Milestone LPR 1.0 - Manual (Page 38)

Milestone XProtect
®
LPR 1.0 Administrator's Manual
www.milestonesys.com 38 About LPR cameras
interfere with the algorithms used in the LPR process. It is therefore recommended that you
disable cameras’ contour, edge and contrast enhancement algorithms whenever possible.

Automatic compression: High compression rates can have a negative influence on the
quality of license plate images. When a high compression rate is used, more resolution (see
"Resolution" on page 36) is required in order to achieve optimal LPR performance. If JPEG
compression is used, it will have almost no negative influence on license LPR, as long as the
images are saved with a JPEG quality level of 80% or above, and images have normal
resolution, contrast and focus as well as a low noise level.
Left: License plate image saved with a JPEG quality level of 80% (i.e. low compression); acceptable
Right: License plate image saved with a JPEG quality level of 50% (i.e. high compression); unacceptable