The document discusses network video and image usability. It begins by explaining the transition from analogue to network video systems and how these systems allow for real-time monitoring and predictive capabilities. It then covers resolutions like HDTV and how pixel density rather than resolution determines image quality for network video. Finally, it shows examples of bandwidth and storage needs at different resolutions.

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Network Video – Image Usability
David Thomasson
Business Development Manager - Transportation

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F
Image Usability - Timetable
TIME DESTINATION
00:01 Analogue to Network Video
00:03 Resolution - HDTV
00:04 How Many Pixels?
00:10 Pixel Density v Resolution
00:12 Corridor Format
00:13 Light
00:14 More Than Security

3. From Analogue to Network Video

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Detection
Prioritization
Response
Investigation
Security Incidents – The Challenges

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Surveillance Systems
Analogue Digital
PredictiveReal-timeForensic
> Yesterday – investigate after something has happened
> Today – act on incidents in real-time
> Tomorrow – predict incidents before they happen
Network
Video

6. Resolution

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HDTV
Analogue Camera (JPEG image)
Interlaced Scan
Network Video Camera (JPEG image)
Progressive Scan
SMPTE HDTV Standards guarantee:
> Spatial resolution - 16:9
– SMPTE 296M 1280x720 720p
– SMPTE 274M 1920x1080 1080i/p
> Better colour representation
> Full frame rate
> Improved audio
> Pan, Tilt & Zoom (PTZ)

8. How Many Pixels?

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What Level of Detail is Required?
There are three main quality levels normally used to determine the image detail required
for a camera:
 Detection:
To detect the presence of a person in the image, without needing to see
their face.
 Recognition:
To recognise somebody you know, or determine that somebody is not known to
you.
 Identification:
To record high quality facial images which can be used in court to prove
someone’s identity beyond reasonable doubt.

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Historically with analogue systems these levels were defined using a percentage (%) of
the screen height:
Detection:
What Level of Detail is Required - Analogue?
10%

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Recognition:
Historically with analogue systems these levels were defined using a percentage (%) of
the screen height:
What Level of Detail is Required - Analogue?
50%

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Identification:
Historically with analogue systems these levels were defined using a percentage (%) of
the screen height:
What Level of Detail is Required - Analogue?
120%

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 For Network Video systems we need a measurement system that is:
 Consistent for all camera resolutions
 Consistent for all specifiers, manufacturers etc.
 Easy to use and define
What Level of Detail is Required – Network Video?
Analogue Network Video (IP)
Detection 10% 25 pix/m
Recognition 50% 125 pix/m
Identification 120% 250 pix/m (500pix/m)
 Horizontal Pixels per Metre defines image quality
 EN50132-7: CCTV Surveillance Systems for use in Security Applications - Part 7

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1 m
Pixels per Metre
250

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1 m
250 pixels
Pixels per Metre
250

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Pixels per Metre
= 250 pix/m
> 250 pix/m
< 250 pix/m
250

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HD Camera View Examples (1280 x 720 pixels, 3 - 9mm Lens)
1080p1080p
Horizontal View
(Bird’s Eye View)
Blind
area
Vertical View
250px/m
250px/m
125px/m
125px/m

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5MP Camera View Examples (2592 x 1944 pixels, 3 - 9mm Lens)
1080p1080p
Horizontal View
(Bird’s Eye View)
250px/m
250px/m
125px/m
125px/m
Blind
area
Vertical View

19. Pixel Density v Camera Resolution

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You will always get a better pixel density from a higher resolution camera.
True or False?
It depends on the Field of View (FoV).
If the FoV is the same, the higher resolution camera gives a better pixel density.
If the FoV is different, a lower resolution camera may provide a better pixel density.
Pixel Density v Camera Resolution

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Resolution Comparison
Resolution: HD1080p
118°
Resolution: HD720p
80°
2m
Scene width of 3.36m Scene width of 6.66m
= 381 pix/m
1280 pixels
3.36m
= 288 pix/m
1920 pixels
6.66m

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Higher Resolution Increases Image Area (with Same Pixel Density)
5 Megapixel
3 Megapixel
1080p1080p

23. Bandwidth and Storage

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RECEPTION SCHOOL YARD INTERSECTION STAIRWAY STATION
RESOLUTION
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
VGA 0.13 1.38 0.20 2.21 0.24 2.62 0.31 3.33 0.92 9.89
720p 0.38 4.13 0.61 6.62 0.73 7.86 0.93 10.00 2.75 29.70
1080p 0.86 9.29 1.38 14.90 1.64 17.70 2.08 22.50 6.18 66.70
3MP 1.31 14.10 2.09 22.60 2.49 26.80 3.16 34.10 9.37 101.00
5MP 2.04 22.00 3.27 35.30 3.88 41.90 4.94 53.40 14.60 158.00
Settings: 12 images per second, H.264, Image compression 30, Continuous recording
Bandwidth & Storage Comparisons

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 For Network Video systems we need a measurement system that is:
 Consistent for all camera resolutions
 Consistent for all specifiers, manufacturers etc.
 Easy to use and define
What Level of Detail is Required – Network Video?
Analogue Network Video (IP)
Detection 10% 25 pix/m
Recognition 50% 125 pix/m
Identification 120% 250 pix/m (500pix/m)
 Horizontal Pixels per Metre defines image quality
 EN50132-7: CCTV Surveillance Systems for use in Security Applications - Part 7

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1 m
Pixels per Metre
250

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1 m
250 pixels
Pixels per Metre
250

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Pixels per Metre
= 250 pix/m
> 250 pix/m
< 250 pix/m
250

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HD Camera View Examples (1280 x 720 pixels, 3 - 9mm Lens)
1080p1080p
Horizontal View
(Bird’s Eye View)
Blind
area
Vertical View
250px/m
250px/m
125px/m
125px/m

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5MP Camera View Examples (2592 x 1944 pixels, 3 - 9mm Lens)
1080p1080p
Horizontal View
(Bird’s Eye View)
250px/m
250px/m
125px/m
125px/m
Blind
area
Vertical View

31. Pixel Density v Camera Resolution

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You will always get a better pixel density from a higher resolution camera.
True or False?
It depends on the Field of View (FoV).
If the FoV is the same, the higher resolution camera gives a better pixel density.
If the FoV is different, a lower resolution camera may provide a better pixel density.
Pixel Density v Camera Resolution

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Resolution Comparison
Resolution: HD1080p
118°
Resolution: HD720p
80°
2m
Scene width of 3.36m Scene width of 6.66m
= 381 pix/m
1280 pixels
3.36m
= 288 pix/m
1920 pixels
6.66m

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Higher Resolution Increases Image Area (with Same Pixel Density)
5 Megapixel
3 Megapixel
1080p1080p

35. Bandwidth and Storage

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RECEPTION SCHOOL YARD INTERSECTION STAIRWAY STATION
RESOLUTION
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
Bandwidth
(Mbps)
1 Day
storage
(GB)
VGA 0.13 1.38 0.20 2.21 0.24 2.62 0.31 3.33 0.92 9.89
720p 0.38 4.13 0.61 6.62 0.73 7.86 0.93 10.00 2.75 29.70
1080p 0.86 9.29 1.38 14.90 1.64 17.70 2.08 22.50 6.18 66.70
3MP 1.31 14.10 2.09 22.60 2.49 26.80 3.16 34.10 9.37 101.00
5MP 2.04 22.00 3.27 35.30 3.88 41.90 4.94 53.40 14.60 158.00
Settings: 12 images per second, H.264, Image compression 30, Continuous recording
Bandwidth & Storage Comparisons