Lev WeisfeilerAware, Inc.

Streaming and JPEG2000 Compression for use in Uncompressed Image Archives

Streaming and JPEG2000 Compression for use in Uncompressed Image Archives

Archives of Uncompressed ImagesArchives of Uncompressed Images

Data stored uncompressed in PACS

2000x2500 CR

– Total Image size: 10MB

512x512 CT

– Total Image size: 0.5 MB

Great for fast networks since no time spent on decoding

Lossless data quality

Viewing Images over Slower NetworksViewing Images over Slower Networks

User connecting over slower link may prefer compressed

data, to minimize time to display of full fidelity images

Total time to display =

compression time on server +

transmission time +

decompression time on client

Streaming of Compressed DataStreaming of Compressed Data

The total time can be reduced if any of these processes

can be done in parallel

Streaming: decompression and transmission can be

interleaved

– data is decompressed and displayed progressively, as it is

received, without waiting for full image data

Compression and transmission can be interleaved as well

JPEG StreamingJPEG Streaming

JPEG encodes data in blocks of 8x8 pixels;

Blocks can be  transmitted as they are encoded, without

waiting for the rest of the data.  

– Precludes the use of the progressive mode of JPEG

• In progressive mode, the DC terms from each block are

grouped at the front

– Image can be progressively decoded in 8 row chunks,

essentially appearing line-by-line from top to bottom.

A significant proportion of the image data is necessary for

a meaningful first view

JPEG2000 Progressive EncodingJPEG2000 Progressive Encoding

Progressive Encoding By Quality

– Image is processed by the wavelet transform

– First quality layer is produced by encoding some of the

wavelet transform data; the layer is transmitted in a “tile part”

• “tile part” is a JPEG2000 codestream unit

– Process repeated for production of next layer

Progressive Encoding By Resolution

– Image is processed by the wavelet transform

– The lowest resolution data is encoded and transmitted in a

tile part

– Process repeated for production of next resolution data

JPEG2000 Progressive EncodingJPEG2000 Progressive Encoding

Progressive Encoding By Color Channel

– First color channel is processed by the wavelet transform,

fully encoded, and transmitted in a tile part

– Process repeated for production next channel

Progressive Encoding By Spatial Region

– In a tiled image, each tile can be processed and transmitted

independently

– In an untiled image, precincts are defined for the image and

are encoded in their proper order, with each one being

transmitted once it is fully encoded

• Precincts are a spatial division of the wavelet transform data

CR ExampleCR Example

Network: DSL 2Mb/sec, 50% utilization, 10% overhead

2500x2048 CR   10MB Uncompressed

– Transmit time ~ 90 seconds

– Total time to display: 90 seconds

2500x2048 CR  Losslessly Compressed (4MB)

– Compression:1.77 sec

– Decompression: 1.44 sec

– Transmit time ~35 seconds

– Total Time to display: ~39 seconds

CR ExampleCR Example

2500x2048 CR  Losslessly Compressed with 3 Quality Layers– Thumbnail: 70KB

– Visually lossless (20:1) : 540KB

– Lossless: 3.4 MB

Progressive Encoding Time:– Layer 1: 0.42 sec

– Layer 2: 0.41 sec

– Layer 3: 1.08 sec

Decompression Time:– Layer 1 only: 0.14 sec

– Layer 1 and 2: 0.35 sec

– All three layers: 1.45 sec

Time to View:– Layer 1: (0.42 sec + 0.6 sec + 0.14 sec) ~= 1.2 seconds

– Layer 1 and 2:  (0.41 sec+ 5 sec +0.35 sec) ~= 6 seconds

– All three layers: (1.08 sec + 30 sec +1.45 sec) ~= 33 seconds

CT ExampleCT Example

Network: DSL 2Mb/sec, 50% utilization, 10% overhead

512x512 CT   500 KB Uncompressed

– Transmit time ~ 4.5 seconds

– Total time to display: 4.5 seconds

512x512 CT Lossless Compressed 1 layer: 130 KB

– Compression: 0.13 sec

– Decompression: 0.10 sec

– Transmit time 1.1 seconds

– Total Time to display: 1.33 seconds

CT ExampleCT Example

512x512 CT  Lossless Compressed 3 Layers– Thumbnail: 10 KB – Visually lossless (25:1) : 20 KB– Lossless: 130 KB

Compression: – Layer 1: 0.08 sec (encoding + x-form time)– Layer 2: 0.02 sec (encoding only) – Layer 3: 0.03 sec (encoding only)

Decompression:– Layer 1:     0.05 sec– Layer 1+2:   0.06 sec– Layer 1+2+3: 0.10 sec

Time to View:– Layer 1: (0.08 sec + 0.09 sec + 0.05 sec) ~= 0.22 seconds– Layer 1+2:  (0.02 sec+ 0.18 sec +0.06 sec) ~= 0.26 seconds– Layer 1+2+3: (0.03 sec + 1.17 sec +0.10 sec) ~= 1.3 seconds

Adaptable ProcessAdaptable Process

JPEG2000 encoding progressions can be mixed

– E.g.: First resolution and then quality progression orders

would have the lowest resolution data progressively encoded

by quality and transmitted, followed by the next resolution

Granularity of the interleaving of the compression process

and the transmission process can be adapted for:

– time to first image display

– time to full image display.

Optimized based on:

– application needs

– relative loads on the processor

– network speed