I’ve just had my head candled like a new-laid egg and the procedure, a CAT scan of my sinuses, which are revolting in both senses, got me thinking about uses for video in science. While the scanner snapped my head in 3mm slices for a computer to stack like Necco Wafers, I was thinking about all the ways video and science can stimulate your creativity. Put your labcoats on and get ready to push your ideas beyond weddings and vacations and all the usual video suspects–we’re going to the science lab for a little creativity stimulation.
When you come right down to it, video performs four basic services for science:
- Revealing the invisible
- Reaching the inaccessible
- Preserving the temporary
- Projecting the imaginary.
Summarized in this abstract way, these functions may seem remote and highfalutin’. But each of these abilities can be useful in your own video projects, as we’re about to see.
Revealing the Invisible
Generally speaking, science videos record natural phenomena (or experiments upon said phenomena). But the inconvenient fact is that many events take place at a speed or in an illumination that effectively renders them invisible.
In the speed department, many natural processes operate so slowly that no human can perceive them in real time. But video doesn’t observe like a human. Instead of watching continuously, it wakes up, takes a single snapshot (called a frame) and then goes to sleep again. Because this cycle repeats so rapidly (30 times per second in NTSC video) the recording of events appears to be continuous.
Ah, but if you set the camera to awaken only once every second–or every minute or hour or day, for that matter–but still view the resulting frames at the standard 30 per second, you can compress even agonizingly slow processes into watchable time units.
For those of us who aren’t excited by grinding glaciers or drying paint, how is this practical? How about capturing your favorite rose as it blooms or showing a new school building go from dirt lot to finished project in two minutes of screen time.
Cool, but could you do this with your average consumer video equipment? The answer is complex. Generally speaking, consumer camcorders can’t record single frames, though better models can shoot in timed bursts of four to six frames. On playback, the results are slightly jerky, as you’d expect, but quite acceptable.
To get true single-frame capability you need to spend a few thou’ for a VCR that can indeed record one frame at a time. Then you set up your rig so that the camera captures images at the usual 30 frames per second (fps) but the specialized VCR does the actual recording, selecting a frame to lay down only as often as it’s programmed to do so.
You can do true single-frame fast-motion with prosumer hardware if you can digitize your footage. The procedure might work (very roughly) like this:
- Shoot in the usual 4-6 frame bursts.
- Digitize the resulting footage.
- Use the filmstrip capabilities of software like Adobe Photoshop to extract one frame from each burst.
- Assemble the single frames in order.
- Compile and export the result as a movie.
If your background is live-action video, you may find this process agonizingly slow; but for graphic or stop-motion animators, the work actually goes faster than usual!
Back in the real world, on the obverse side of the speed problem, insect wings flap so fast that they’re nothing but tiny blurs. To see them, you must slow them down, and that requires the opposite recording technique: a shooting frame rate that is higher than the viewing rate. Photographed at 1200 frames per second, for example, dragonfly wings played back at 30 fps flap as majestically as six-foot palm frond fans.
The trouble is that video outfits (with a few very expensive exceptions) can’t shoot at 1200 frames per second or even 120. Video records at 30 fps and only 30 fps. To record true slow motion you must use a cine film camera instead.
Hold it! you say. If that’s true, how come my expensive camcorder has shutter settings that go up to 1/12000 sec.? The answer lies in the difference between shutter speed and frame rate. Even when your camera’s exposures are as short as 1/12000 sec., it is still recording only 30 of these super-brief shots per second. This means that you can reduce the blurring of very rapid motion, but you cannot break it into more pieces for close analysis.
Okay, you say, why don’t I just use the slo-mo playback feature on my VCR? Because that technique doesn’t increase the number of frames per second, but merely repeats each of the standard 30. So at 1/4 apparent speed you’re not watching 120 frames per second, but only the usual 30 frames, re-displayed as 1, 1, 1, 1, 2, 2, 2, 2, and so-forth.
Video can also reveal the invisible by translating radiation other than "light" as we see it into frequencies that human eyes can pick up. For example, a recent issue of Archeology magazine showed how infrared videography disclosed details of ancient Mayan paintings not visible in ordinary light. In the same way, a fluoroscopic examination of coronary arteries translates X-rays, which we cannot perceive at all, into light waves within the visible spectrum.
You can use similar techniques, now that night vision optics are available from Edmund Scientific and other sources. Simply attach an infrared monocular to the front filter thread on your camcorder lens, bathe the target area in infrared light, and document the skunks, deer, and other critters that are decimating your vegetable bed.
The results can be spectacular, but don’t expect them to look like "normal" video. Remember that your electronics are not displaying subjects in infrared light, but translating infrared images into rough approximations in the visible spectrum.
Reaching the Inaccessible
Going back to the fluoroscopic journey through human arteries, video can also take scientists places that are otherwise inaccessible. In this case, the environment is too small for people to access, while in the case of my sinuses, the alternative would be too invasive. You could actually saw my face into slices three millimeters thick, but the process would kill me, a side effect that you will acknowledge as at least inconvenient.
In other situations it’s not the camera’s invasion that kills humans but the environment that’s being invaded. There’s nothing to prevent you from observing events in the vacuum of space if you don’t mind exploding, or the busy life a mile beneath the ocean surface if you’re willing to be squeezed by unimaginable pressure into the shape of a very wide dime.
It’s much more sensible to send an impervious video camera instead. This is an application where video is superior to film: because the image is recorded as an electrical signal rather than as latent changes in the chemicals on a film sheet, it can be instantly transmitted back to Earth or up to the surface for safe inspection by humans.
You too can send your camcorder to inaccessible places even if you’re not Carl Sagan or Jacques Cousteau. For instance, my students needed a point-of-view shot of a human fly climbing a tall building. Since having a student scaling the school wall would be impractical (and get me summarily canned) we rigged a camera platform slung from two fishing poles instead. Why two? Because a single line allowed the camera to spin uncontrollably. It took a second line to stabilize it and point the rig in the desired direction.
Preserving the Temporary
The most widespread use of video in science is for simple documentation: the recording of otherwise transitory events. Theoretically, you could describe verbally every move a rat makes in the process of learning to trip a lever to obtain a treat, but why not just train a camcorder on its maze and painlessly preserve the whole process?
This, of course, is what you use your camcorder for already: recording birthdays and holidays and school wingdings and such for a posterity presumably interested in these fascinating events. So the point here is not to tell you how to document things with your camcorder, but how to expand your awareness of things to document.
For instance, do you often get your Harley chopper back together with three anonymous parts left over? If you prop a camcorder on a tripod where it can record the process of dismantling your hawg, you’ll be able to see where everything came from and therefore, where to put everything back.
In my own case, I realized in the nick of time that the complex plumbing and electrical lines to and from our newly built swimming pool were about to be covered forever with poured concrete decking. Hastily I recorded the positions of all these components before they were entombed. Some years later, when a baby possum committed hari kiri in a water line (don’t even ask) we reviewed the tape in order to bust a minimum of concrete in reaching the site of its regrettable demise.
Projecting the Imaginary
The newest role of video in science lies in recording and displaying the computer’s ability to make visual analogies of nonvisual information.
This is not the same task as translating normally invisible images made from infrared or X-ray radiation, but of creating pictures from scratch out of non-pictorial information.
If all this sounds esoteric, consider a simple bar graph of sales figures. These are numerical quantities that don’t emit or reflect any radiation whatever, so they’re impossible to "see." But the computer makes them seem visible by assigning them analogous visual traits such as size, shape, color, and position.
In a similar way, scientists take satellite data on ground moisture, assign different colors to different levels of wetness, and produce maps full of hues that don’t exist in nature, but that disclose environmental patterns to observers.
How could you use video to make statistics visible? Maybe you could graph your debt history as a Sierra Nevada in order to scare yourself out of credit card abuse, but here the practical relevance for you lies not in the technique but in the marriage of computer and video. Unlike a computer, a camcorder doesn’t manage and manipulate information; instead, it just passively records it. But it is precisely as a storage medium that video easily outperforms its otherwise smarter partner.
If you’ve made the jump to computer-based nonlinear editing you know that you can fill a jumbo hard drive with a ten-minute video program–a program that will comfortably fit in less than ten percent of a standard tape. So the important point here is not that video can record the abstract made visible but that it can record this–or anything else–with such incredible efficiency.
So there, as promised, is a brief rumination on video in science. Even if you don’t launch probes toward Jupiter or journey with gun and camera through the alimentary canal, you can pick up on some of the ideas behind scientific video and put them to work in your own shooting.