Digitizing Units
Structure
A digitizing unit is a set of analog and digital resources aimed at conditioning an analog video signal and transforming it into a digital format.
The digitizing unit receives the analog information from a designated video lane.
The digitizing unit delivers the digital information to the internal frame buffer.
Domino Alpha 2 owns two identical high performance digitizing units, referred to as A and B.
Structure
The analog router device consistently assigns one of the four available video lanes to each digitizing unit. This is automatically taken in charge by the MultiCam system according to the connection topology and configuration requested by the user.
Before storing the image into the frame buffer, the data issued by the digitizing unit is re-arranged in a consistent way. This is the purpose of the frame buffer write control device. The idea is that, whatever the digitizing unit assignment to a camera, the digital image deposited into the frame buffer is a well-organized array of 8-bit or 16-bit pixels exactly representing the camera picture.
Look-Up Table
Each digitizing unit includes a transformation table operating in real-time. The purpose is to establish a one-to-one map for each gray value delivered by the digitizer towards another set of values previously entered in a table.
This is figured in the following drawing.
Look-up table
The look-up table device can be thought as a high-speed memory belonging to the digitizing unit.
This memory is addressed by the data coming from the digitizer, and the read data is the transformed data. For each pixel delivered at the sampling rate, the table issues a value depending on the digitized gray-level and on the contents of the memory.
The user is provided with software means to load the table in advance. The loaded contents implement the transformation law that will be applied to the data flow when acquisition proceeds.
The Domino Alpha 2 look-up table is an 8 x 8 device because both input and output ports are 8-bit wide.
A total of two look-up tables are found, one for each digitizing unit.
Refer to user note "How to control the look-up tables in Alpha" for full details.