What I want to do
We'd struggled a year ago to get a CMOS-sensor based Canon SD4000IS working as an Infragram modified camera, so when @nedhorning, @mathew and @cfastie posted about the red filter Infragram technique, I was eager to see if that could get this excellent camera working. You can read more about Mathew and Chris's research here: http://publiclab.org/notes/mathew/04-30-2014/rosco-replacements-for-wratten-25a-pt-2
My attempt and results
My SD4000IS already had its infrared block filter removed, so I just taped a piece of Rosco Fire filter over the front. It seems to have worked very well! Much better differentiation than with a blue filter:
http://infragram.org/i/53e519b10ab503231b000c17 (lead image)
http://infragram.org/i/53e519870ab503231b000c16
http://infragram.org/i/53e519440ab503231b000c15
Questions and next steps
It'd be more ideal to test these in a grassy field, but these are encouraging!
9 Comments
Your new Infragram SD4000 seems to have promise. Here is one with my new lut:
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Oh cool! do you want to post your LUT in a numeric format so we can post it as an Infragram.org option?
The format is:
colormap = segmented_colormap([[0, [0, 0, 255], [38, 195, 195]], [0.5, [0, 150, 0], [255, 255, 0]], [0.75, [255, 255, 0], [255, 50, 50]]]);
where the outermost
[ ]
contain a set of[x-position,[r,g,b]]
items -- x-position measured from 0-1.And a name for your LUT and a place to link to for more information about it. Maybe http://publiclab.org/wiki/infragram-luts ?
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I will have to see if Fiji can output the values for a lut. Fiji has a GUI lut editor, so I have no idea what the values are. Maybe Ned can help. Here is my lut in the editor:
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I was hoping to post a note on this lut. I just tried to attach the lut file to this comment but dragging it here seemed to make somebody mad.
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we only accept certain types of files for upload, for security reasons. I can add .lut, is it an image file or a text file?
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I'm not sure what a Fiji lut file is. Might be binary. I got the values into a tab delimited text file.
NDVI_VGYRM-lut.txt
And I was able to circumvent the dastardly security measures to attach it here.
I guess it might be easy for certain people to make this usable at infragram.org. I wouldn't know.
But this is a very new lut and I am just starting to put it to use and evaluate it. So I will post a note about it and see if people have opinions.
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Whoa... no, a bit tough to use. If you can describe it as a sequence of colors, the format I mentioned will interpolate gradients between them. Just looking at yours, it seems like it could be:
0: white
0.167: black
0.33: white
0.5: black
0.55: blue
0.7: yellow
0.9: red
1.0: magenta
what do you think?
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I get it now. Your translation is good. The blue is actually a light blue, I think [140 140 255] at 0.56. And I put pure green in there explicitly at 0.63 instead of deriving it from a gradient from light blue to yellow (at 0.75). Red is at 0.94.
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OK - try it out! I don't think it works in the WebGL version but in the basic version it should: http://infragram.org/sandbox/
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Good stuff.
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