HD VIDEO IN TELEMEDICINE

A Study of Local and Remote Video Distribution

based on ITU-T H.264 Video Coding

Cristian Perra

Department of Electrical and Electronic Engineering , Cagliari University, Piazza D’Armi, Cagliari, Italy

Barbara Podda

Clinical Engineering Service, ASL 5, Via Carducci, 35, Oristano, Italy

Keywords: HD Video, Telemedicine, Videoconference.

Abstract: Modern operating room devices produce several video streams at resolutions up to Full HD. Managing the

high quantity of information produced during operating room activities requires a careful analysis and

dimensioning of the video storage and streaming systems. A service for telemedicine and e-learning is

proposed. The system is based on the ITU-T H.264 video coded for both storing and streaming medical

video data. Different scenarios are compared in order to evaluate which solutions can better fit the video

services deployment from operating rooms.

1 INTRODUCTION

Technological innovations in surgical operation and,

in particular, in endoscopy is enabling minimally

invasive procedures. Surgical operation augment

their efficacy together with the patent’s safety.

Surgeon’s risk is reduced by the use of most

advanced technologies.

Integrated operating rooms can lead to a

substantial improvement of surgical activities since

last generation operating rooms will allow a

simplified and secure management of innovative

technologies and leave, at the same time,

possibilities for future integration with

communications and learning systems

(Nocco,2008).

Current available systems are mainly closed. On

the contrary, the introduction of open systems, and

in particular based on standards, can reduce the

dependence from proprietary solution augmenting

the possibilities of development of the operating

rooms with new and advanced technological

products. This imply that with open systems it is

possible to chose the technological solution that

better matches the single needs (departments or

operating room).

There is a rapid growth of mini-invasive surgery,

new surgical methodologies as combined-surgery,

natural orifice transumbilical endoscopic surgery

and intra-operatory diagnosis. The effect is that new

management needs are arising inside the operating

rooms.

In particular there is a need for an harmonization

of all the chain of surgical process in order to have

an operating room as flexible as possible with

respect to the different necessities that arise and

change continuously (aa.vv. 2008).

Moreover, it is necessary to integrate the

different IT systems that are available in the

hospital, as for example:

- HIS, hospital information system: management

of the information system: patient

acceptance/discharge, case history, warehouse,

statistics;

- RIS, Radiology Information System: gathering,

distribution, radiology reports;

- DICOM, Digital Info and Communication

Tecnology: possibility of sending, receiving,

displaying, storing high resolution images and

videos;

- PACS, Picture Archiving and Communication

System: system of distribution, storing and

442

Perra C. and Podda B. (2010).

HD VIDEO IN TELEMEDICINE - A Study of Local and Remote Video Distribution based on ITU-T H.264 Video Coding.

In Proceedings of the Third International Conference on Health Informatics, pages 442-445

DOI: 10.5220/0002740504420445

 SciTePress

displaying of images and video integrated with

the other subsystems in the hospital network.

This paper focuses the attention to the

transmission of high definition video originated by

endoscopy instruments for supporting the surgical

activity, and to the storing and distribution for

additional services as, for example, teleconsulting or

e-learning.

In particular, this paper presents the study of a

system for storing and distributing high definition

medical video of mini-invasive endoscopic surgery.

The paper is organized as follows. Section 2

presents the reference architecture. Section 3

presents the experimental tests performed on the

reference application for exploring storing and

streaming functionalities. Section 4 draws the

conclusions.

2 REFERENCE SCENARIO

The reference scenario takes into consideration an

operating room with video data produced by a single

endoscopic column and a single scialitic lamp for

endoscopic and laparoscopic surgery.

The endoscopic probe contains not only the

surgical instruments but also a camera that can

acquire high definition color images. In particular,

the camera used for the experimental tests has a

3CCD wide megapixel providing a true acquisition

in 16:9, with a frame aspect similar to the one

perceived by the human eyes.

Such sensor is compose by three different CCDs

providing, each one, a resolution of 1.12Mpixels

(1.07 effective) devoted to the acquisition of the

three different chromatic channels (Red, Green, and

Blue). The advantage is a chromatic quality highly

superior to the one achievable with a single CCD.

The camera is enable to acquire video images in HD

1080i. The frame format is called 1080i60 meaning

that a video frame has a resolution of 1920x1080 in

interlaced mode and a video frequency of 30 fps.

On the scialitic lamp is installed a second camera

that records the video of the operating room. In this

case, the camera is SDTV and the videos can be

used for teaching activities, legal medicine, for

transparency and protection towards the patient. The

video from the scialitic lamp is a 3CCD, 1/3”,

800000 pixel, SDTV 576i50, with a frame resolution

of 720x576 pixel, in interlaced mode and a video

frequency of 25 fps.

Table 1 synthesizes the reference parameters

used for setting up the experimental environment.

The reference scenario if composed by four

operating rooms equipped for endoscopy.

The average duration of operation is established

in 45 minutes.

A video stream HDTV, coming from the

endoscopic probe, and a video stream SDTV,

coming from the scialitic lamp are assumed to be

continuously produced during the operation time.

Moreover, it is assumed that each room can

operate at maximum five times per day for a total of

3 hour and 45 minutes of video stream data. Table 1

synthesizes the reference parameters for the

analyzed scenario.

Figure 1 show the reference architecture for

video storage and streaming.

Table 1: Video data reference parameters.

Operating rooms 4

Full HD Video (1080p) 1

Standard Video (PAL) 1

Video activity per day 225min

Figure 1: Reference architecture for video storage and

streaming

The video coding architecture makes use of the

ITU-T H.264 standard (Sullivan, 2004), (Wiegand,

2003).

H.264 is a state-of-the art video coding system

capable of providing very good video quality at

lower bit rates than previous standards (namely

MPEG-2, H.263, MPEG-4 Part 2) without

increasing the complexity of the design.

The Server receive through the LAN the video

streams originated by the endoscopic camera and by

the scialitic lamp. The video streams are encoded

and stored into the NAS (Chen, 1994).

Referring to Table 1, the quantity of data

produced for each surgical operation is equal to

HD VIDEO IN TELEMEDICINE - A Study of Local and Remote Video Distribution based on ITU-T H.264 Video Coding

443

7.5Gbytes. Table 2 reports the quantity of data

produce considering full activity all day in each

operating room, which is the worst case and the

maximum amount of video information produced in

a day.

Table 2: Video data produced each day in each operating

room considering full activity (worst case).

Format

Bitrate

(Mbps)

GB/gg/Room

HDTV 20 31.4

SDTV PAL 4 6.2

3 EXPERIMENTAL TESTS

Experimental tests have been conducted on a

machine with the following characteristics:

Processor, 2X Intel Xeon Dual Core X5460@3.16

GHz; Front Side Bus (FSB): Intel 500X, 1066MHz e

1333MHz; RAM: 4 GB DIMM DDR2 dual-Rank;

SAS/SATA RAID 5, PERC5i controller for 1÷4

HDD; 3 HDD SATAμ, 3.5”, 7.2K rpm, 1 TB;

Network card: BroadCom BCM 5708 NET Extreme

II GIGE. VideoLAN's VLC media player where

used both as video streaming server and video client.

Several tests have been performed coding HDTV

and SDTV videos at different bitrates and different

coding modes in order to evaluate the coding speed

and the average quality.

The objective video quality measure is the PSNR

(peak-signal-to-noise-ratio) measured in dB.

Tables 3-5 report the result for the HDTV tests.

Tests were performed encoding the HD video at

three different bitrates (20Mbps, 10Mbps, 5Mbps)

and at three different encoding modes (Max speed,

Intermediate, Good quality).

Tables 3-5 show that the experimental set-up is

able to encode in real time only if the Max Speed

mode is chosen. Nevertheless, the quality

improvements when using advanced modes as

Intermediate of Good quality are not so purposeful.

Encoded video streams are stored in the Network

Attached Storage and are available for further

processing and applications. In particular the

proposed system provides video transcoding and

video streaming services. This allows a real time

access at high/medium quality from the LAN clients

and at medium/low quality from remote location

outside the LAN. The main applications are

teleconsulting and e-learning.

The transcoding experimental set-up considers

two different scenarios.

The first one is based on the downsampling of

the video resolution from HD (1920x1080) to PAL

(720x576). PAL resolution allows streaming of

video data at high/medium quality depending on the

available bandwidth for a given service. Table 6

shows an example of the experimental tests. Four

different bitrates were chosen: 2Mbps, 1Mbps,

700Kbps, 500kbps.

Table 3: HDTV Max speed mode.

Bitrate

(Mbps)

Coding speed

(fps)

PSNR

(dB)

20 32.8 43.3

5 32.7 39.0

2.5 33.2 36.9

Table 4: HDTV Intermediate mode.

Bitrate

(Mbps)

Coding speed

(fps)

PSNR

(dB)

20 17.5 43.6

10 21.2 41.0

5 24.6 39.8

Table 5: HDTV Good quality mode.

Bitrate

(Mbps)

Coding speed

(fps)

PSNR

(dB)

20 11.8 44.2

10 14.0 41.8

5 17.9 40.0

Table 6: Downsampling HD video to PAL, example of

video streaming quality at destination at different bitrates.

Bitrate (kbps) PSNR(dB)

2000 41,6

1000 39,2

700 37,8

500 36,6

Table 7: Downsampling HD video to CIF, example of

video streaming quality at destination at different bitrates.

Bitrate (Kbps) PSNR (dB)

500 41,5

250 38,5

150 36,4

125 35,7

For bitrates lower than 1Mbps the quality at

destination is poor and a real time video streaming

becomes not reliable over network without

guaranteed bandwidth as the Internet.

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On the contrary, since modern LAN are able to

accommodate gigabits of data, all the bitrates in

Tables 6 will allow high/medium quality LAN video

streaming.

The second scenario is based on the

downsampling of video resolution from HD to CIF

(352x288) format. CIF resolution allows streaming

of video data at medium/low quality depending on

the available bandwidth. Table 7 shows an example

of the experimental tests. Four different bitrates

were chosen: 500Kbps, 250Kbps, 150Kbps,

125Kbps. For bitrates lower than 150 Kbps the

quality at destination is very poor. At these rates real

time video streaming becomes feasible through the

Internet even if, of course, the quality of service

cannot be guaranteed. The application for this

resolution/rates is mainly distance learning.

4 CONCLUSIONS

After the definition of a reference scenario it has

been analyzed the activity of the video data flow

production in order to set-up a multimedia storage

and streaming system. A general architecture for

storing and streaming the video data has been

designed. The system is bases on the ITU-T H.264

video coding standard. The proposed system has

been tested for different available network capacity

in order to evaluate the loss of quality when

streaming the content for tele-consultancy of e-

learning.

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Nocco, Lettieri, Cassoli, Sala operatoria integrata.

Miraggio tecnologico o valore sostenibile, Tecnica

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Introduction to the Fidelity Range Extensions, SPIE

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