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infragram-sandbox

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: <iframe width="640" height="480" src="//www.youtube.com/embed/7sQZZoXnLlc" frameborder="0" allowfullscreen></iframe> ##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. [![infragrammar](http://publiclab.org/system/images/photos/000/001/174/medium/Screen_Shot_2013-08-17_at_11.52.00_AM.png)](http://publiclab.org/system/images/photos/000/001/174/original/Screen_Shot_2013-08-17_at_11.52.00_AM.png)

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