Glossary Archives - Page 5 of 15 - book❷net book scanners

White balance

Posted on 18. July 202218. July 2022 by Karin

The white balance adjusts the scanner’s camera to the prevailing lighting conditions to ensure a uniform color temperature and thus constant image quality. The color sensitivity of the sensor is thereby adjusted to the respective lighting conditions.

The perception of white is strongly dependent on the environment and the respective light source. In daylight, a pure white appears colder than in fluorescent light, for example, where it appears greener. Even in a controlled environment, this can become a problem.

While the human eye or brain can adjust to the respective light situation and quasi intuitively performs a white balance and compensates for color casts, a digital camera mercilessly reproduces them: If the digital camera is set to daylight, for example, and the picture is taken in artificial light, the image will appear reddish.

A user-defined white balance directly during installation therefore guarantees accurate colors right from the start. Since a change in the lighting environment always necessitates a new white balance, a constant and uniform lighting situation should generally be ensured when using planetary scanners.

White balance should be achieved by means of a full-format scan of a surface that is as white or at least neutral gray as possible. Plain white paper is often used for this purpose, but it often contains optical brighteners and can therefore lead to distorted results with color casts.

At book2net, we therefore use high-precision, spectrally neutral white balance targets to ensure precise user-defined, in-camera white balance under local lighting conditions.

Color temperature

Posted on 18. July 202218. July 2022 by Karin

The color temperature is a measure for the quantitative description of the color impression of light sources; the unit of measurement of the color temperature is the temperature unit kelvin (K).

The spectrum of an ideal thermal radiator (“black body”, “black body radiator” or “Planckian radiator”) serves as the reference model for determining the color temperature. This emits electromagnetic radiation in the visible and invisible range, whose wavelength distribution is determined solely by the temperature. For real thermal light sources (flame, light bulb, sun) this is approximately true.

When a black body is slowly heated, it passes through a color scale from dark red, red, orange, yellow, white to light blue. The temperature of the black body at which there is the best possible color match with the light source to be determined is the color temperature of the illuminant. Each natural or artificial light situation can thus be assigned approximately a temperature, which can then be used to describe a light situation mathematically.

Since reddish colors are perceived as “warm” and bluish colors as “cool,” a higher color temperature corresponds to a “cooler” color. Common light sources have color temperatures in the order of magnitude of less than 3,300 K (warm white), 3,300 to 5,300 K (neutral white) to more than 5,300 K (daylight white).

For the practice of photography and digitizing, this means that depending on the existing lighting conditions of the location, a certain color temperature must be set in order to achieve a correct reproduction of colors. In digital photography, this process is called white balance.

Kelvin

Posted on 18. July 202218. July 2022 by Karin

In science and technology, absolute temperatures and temperature differences are not specified in the generally used unit of degrees Celsius but in kelvin (symbol: K).

The kelvin is also used to indicate the color impression of “white” light. The spectrum of a thermal radiator (e.g. light bulb, gas flame, and sun) is given by its temperature, and accordingly one also assigns a “color temperature” to the light of a non-thermal radiator (e.g. LED, fluorescent tube).

If, for example, the color temperature of an LED lamp is given as 3000 K, this means that it produces the same color impression as a thermal radiator with a temperature of 3000 K. This color would be called “warm white”. This color would be called “warm white”, whereby “warm” in this context is not related to temperature, but to the division of colors into “warm” (rather reddish) and “cool” (rather bluish) colors. Thus, high color temperatures stand for rather cold color impressions. Common light sources have color temperatures ranging from below 3,300 K (warm white), 3,300 to 5,300 K (neutral white) to over 5,300 K (daylight white).

LPI

Posted on 12. July 202212. July 2022 by Karin

LPI is an abbreviation for „lines per inch“.

Similar to DPI or PPI, LPI Lines per inch (LPI) is a measurement of printing resolution. A line consists of halftones built up by physical ink dots made by the printer device to create different tones. Specifically LPI is a measure of how close together the lines in a halftone grid are. The quality of printer device or screen determines how high the LPI will be. High LPI indicates greater detail and sharpness.

Conversion of the LPI to DPI can be done by simple multiplication: z.B. 150 LPI x 16 = 2400 DPI

Stitching

Posted on 12. July 202212. July 2022 by Karin

In photography, stitching refers to the use of special software to create a large photograph from various smaller individual shots, which usually show overlapping sections of the subject, e.g. for panoramic shots, if the individual shot does not capture the desired image angle.

In scanning, stitching is used sporadically to achieve a higher resolution in the large format range than would be possible with a full-format single shot.

Glossary, S

Surface structure

Posted on 30. June 202224. August 2023 by Karin

In addition to a distortion-free and true-color imaging technique, the optimal reproduction of surface structures requires in particular a differentiated lighting technique. Not every original to be digitized has a flat surface or texture that is sufficiently illuminated by a simple, conventional light source to be digitized without shadows or reflections./span>

For example, valuable illuminated old manuscripts with heightened and waved surfaces, special inks and colors and especially gold grounds and gildings require a special and equally gentle, conservational illumination technique.

Therefore, we at book2net have developed special lighting systems for the optimal illumination of a wide variety of objects. Whether you want to digitize stamps or large formats, coins or paintings, sealed letters or glass negatives, loose, bound, flat, raised or corrugated originals, glossy or matte surfaces or a wide variety of material structures (transparent, metallic, wooden, textile, earthen etc.) – the book2net scanning systems meet all requirements.

Gentle illumination from cold-light LEDs and Fresnel lenses ensure uniform, flat illumination with a soft edge and infinitely variable regulation of the light emission angle. Depending on the system, additional lighting or individually controllable and synchronized lighting units provide the greatest possible flexibility in the design of desired lighting scenarios such as incident light, sided light or transmitted light.

Multispectral imaging

Posted on 30. June 202228. September 2022 by Karin

Multispectral imaging is one of the imaging techniques that make it possible to take images of objects in the range of selected, very narrow wavelength ranges of the reflected light in order to obtain information about objects that cannot be perceived by the human eye. It can be used to detect and visualize materials and structures that are invisible to the human eye.

Many scientific fields, such as forensics, geology, meteorology and art technology, use multispectral imaging to document and analyze important data about nature as well as man-made objects.

When multispectral imaging is performed, images are usually first taken in the visual spectrum, which means that an object is imaged as it is seen by the naked eye. Then, specific images are taken in different wavelength ranges (e.g., ultraviolet, infrared, and near-infrared) where specific content becomes visible. Such imaging can also be done in combination: i.e., one constructs a composite image that combines the input of multiple spectra, a so-called false-color image. In this case, data from spectra outside the visible range are represented either with an artificial color such as red or blue, or in grayscale. Composite images can show high-energy regions and other interesting things.

In art technology, multispectral imaging is used especially in painting and graphics analysis to reveal image supports, overpaintings (pentimenti), underdrawings, or watermarks, among other things.

Book2net has developed a novel, filterless method that is particularly suitable for the multispectral analysis of graphics, hand drawings and written material.

The book2net multispectral system works without changing filters (i.e. vibration-free) and without post-correction of sharpness and focus in the spectral ranges (i.e. pixel-scale accurate).

Single or series of scans can be performed in definable nm intervals. The scan results can be superimposed and analyzed with pixel accuracy.

For further information see: https://book2net.net/en/multispectral-imaging/

Scanning time

Posted on 30. June 202223. August 2023 by Karin

Scanning time basically refers to the speed at which a scanner performs a scan. It should be noted that, in contrast to the process time, which covers the entire cycle including image processing and data storage, the scanning speed only includes the pure capturing time.

In order to achieve comparability between different scanning systems, it is therefore essential that the scanning speed is always specified in relation to the format and resolution, e.g. 400 dpi for A2 color.z.B. 400 dpi bei A2 Color.

V-shape scanner

Posted on 28. June 202224. August 2023 by Karin

V-shape scanners are special book scanners whose book cradle can be adjusted to an opening angle smaller than 180° to a V-shaped support form to ensure the gentle capturing for particularly valuable or sensitive bound books and documents that can only be digitized at a small opening angle.

book2net offers a wide range of V-scanners − from mobile tabletop devices to high-performance scanners with semi-robotics.

Benefit from our book scanners with the latest CMOS sensor technology, as they combine highest quality with high performance, versatility and ease of use.

With our V-shape scanners you can scan books in various formats from A1 to A6, from large format to miniature books; always conforming to Metamorfoze, FADGI and ISO/TS 19264-1:2017 standards.

Our V-shape scanners are specifically designed for the gentlest handling of delicate, valuable and rare books, especially illuminated manuscripts and incunabula. Therefore, they provide special components to make digitization as gentle as possible:

Innovative CMOS sensor technology for high-quality, high-speed imaging
V-shaped, conservation book cradle with spine release and special coating as desired
V-shaped, easy-to-operate and lockable glass plate (for systems with semi-robotics with precision-guided linear drive)
Our semi-robotic systems (such as book2net Cobra and Dragon) feature freely selectable fully automatic, semi-automatic or manual book rocker and glass needle pressure operation options.
Smooth and adaptable LED lighting system to prevent damage from high light intensity
User-friendly software with modules for live preview and programmable scan processes ensure a smooth workflow

Get more information about our systems book2net Cobra, book2net Dragon, book2net Lizard and book2net Falcon.

Semi-robotics

Posted on 28. June 202224. August 2023 by Karin

The book2net scanners Cobra, Flash, Mosquito, Hornet and Dragon are designed as special and production scanners for mass digitization of large formats as well as bulky and heavy originals.

In order to guarantee a gentle, efficient and at the same time user-friendly process, these systems are equipped with an automatic scanning system for convenient and variable control of the book cradle/layout table and glass plate.

Industrial standards and components such as precision guidance, linear drive and PLC control guarantee smooth and consistent guidance and adjustment of all moving elements.

Thus, the systems can be adapted to the workflow processes of the respective project requirements by individually configured scanning processes. Different programs are available for fully automatic, semi-automatic or purely manual operation. The travel paths are optimized according to the original format.

Variable control: