{"id":4349,"date":"2022-08-10T17:30:42","date_gmt":"2022-08-10T21:30:42","guid":{"rendered":"https:\/\/faculty.fiu.edu\/~theobald\/?page_id=4349"},"modified":"2022-08-10T17:53:38","modified_gmt":"2022-08-10T21:53:38","slug":"visual-pooling","status":"publish","type":"page","link":"https:\/\/faculty.fiu.edu\/~theobald\/fun\/visual-pooling\/","title":{"rendered":"Visual Pooling"},"content":{"rendered":"\t\t
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Visual summation for dark and fast scenes<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Images from cameras, telescopes, or just your eyes all suffer when light is dim because photons, which actually make the images, are scarce. Photons are absorbed discretely and randomly, so in the dark you get an increasingly unreliable image. These images show two animals that might be concerning to a foraging insect, a spider, camouflaged on a flower, and a bat, patrolling in the air. As light gets dimmer (left to right), both images are lost (underexposed).<\/h4>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Both spider and bat are lost to dark, random, photon noise<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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The best way for an animal to <\/span><\/span><\/span>improve the <\/span><\/span><\/span>underexposure<\/span><\/span><\/span> associated with photon count is to gather more photons.<\/span><\/span><\/span> B<\/span><\/span><\/span>igger lenses<\/span><\/span><\/span> are the<\/span><\/span><\/span> ideal <\/span><\/span><\/span>solution, which<\/span><\/span><\/span> is why<\/span><\/span><\/span> photographers in dark areas or at fast sporting events haul around large, heavy lenses (sometimes called \u201cfast\u201d lenses, for photographing quick events)<\/span><\/span><\/span>.<\/span> But it <\/span><\/span><\/span>becomes im<\/span><\/span><\/span>practical to carry ever larger optics. <\/span><\/span><\/span>A<\/span><\/span><\/span>n alternative <\/span><\/span><\/span>strategy, summation,<\/span><\/span><\/span> gather<\/span><\/span><\/span>s<\/span><\/span><\/span> more photons by broadening image parameters, sacrificing some <\/span><\/span><\/span>visual sharpness<\/span><\/span><\/span> (<\/span><\/span><\/span>acuity<\/span><\/span><\/span>)<\/span><\/span><\/span> for increased reliability<\/span><\/span><\/span>.<\/span> Spatial summation increases the solid angle of photon collection<\/span><\/span><\/span>,<\/span> the strategy of our rod cells, which form images for us in the dark.\u00a0 Although they are tiny, they pool in groups to <\/span><\/span><\/span>form<\/span><\/span><\/span> blurry but highly sensitive <\/span><\/span><\/span>images<\/span><\/span><\/span>. They <\/span><\/span><\/span>give<\/span><\/span><\/span> us <\/span><\/span><\/span>the ability <\/span><\/span><\/span>to see a book in the dark, but <\/span><\/span><\/span>without<\/span><\/span><\/span> the resolution to read it<\/span><\/span><\/span>.<\/span><\/span><\/h4>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Spatial pooling recovers a blurry form of the predators, but detail that let us resolve that ther is a spider hidden on the flower is gone<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Temporal summation increases light catch with long integration times, essentially waiting longer before forming each pixel in <\/span><\/span>an<\/span><\/span> image. Rod cells respond slowly, <\/span><\/span>allowing us to see dim lights, but <\/span><\/span>leaving us unable to distinguish a flickering light from a steady one<\/span><\/span>.<\/span><\/span> These principles are the same for photography. A large lens is an <\/span><\/span>expensive<\/span><\/span> optical solution to capturing dim or <\/span><\/span>moving<\/span><\/span> images, but a <\/span><\/span>poor<\/span><\/span> photographer can choose faster film\u2014the large granules producing a blurry image\u2014or <\/span><\/span>slower<\/span><\/span> shutter speed<\/span><\/span>\u2014which takes <\/span><\/span>longer<\/span><\/span> and blurs anything <\/span><\/span>in <\/span><\/span>mo<\/span><\/span>tion.<\/span><\/span><\/h4>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Temporal pooling also recovers images in the dark, and the spider is again visible, but the fast moving bat is lost while we slowly expose our photoreceptors<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

Visual summation for dark and fast scenes Images from cameras, telescopes, or just your eyes all suffer when light is dim because photons, which actually make the images, are scarce. Photons are absorbed discretely and randomly, so in the dark you get an increasingly unreliable image. These images show two animals that might be concerning […]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":4040,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4349","page","type-page","status-publish","hentry","entry"],"_links":{"self":[{"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/pages\/4349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/comments?post=4349"}],"version-history":[{"count":4,"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/pages\/4349\/revisions"}],"predecessor-version":[{"id":4357,"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/pages\/4349\/revisions\/4357"}],"up":[{"embeddable":true,"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/pages\/4040"}],"wp:attachment":[{"href":"https:\/\/faculty.fiu.edu\/~theobald\/wp-json\/wp\/v2\/media?parent=4349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}