Multispectral Laboratory

 

The Institute of Imaging and Computer Vision has its own multispectral laboratory for multispectral imaging, analysis and rendering. The facilities range from elementary color charts to complex measuring instruments like the spectroradiometer CS 2000.

Multispectral camera

Due to the sampling of the visible electromagnetic spectrum, the multispectral camera enables a considerably better quality of the color images than conventional RGB cameras. Hence, the multispectral camera is utilized for reference color imaging.

  • 1/2″-IT-progressive scan-CCD
  • 1392 x 1040 pixels
  • Pixel size 4.65µm x 4.65µm
  • Multispectral imaging with seven color channels using spectral bandpass filters between 400nm-700nm (in 50nm steps)
  • Fully automatic control of the filter wheel
  • Digital interface 1394 IEEE
  • Objective thread: F-mount

 

Multispektralkamera
Multispektralkamera

Filter wheel

The high-speed filter wheel HS10 enables to flexibly assemble a multispectral camera using the filter wheel technique. Thanks to the C-mount adapter at the camera side of the filter wheel, any industrial camera can be used. With the F-mount adapter at the objective side, F-mount objectives can be easily be added to the multispectral camera.

  • 10 filter positions
  • Diameter of the filters: 32mm, or 25mm using adapters
  • Camera thread: C-mount
  • Objective bayonet: F-mount
  • Change to a neighboring position: 30ms

 

Filterrad
Filterrad

Monochrome camera uEye 2240

This monochrome camera is used for instance with the filter wheel to take multispectral images.

  • 1/2″ CCD sensor (Sony ICX205)
  • 1280 x 1024 pixels
  • Pixel size: 4.65µm x 4.65µm
  • IR-cutoff filter interchangeable with a glass filter
  • Digital interface: USB 2.0
  • Objective thread: C-mount

 

Graustufenkamer
Graustufenkamer “uEye 2240”

Optical bandpass filters, 50mm diameter

Smaller models of these optical bandpass filters are utilized in the multispectral cameras described above.

  • Central wavelengths: from 400 to 700nm with 50nm steps
  • Full width at half maximum: 40nm +/- 8nm
  • Diameter: 50mm

 

Optische Bandpassfilter, 50mm Durchmesser

Spectroradiometer Konica-Minolta CS 2000

The spectroradiometer CS 2000 allows extremely accurate spectral measurements with a precision of 1nm in the visible light range.

  • Wavelength range: 380 to 780nm
  • Wavelength: 0.9 nm/pixel
  • Display wavelength bandwidth: 1.0 nm
  • Measuring angle (selectable): 1°, 0.2°, 0.1°
  • Wavelength precision: +/- 0.3nm
  • Spectral bandwidth: 5 nm or less (half bandwidth)

 

Monochromator Oriel Cornerstone 130, 1/8m with lamp

The monochromator emits a narrowband light whose bandwidth and central wavelength can be exactly adjusted mechanically or per software. The incoming light is reflected to one of the two gratings, where it is diffracted. The spectrally expanded light is then reflected to the output of the monochromator.

  • Grating 1: 200-1600nm (1200 lines/mm)
  • Grating 2: 450-1600nm (1200 lines/mm)
  • Lamp: 75 W Xenon ozone free, including a motorized filter wheel
  • Micrometer driven slit assembly: variable width from 4µm to 3mm and variable height from 1 to 15mm

 

Monochromator Oriel Cornerstone 130, 1/8m mit Lampe

Spectrophotometer X-Rite EyeOne Pro

The EyeOne Pro spectrophotometer enables reflectance and emission measurement with an optical resolution of 10nm in the wavelength range of visible light. Ambient light can also be measured using a specific measurement head.

  • Wavelength range: 380 to 730nm
  • Wavelength resolution: 10nm
  • Physical sampling interval: 3.5nm
  • Measurement geometry: 45°/0° with a ring illumination optics
  • Light source: gas filled tungsten (Type A)

 

Spektralfotometer X-Rite EyeOne Pro

Various X-Rite ColorChecker targets

The color charts are utilized to test and calibrate the color reproduction and to create ICC-profiles.

  • The ColorChecker White Balance enables a custom white balance of the images.
  • The ColorChecker Classic contains 24 different colors, including 6 gray scale colors.
  • The 24 colors of the ColorChecker Classic, 17 gray scale colors and 14 skin tone colors are included in the 140 color patches of the ColorChecker Digital SG, among other reference colors.

 

Software for optical simulation Zemax (Zemax Development Corporation)

Optical systems can be modelled and analyzed using the Zemax software. The design of optical systems is also supported. It is for instance possible to display the 3D layout of a system, its aberrations and its spot diagramm for various angles of incidence and wavelengths.

Software für optische Simulation Zemax (Zemax Development Corporation)

Calibration software Eye-One Match 3 (X-Rite)

The Eye-One Match Software allows a user friendly creation of ICC-profiles to calibrate

  • monitors
  • digital cameras
  • RGB- and CMYK-printers
  • scanners
  • digital projectors

The measuring device used with this software is the X-Rite EyeOne Pro.

 

Kalibrationsoftware Eye-One Match 3 (X-Rite)

Professional profile creation software Profile Maker 5 Platinum (X-Rite)

With Profile Maker 5 Platinum, ICC-profiles of

  • monitors
  • digital cameras
  • printer (RGB, CMYK, multicolor CMYK + n colors)
  • scanners

can be professionally created, edited, optimized and tuned. The spectrophotometer X-Rite EyeOne Pro is also utilized with this software.

 

Professionelle Profilerstellungsoftware Profile Maker 5 Platinum (X-Rite)

Softproofing station

The softproofing station enables a direct visual comparison between a model and its image displayed on a monitor. It is placed in a cabinet to avoid extraneous light during the comparison. The softproofing station has been developed and built by the Color and Image Processing research group.

  • Monitor: LCD display with a 1680 x 1050 pixel resolution
  • Lamp types: D50, D65

 

Softproof Arbeitsplatz

CTF measurement station

The CTF measuring station allows the measurement of the camera transfer function (CTF) and of the opto-electronic conversion function (OECF) respectively, that describes the relation between the irradiation power on the sensor of a camera and the digital output value. Using the CTF, the measurement values coming from the camera can be linearized. The camera is illuminated by an integrating sphere and can be moved automatically on a sliding carriage, which changes the irradiance impinging on the sensor. The position of the camera is measured accurately by a position sensor with a resolution of 50µm.

  • Resolution of the sliding carriage: 50µm
  • Range of the sliding carriage: 100mm to 5000mm
  • Illumination: integrating sphere (500mm) with halogen lamp (100 W)

 

CTF Messplatz