LMK 6

luminance measuring video photometer
LMK Color - inside

The LMK 6 is the center-piece of the entire LMK product family and optimized for your CMOS image sensor as it is equipped with a full color glass filter. Each camera has a unique filter glass made for it, which ensures a high-quality V(λ)-adaptation.
The LMK 6 is robust in construction, lightweight and has compact dimensions. So, it can be used in almost every process for a wide range of lighting measurement tasks.
In conjunction with the supplied system and measuring software, LMK6 can be used in areas of application where imaging determination and evaluation of luminances is required.
A large selection of high-quality standard lenses and special imaging systems in combination with an interchangeable lens mount further increase the flexibility of the LMK 6. As a result, the LMK 6 is able to meet a wide range of requirements and combines a wide variety of measuring devices in one system.

Flicker detection

With the use of a CMOS image sensor array, it is not necessary to transfer a complete image during image acquisition (global shutter). Rather, the CMOS technology makes it possible to partially read the image data. For example, individual image pixels or image lines (rolling shutter) can be recorded.
Using this option, it is possible to realize a very fast image capture.

For the flicker detection, 4 image lines with a total exposure time of 21μsec are continuously recorded and written to each other in a single measurement image. This makes it possible to show the periodicity of the input signal on the time axis.
With the aid of this evaluation method, the frequency and the modulation depth of the input signal can be determined.

If the option of flicker detection is activated for the image acquisition, the exposure time control of the LMK is automatically adjusted to the flicker frequency of the light source (DUT).

Technical data

Sensor - imaging CMOS matrix system
Standard resolution (LMK 6-5)
2464 x 2056 Pixel
Sony-CMOS [ IMX 250 (2/3"); 12 Bit digital ]
High resolution (LMK 6-12)
4112 x 3008 Pixel
Sony-CMOS [ IMX 253 (1,1"); 12 Bit digital ]
Measurement time
starting with 1 sec. up to 15 sec. depending on luminance level, adjusted lens and exposure/integration time
Dynamic range
High-Dynamic measure (exposure bracketing series)
[ 1:10000000 (~140 dB) ]
Data interface
Gigabit Ethernet Interface(GigE®)
Spectral matching
using V(λ)-function matched full glas filter for luminance measures

Metrological data

Metrological specification
V(λ) [ f´1 < 4 %1]
Measuring quantity
Luminance: L (cd/m²)
Measuring range (integration time)
100 µsec. ...15 sec.
Measuring range depending on lens aperture value (F)
1 msec. ... appr. 7500 cd/m² & 3 sec. ... appr. 2.5 cd/m² (F = min.)
1 msec. ... appr. 60000 cd/m² & 3 sec. ... appr. 20 cd/m² (F = max.)
Measuring range for the preset f-number (F/4)
1 msec. ... ca. 10000 cd/m² & 3 sec. ... ca. 3.3 cd/m²
Calibration uncertainty2
fix focused lenses ∆L [ < 2 % ]
focusable lenses ∆L [ < 2.5 % ]
Repeatability3
∆L [ < 0.1 % ]
Measuring accuracy
∆L [ < 3 % (for standard illuminant A) ]
Uniformity
∆L [ < 2 % ]

Dimensions and weight

Housing dimensions without lenses
stable black anodized aluminum housing: 80 mm x 80 mm x 47 mm (HxWxD)
Weight
camera housing without lens: 600 g

available lenses: 120 g - 800 g

Advantages

  • Complex evaluation of luminous and illuminated scenes by means of the photograph of an image-resolved luminance distribution
  • Simultaneous recording of a large number of connected measuring data for easy data analysis (at a glance)

Result data

  • Luminance distributions in measuring images L(x,y)
  • Derived lighting-engineering parameters such as illuminance distribution E(x,y) and luminous intensity distribution I(x,y)
  • Statistical data for use in various calculation programs (z.B. EXCEL®, MatLAB®, LabVIEW®)

1 Measurements according to DIN 5032 Part 6/CIE Pub. 69 | 2 Calibration according to DIN 5032 Part 6 using a luminance standard led back from the Physical-Technical Federal Institute | 3 Measurement performed on a stabilized white LED light source L=100 cd/m². Mean value over 100 Pixel; repeatability as variability of the mean value.