Lecture capture, the recording of lectures and other classroom presentations, is becoming more popular. Schools provide recorded lectures to help students prepare for classes, view lectures remotely, and catch up on classes they may have missed.
The AV components comprising a lecture capture system usually include a microphone, a lecture capture recorder, a mixer, and a wired or wireless content connection to the presenter’s devices. The most important element for producing an engaging digital classroom experience that a student will want to watch, however, is the camera.
Fixed or Robotic?
The lowest cost cameras are fixed: once adjusted, their fields of view don’t change. This makes them compact, reliable, inexpensive, and capable only of capturing a fixed area of view. When installed to capture images of instructors in teaching spaces, fixed cameras are generally adjusted to “see” the entire well, or teaching wall. While that gives them a view of teaching activities, they don’t provide an engaging experience. Not only are instructors’ faces difficult to view, but generally, they also provide illegible views of teachers’ marker boarding.
Robotic, or PTZ (pan/tilt/zoom), cameras are remotely steerable. Like the cameras used in TV studios, they can be pointed at instructors. By making their facial expressions visible to viewers of the captured or streamed video, they provide a more engaging experience.
PTZ cameras can also be focused on classrooms’ writing surfaces. By zooming in, they provide a much more legible view of instructors’ notations.
PTZ cameras are larger than fixed cameras, which generally isn’t a problem. And they’re more costly, which can be problematic. But their greatest challenge is figuring out how to steer them.
Steering Robotic Cameras: Who’s Driving?
Steering PTZ cameras is a persistent challenge in the design and operation of lecture-captured teaching spaces. I’m aware of the following alternatives:
- Human: a person controls camera positioning. This alternative has both upfront costs, like providing a work space where the remote camera operator can watch the class and control the camera(s), and ongoing costs, like paying operators’ salaries. The upside is that human camera operators tend to do good job.
- Pressure mats: hidden under carpeting, these sense when they’re stepped on and trigger the camera to reposition itself to view the instructor. The risk: they can be unreliable, and they can be fooled by items, like chairs, left on them.
- Motion detectors: these are generally incorporated into the ceiling over the instructor space. These work like the detectors that turn on lights in office spaces when they detect motion. They can be fooled by a person staying immobile too long.
- “Look at me” buttons: a pushbutton is placed at each location the classroom designer would want the camera to view: the lectern, each marker board, etc. While this approach is technically highly reliable, getting instructors to push a button each time they move from one location to another is not.
- Infrared lanyards: an instructor dons a lightweight “necklace” prior to beginning the class. Infrared light-emitting diodes (EDs) are embedded in the lanyard; their light is invisible to human eyes. As the instructor moves, a tracking system “sees” the moving lanyard and steers the camera to follow it. This too is a reliable system, as long as the instructor leaves the lanyard in the classroom at the end of the class. In practice, the lanyards tend to be misplaced.
- Instructor-trackers: these systems utilize a fixed camera that views the front of the classroom constantly and looks for anything that doesn’t look like the front wall. Under ideal conditions – a consistently lit and colored wall – these can work, but they’re sensitive to variations in lighting, and they can work poorly with front walls that aren’t a solid color.
What’s next? TEECOM is working on a reliable, cost-effective camera control solution. Email us for updates.
Lecture capture systems are capable of recording interaction between instructors and students present in the classroom. In many classes, the ability to view this interaction provides much greater engagement for online students.
Some institutions do not allow images of students to be recorded. In these schools, however, students’ voices may be recorded, even if cameras may not capture their images. That’s why microphones are provided both for instructors and students in typical lecture capture spaces.
Lecture capture will only become more popular as education continues to extend beyond classroom walls and time zone boundaries. It’s incumbent on classroom designers to provide these spaces with reliable recording systems that are cost-effective to install and use.