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.)
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.
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”...
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.
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.”...
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.
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.
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.
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.
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.
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