| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| cfastie | "If you have two cameras, and your goal is NDVI or false color infrared, the best way to get what you need is one unmodified camera and one with the..." | Read more » | over 10 years ago | |||
| PeeBee | "I am new to this field, and am busy trying to mod a Mobius by removing the IR filter and adding a blue (red remove) filter. I have made a side by ..." | Read more » | over 10 years ago | |||
| cfastie | "More tests are definitely merited. First, I was assuming that Carl was using a Rosco blue filter, and my original conclusions were based on that. ..." | Read more » | over 10 years ago | |||
| warren | "Hey just bumping this back up -- using Infragram.org Mathew L and I did a quick re-try on this, using the expression ((R-B)/(R+B))*-1 in the Hue fo..." | Read more » | over 10 years ago | |||
| Roolark | "Ok that's good to know. At the moment, I have a canon ps g12 with the schott bg3 infrablue filter that is saving photos as raw, and my canon dslr r..." | Read more » | almost 11 years ago | |||
| cfastie | "These are Brenden's photos, so I'm not sure, but I think he was experimenting with different camera settings, which are mostly irrelevant if you wo..." | Read more » | almost 11 years ago | |||
| Roolark | "I'm very interested in the work you've done with these and other cameras. With this set of photos, were they taken in JPEG or RAW? I know many poin..." | Read more » | almost 11 years ago | |||
| nedhorning | "My guess is that you would get the same effect that you get with a blue card if you used a gray card and then multiply the blue channel by a factor..." | Read more » | about 11 years ago | |||
| warren | "Definitely the IR and vis are mixing unmeasurably, but I'm wondering if the blue card contributes to the sum amount of light being reflected in the..." | Read more » | about 11 years ago | |||
| cfastie | "Jeff, Our goal is to have 1) a red channel which records how much NIR is reflecting from plants, and 2) a blue channel which records how much blue ..." | Read more » | about 11 years ago | |||
| cfastie | "Ned, The G11 photos in the panel above were recorded in camera raw. According to my naïve model of what camera raw does, it should be possible to t..." | Read more » | about 11 years ago | |||
| warren | "I love the theory that the blue card is flooding the blue channel to minimize or outweigh or "wash out" the infrared from that channel. I think tha..." | Read more » | about 11 years ago | |||
| nedhorning | "This white balance stuff got me thinking. I don't think the white balance actually changes the amount of light recorded by the sensor but instead m..." | Read more » | about 11 years ago | |||
| warren | " " | Read more » | about 11 years ago | |||
| cfastie | "The relative amounts of NIR vs visible light in each channel is definitely a big and important unknown. The camera can't do anything to change that..." | Read more » | about 11 years ago | |||
| warren | "I guess the WB introduces a big unknown about the relative amounts of NIR vs visible light. One way the NIR and VIS might mix in blue is that perha..." | Read more » | about 11 years ago | |||
| cfastie | "There might be some math magic that will help, but that is beyond me. It will be important to check that whatever math is done, the resulting index..." | Read more » | about 11 years ago | |||
| warren | "I wonder if, although the absolute NDVI values seem not to be helpful, the images may still be able to distinguish between healthy and unhealthy ve..." | Read more » | about 11 years ago | |||
| cfastie | "In case others are interested in the answer to this question: The histograms of the infrablue photos are screen captures from Photoshop pasted ont..." | Read more » | over 11 years ago | |||
| cfastie | ""Tweaking things until the histogram looks right," and especially "tweaking things until the NDVI looks right," are exactly the approaches that mus..." | Read more » | over 11 years ago | |||
| warren | "I wonder if thinking about "tweaking things until the histogram looks right" is the right approach -- in some ways, the idealization is that there ..." | Read more » | over 11 years ago |