What makes a dome good? A&S examinesperformance and installation issues to illustrate
how fixed, speed and PTZ domes make the cut in an increasingly IP-enabled world.
What makes a dome good? A&S examines performance and installation issues to illustrate how fixed, speed and PTZ domes make the cut in an increasingly IP-enabled world.
Dome cameras are characterized by their distinctive bubbles, offering installers an extra option for demanding sites. They can be adapted for different applications, depending on user requirements and monitoring purposes.
Fixed domes are much like box cameras, except for a rounded form factor for easy installation and aesthetics. Mostly deployed for indoor surveillance, installers can adjust fixed domes for lens position, viewing angle and focus. Once the dome is installed, operators can only view a set area.
Speed and PTZ domes overcome the viewing limitations of fixed domes. They can monitor specific scenes or targets by size, position or both. Other uses for speed and PTZ domes include patrolling specific routes at a set time, or integration with intrusion detection for alarm verification.
PTZ cameras are not always housed in bubbles, offering more lens options and camera functions. However, they are usually larger, heavier and pricier than speed domes. As speed domes are housed in a single unit, they have a smaller form factor, more mounting options and greater pricing flexibility.
Ease of Installation
Regardless of dome type, the cameras must be easy to install. As most domes are suspended from ceilings or poles, they require installers to climb ladders, or utilize basket cranes or cherry pickers. This altitude limits the time and amount of tools installers can use placing the dome, which can be quite heavy, said Rich Huang , PM at EverFocus Electronics.
Installation is a two-step process for most domes. “Construction and industrial design affect performance,” said Alf Chang, Senior Consultant for A&S magazines and a former integrator. First, the housing is placed,and then the camera is fitted into the back box and enclosure.
The mount, or where the camera attaches to the back box, has a crucial effect on performance, Chang said. Metal mounts tend to be too rigid and cause too much interference. Plastic mounts can be too soft and loose, which may result in the camera dropping out of the mount and landing in the bubble. Understanding what materials a dome is made of can reduce maintenance calls.
Reliability is another benchmark of a good dome. “We look at good value for money, whether it's for the top-end, medium or budget applications,” said Andrew Pigram, Technical Director at Norbain. “But you can't sell rubbish to anyone.”