Fairchild CAM CCD-2KLV.TDI user manual Camera Hardware Interface, Installation Overview

PRELIMINARY

SECTION 2

Camera Hardware Interface

2.1 Installation Overview

Before you integrate your camera into your system you should first determine some basic operating parameters such as what resolution you need. Do you know the speed of the object that your camera will be inspecting? One additional point you want to keep in mind is your lighting requirement.

Some other major items that you should identify early on in developing your system is the source of your EXSYNC control signal (framegrabber, custom controller, shaft/web encoder, etc.). You should also know—in advance—your sensor resolution and magnification requirements.

We will use a simple example to reinforce what we just told you in the above. Let’s say that you have the following system to set up: inspect a web 10cm wide, moving at 2m/s, and you want 100∝m on the web to be represented by one pixel (7∝m).

Number of Pixels	Total width of image =			10 cm		= 1000 pixels
Necessary	Desired resolution		100∝m per pixel
Magnification	Pixel size	=			13∝m	= 0.130
	Desired resolution		100∝m per pixel
EXSYNC	Web speed	=			2m/s	= 20KHz
	Desired resolution				100∝m
Shaft Encoder	You require one pulse for every 100∝m of
Circumference	object travel. Assuming a shaft/web encoder = 0.10m
	Producing 1000 pulses/rev., shaft
	Circumference must be 1000 x 100∝m

Remember, TDI cameras require PRECISE synchronization with the object velocity! (See example images below.)

Good TDI Synchronization Bad TDI Synchronization

Fairchild Imaging • CAM/CCD-2KLV.TDI & CAM/CCD-4KLV.TDI Line Scan Camera User’s Manual • Rev 073004 • 13 of 38