Image Display Systems And Highdefinition Video Systems

The development of high-quality image display systems has become essential during endoscopic surgery.

Previous studies have demonstrated that the inherent optical quality of most endoscopes and charge couple device camera exceeds the display resolution of standard television (26). Because of the limited resolution of current analog National Television Standards Committee, phase-alternation-by-line, and sequential color and memory monitors, there is a demand for higher resolution image display systems. One such digital display system is the high-definition television. The most common highdefinition television formats used in the United States are 720p and 1080i. The "p" represents progressive scanning, meaning that each scan includes every line for a complete picture, whereas the "i" signifies interlaced scanning, with each scan including alternate lines for half a picture. These scan rates translate into a frame rate of up to 60 frames per second, doubling the frame rate of conventional television monitors. high-definition television offers greatly enhanced picture quality with improved image resolution. high-definition television pixel number ranges from one to two millions, compared to National Television Standards Committee, phase-alternation-by-line, or sequential color and memory's pixel number ranging from 300,000 to 1000,000 pixels (Table 1).

The other significant feature of the high-definition television format is its wider aspect ratio (the width-to-height ratio of the screen) of 16:9 as compared with National Television Standards Committee, phase-alternation-by-line, and sequential color and memory screens, which have an aspect ratio of 4:3. The wider aspect ration provides more information for the viewer, thereby enhancing both diagnostic and therapeutic interventions (6,27).

Current applications of high-definition television in medicine include diagnostic and therapeutic maneuvers during endoscopic surgery. This increased resolution and clarity have been shown to greatly facilitate surgical performance (6).

The extremely high-resolution image afforded by high-definition television may resemble a three-dimensional (3-D) video image. Although not a true three-dimensional image, the increased video information provides the perception of depth.

The future application of high-definition imaging technology based on charge couple device chips would improve endoscopic image resolution. The European standard high-definition imagingchip resolution is 2,340,250 pixels, resulting in 1250 horizontal lines. high-definition imaging has the advantage of resolution enhancement for image brilliance and the augmentation of secondary depth clues such as shadows. Other techniques under development for image resolution enhancement include

TABLE l ■ Broadcast Formats

Format

Lines of resolution

Cycles/sec

Aspect ratio

National Television

525

B0

4:3 (standard

Standards Committee

screen)

Phase-alternation-

525

50

4:3

by-line/sequential

color and memory

HDTV - United States

1125

B0

16:9 (wide screen)

HDTV - Europe

1250

50

1B:9

Abbreviation: HDTV, high-definition television.

Improved resolution and color separation of high-definition imaging provides better diagnosis and enhances the effect of secondary spatial cues, resulting in easier orientation, particularly if the images are combined with improved illumination.

the use of complementary metal oxide semiconductor technology to replace the charge couple device sensors (4). Both complementary metal oxide semiconductor and charge couple device imagers are manufactured in a silicon foundry; and the equipment used is similar. However, alternative manufacturing processes and device architectures make the imagers quite different in both capability and performance. Although not cost-effective, the use of a charge couple device processor to integrate other camera functions, like the clock driver and signal processing, is technically feasible. Such functions are normally implemented into secondary chips. Thus, most charge couple device cameras contain several chips. One of the major benefits of complementary metal oxide semiconductor cameras over the charge couple device design lies in the high level of product integration that can be achieved through virtually all of the electronic camera functions onto the same chips. Typically, complementary metal oxide semiconductor processor allows lower power usage and lower system cost.

Improved resolution and color separation of high-definition imaging provides better diagnosis and enhances the effect of secondary spatial cues, resulting in easier orientation, particularly if the images are combined with improved illumination.

Despite its current high cost, the price of high-definition television cameras and monitors will continue to decline as newer high-definition television products come onto the consumer market. With further optimization of size and weight of the camera system, high-definition television can become a standard feature for endoscopic imaging and display during endoscopic and laparoscopic procedures.

Stereoscopic vision is essential for precise surgical performance and operative safety during laparoscopic and endoscopic surgery.

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