Honeywell Imaging and Mobility (formerly Hand Held Products)
Comparison of Bar Code Scanning Technologies
Laser Scanning
Laser scanners use a suspended mirror assembly to sweep a laser beam
back and forth over a line. The beam of collimated light forms a
sharp aiming line on the target. The typical scan rate is 36 or 186
scans per second.
Laser scanning is clearly the incumbent data capture technology in
PDTs. Despite winning the battle of durability and scan speed, early
CCD scanning technology failed to match the laser’s performance in
three key respects: it had a short reading distance, it lacked a
well-defined aiming line, and CCD engines were larger than laser
engines.
Linear Imaging
Linear imaging has benefited from numerous advances in image sensor
and illumination technologies. Image sensors are now available with
higher resolution, smaller size, and with pixel geometrics that
enhance light sensitivity. Brighter LEDs combine with a new
generation of optics to produce a bright, crisp aiming line. There
are no moving parts in a linear image engine. The typical scan rate
is 270 scans per second. Linear imagers match the durability and
scan speed of CCDs, and they
match the reading distance of a standard laser.
Raster Laser Scanning
Raster laser scanners use two suspended mirror assemblies, one
mounted perpendicular to the other, to sweep the laser beam in two
dimensions. Raster lasers typically capture 22.5 scans per frame,
and 22 frames per second. Some are capable of omni-directional
reading, but the number of scans per frame is not sufficient to
completely cover an area without holes. Thus, raster laser scanners
are not capable of capturing an image.
Area Imaging
Area imagers take a digital picture of the Data, and then use
software algorithms to search through the image, find codes, and
decode them.
Area imaging is another benefactor of modern image sensor and
illumination technologies, Area sensors are available in smaller
sizes, with greater light sensitivity, and reduced power
consumption. Brighter LEDs and refined optics can blanket an area
with light from over a foot away. There are no moving parts in and
area image engine. Area imagers typically capture 480 scan lines per
frame, and 30 frames per second. The effective scan rate is 14,100
lines per second.
Area image engines are already on the market in the Symbol SE 1200
form factor, the
industry standard size for integrating into a PDT.
Comparison of Bar Code Scanning Technologies
|
|
Laser |
Linear Imager |
Raster Laser |
Area Imager |
|
Scan Method |
Suspended, sweeping mirror and laser
illumination |
High resolution image sensor and directed
LEd illumination |
Two suspended sweeping mirror assemblies
and laser illumination |
Area image sensor and directed LED
illumination |
|
Scan lines per frame |
NA |
NA |
25.5 |
480 |
|
Frames per second |
NA |
NA |
22 |
30 |
|
Scan lines per second |
36 or 186 |
270 |
560 |
14,400 |
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