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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

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

Predictive Real-time Forensic

> Yesterday – investigate after something has happened

> Today – act on incidents in real-time

> Tomorrow – predict incidents before they happen

Network Video

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)

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)

1080p 1080p

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)

1080p 1080p

Horizontal View

(Bird’s Eye View)

250px/m

250px/m

125px/m

125px/m

Blind

area

Vertical View

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

1080p 1080p

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

www.axis.com

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)

1080p 1080p

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)

1080p 1080p

Horizontal View

(Bird’s Eye View)

250px/m

250px/m

125px/m

125px/m

Blind

area

Vertical View

Pixel Density v Camera Resolution

www.axis.com

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

1080p 1080p

Bandwidth and Storage

www.axis.com

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