Instruction manual

PerkinElmer Optoelectronics 22

7.2 Sample Imaging Setup

The following example assumes that you have determined the following:

· Target width X

· Image resolution # of pixels (By choice of camera)

· Required feature resolution. i.e. the smallest feature

dimension “D” to be detected.

Example: To image a feature .020” dia. on an 18” web using a LC 3013 Camera.

Satisfying the Nyquist criterion, the effective y sample size

eff

y=0.01”.

Since the maximum line rate corresponding to the minimum line period from

Table 1 on page 8 is

sec

9.208

, the web velocity to assure contiguous y samples

must be such that the web moves 0.010” during the line period.

min/4.239minsec/60*

/"12

sec/"87.47

sec10*9.208

"010.0

web

====

The required exposure

exp

t is then computed as follows:

sec10*3.25

87.47*2048

182048*010.

exp

web

eff

Vpixelsof

Xpixelsofy

Note 1. The calculated exposure time guarantees the effective spatial resolution of 0.010”

at the maximum line period. Reliable imaging will require adjustment of the web

light source and/or camera gain.