NIR photography for "plant health"


let’s explore once more that infragram, using the public lab instructions and filters.

I already hacked a cheap action cam during the science hack-day in berlin with @lu_cyP
but maybe the cam quality is really tooooo bad. issues with auto white balance and other other things.

also a time lapse would be great!

what about VVLS mapping? not ballons, but a very very long stick?


I did my master’s thesis on how to measure evaporation based on the temperature of a leaf. Unfortunately my thesis is in Finnish, but the fundamental physics is quite simple.

The method I was using cannot be utilized with near-infrared-measurement, but real infrared-measurement. Those instruments cost less than 100€ and it is not important how accurate they are (absolute), but the resolution an repeatability is much more important (analog signal output would totally do it!). It’s important that the IR-meter can focus on a small object, and as mentioned, an analog output would mean it can obtain as good data as a 1000€ sensor (especially if we have a reliable ‘dark matter’ control temperature measurement.

This is not pure soil geeking, but this in fact it’s very closely connected.

Edit.: As far as I know, this method has not been actually ever used (I have not checked since), but as I wrote in the the thesis, it’s a low-cost although at the moment labor-intensive method.


The whole idea of IR (edit: IR=infrared, meaning basically remote temperature measurements) being a proxy for plant health is that when plants have their stomata open, they transpire (evaporate water). Plants do not transpire for nothing, and this means that when the they are transpiring, they are also taking up carbon dioxide (CO2) from the atmosphere. Carbon dioxide uptake is the same as photosynthesis, which is the same as taking up the solar energy that all the living organisms (including themselves) on Earth can use to survive. If the plants are not photosynthesizing, they will close the stomata, and stop transpiring.

In plants, a stoma (in plural stomata) is the place where the transport happens between living and non-living world. For mammals, kind of similar place is the lungs. Understanding the simple principles how they work is key to understanding a lot of things in plant physiology.

When plants are happy, they take up a lot of carbon, but because of fundamental physics (diffusion), at the same time, they invertedly also lose water (it’s evaporation but when it happens through living organisms, it’s called transpiration). Transpiration cools down the surface (leaf), and that can be measured with infrared-measurements. Other things affect the surface temperature as well, but in a somewhat controlled environment with help of simple mathematics that can be taken care of.


Mission 1_ double sided tape stuck to camera and kite. SUKSESS!

but what do we really “see”?