Re: [APD] Aquatic-Plants Digest, Vol 31, Issue 19

[Alan and Kim Van Nevel <van_nevel at verizon.net>]

In remote sensing and terrestrial agriculture, hyperspectral imagery as 
well as laser induced fluorescence has been used as indicators of crop 
health.  The plants will demonstrate stress through the hyperspectral 
signature .  Using a single band, or color imagery it _might_ be possible, 
but it may be difficult to control everything.  For example, as we all know 
water absorbs light very well, in many wavelengths.  The content of the 
water will also change those absorption bands, and that may lead a single 
band measurement (eg IR) to vary even in the absence of plant 
fluctuations.  If you have a hyperspectral web cam, then I know algorithms 
and tools could be developed.  For single band, either IR or color, I doubt 
that there will be enough information to allow for accurate determination 
of plant stress before we can note it visually.



>    3. Webcam as plant health monitor? (Daniel Larsson)
>
>
>Message: 3
>Date: Fri, 10 Mar 2006 14:44:51 +0100
>From: "Daniel Larsson" <defdac at hotmail_com>
>Subject: [APD] Webcam as plant health monitor?
>To: <aquatic-plants at actwin_com>
>
>Hi everyone.
>
>I've made my webcam take one picture every ten
>minute and plot color values:
>http://82.183.138.227/webcam/charttest.html
>
>Why? Don't know. Because I thought it was cool
>and perhaps the chart could somehow tell me when
>to dose.
>
>Well, I'm having trouble making anything useful out
>of the chart, but today I remembered my CoolPix
>4500 is sensitive to IR and that chlorophyll meters
>measure the amount of reflected IR-light from plants.
>
>I also found this article on how to make a webcam
>take IR-pictures:
>http://homepage.ntlworld.com/geoff.johnson2/IR/
>So I will be doing that as soon as possible.
>
>Now to my question - have onyone been taking
>IR-pictures of their planted tank and been able
>to see when the plants are "sad"?
>
>
>Best regards
>Daniel Larsson, Sweden
>http://www.defblog.se
>
>

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