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Wednesday, July 12, 2023

Parrots love looks !! - பார்த்த விழி பார்த்த படி !!

பார்த்த விழி பார்த்த படி - நோக்கி இருக்க !!


தமிழ் சினிமாவின் கிளிஷே !  - அழகான படித்த பணக்கார பெண், பஸ்ஸில் பயணம் செய்வாள் ! ஒரு கும்பலே அவள் பின்னால் அலையும் !  - படிக்காத முரட்டு தாடிக்கார ஹீரோ அவள் முன் சாகசம் செய்வான்.  கூட இருக்கும் காமெடி நடிகன் சொல்வான் - அவள் உன்னை விரும்புகிறாள்,  பார், கொஞ்சம் தூரம் சென்று மறுபடி உன்னை திரும்பி பார்ப்பாள்.  அழகு கதாநாயகி காதல் வயப்பட்டு ஹீரோ மனசு எவ்வளவு நல்லது தெரியுமா என  தன் பெற்றோரிடம் சண்டையிட்டு மணமேடையில் இருந்து ஓடி வருவாள் !! 

சினிமா கதை அல்ல இந்த பதிவு ! - கண்கள் பற்றியது ! - உங்கள் கண்களால் எவ்வளவு விஷயங்களை ஒரே சமயத்தில் காணமுடியும் ?? 

How much you can see – meaning – the wide angle say from left to right – how much you can see while in a stadium or elsewhere !! Visual angle is the angle a viewed object subtends at the eye, usually stated in degrees of arc. It also is called the object's angular size.  We have two eyes – so also many animals and birds but the location could be different.  Birds and fish have eyes on their sides !!   Having two eyes means one can see a three dimensional image of what’s around them. So they can perceive the height, width and depth of an object, as well as how far away it is. Pigeons and parrots like most birds have eyes on sides , then there is Owl  that has large eyes placed close together at the front of their heads – a bit like ours.  

The field of view (FOV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles  or virtual reality goggles. Though  eye movements are allowed in the definition. They  do not change the field of view when understood this way.  

If the analogy of the eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. It is defined as "the number of degrees of visual angle during stable fixation of the eyes".  Humans have a slightly over 210-degree forward-facing horizontal arc of their visual field (with eye movements included) it is slightly larger, while some birds have a complete or nearly complete 360-degree visual field.  

Medical anatomy is very advanced and complex – there is ‘Occludable angle’!.  The “angle” is the part of the eye where the iris meets the cornea and sclera. The drainage system of the eye is located at this region – trabecular meshwork . Angle closure glaucoma typically affects anatomically “small eyes” – in which intra-ocular structures result in a crowded anterior segment.  That is more for diabetic patients to worry !!   

Because owls have eyes at the front of their heads, they have a smaller field of vision – around 150 degrees for a barn owl (though they can turn their heads very far to look around). Parrots, pigeons and other birds with eyes on the sides of their heads have a much bigger field of vision, of about 300 degrees. Amazingly, this means that they can see in front and a long way to the side, at the same time.


Believe me, this has nothing to do with field of vision, this beautiful parrot was ogling me, fixing its looks on me. 

With regards – S. Sampathkumar


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