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Cucurbita cf. pepo [Ornamental Gourd]

Multispectral
1 reply to this topic

#1 Andrea B.

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Posted 16 February 2014 - 17:23

Blum, A.G. (2013) Cucurbita cf. pepo L. (Cucurbitaceae) Ornamental Gourd. Gourd photographed in ultraviolet, visible and infrared light. Channel stacks. http://www.ultraviol...namental-gourd/

Middletown, New Jersey, USA
12 November 2008
Purchased at grocery store

Comment:
This pretty orange Gourd made a nice still life subject. In UV the irregular growth flaws and various scrapes from handling are more obvious although some of that still shows up in the IR photo.

Reference:
1. The American Gourd Society (2014) This is a nonprofit organization dedicated to the education and instruction of those persons who are interested in the culture, uses, history, and/or crafting of gourds.

Equipment [Nikon D200-broadband + Novoflex 35mm f/3.5 Noflexar]

Visible Light [f/11 for 1/180" @ ISO 400 in Sunlight with Baader UVIR-Block Filter]
Click, then click again to see the largest version.
Attached Image: orangeGourdVis121108wf_25394origpnpf.jpg

Ultraviolet Light [f/11 for 4" @ ISO 400 in Sunlight with Baader UV-Pass Filter]
Shooting UV with my old D200-broadband could really bring out the noise. That combined with resizing has induced a few artifacts.
Click, then click again to see the largest version.
Attached Image: orangeGourdUV121108wf_25390origpnpf.jpg

Infrared Light [f/11 for 1/125" @ ISO 400 in Sunlight with B+W 092 IR-Pass Filter]
Click, then click again to see the largest version.
Attached Image: orangeGourd092IR121108wf_25387origpnpf.jpg

Composite
The preceding Visible, UV and IR frames were stacked as difference layers in Photoshop. Making a composite like this does not always reveal anything particularly unusual. It's just fun to do. The layers do not match up perfectly, so you can detect a few edge discontinuities in the full-sized version.
Attached Image: orangeGourd121108wf_25394origpnpfDiffStack.jpg

Multispectral Channel Stack [UV->Purple, Visible->GreenBlue, IR->Orange]
Each frame was assigned to a colour channel. Typically this is done via an RGB channel assignment. I sometimes like to use Purple (128,0,255), GreenBlue(0,255,128) and Orange(255,128,0) instead. Again, such a composite may not be particularly meaningful, but the result is pretty.
Attached Image: orangeGourdVis121108wf_25394pnpfUvPIrOViGComp1.jpg

Multispectral Channel Stack
This is the preceding stack with a 45° turn of the colour wheel. The gourd is starting to look like an apple!
Attached Image: orangeGourd121108wf_25394pnpfUvPIrOViG45Comp2.jpg


Colorized Triptych
I put the Visible frame as a Color layer over the UV frame and then the IR frame in order to "colorize" them. The three photos were then combined in this triptych. The forum software's auto-resizing has clobbered the result a bit, but you can still get the general idea. From left to right, the UV, the Visible and the IR frame, respectively.

Attached Image: gourdTriptychResizeLabel.jpg

.
Andrea G. Blum
Often found hanging out with flowers & bees.

#2 colinbm

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Posted 16 February 2014 - 20:25

You are too good Andrea, a beautiful presentation.
Col