Hemispheric cameras with
fisheye lenses have the ability to give a 180-degree wide angle view,
making them ideal for a range of applications from retail to foyers, to
lifts, to transportation.
IT was inevitable that a camera with a 180-degree wide angle lens
be developed. The combination of PoE, compact size, robust construction
and a quality fish eye lens makes for an extremely capable camera that
is perfect for applications demanding 180-degree views out to a distance
of about 15-20m.
Their
lenses characteristics really are the key feature of hemispheric
cameras. Among the first practical uses for fish eye lenses after their
invention in 1906 was in meteorology where they were known as ‘whole-sky
lenses’ and were used to study cloud formation. If you take the visual
image in your mind of a whole-sky lens and turn it upside down over a
scene then you get a very good impression of what these cameras offer.
Important
to bear in mind here is that the 180-degree views we are talking about
are the lower 180 degrees of a 360-degree sphere – that means a
hemispheric camera with a 180-degree lens actually gives a 360
compass-degree view of a scene. If wall-mounted the camera may give
180-degree views and some cameras offer this configuration as a
selectable option.
A
great strength of hemispheric cameras is that they don’t miss any
action in a scene – a person will not move from one camera to another as
they would with fixed cameras or standard PTZ units. This continuity
applies to recordings, too, and greatly enhances court admissibility of
image streams.
A
fisheye lens uses visual distortion to create a hemispherical view –
what this means is that these lenses don’t give rectilinear images –
there are no straight lines. Instead you get equisolid angles leading to
a convex image. Hemispherical surveillance cameras use image correction
to straighten out scenes when users zoom into scenes. Some do this so
well their digital zooms appear flawless.
Things
to bear in mind when comparing hemispheric cameras include the fact
different fisheye lenses have different characteristic distortions –
different lens mapping functions. There are variations in image quality
that are best directly compared by objective test.
Hemispheric
cameras with their wide angle views and fixed focal lengths are very
much all rounders. They are perfect for a range of internal applications
where a complete synthesis of a scene is most desirable and where
distances are not so great that face recognition is impossible.
Mobotix Q24
The
PoE IP65-rated Q24 from Mobotix is the original IP-based hemispheric
camera. It’s key components include a hemispheric camera comprising a
fisheye lens, an image sensor and integrated image correction software.
The
Q24, like other hemispherics, is designed to be ceiling mounting
(though it can be wall mounted using a special bracket) and if located
in the centre of the room it gives a 360-degree of the entire room. I’ve
seen the Q24 in a number of applications and its performance is
excellent. The camera is more than capable in areas with a 20m diameter
from the camera point – that’s a very large hall or foyer.
Same
as all hemispherics, the fisheye gives a convex image but this is
corrected by the integrated distortion correction software, so the scene
actually appears very true to the eye. Something that’s very nice about
the Mobotix camera and management software is that it allows users to
view several image sections at once. These image sections can be
recorded separately, as well as being monitored separately.
The
Q24 has a ½-inch CMOS progressive scan chip whose specifications
include minimum scene illumination of 1 lux in colour and 0.1 lux in
monochrome. Maximum image resolution is 2048 x 1536 (3MP) in colour and
1280 x 960 in monochrome.
Images
format selections include 160 x 120 pixels to 2048 x 1536 pixels with
an L11 lens. There’s also PTZ view, quad view, panorama broad view
image, double panoramic view, and a panorama focus with 3 views.
Image
compression is MxPEG, M-JPEG, JPG, H.264 (Video-VoIP-Telephony) and
maximum frame rates in MxPEG VGA is 30 fps, 1MP is 30 fps and 3MP is 20
fps.
Other
features include internal DVR MicroSD slot (camera internal video
recording up to 64 GB), external storage directly on NAS and PC/Server
without additional recording software. VMS is MxEasy for remote
management while control room software is MxControlCenter 2.1
Image
processing capabilities include backlight compensation, automatic white
balance, image distortion correction (panoramic image correction
included), video sensor (motion detection). There’s a virtual PTZ with
digital PTZ and a continuous 8x zoom.
There’s
triggering of events by integrated multiple-window motion detection,
external signal, temperature sensor, notification over email, FTP,
IP-Telephony (VoIP, SIP), visual/acoustic alarm Pre- and post-alarm
images.
I
can’t jump away from Mobotix hemispheric cameras without mentioning the
S14, which combines the P3 camera board with a pair of hemispheric
cameras on 2m cables to increase the flexibility of installations.
Vivotek’s 5MP FE8172
Vivotek’s
FE8172 is a hemispheric fisheye fixed dome network camera, with a 5MP
resolution sensor. The Vivotek FE8172’s fisheye lens delivers a
180-degree panoramic view when wall-mounted or 360-degree surround view
when ceiling/floor/table-mounted.
The
VIVOTEK FE8172 offers various display layouts, including original
surround view, panoramic view, and regional view for various mounting
applications. There are strong image processing capabilities that allow
hemispherical images captured from the fisheye camera can be converted
into conventional rectilinear projection for viewing and analysis.
In
both the panoramic as well as regional viewing modes, users can utilize
the ePTZ function to zoom in and focus on a region of interest (ROI).
The new pixel calculator function helps the user to ensure the image
quality of a desired area.
Features
of the Vivotek FE8172 include up to 30 fps at 1080p Full HD with the
1.05 mm fisheye lens giving 180-degree panoramic view and 360-degree
surround view. There’s a removable IR-cut filter for day/night function
There’s
real-time H.264, MPEG-4 and MJPEG Compression (Triple Codec) and WDR
enhancement, built-in 802.3af compliant PoE and an integrated
MicroSD/SDHC/SDXC Card Slot for on-board storage.
I’ve
seen the FE8172 deployed and was impressed with its performance. For
such a small form factor there’s a huge amount of information generated
by this camera. Also impressive was Vivotek’s management software which
is intuitive, with plenty of display options.
AXIS M3007-PV
The
AXIS M3007-PV PoE network camera is a fixed mini dome with 360-degree
and 180-degree panoramic views at up to 5MP resolutions. The camera is
compact, vandal and dust-resistant design, and can be installed on walls
or ceilings. There’s a digital PTZ and multi-view streaming with
de-warped views, along with edge storage with support for micro-SDHC
cards.
According
to Axis the camera offers useful panoramic views of areas as large as
650 square metres – that’s about the size of a large hall or hotel
foyer. AXIS M3007-PV offers different views – including a 360-degree
overview and de-warped views such as panorama, double panorama and quad
views. The quad view is ideal when the camera is positioned at an
intersection of corridors.
The
camera also provides 4 individually cropped out and dewarped view areas
where users can digitally pan, tilt and zoom in on areas of interest.
Multiple video streams in H.264 and Motion JPEG can be sent
simultaneously.
The
AXIS M3007-PV offers video motion detection and active tampering alarm.
In the 360-degree overview mode, the camera also supports the
installation of intelligent video applications, such as people counting
and heat mapping.
Panasonic panoramic family
The
new kids on the hemispheric block, Panasonic’s panoramic cameras are
built around the company’s i-Pro SmartHD technology. The models are the
indoor camera WV-SF438E and the outdoor WV-SW458E, which features a
dehumidification device to prevent fogging, in an IP66-rated weather
resistant dome. Meanwhile, the WV-SW458M is designed specifically for
transport applications such as buses or trains.
These
cameras use high profile H.264 compression to keep bandwidth
requirements low and have Super Dynamic technology for difficult, wide
dynamic lighting conditions. Their 3MP/1080P resolutions can be used for
a multitude of views including, fisheye view, double panorama which is
two 180-degree horizontal views one upon the other, quad views, and many
more.
Pan
Tilt Zoom operation is possible including preset positions and auto
panning, all without any mechanical movement. Full duplex audio is
built into the camera; SD/SDHC/SDXC card slot for recording in the
camera, and all images are compensated for distortion by the camera.
To
reduce the bandwidth further, the cameras use VIQS (Variable Image
Quality on Specified area). It allows the installer to draw a box around
a low priority area of the picture then the bit rate within the box is
reduced, reducing overall bandwidth.
Installation
is easy using PoE or 12vdc to power the camera and is compatible with
the Panasonic Network Recorder WJ-NV200 for quick easy setup. Neat
features include Face Detection, Video Motion Detection, and Privacy
Zones are also incorporated in the cameras, ensuring optional
performance.
I’ve
seen these cameras in operation and their performance is extremely
good, just as you’d expect, with excellent colour rendition and strong
WDR capability.
Source: http://www.securityelectronicsandnetworks.com/NewsDetail/13-06-19/hemispheric_hd_camera_options.aspx
