Streak Photography

Streak photography gets its name from the way the pictures are produced. They are composite images built up from a single streak (or strip) out of many different images. The images I show here were created using the Time Machine, a programmable rotary table, and an Olympus E-10 digital camera. I was first shown how to make these images by Ted Kinsman of Kinsman Physics Productions. Check out his web site for many interesting examples of the creative work he does.

The streak images start with a simple subject. The image shown here is what I started with ... an iris in a bottle. The bottle is sitting on a rotary table. The rotary table is computerized and can be instructed to move by specific amounts. The Time Machine's flash output is used to trigger motion in the rotary table. The procedure is as follows:
   1) take a picture of the iris
   2) rotate the flower 1.8 degrees
   3) take another picture

This process is repeated over and over until 500 to 800 pictures have been taken from all different angles.

 

 

Once the pictures have all been taken they are processed to extract one row of pixels from each image, and a new picture is created by stacking these rows on top of one another. With the iris, if you were to extract the row that's 201 pixels from the bottom of the picture, you would be looking at the green stems above the bottle and below the flowers. When one row of each rotated view of these stems is stacked one on top of the other, you get the image shown at the left. The sinuous curves are the result of the rotation between each image. The stripy background is really a flaw in this project. I didn't control the lighting sufficiently and the exposure of each frame was a little different.

 

  

 

  

If the strip you took out of each frame was further up in the picture, say at a height of 360 pixels, you'd be looking at the flower. This will produce an entirely different image. To me, it looks very much like a hand-blown glass marble.

We can take this yet another step farther. We can create dozens of composite streak images at increasing distance from the bottom of the image and build them into a QuickTime movie. This shows us a fascinating view of the rotational perspectives of the flower, scanning from bottom to top.

I have created two versions of such a movie. CLICK HERE to see a smaller version, which is 446K in size. You'll need to have a QuickTime plug-in for your browser to see it. If you don't have the QuickTime plug-in, you can get it as a free download from Apple Computer. If you have a fast modem and a big video screen, you can see a larger version of the iris movie if you CLICK HERE. It's 1.3 MB and 650 pixels tall.

I've posted several other interesting QuickTime movies prepared with the streak process. If you have QuickTime installed, click on the links to see them. For best effect, be sure the whole movie has downloaded before you play it.

The individual frames in these movies are each fascinating in themselves. When the movie is on your screen there will be a slider at the bottom of the picture. You can drag this around with your mouse to see the individual streak images. These movies are all pretty small so they can be downloaded. The full movies are much bigger both on the screen and on the hard disk ... commonly 40 or 50 megabytes.

Here's another interesting picture made by the same streak process:

How the Time Machine makes these images possible
The Time Machine is the perfect tool for automating the collection of these pictures. The Sherline CNC Rotary Table is also required.

The Time Machine is configured to the Setups Mode. This mode allows complex programming of repeating operations. We configure the Time Machine to trip the camera shutter, wait three seconds, trigger the flash output, wait 7 seconds (while the camera stores the image), and then repeat. The flash output is connected to the trigger input of the CNC rotary table. This means that, whereas the Time Machine would usually trigger an electronic flash, it is now instructing the rotary table to turn. This presents a different view to the camera for each picture. Once started, the system does all the work for you and you can walk away until you have collected as many pictures as you want.

Processing the hundreds of frames into streak pictures is another matter. You need to extract one row of pixels from each frame and build a new picture with them, and repeat this hundreds of times. We have created a computer program to automate this process and build the streak images from a folder full of source files. It's a simple matter to specify the pixel offset for the streak and, in about 45 seconds (depending on image size), the image is assembled, displayed on the computer screen, and saved on disk. To process hundreds of large files into a movie can take a couple of days of procesing.