{"id":186,"date":"2022-03-11T16:30:43","date_gmt":"2022-03-11T16:30:43","guid":{"rendered":"http:\/\/michaeltsmith.org.uk\/?p=186"},"modified":"2022-03-11T16:30:43","modified_gmt":"2022-03-11T16:30:43","slug":"bayer-filter","status":"publish","type":"post","link":"http:\/\/michaeltsmith.org.uk\/?p=186","title":{"rendered":"Bayer Filter"},"content":{"rendered":"\n

One issue I thought might be a problem is that the pixels on a camera don’t really each measure all 3 colours. Instead, they each measure one colour & the colours are then interpolated. This isn’t a problem if the object being photographed spans many pixels, but what if the object is a tiny bright dot, as in our situation.<\/p>\n\n\n\n

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An example Bayer filter (from wikipedia<\/a>)<\/figcaption><\/figure>\n\n\n\n

An example photo of “What the ladybird heard”:<\/p>\n\n\n\n

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Example photo of What the Ladybird Heard cover: The raw data from the camera. The yellow cover of the book doesn’t have much blue, so the blue pixels are darker.<\/figcaption><\/figure>\n\n\n\n

Sadly the problem of the filter seems to be impacting our bee-orientation\/id experiment. Here I rotate a tag 360:<\/p>\n\n\n\n

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The in-focus result (notice the dot colours don’t smoothly transition)
<\/figcaption><\/figure>\n\n\n\n

The result is less accurate predictions of orientation:<\/p>\n\n\n\n

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Points plotted on colour triangle (number = angle in degrees)<\/figcaption><\/figure>\n\n\n\n

If we adjust the focus of the lens so the tag isn’t in focus, the colours are more reliable:<\/p>\n\n\n\n

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Progression of tag colour as it rotates (in 14-16 a non-tag was found by mistake)<\/figcaption><\/figure>\n\n\n\n

This leads to a more reliable prediction:<\/p>\n\n\n\n

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Points plotted on colour triangle (number = angle in degrees)<\/figcaption><\/figure>\n\n\n\n

I think the plan now is to:<\/p>\n\n\n\n

  1. Collect more data but download raw (without interpolation) – this also saves bandwidth from the camera.<\/li>
  2. Look at fitting the PSF using this raw data.<\/li>
  3. Maybe leave the camera just a little out of focus, to ensure all the colours are detected.<\/li><\/ol>\n\n\n\n

    <\/p>\n","protected":false},"excerpt":{"rendered":"

    One issue I thought might be a problem is that the pixels on a camera don’t really each measure all 3 colours. Instead, they each measure one colour & the colours are then interpolated. This isn’t a problem if the object being photographed spans many pixels, but what if the object is a tiny bright … <\/p>\n

    Continue reading “Bayer Filter”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-186","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=\/wp\/v2\/posts\/186","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=186"}],"version-history":[{"count":1,"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=\/wp\/v2\/posts\/186\/revisions"}],"predecessor-version":[{"id":192,"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=\/wp\/v2\/posts\/186\/revisions\/192"}],"wp:attachment":[{"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=186"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/michaeltsmith.org.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}