MkI Video digitiser circuit description


Posted on Feb 6, 2014

A `video-digitiser` (also known as a `frame grabber`) captures pictures from a TV set, camera, or video recorder, etc. , and forwards them to a computer for display, storage, or general manipulation. This document describes a home-built digitiser which interfaces to an EPP (or bi-directional) parallel port on IBM PCs. This frame grabber


MkI Video digitiser circuit description
Click here to download the full size of the above Circuit.

design digitises pictures to very high quality in monochrome (8-bit black & white). Although designed for the European standard 625-line / 50Hz TV system, it should work with the American 525-line / 60Hz standard with minimal modification. Before embarking on the project, please be sure to realise that this design will not capture movies. At best, it can manage a couple of frames per second. Note also that as described, the circuit collects its picture from a succession of frames. Consequently the image must remain fairly still for the half-second or so taken to capture it. A competent constructor could purchase a larger and more expensive memory chip and modify (simplify) the circuit to overcome the latter limitation if desired (see the Mk. II Video Digitiser ). Television equipment uses a simple composite video signal which carries all the picture information. Pictures are conveyed as a continuous sequence of frames, each taking 1/25 second. Within each frame are 625 horizontal scan lines, transmitted in turn starting at the top. [To reduce flicker, each frame is actually transmitted as two consecutive fields, the first containing odd-numbered lines, and the second filling in the even numbered, a technique known as interlacing. This cunning trick ups the refresh rate to 50Hz, without increasing the signal bandwidth. ] All video recorders and many TV sets will have a composite video output, usually using a BNC or phono...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Remote Solar LED light
    My Arduino In Circuit Programmer
    3-30V 3A Adjustable Regulated DC Power Supply
    electronic touch switch
    relay driver board project
    BJT Astable Multivibrators
    High Voltage Generator



    Top