Mitsubishi VS-6043 Uživatelský manuál stáhnout pdf (Strana 9)

EXTRONEWS MAY/JUNE 1999

Image Scaling

Technology

by Roger McCarten,

Product Manager

FIGURE 1. Converting image's resolution to match display device's native resolution

Recent advances in video processing tech-

nology have brought the price of image

scalers down to the point where they can be

considered in even low to mid price AV

systems. As scalers have become more

prevalent in AV systems, questions and

misconceptions have arisen regarding scaler

operation. Therefore, this column will be

devoted to providing a basic and accurate

understanding of scaler operation and applica-

tions.

SCALER TECHNOLOGY

Scalers operate similar to a line doubler or

line quadrupler. Like a line doubler/quadru-

pler, a scaler takes an interlaced video signal

(NTSC, PAL and SECAM) and outputs a

progressive scanned signal and varies the

number of scan lines to change resolution.

The signal processing technique is essentially

the same. In fact, a line doubler/quadrupler

can be thought of as a fixed resolution scaler.

A scaler does not process pixels and then

transmit an image in pixel form. The output of

a scaler is a video signal.

Most upscalers will accept a composite or

S-video signal and convert it to any of a

number of output resolutions. However,

scalers are not limited to accepting composite

or S-video, and then converting them to

computer signals. Some scalers will accept

computer signals, and down-convert them to

composite, S-video, or even up-scale and

down-scale them to other computer resolu-

tions, like Extron’s VSC 300. Other scalers

will accept computer signals and either up-

scale or down-scale them as needed, like

Extron’s DDS 100.

SCALER FEATURES

The main advantage of a scaler is that it can

change its output rate to match the abilities of

a display device. This is especially advanta-

geous in the case of digital display devices.

Digital display devices produce images on a

fixed matrix. In order for the digital display

device to provide optimal light output, the

entire matrix should be used (Figure 1). To

do this, the digital display device uses its

internal pixel map processor to do scaling.

An external scaler is designed to do the same

thing, but generally provides better decoding,

more user control, and will store picture

settings information. This increases flexi-

bility, making changing sources and

changing image attributes easier.

Since a scaler can scale the output both hori-

zontally and vertically, this allows it to

change aspect ratios. So a scaler can take a

standard NTSC video signal and convert it to

a 16 x 9 HDTV output. If a system has a

HDTV type of display, but sources include

NTSC, PAL or SECAM, this feature can be

particularly useful. Extron's new scaler, the

DVS 100 offers HDTV output. HDTV output

resolutions include 480p, 720p, and 1080p.

(Both of Extron’s new scalers, the DDS 100

and the DVS 100, have been preprogrammed

for the most common LCD, DLP and plasma

displays. They will output an image that will

fit the display area exactly).

Another advantage a scaler can offer is the

ability to adjust horizontal and vertical size

and positioning, for a variety of video inputs.

Many digital display devices don't have the

memory to adjust for multiple input signals.

This makes it necessary to make adjustments

for each new signal. Extron’s DDS 100 has

the capability to store settings for up to 30

sources. Each source can be set up in terms of

horizontal and vertical sizing, and position.

The horizontal and vertical filtering settings

will also be automatically saved for each

source. Once each source is set up, the DDS

100 will recall the settings for the appropriate

source signal when its reconnected.

THE DVS 100 AND THE DDS 100

Extron will be introducing two scalers at

Infocomm, the DVS 100 and the DDS 100

(see articles on page 1 and page 8). These

scalers will allow you to considerably simplify

your AV system. NTSC, PAL, SECAM and

computer sources can be converted into any

of the major computer or HDTV, LCD, DLP

or Plasma resolutions, to match other signals

in the system. This will make signal routing

and display device selection much easier.

Digital display device

A scaler can

match an image

exactly to the

pixel matrix

Pixel

matrix

Image

DDS 100—Digital Scaler

1 2 3 4 5 6 7 8 9 10 11 12 13 14 ... 19 20

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