Instructional A.V Media and Instructional A.V Media and Educational TechnologyEducational Technology
Dr. Antar S. Abdellah
Movie Projector theory
• the brain and the retina of the human eye retains an image for a brief moment of time
• illusion of motion which results when a series of film images is displayed in quick succession
• At least 16 frames per second (fps)
• Was famous with Silent films (16-24 fps)
Components
• Light source• Reflector and condenser lens
• Douser (A metal blade which cuts off light before it can get to the film)
• Film gate and single image• Shutter (gives the illusion of one full frame being
replaced exactly on top of another full frame)• Imaging lens
Types of projectors
• classified by the size of the film used
• 8 mm (no sound)
• Super 8 (Magnetic stripes could be added to carry encoded sound to be added after film
development.)
• 9.5 mm
• 16 mm (audio-visual )
• 35 mm (wide screen movies )
• 70 mm (with digital soundtracks)
Sound in movie projectors
• Analog method (aligned with the frame)
• optical• Digital• Dynamic digital• Dolby Digital• Digital Theatre sound
Appearance and configuration
• a master console (teacher position) • student booths (a student tape recorder and
headset with a boom arm microphone)• The control panel includes:
– master playback source equipment (tape recorder),
– some means of monitoring of each booth in the class via the teacher headset and
– an intercom facility offering 2-way communication between teacher and student
Use and Operation• Language labs were important parts in the
audio-lingual method• Since there were not enough numbers of
native speakers around, schools had to depend on language labs for providing Ss with native speaking quality
• The teacher would normally play a tape, pauses it, Ss repeat, then Ss record parts of the tape, and continue practicing the repetition on their own or at home.
Operation • If a student needed help, he could press a
call button, the teacher would respond and open a uni-channel with that student
• A teacher can also stop all Ss’ tapes and provides instructions or comments to all at the same time.
• A video can also be played for language training purposes with no facility of Ss copying it.
Problems• Language laboratories in
the 1970s and 1980s received a bad reputation due to breakdowns
• No remote control of the tape
• Poor quality due to overuse • No continuous maintenance• No supply for new
materials • Students’ independency
caused many problems
Change In media
• By the 1980s, the audio-lingual methods was fading out
• Many schools transformed their old language labs into computer suites
• With new technologies, old language labs turned into digital language labs (no tape, or recorder, just computers and software.
However
• New digital labs lack the teacher’s control, the needed software, and are mainly used as computer labs rather than for language purposes.
• First used in 1942 for recording launching rockets
• Used widely for safety purposes CCTV
• 2,200 CCTV systems in Chicago
• Based on CCTVs, CCDPs (Closed Circuit Digital Photography) are generated
• Images of the camera scene are transferred automatically to a computer every few seconds
• Used for monitoring crime, tests, teaching
Problematics
• Illegal use • Personal liberty, Britain is sleepwalking into
a surveillance society• Developments included high resolution
photos, color, linked to databases. • Data Protection Acts• Special uses: recording UFOs, Big Brother
How people react to CCTVs
• Generally acceptance but:
• Some make break them, spray them, focus laser on them or destroy the recorded tapes.
• CCTVs are very popular in movies.
Other uses • Monitoring traffic on a
bridge.• Recording the inside of a
baking oven to find the cause of problems.
• A temporary system to carry out a traffic survey in a town centre..
• Used by the stage manager of a show to see obscured parts of a set.
• The well-publicised use at football stadiums.
• Hidden in buses to control vandalism.
• Recording the birth of a gorilla at a zoo.
• Making a wildlife program using a large model helicopter.
• Aerial photography from a hot air balloon.
• Production control in a factory.
• Teaching women in KSA