Cartometric Blog

A scrapbook of GIS tricks, with emphasis on FOSS4G.

Nikon Coolpix 3100 Near Infrared Hack

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While this post is not in-theme with the stated goals of the blog, I wanted to save my notes somewhere as well as make a URL to show-off for my friends. On the other hand, I’m opimistic my experiment will enable some “eco-minded research”, so perhaps there’s still a loose tether linking this back to the GIS community..

Basically, I hacked my old, 3 megapixel Nikon Coolpix 3100 today so that I could take NIR (near infrared) pictures. The following images serve as a storyboard for the process.

0:  The tools and materials involved include (clockwise from bottom-left)
—-> small round-nose pliers (my wife uses these for beading)
—-> small phillips head screwdiver
—-> butt-end of unprocessed camera film
—-> small curve-nosed pliers
—-> scissors
—-> electrical tape
—-> the Nikon Coolpix 3100 (the pic is post-hack)
—-> one depleted roll of hockey tape*

* The expired roll of hockey tape became the “housing” for a DIY visible bands filter, which you see fitted to the front of the camera. By some amazing coincidence the cardboard tubing holding the tape fit the camera perfectly. The “donut hole” was just the right diameter to cling to the face of the camera; plus, it was just deep-enough to stay clear of the lens when in use.

 

 

1:  Looking at the guts –I had to pull 22 screws to reach the NIR filter and CCD mount. At this point, I was relatively convinced the sucker was dead meat. The IR filter was just a piece of pinky-nail-sized-glass clinging to a rubber footing. I was able to gently tease the filter from the footing using my index finger.

Caveat: If you try a similar project, I recommend going to the trouble to illustrate or take notes documenting the locations of screws as you remove them. While my camera still worked without any screws being replaced (no kidding), once I was finished experimenting, I wasn’t able to replace 7 of 22 screws into the camera assembly. There wasn’t a functional consequence in my case, but I hate knowing that I didn’t get it 100% back together.

 

2: After removing the NIR filter, I snapped the camera back together (using ZERO of the 22 screws, expecting to crack it open again shortly) and was fully amazed when it powered-on following surgery. Next, I fired-up a burner on the stove and photographed the hot burner across from its cool neighbor. At this point, without the NIR filter the rear-burner coils appear bright-pink, which I expected, but the distinction between the active burner and the inactive burner was not as pronounced as I hoped. So I decided to incorporate another trick revealed by my research.. 

Note: The coils were not visibly red; that is, I could not distinguish the hot burner from the cool burner by sight alone at the time of the exposure.

 

3: One of the related articles I researched provided the idea of making a DIY Visible Bands Filter out of a slice of unprocessed camera film. So I tried it. I found a nearly-depleted roll of hockey tape to serve as the filter housing. Then I “sharpied” the insides of the tape’s cardboard tubing and used elecrical tape to attach a choice cut of unprocessed camera film. As you can see, the end result fit the camera very nicely —I can’t exaggerate how perfectly the depleted roll of hockey tape fit the camera exterior. Would it work? 

Regarding the cut of film, you don’t want to use the see-through, sepia-toned portion with off-color images, as those are processed negative frames. Instead, you want the black, unprocessed portion. I found a good piece  with plenty of slack at the butt-end of some old negatives.

 

4: With my visible bands filter attached and an enthused state-of-being, I returned to the stove for another experiment. Once again I fired up the rear burner, waited for it to radiate a reasonable amount of heat, then took another pic. As you can see, the hot burner is about the only thing visible in the photo.

Our stove is white, so clearly my visible bands filter leaks some light into the exposure. However, note how dark/black the forward burner is. Once again, there was no difference between these burners at the time of exposure (at least, as a human can see). This was the sort of result I was hoping to get.

 

Blurry Images: In my Nikon Coolpix 3100, it seems the stock NIR Filter pulls double-duty, behaving not only as a spectral sieve, but also providing some optical focus. James Wooten’s blog post provides some insight into this issue noting that without the NIR Filter/Glass..

..the camera will be “near-sighted” without it. I used a optical glass that has about 85% transmission in the IR and visible range. It helps if you have a friend that cuts glass for a living.

 I happen to have a specific goal in mind for my NIR camera, so I’m not immediately concerned about this shortcoming; however, if I want to take photos with a reasonable amount of visual acuity, I’ll have to resolve this issue at some point. When and if I get around to that, I’ll return to this post and update my notes.

Related Pages: Each of the following sites povided some form of inspiration or insight, so I wanted to log them along with the article–

http://4photos.de/camera-diy/index-en.html: Many, many links devoted to camera repair, modification, and hackery..

http://www.lifepixel.com/tutorials/infrared-diy-tutorials/nikon-coolpix-5400: These people will do the camera hack for you if you’re willing to part with some money (my Nikon would’ve cost about $200). However, I’m wondering if LifePixel may sell the clear optical lens I need to fix the blurred images problem? Theirs is the first site I’ll check when I decide to cross that bridge. This URL goes to their tutorial for hacking a similar Coolpix model, but they had several such tutorials, so if you’re considering your own project, I recommend perusing their site for a tut describing the hack on a camera model near to the one in your crosshairs.

http://www.geektechnique.org/projectlab/254/how-to-turn-a-digital-camera-into-an-ir-camera.html: Mark Hoekstra does a nice job of presenting his camera hack using several step-by-step images. Read his site in full before you jump head-first into your own poject. In the end, I felt my project required going to a similar “component depth”.

http://www.abe.msstate.edu/~jwooten/camera/lense.html: The original James Wooten post, cited in the body of my article.

http://www.echeng.com/photo/infrared/faq/
http://www.echeng.com/photo/infrared/wooten/
http://www.echeng.com/photo/infrared/hot_mirror_replacement.gif
http://www.echeng.com/photo/infrared/wooten/IR_Block.GIF: Eric Cheng maintains an interesting site; it was actually through his page that I ran across the Wooten article. Eric did the research and posted some details related to the much-needed replacement lens, which I appreciated.

http://www.diyphotography.net/take_infrared_pictures_with_digital_camera_ir_filter: This post inspired my implementation of the DIY visible bands filter. They do a swell job of documenting the materials and steps involved in making the filter (this is if you don’t happen to have a used roll of hockey tape langushing somewhere in your gear bag).

http://www.jollinger.com/photo/articles/cheap_ir.html: One of the first posts I ran across; however, James’ camera was quite different from mine, so most of the post wasn’t applicable. But, it was open in my tabs when I embarked on this venture, so I’ll cite it anyway.

Home Energy Audit: So, why would I make an NIR camera if my chief interest isn’t taking unique and stunning photographs? Well I hope can photograph my house from all sides to learn where the structure leaks the most heat. On the other hand, NIR isn’t exactly heat, so this may not correlate in practice, but it’s worth a shot if only for the fun of trying. My wife and I have been thinking about replacing some of our windows, so if we can’t afford to replace all our windows, I thought perhaps we could zero-in on those windows that are costing us the most money. I don’t know if this will work but, once I think it’s cold-enough to try it, I’ll take some pics of the house in all its raging un-eco glory and post them here in the article.

:)

/Elijah

Written by elrobis

November 5th, 2011 at 2:57 pm

Posted in Uncategorized

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