- Forest? Check. Trees? Check. Blade of grass? Check!
CAREN B. LES, CAREN.LES@PHOTONICS.COM
From agriculture to ecology, it’s important to keep tabs on changes in a given ecosystem – although sometimes
it can be difficult to see the forest and the trees all at once. But now, a new technique for panoramic, very high resolution time-lapse photography allows a field or forest to be observed over time.
Time-lapse photography for plant studies previously was limited to a few plants at a time in a laboratory setting. The GigaPan system overcomes that, enabling zooming from landscape view down to individual plant in the same scene – and could help scientists study plant behavior as well as environmental effects on plants and ecosystems.
From a GigaPan time-lapse sequence of plants, showing (a) the entire group of plants and (b) the flowers on three plants. The GigaPan system enables the user to zoom from broad view to specific detail while the sequence is running.
“The technique offers the opportunity to observe and understand interactions between individual plant behavior and the environment within which they grow, at a range of spatial and temporal scales,” said Mary Nichols of the US Department of Agriculture. She is the lead author on a report published in Applications in Plant Sciences (doi: 10.3732/apps.1300033).
The method was developed by Randy Sargent and colleagues at the Robotics Institute at Carnegie Mellon University in Pittsburgh. The hardware includes the GigaPan Epic Pro robotic camera mount, set up on a tripod and leveled; the researchers used a digital camera set to full zoom to establish the field of view: They picked a point on the horizon and sequentially aligned the top and bottom of the LCD screen with this point using control buttons on the robot. They then rotated the camera left, right, up and down to establish the top left and bottom right corners of the panoramic image.
The alignment and image extent parameters are stored in the robot’s memory; a gridded sequence of pictures is then taken automatically. Individual images are stitched together via software to create a very high resolution image, which is then uploaded to GigaPan.com for open exploration.
Time Machine Creator software enables sequences of panoramic images to be stitched together, creating time-lapse videos that can be zoomed and explored in both space and time, Nichols said. The time-lapse sequence is scalable from hours to years.
To demonstrate the technique indoors, the researchers created a panorama three photos high by seven photos wide of a time-lapse sequence of a quick-growing plant. Viewing this panorama – 21 photos captured at 15-minute intervals for 21 days – they were able to see the changes among the plants in response to caterpillars, stinkbugs and other environmental factors during the experiment. In outdoor testing, they used a solar-powered setup to photograph grassland.
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