SONY’S latest Exmor
sensor technology is combined with the company’s wide dynamic-video range
(View-DR) technology – to provide visibility enhancement. Optimising the
camera’s ability to capture high quality images in harsh lighting conditions,
View-DR enables the camera to capture multiple images when reproducing each
frame.
“With large
segments of the security industry now adopting HD, we chose the Exmor CMOS
imager due to the sensor’s ability to capture HD images using a very high-speed
imager,” said Simon Nash, senior marketing manager video security, Sony
Professional Europe.
“In contrast
to many other sensor technologies in the industry that discard approximately
half of the data collected during image capture, the newly developed View-DR
algorithm nearly doubles the sensitivity of the new cameras making the capture
of high-quality HD images possible in almost any lighting environment.”
The cameras also benefit
from improved noise reduction capabilities. This is beneficial when capturing
images effectively in low-light settings – a common challenge for the security
industry. Each uses Sony’s latest XDNR technology to selectively employ 2D and
3D noise reduction methods providing clear images for both moving objects and
still sections of an image in low light conditions. The result is clearer
images while unwanted motion-blur is minimised.
Image quality is
further enhanced through the integral encoding capabilities. To provide
end-users with a wide number of options, the new cameras support dual-streaming
in H.264, MPEG-4, or JPEG compression formats enabling them to deliver superb
picture quality in HD (1280 x 720p) resolution at 30 fps in 16:9 aspect radio.
The inclusion of
additional advanced features, such as DEPA advanced architecture, allows users
to access features including intelligent video and audio analysis, and
intelligent motion detection. Other features include Power over Ethernet (PoE)
capability for all-in-one operation; CF slots for on-board recording and
streaming using RTP/RTCP protocol; and ONVIF (Open Network Video Interface
Forum) compliance that supports open interoperability among different
manufacturer’s products.
Sony’s CMOS
Sensor ‘Exmor’, adopts the Column-Parallel A/D Conversion Technique to create
images containing more detail than ever before. It combines the speed of the
CMOS sensor with advanced-quality image sensor technologies accumulated through
the development of CCDs. The result is enhanced resolution along both the space
and time axes. With these innovations, Sony is exploring the limitless
potential of the world of imaging.
A high-speed
imaging sensor must combine high-sensitivity with low noise. In a CMOS sensor,
the pixels, signal readout circuit, analog-to-digital conversion circuit and
controller are all built into a single chip. By optimizing the composition and
operation of each circuit, Sony has achieved previously incompatible goals of
increasing both speed and image quality.
The key to
increased speed can be found in parallel signal processing. CMOS sensors have
analog-digital (A/D) conversion circuits that convert analog pixel signals into
digital signals (Figure 2). Speed is increased by arranging thousands of these
circuits in a horizontal array and allowing them to operate simultaneously.
The A/D
conversion circuits used in Sony’s CMOS sensors have important characteristics,
including the reduced size of the analog circuits in which noise is created,
and automatic noise cancellation. This circuit design enables noise reduction
to be combined with enhanced speed.
Pixel signals are
read as output from the transistors in the pixel. However, there is variation
in the threshold voltages for the transistors in each of the millions of
pixels. This variation can be eliminated by reading just the original pixel
signal (VSIG), which is obtained by reading the difference between the initial
value (reset level, VRST) of each transistor and the signal level corresponding
to the incident light (VSIG+VRST) through correlated double sampling (CDS).
Sony’s CMOS sensors perform this CDS operation by means of digital signal
processing.
