Capturing a mathematics lecture
(Page created: 2007-12-18)Capturing a lecture, Capturing a mathematics lecture, Manual Audio and Slide Capture, Automated Audio and Slide Capture, OpenOffice Slide Capture, Lecture browsing system.
Contents |
Some general comments were given on Capturing a lecture, as well as Manual Audio and Slide Capture. Here we are concerned with capturing a 'traditional' mathematics lecture, that is to say, a lecture that heavily depends on black boards.
The last point requires a little of discusion: A mathematics lecture often uses all blackboards available, with the lecture being developed across all available blackboards in the course of an house. This is because mathematics proceeds progressively, referring back to previous results. Hence those results need to be visible. In some ways this rules out using a single electronic whiteboard or similar.
If the lecture could be delivered just using a whiteboard (or ohps), then this would make things easier. In the first case, the lecture could be captured electronically off the whiteboard. If delivered on OHP, a single camera could be pointed at the OHPs, recording OHP along with voice. This could be made available as video (or set of stills), and scans of the OHPs could be made available alongside the movie. This would be quite satisfactory in many ways. However, the case we're looking at here is one where the lecturer feels that it is absolutely essential to use all available blackboard space. (Or where allowing the lecturer to use all available blackboards is the only way of getting consent for recording the lecture.)
All the methods discussed below rely on a single person ('producer') being available to capture the lecture.
A digital stills camera is used by the producer to photograph whatever blackboards need photographing, e.g. every minute. The camera records the time at which the photographs are taken. At the same time, audio is recorded, in such a way that a timestamp is available at the end of the recording (alternatively, the first picture is taken when the audio is started, so that we can synchronise this way). Using timing of slides and audio, the two can be synchronised.
Total cost of system about GBP 500-1000. However, many of those components may already be available, and only some may need to be bought. Details (as of 2007):
You can then follow the procedure given on Manual Audio and Slide Capture. Except that you simply ignore the instructions about powerpoints, but you simply take pictures of the board as and when necessary. You'll need to find a compromise between the amount of images you need, and the amount of detail that might be lost between images.
The Sony ICD-CX50 voice recorder has got a camera built in, and can take pictures while recording. It's not too expensive, and has a mic in (automatic gain). The image quality may well be good (resolution is quad-vga), but what the audio quality is like remains to be seen.
The ICTP EyA system implements a combination of methods 1 and 2, and can be recommended if you need to record a lot of lectures.
Standard definition video. If you have a large set of boards, and the lecturer uses all of them, then you'll need a producer in the room, who can follow the lecturers. If the blackboards are very wide, and the lecturer writes small, and across the whole width, you might need to split split in two by a vertical line down the middle. The remaining sections are small enough so that they can be captured in enough detail using standard definition video (e.g. 720x576 for PAL). The producers pans the camera between the sections of the blackboards, and audio is recorded onto tape.
If the lecturer writes large enough, and uses only a single set of sliding boards, you might be able to set up the camera in 16:9 (effective pixels 1024x576 in PAL), which may give you enough resolution.
In order to facilitate processing of the lecture afterwards, it may be best to capture the tape in realtime, e.g. using a FireStore FS-4 recorder, or onto a hard disk.
Total cost of system about GBP 2500-3500, as follows (as of 2007):
Notes on tape length/XLR: Tapes will typically last 62 minutes on SP.
High-definition video. Using a high definition camera (HDV), you'll get better resolution. Where you are filming lectures of a single (set of sliding) boards, you might have enough resolution.
Cost of system: As for previous option, but greater price for the camera, e.g. Sony Z1. (Need to get a FireStore-like recorder capable of HDV, or an HDV capture system.)
You might be able to use a Sony V1 to capture the whole lecture as progressive HDV, which would save you deinterlacing, and thus gets your higher resolution more easily. (In principle, on non-moving areas, with a good de-interlacer, you'd get similar quality with the Z1, but using a V1 straight away will remove that extra work.) This remains to be investigated.
Multicamera capture is always an option, and you could set up an Anycast system to do this. It's expensive (say several GBP 10k), but it will give you good quality, but you'll need to have somebody there to operate it. You'll only need one person to operate. More notes on Tutorials/Multi-camera production.
For instance, can you use a electronic white board running a capture application to record the lecture? In principle, this is a very interesting option. Most mathematics lectures require more than one board to be delivered effectively, and I am unaware of an electronic white board system that lets you combine various boards.