Compression Processing among Four (4) Fields
(Conditional Refresh Compression)
Temporal Transforms
(Movement Level)
movement : None
movement : Low
movement : Mid
movement : High
D1-None
D1-Low
D1-Mid
D1-High
D2-None
D2-Low
D2-Mid
D2-High
D3-None
D3-Low
D3-Mid
D3-High
D4-None
D4-Low
D4-Mid
D4-High
A4-None
A4-Low
A4-Mid
A4-High
Intra-field Compression Pr
ocessing
(Full Frame Compression)
Detail
High pass filter
Approximation
Low pass filter
D1
D2
D3
D4
A1
A2
A3
A4
D1-4
D1-3
D1-2
D1-1
D2-4
D2-3
D2-2
D2-1
D3-4
D3-3
D3-2
D3-1
D4-4
D4-3
D4-2
D4-1
A4-4
A4-3
A4-2
A4-1
HEADER
Output
Memor
y
As a cutting edge core technology, the WJ-HD300 Series provides proprietary algorithm
for high picture quality and high data compression. The new technology dramatically
compresses image data size while retaining high picture quality.
The WJ-HD300 Series enables higher disk saving and extended capability.
In addition, the new compression realizes higher ips (image per second)
live monitoring/playback and improved downloading speed via a network.
Intra-field Compression
(Full Frame Compression)
New algorithm compresses the entire screen, and reduces artificial
distortions and noise compared to conventional compression.
Conventional Compression
Conventional intra-field type algorithm divides a picture to small blocks for the compression
process. Since it would be difficult to maintain continuity of compression between blocks, block
pattern distortion is noticeable. In addition, transition noise, which would degrade sharpness of
the edge signal, could be observed at high compression.
WJ-HD300 Series Compression
The entire screen is compressed after being divided into high- and low-frequency elements.
The result is significantly reduced artificial distortion and noise that are inherent in conventional
systems.
Division into
Blocks
Original image
De-compressed image
Compression
Compression
Playback
Block and transition
noise are visible.
1 block
8 x 8 pixels
Extraction of Elements
High-Frequency Elements
(Edges signal of Objects)
Low-Frequency Elements
Conventional artificial
distortion and noise
are reduced.
Original image
De-compressed image
Playback
Inter-field Compression among Four (4) Fields
(Conditional Refresh Compression)
New Compression Algorithm is Embedded into Proprietary LSI Chip
• Flexible compression settings for
independent cameras.
The proprietary compression chip
provides a combination of high picture
quality and high compression
with 60ips (image per second)
real time image processing.
• Accurate compression processing for sharp edge image areas.
• High speed temporal transforms processing. (Compression processing
among four (4) fields)
Half the data, the same picture quality
Further disk saving, longer
recording time, and high
image quality is realized
as shown below.
40KB
Data Siz
e
at 720 X 240
Compression Mode
30KB
20KB
10KB
Super Fine
Fine
Normal
Extended
Mode A
Mode B
Conventional
Compression
WJ-HD300 Series
New Compression
High compression by eliminating redundant data between adjacent fields.
Conventional Compression
Images from a camera are compressed
field by field.
WJ-HD300 Series Compression
Data calculation within four (4) field images (called “Temporal Transforms” ), outputs data according to the
amount of movement; “No Movement,” “Slow Speed Movement,” “Medium Speed Movement,” and “High Speed
Movement.” As shown below, redundant data can be reduced through this compression process.
All fields are independently compressed.
Processing of
Movement
Only this data
needs to be
compressed.
High efficiency is ensured since redundant data is not only within
the same field (“Intra-Field”), but also between fields (“Inter-Field”).
Compressed
field by field
Extraction of elements
with
no movement
Extraction of elements
with
slow-speed
movement
Extraction of elements
with
medium-speed
movement
Extraction of elements
with
high-speed
movement
Field 1
Field 4
Field 3
Field 2
Field 1
Field 4
Field 3
Field 2
Compression mode
Algorithm
Features
Mode A
Intra + Inter field
Temporal transforms among 4 fields
Mode B
Intra field only
Field by field compression
Содержание WJHD316 - DIGITAL DISK RECORDER
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