Thursday, September 14, 2017

How to simulate what birds may see: simulated bird vision

Birds (many of them) have the ability to see UV (ultraviolet) light, which we humans cannot see.

The following graphic illustrates that by comparing our (rather limited) human spectral range to the larger one birds have, including UV (ultraviolet), based on them being tetrachromats (they see 4 colors: UV, Blue, Green, Red approx. 300-700nm), whereas we humans are trichromats (we only see 3 colors: Blue, Green, Red, approx. 400-700nm).

Be reminded: The pink-magenta UV "color" shown here has been chosen to make it better visible for us humans, it is a "false color", as per definition UV light (approx. 300-400nm) has no color!

A flower such as a Rudbeckia fulgida with an underlying UV pattern, invisible to us humans, then looks like this in human vision (left) and simulated bird vision (right):



So how may then birds look like, seen through birds eyes? Possibly like this (it is simulated bird vision on the right):


I have used this to make visible in still photography and videography what birds may seen of a bird protecting device, the FireFly bird diverter, which may bee seen HERE

But how has this been done? Well, in principle using photographic technology, but with a twist:

Normal photography uses (as per today) a digital camera with a built in sensor, a greenish/blue filter stack in front of that sensor, which limits and adjusts its much broader sensitivity range (UV to IR, approx. 300-1000nm) to the human vision range (approx. 400-700nm), using a suitable standard taking lens, made of optical glass. And of course a suitable lightsource is needed, sun being the best, as it provides a useful amount of UV in its light spectrum

Now this type of multispectral photography needs a modified camera (internal filter stack removed and replaced by an UV and visible light transmitting, clear fused silica window), a suitable UV transmitting special quartz-fluorite lens (the UV-Nikkor 105mm being one of only a few ever made ones), and special filters which allow to record UV images (such as the Baader-U UV transmitting, but visible light blocking filter), as well as filters to record the normal visible light (Blue, Green, Red).

The resulting UV and VIS (Blue, Green, Red) images are then suitably combined into one "multispectral image", in our case here the "simulated bird vison" image. [That term "suitably" describes a rather complex mapping process which I will not describe in detail here. NASA uses similar processes to generate their amazing images from their Hubble space telescope or their Earth observation satellites]

[all graphics shown here are (C) Hammarprodukter AB and Dr Klaus Schmitt, used with permission]

HERE is more about birds and bird vision!

If you are interested into that type of photography, HERE on my site is a lot about it, including my "cook book" style tutorial how to do it.

Stay tuned, more will follow on this fascinating subject...

Wednesday, September 13, 2017

Bird Protection using FireFly Bird Diverter

Today about birds and how to protect them against collision with power lines. Each year millions of birds die, especially when migrating in spring and autumn. The patented FireFly device was invented and manufactured by Hammarprodukter AB to protect them.

The following videos were shot at Kübassaare / Saaremaa Island, Estonia in 2017, as a proof that a carefully designed bird diverting device, such as the patented FireFly (and BirdMark) made by Hammarprodukter AB of Sweden, works efficiently to divert birds and make them change their flight path, hence protecting their lifes.

[click images to see larger ones]

Power line at Kübassaare / Saaremaa island / Estonia:
 
(C) Hammarprodukter AB

The following video was shot in June and August 2017 in normal human vision, in simulated bird vision at daylight, but also at dusk / night to show the afterglow effect this FireFly device has, aside from its intense flickering when rotating,  which can be seen up to 350-400 meters, which is the visible distance covered in this video. Several overflights were recorded, where birds actively changed their normal flight path.

[best to watch in HD full screen]




Here now a screen shot showing how efficient FireFly was able to divert the flight path of the birds.

Simulated bird vision still image from video with diverted flight path:
 

Birds (many of them) have the ability to see UV (ultraviolet) light, which we humans cannot see! This grahic here makes this visible by comparing our human spectral range to the larges one birds have, based on them being tetrachromats (they see 4 colors), whereas we humans are trichromats (we see 3 colors).

Be reminded: The pink-magenta UV "color" seen here has been chosen to make it better visible for us humans, it is a "false color", as per definition UV light has no color!


So how may then birds look like, seen through birds eyes? Possible like this (it is simulated bird vision on the right):


The Hammarprodukter FireFly also makes use of this knowledge, to scare birds away from high voltage powerlines, which may harm birds!

HERE is more about bird vision!

HERE a link to the manufacturer product site Hammarprodukter.se

And HERE more about human vision vs bird vision and how to make that visible.

[all graphics shown here are (C) Hammarprodukter AB and Dr Klaus Schmitt, used with permission] 

More about that here later, as I took on the task to scientifically assist Hammarprodukter AB.

Stay tuned, more will follow on this fascinating subject...