confirms that infragram.org..." | Read more » | almost 9 years ago | |||
| cfastie | "The link above to the Python code for converting photos to NDVI images is not a link at Public Lab. However, a version of this Python code is avail..." | Read more » | almost 9 years ago | |||
| cfastie | "Those basil leaves should not be the same color as the flower pot. They need to be more orange. To get NDVI values in the appropriate range, the va..." | Read more » | almost 9 years ago | |||
| cfastie | "Thanks wmaiouiru, that's a good point. All three NDVI images use a different color map. I don't know what the Python code image uses for a color ma..." | Read more » | almost 9 years ago | |||
| cfastie | "That orange color of the leaves is promising. It should be even oranger. If you can put the plant in brighter outdoor light and take two photos -- ..." | Read more » | almost 9 years ago | |||
| cfastie | "It is not clear that the other respondents at the Pi forum understand what you are asking about. Using awb_gains will allow every photo to exaggera..." | Read more » | almost 9 years ago | |||
| cfastie | "Thanks Erwan, It looks like awb_gains allows the red and blue channels to be adjusted relative to one another which is just what is needed. Howeve..." | Read more » | almost 9 years ago | |||
| cfastie | "LaPa, The custom white balance procedure you refer to works only for certain cameras. A year ago it was not possible to set a custom white balance..." | Read more » | almost 9 years ago | |||
| cfastie | "Just in case everyone is not familiar with all the acronyms like ADC and RTC: https://en.wikipedia.org/wiki/Automated_dispensing_cabinet https://en..." | Read more » | almost 9 years ago | |||
| cfastie | "Hi Thomas, There has been a long discussion of this very topic here today. It happened in the comments to a four year old research note on a mostl..." | Read more » | almost 9 years ago | |||
| cfastie | "Correct. If the Wratten 25A camera requires exposures that are too long, you can just shoot normal photos and use the red channel for VIS (so don't..." | Read more » | almost 9 years ago | |||
| cfastie | "If you use the Fiji plugin to make NDVI, you will not need the techniques in the video above. The plugin does the comparison of NIR and VIS for eac..." | Read more » | almost 9 years ago | |||
| cfastie | "As you move to longer wavelengths, contamination by sunlight becomes less of a problem underwater because longer wavelengths can't pass through muc..." | Read more » | almost 9 years ago | |||
| cfastie | "Can you operate two Pi cameras from one Pi? If so, you should be able to trigger the shutters simultaneously which is important. The Pi NoIR could ..." | Read more » | almost 9 years ago | |||
| cfastie | "There are a few options for getting both a visible light image and an NIR image of the same scene. The DIY approaches vary in their ability to dist..." | Read more » | almost 9 years ago | |||
| cfastie | "Hi Steven, This type of analysis should be viable. I have not seen examples of pure NIR photos providing more information than good normal photos ..." | Read more » | almost 9 years ago | |||
| cfastie | "Your underwater NIR device would not need as much light baffling as a visible light device, but it might need some. It would depend on how sensitiv..." | Read more » | almost 9 years ago | |||
| cfastie | "This looks excellent. John Wells in Scotland has been working on pendulums for keychain cameras and settled on a coat hanger. A nice feature is th..." | Read more » | almost 9 years ago |