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  1. #1
    Mustafa Umut Sarac's Avatar
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    Cultural Heritage Imaging

    Its a multiple led array light source filtered by White paper. Same height with camera and around 35 degrees to the subject. Text taken from a website.

    Illumination: EV™ LED Illumination System

    A revolutionary EV™ LED illumination system provides unprecedented opportunities in imaging and image quality. This system enables imaging in multiple distinct narrow spectral bands or combinations of spectral bands over a range of wavelengths from the near ultraviolet to the near infrared.

    The lighting system is fully integrated with MegaVision’s Photoshoot™ software and typically include light emitting diodes (LED’s) with up to 13 specific wavelengths, including:

    UV 365nm
    Visible 445, 470, 505, 530, 570, 617, 625nm
    Infrared 700, 735, 780, 870, 940, 1050 nm

    Choice of 2 different spectral bands for optional SideLong™ raking illuminators.



    Advantages of LED illumination

    1.High efficiency reduces heat and stress on the objects in the scene.
    2.Elimination of unwanted IR wavelengths prevents registration difficulties caused by object motion due to heating.
    3.The light is utilized more efficiently than white light. Ordinary photography which employs broad-band white light subjects the object to a great deal of unnecessary light energy. The majority of the light energy in white light is discarded by normal color camera filtration after the light has interacted with the objects in the scene. White light must be filtered at the camera after the scene is subjected to unnecessary light energy. With narrow band LED illumination, no filtration is required. The light energy is used much more efficiently, and only enough light to properly expose the objects in the spectral band of interest is generated. Unused light energy is eliminated before it is created at the source of the light, rather than after the light hits the object in the scene. This means that the object is subject to less light stress, and the lighting system requires dramatically less power.
    4.Because narrow-band LED’s emit no light outside the specified band, there is no need to filter IR light from the sensor. The IR cutting filter can be eliminated. Eliminating the IR filter removes an optical element from the image forming path and substantially increases light efficiency, enabling reduced exposure and greater S/N.
    5.EV LED’s provide highly specific, low maintenance, and very repeatable light. Panel spectral properties are consistent from shot to shot and year to year. Lumens/watt is stable.
    6.Normal lifetimes of up to 50,000 hrs.
    7.Rapid switching times (< 50 µSec) allow pulse width modulation and precise exposure durations.



    Lighting Configuration

    Each light head is 19cm X 12cm X 5.2cm (7.4” X 4.7” X 2” ). The panels mount with standard professional light stand mounting studs. Inside each panel are modules that are configurable. Each panel may be configured to include up to 13 different spectral bands with a total power of about 240 Watts. For example, the panels may be configured with only 7 visible bands, or may additionally include several IR bands and a UV band. Custom configurations are available to satisfy specific customer requirements.

    The panels are powered and controlled via a power pack with an integrated USB Hub. Up to 6 panels may be powered from a single power pack. A single USB cable from the power pack to the computer enables Photoshoot™ software to control multiple light panels. Panels may be tiled to form larger units. Photoshoot™ can simultaneously control up to 14 individual panels.

  2. #2
    Mustafa Umut Sarac's Avatar
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    Color Capture With a Monochrome Sensor and LED Illumination
    While the human color vision system is functionally tri-stimulus, our retinal spectral response curves can't be replicated by a simple set of 3 band-pass filters. Somewhere in the range of 5-8 bands are required to get enough spectral information to make a good match to human vision. Attempts to make practical systems utilizing multiple band capture with color filters between the scene and the sensor have not been successful (for reasons that can be readily appreciated).

    By coming at the problem from a different angle, namely, creating the color bands at the source of the light (using LED's), the EV™ system solves the intractable practical problems.

    Capturing sufficient perfectly registered and highly repeatable spectral bands is an enabling technology for deploying semi-automated, high-quality color reproduction. With tri-stimulus capture, color matching over a practical range of commonly encountered dyes, pigments, plastics, and other materials is sufficiently poor that individual, scene-specific color adjustments must be performed to obtain the desired quality. This color-matching step is sufficiently time consuming and costly that it is practical to create high-quality color reproductions of only the most expensive originals. The EurekaVision™ approach can dramatically reduce the amount of labor intensive post-processing of the image data and provide highly accurate color reproduction of a very wide range of difficult subjects.

  3. #3
    Mustafa Umut Sarac's Avatar
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  4. #4
    Mustafa Umut Sarac's Avatar
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  5. #5
    Mustafa Umut Sarac's Avatar
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    UV 365nm
    Visible 445, 470, 505, 530, 570, 617, 625nm
    Infrared 700, 735, 780, 870, 940, 1050 nm

    These narrow band led lights are sold at ebay for few cents or dollars each, I saw 3 watt 445nm for 1 dollar or less.

    umut



 

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