The [Infragram Sandbox](http://infragram.org/sandbox) is a browser based tool for experimenting with image compositing, intended for use with Public Lab [Infragram cameras](/wiki/infragram). Read [this research note](/notes/warren/08-17-2013/infragrammar-compositing-infrared-images-with-simple-mathematic-expressions#c6664) and watch this short video to get a quick idea of how to use it: ##Infragrammar Infragram Sandbox uses simple math expressions, which are actually written in JavaScript. Here are some examples: * [NDVI](/wiki/ndvi) = `(R-B)/(R+B)` for -1..1, or for 0..1 `(((R-B)/(R+B))+1)/2` in the Monochrome input * ENDVI = `((R+G)-(2*B))/((R+G)+(2*B))` which MaxMax uses for its vegetation stress cameras, in the Monochrome input * A colormapped NDVI, scaled to emphasize differentiation: `((R-B)/(R+B)-0.2)*-720`, in the Hue input, and tweaking the 0.2 value to between 0.1 and 0.9 ([read more here](/notes/warren/08-24-2013/infragrammar-with-hsv-color-model)) * (add yours here) ###Math Infragrammar can use [JavaScript math functions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math). These include: * `Math.log()` - logarithms * `Math.abs()` - absolute value * `Math.sin()` - sine ###Sliders You can also link an equation to a slider; for now we are using the letter "X" to represent this value, but in the future, any string represented as {mystring} will generate a slider called "mystring". Move the slider to try different values in real time. [](http://publiclab.org/system/images/photos/000/001/174/original/Screen_Shot_2013-08-17_at_11.52.00_AM.png)...
| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| 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 | |||
| zorn | "Wrote a comment, but it does not show up. damn. once again! Thanks a lot for the instructions! My question is: if i remove the internal filter, c..." | Read more » | over 10 years ago | |||
| zorn | "Thanks for the instructions, after reading this i punchraised a mobius from ebay, hopefully not a fake ^^ English is not my mothers tongue, so i h..." | Read more » | over 10 years ago | |||
| cfastie | "The infrablue photos from the camera for this scene is here: http://publiclab.org/notes/warren/05-27-2013/infragram-test-photos-from-a-plane-window " | Read more » | almost 11 years ago | |||
| bc512 | "I would love to see the raw image of this if possible? what setup are you using etc? thank you " | Read more » | almost 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 » | almost 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 » | almost 11 years ago | |||
| warren | "Is this when you press the "run" button? Can you post which version of Chrome and which OS, and which expression you were using in Infragrammar? Ho..." | Read more » | almost 11 years ago | |||
| bc512 | "Unfotunately this isnt working for me, it just fails and the chrome page does the "oh snap" thing :( " | Read more » | almost 11 years ago | |||
| cfastie | "Maybe try this brute force version with an infrablue photo with healthy plants in it: 1) Select an area of foliage. 2) Calculate means for both ..." | Read more » | almost 11 years ago | |||
| warren | "Chris, it occurs to me that we could try to come up with a way to generate an adaptation of NDVI based on a given un-white-balanced camera's photo ..." | Read more » | almost 11 years ago | |||
| warren | "Maybe we should call our version of NDVI "INDVI" for Infragram-NDVI or something? Or BNDVI for Blue-NDVI? I'm loathe to make an already obscure acr..." | Read more » | almost 11 years ago | |||
| cfastie | "kykytos, you are correct. The equation (NIR-R)/(NIR+R) is the standard one for NDVI. Substituting blue for red as in (NIR-B)/(NIR+B) also works wel..." | Read more » | almost 11 years ago | |||
| kykytos | "A pair of doubts: In the equation in the image, it should say (IR-B)/(IR+B) (like in the video) instead of (IR-R)/(IR+R), Shouldn't it? Is the (IR-..." | Read more » | almost 11 years ago | |||
| warren | "Haha, lots of fun stuff is possible. Try JavaScript math functions: R:Math.pow(R,2) G:Math.pow(G,2) B:Math.pow(B,2) I'm making a docs page here: h..." | Read more » | almost 11 years ago | |||
| cfastie | "Huge Breakthrough! We love sliders! Here is NBG of an astroturf putting green (R*S, B*1.3, G*0.1, WHEN S=100): And here is ENDVI = ((R+G)-..." | Read more » | almost 11 years ago | |||
| donblair | "(... and in case the resultant HTML is at all useful, it's here: https://github.com/Pioneer-Valley-Open-Science/infragram-js ) " | Read more » | almost 11 years ago | |||
| donblair | "I've got your code working locally, and it's gorgeous. Just to play around, I tried adding in some of your video instructions as explanation on th..." | Read more » | almost 11 years ago | |||
| donblair | "HOLY COW. " | Read more » | almost 11 years ago |