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This technical brief provides detailed information on the Image Quality, Performance, and Flexibility of Epson
Scanners.
Image Quality—Factors affecting image quality
When comparing scanners, hardware resolution and color pixel depth are two features often used to gauge
image quality. These two features are important, but there are a number of factors that determine image
quality in a scanner, such as the following: (Many of these elements will be discussed in detail in upcoming
sections of this document.)
Precision stepper motor
for high quality sub-scan
Type of lamp system used
The Epson Expression
lence with respect to image quality, speed, usability, versatility, and durability. These scanners include the
highest quality components.
The Epson Perfection
users, and are designed with the highest quality components in their price class.
Image Quality—Resolution
A scanner's resolution determines the amount of data that is read by the scanner. As resolution increases, so
does the file size. Resolution is measured in a variety of ways.
1. Optical resolution: This is the actual number of pixels read by the CCD (Charge Coupled Device), which
measures the intensity of the light that is reflected from the image to be scanned, and converts it to an
analog voltage. If a scanner has a resolution of 600 x 2400 dpi, its optical resolution is 600 dpi, which
means that it can resolve 600 bits of data per inch.
2. Hardware resolution: Using a precision stepper motor to double-step or
quadruple-step the carriage, the scanner's sub-scanner resolution can be
increased. For example, a scanner can have an optical resolution of 1200
dpi, but a hardware resolution of 1200 x 2400 dpi (because it double-steps
the carriage to increase the vertical resolution).
Scanner Technical Brief—Page 1
resolution
Dynamic range control
Optic system
®
and GT series scanners are Epson's professional series scanners designed for excel-
series scanners are designed for home and entry-level corporate and graphics arts
®
Optical resolution and
color bit depth
Quality of the Analog to Digital con-
verter (ADC); Epson scanners have
optimum performance for minimal
noise and tight color registration.
Type of focus method
Color vs. monochrome CCD
1200 dpi
6/07

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   Summary of Contents for Epson 00000650 - Perfection 3200 PRO Color Scanner

  • Page 1

    This technical brief provides detailed information on the Image Quality, Performance, and Flexibility of Epson Scanners. Image Quality—Factors affecting image quality When comparing scanners, hardware resolution and color pixel depth are two features often used to gauge image quality. These two features are important, but there are a number of factors that determine image quality in a scanner, such as the following: (Many of these elements will be discussed in detail in upcoming sections of this document.)

  • Page 2

    Image Quality—Resolution (cont.) 3. Interpolated resolution: Interpolation is a method to increase the resolution of an image. It uses a complex algorithm to “add” pixels to an image based on the mathematical probability of surrounding pixels. For example, if a scanner has a hardware resolution of 1200 x 2400 dpi, and a maximum resolution of 9600 x 9600 dpi, the scanning software uses interpolation to create scanned images with resolutions greater than the hardware resolution.

  • Page 3

    Image Quality—Pixel depth (cont.) Key Differences 42-bit, or 48-bit Internal/ 24-bit External Color 36-bit, 42-bit, or 48-bit Internal and External Depth Color Depth The scanner captures 42-, or 48-bit image The scanner captures 36-, 42-, or 48- How it works data, but “downsamples”...

  • Page 4

    Greater detail in shadows without distortion 1. Hardware components: Epson scanners use a precise scan carriage with better motors to achieve subscan resolutions that are double or quadruple the scanner’s optical resolution. Additionally, Epson scanners capture Red, Green, and Blue simultaneously, versus other scanners that use one-pass scanning but alternate Red, Green, and Blue lights for each line of a scan.

  • Page 5

    Image Quality—Color CCD All Epson scanners use a color CCD which uses a single white light source, instead of a monochrome CCD and three light sources. The color CCD results in faster scanning speeds and the ability to scan three- dimensional objects without producing color “ghosts.”...

  • Page 6

    The Epson Perfection and GT series scanners use a fixed focus optics system. The newest Epson scanners have a fixed focal point just above the surface of the glass for optimized film scanning.

  • Page 7

    Super resolution lens Film Holder (5.9”) Image Quality—High-Pass Optics Epson High Pass Optics includes anti-reflection optical coatings and a high reflection mirror. There is typically a small percentage of unwanted reflection with standard CCD glass which can  cause abnormal ghost images. The anti-reflection optical coating on the CCD cover glass minimizes this reflection and reduces ghost images.

  • Page 8

    Performance—High-Performance Interfaces In general, Epson scanners targeted to home and small office users have a USB interface for maximum ease of use. Epson scanners targeted to corporate and graphic arts uses have USB and/or SCSI-2 interfaces for maximum performance. An optional interface for some scanners is the IEEE-1394 (FireWire ) interface.

  • Page 9

    Flexibility—Network Scanning Newer networkable Epson scanners offer the ability to connect to the network as a device (through a network card) and don’t have to connect through a specific scan server. Some other Epson scanners can be shared over a network, using the following procedure: Attach the scanner to a single computer on the network.

  • Page 10

    Flexibility—Epson Scan Epson Scan software differs slightly by scanner model. Different scanners offer three of these four distinct scan modes to meet the needs of novice, intermediate, advanced, and business users. Full Auto Mode:  For the novice user—Epson Scan automatically previews the images and recognizes the document source and type.

  • Page 11

    EPSON is a registered trademark and Exceed Your Vision is a trademark of Seiko Epson Corporation. Epson Expression, Epson Perfection, and ColorTrue are registered trademarks and Micro Step Drive, Easy Photo Fix, Epson Smart Panel, are trademarks of Epson America, Inc. All other products and brands are trademarks and/or registered trademarks of their respective companies.

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