Seeing Plant Health In Infrared

July 3, 2013 by Brian Benchoff 13 Comments

aerial

Since the 70s, NASA, NOAA, and the USGS have been operating a series of satellites designed to look at vegetation health around the world. These satellites, going under the name Landsat, use specialized camera filters that look at light reflecting off chlorophyll to gauge the health of forests, plains, oceans, and even farms. It’s all very interesting technology, and a few very cool people want to put one of these near infrared cameras in the hands of everyone.

The basic idea behind gauging the health of plants from orbit, or the Normalized Difference Vegetation Index, is actually pretty simple: absorb red and blue light (thus our verdant forests), and reflect nearly all infrared light. By removing the IR filter from a digital camera and adding a ‘superblue’ filter, the NDVI can be calculated with just a little bit of image processing.

The folks behind this have put up a Kickstarter with rewards including a modified webcam, a custom point and shoot camera, and a very low-cost source of one of these superblue filters. Just the thing to see how your garden grows or how efficiently you can kill a houseplant.

Bullet Time With A Ceiling Fan

July 2, 2013 by Brian Benchoff 29 Comments

Bullet time has been around since at least the first Matrix movie (actually there was a Gap ad before that), and despite it being an oft-used cinematic technique, it still hasn’t gotten old. [Jeremiah] wanted to tap into the awesomeness of bullet time, and managed to come up with a great camera rig using only a GoPro and a ceiling fan.

The build really relies on only two components: a GoPro camera and a ceiling fan. In [Jeremiah]’s videos, a ceiling fan is mounted between two trees on a sturdy piece of lumber. The GoPro is suspended from one of the fan blades with the help of a piece of wood, a hinge, and a short bit of cable. After [Jeremiah] wired up the fan to a dimmer switch he could control the speed of the fan and Bob’s your uncle.

This isn’t the first time a GoPro has been used for a bullet time rig. In fact, our buddy [Caleb] did a similar build by spinning the camera around on a lazy suzan. Gotta love the high frame rate available on the GoPro, huh?

Vidias after the break.

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3D Scanning By Calculating The Focus Of Each Pixel

June 21, 2013 by Mike Szczys 42 Comments

calculating-focus-to-generate-depth-map

We understand the concept [Jean] used to create a 3D scan of his face, but the particulars are a bit beyond our own experience. He is not using a dark room and laser line to capture slices which can be reassembled later. Nope, this approach uses pictures taken with several different focal lengths.

The idea is to process the photos using luminance. It looks at a pixel and it’s neighbors, subtracting the luminance and summing the absolute values to estimate how well that pixel is in focus. Apparently if you do this with the entire image, and a set of other images taken from the same vantage point with different focal lengths, you end up with a depth map of pixels.

What we find most interesting about this is the resulting pixels retain their original color values. So after removing the cruft you get a 3D scan that is still in full color.

If you want to learn more about laser-based 3D scanning check out this project.

[Thanks Luca]

GoPro Panning Time-lapse With Ikea Egg Timer

June 4, 2013 by Mike Szczys 29 Comments

ikea-go-pro-time-lapse

[Sebastian Schuster’s] weekend project was to turn his GoPro camera into a panning time-lapse rig. You’ll notice it’s in a waterproof case as his demo for the hack was an outdoor session and the weather’s not the best right now. He put this together quickly, easily, and on-the-cheap thanks to the Ikea egg timer and a 3D printed camera mount.

An egg timer is a popular choice for panning hacks. Any type that includes a dial that spins on the horizontal axis will do. The Ikea Stam egg timer has that raised handle which is easily gripped by the 3D printed part. You can get a hold of the design files through a web service which is new to us. [Sebastian] used Tinkercad for the design, and shared it in his project post linked above.

This is just one more tool in his collection of camera hacks. A couple years back we looked at a motorized pan and tilt platform he built.

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Nikkor Optical Glass

June 4, 2013 by Caleb Kraft 8 Comments

Glass work is always a feast for the eyes, especially when it is hot glass. Watch as a Nikkor lens is made from beginning to end. It is wonderful to see the care taken to search by eye for defects, refraction issues, clarity etc. It may just be for the video, but it seems that the workers truly do take pride in their product.

What I found somewhat surprising was the amount of work that went into refining the glass BEFORE it was even put into a lens mold. I would have assumed that much of the work would have come after.

High Speed Photography With Friggin’ Lasers

May 31, 2013 by Mike Szczys 14 Comments

[Bruce] built his own high-speed photography equipment for a fraction of the price it would have cost him to purchase it. He was inspired by a friend who showed him some example images. He headed into his shop and built an Arduino-based high-speed flash controller.

To capture an image like this one the camera is placed in a dark room and set for a long exposure. At just the right instant the flash is activating, capturing the image. In this case [Bruce] used an infrared laser diode pointed at a phototransistor to trigger the flash. When the droplet breaks the laser beam the Arduino triggers the flash after a calculated delay. It’s not specifically covered in his guide, but [Bruce] also mentions that this can be modified to use sound as a trigger. Here’s another sound-activated flash controller if you need inspiration.

The image at the top was made by dropping dye from a pipette into a pool of water. If you don’t have a pipette on hand you can head over to our LIFE blog to make one out of heat shrink tubing.