CameraScope: A Tool for Digital Visualization for Science and Mathematics Classrooms

School Science and Mathematics, Nov 2004 by Bell, Randy, Garofalo, Joe

CameraScope: A Tool for Digital Visualization for Science and Mathematics Classrooms

Bill Ferster and Jeffrey J. Steckroth

University of Virginia

The rapid increase of affordable, high quality digital still and video cameras and webcams offer educators a rich set of opportunities for helping science and mathematics students visualize elusive concepts. Students can use these tools to experience and better understand everyday phenomena that are difficult to see with the naked eye. They allow students to observe events too small (e.g., biological microorganisms), too fast (the motion of a dropped ball), or too slow (transformation of a butterfly into a chrysalis) to view under normal circumstances.

Science and mathematics instruction can be enhanced when students are given the capability of acquiring and analyzing digital images themselves. Digital images also provide a compelling way for students to communicate their learning experiences with other students. The student's role shifts from a passive observer to an active participant, facilitating the learning experience.

However, additional software is sometimes required to allow students to tap the learning potential of digital imaging devices. CameraScope is one new software application that provides an interface between digital imaging devices and computers. It is the first in a series of open source software-based tools to be offered at no cost and expressly designed to support K-12 curriculum needs.

CameraScope is available as a free download from www.teacherlink.org/tools. Using Microsoft's DirectShow device standard, CameraScope supports a wide range of digital imaging devices, including digital microscopes, digital cameras, and most commonly available webcams and video-based devices. This universality allows CameraScope to support most of the imaging devices a school has, or is likely to acquire in the future-an important feature in a climate in which both software and hardware quickly become obsolete. Regardless of the digital imaging device utilized by any given school, there is a consistent look and feel for using CameraScope, making it possible to create lesson activities that will apply to a wide range of school environments.

CameraScope has three primary purposes: to capture digital images, to provide capability to perform measurements on those images, and finally, to facilitate analysis of the images to gain a deeper understanding of the subject being studied.

Capturing Images

CameraScope provides an easy way to capture both still images and digital movies. When used with digital cameras, such as those from Canon and Olympus, students can capture exceptionally high-resolution images that far surpass what can be obtained by the video-resolution devices found in most digital microscopes. Adapter kits from several manufacturers are available to connect these digital cameras to traditional optical microscopes as well as telescopes (see the resource section).

Whatever type of digital camera is physically attached, the process is the same. Students can change the exposure, quality, and image size and capture still images with a click of a button. Real-time movies can be recorded easily to slow down the motion of fastmoving events.

To record time-lapse movies, the student first specifies the amount of time to elapse between each image captured. CameraScope then captures still images according to the specified interval of time and places them as frames within a digital movie (AVI or QuickTime format), effectively "speeding up" time.

For example, to record a chrysalis emerging, students could record an image every 96 seconds for 2 days until the process was complete. This would save some 1,800 still images into a single movie file. When that movie was played back at 30 frames per second, the whole process that originally took 2 days would unfold in a 1 -minute movie.

In controlling both the imaging and analysis, students gain ownership of the entire project and must use critical thinking skills both to set up the data collection parameters and analyze the resulting time-lapse video.

Measuring Images

Another advantage of capturing images digitally is the ability to perform measurements on those images after the data are collected. CameraScope facilitates this process by providing simple but accurate measurement tools that allow students to measure objects in an image. Students can measure the absolute position of an object on the image, find the span between any two points (the Pythagorean distance), and place a "digital protractor" on a line to measure its relative angle.

These measurements can be calibrated to realworld dimensions by capturing an obj ect of known size (such as a meter stick or a ruler) within the image. CameraScope has an image calibration option that will convert the pixels on the screen into real-world units, such as meters or inches. As the cursor is moved through the image, the current position in real-world coordinates is displayed at the bottom of the viewer's screen.