FAQ – Frequently Asked Questions

FREQUENTLY ASKED QUESTION

HOW DO INFRARED ILLUMINATORS PROVIDE NIGHT VISION?

Human eye can perceive wavelegths between  400 – 700 nanometers (nm) . But CCD cameras can perceive wavelengths up to 1000 nm. UNIVERSAL  INFRARED ILLUMINATORS illuminate the scene at a wavelength which is outside the human eye perception limits but inside the perception limits of the CCD cameras. In this way while human eye can not see anything at absolute darkness, crystal clear vision can be obtained  by the CCD camera supported by UNIVERSAL INFRARED ILLUMINATORS.

WHAT ARE THE PERCEPTION LIMITS OF THE HUMAN EYE?

Human eye can perceive wavelengths from 400nm to 700 nm. This corresponds as color from violet to red. 

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FROM RED TO VIOLET THE VISIBLE RANGE

Graphical Expressions of Human Eye – CCD Cameras and Sun Emission

irprojektor

DO EVERY CCD CAMERA PERCEIVE INFRARED? 

Only Black&White cameras and Day/ Night cameras can perceive infrared. Color cameras can not perceive infrared because of the “infrared cut filter” used infront of their sensors.. Day/Night cameras give color picture during daytime and when the light level decreases they automatically change over theirfilter and switch to (monochrome) black&white mode during night time and start to perceive infrared. This feature is called ICR (Infrared Cutfilter Removal). There are also some simple CCTV cameras with  ir LEDs around their lenses. Such cameras generally are not equipped with Infrared Cut Filter. Therefore such cameras are also sensitive to infrared. Although these cameras have ir leds, their night vision range is rather low, they require the support of an ir illuminator for a long range, homogenous and clear night vision.

WHAT IS THE INFRARED EXPERIENCE OF UNIVERSAL?

UNIVERSAL has imported infrared illuminators from Europe since 1989 and used them in several facilities for night vision. Since 1998 UNIVERSAL has developed his own Infrared Illuminators using semiconductor (LED) technology. Infrared Illuminators produced by UNIVERSAL have been widely used all over Turkey, at  Military and Security Forces premises as well as several governmental and private complexes. mini robust UNI 100 and UNI 200 models have been designed and produced for safe and long life operation at heavy duty conditions

MAY INFRARED ILLUMINATORS HARM EYES?

Human eye does not react to infrared since it can not perceive the infrared. At very
close distances to the infrared illuminators intense infrared radiation may cause
permanent demage to the human eye. For this reason especially the persons who
may work at close distances to the infrared illuminators need to be trained about the
danger to the eyes. While working at very close distance to thr infrared illuminators,
either they have tobe disconnected from electrical supply or protective eye wear has
to be used. Please apply to UNIVERSAL for the specification of protective eye wear.
Please note that sun glasses have no protection against intense infrared.

WHAT LOWERS THE RANGE OF INFRARED ILLUMINATORS?

Light sources inside the scene (flodlights, car headlights) or a very close object (e.g. a tree or a building wall) that is not the main monitored subject may reflect the IR light and cause a closing of the camera iris. This would decrease the effectieness of the IR ILLUMINATOR. Therefore closeby reflecting surfaces, and floodlights at the scene  should, if possible, not be included in the scene viewed by the camera.

WHAT IS THE DIFFERENCE BETWEEN 850nm and 940nm ILLUMINATORS?

Night vision by 850 nm waevlength is more effective, the range is longer. Because CCD cameras are more sensitive at 850nm. But at this wavelength faintly reddish color can be noticed at the glass surface of the illuminator. For that reason 850nm illuminaton is generally called as semicovert illumination. Since this is not a problem at several applications such as city surveillance, plate recognition systems, perimeter systems, 850 nm is preferred due to its efficiency.  In case of fully covert application 940nm illumination is used. This wavelength of illumination is not noticable at all. 940nm infrared illumination is unevitable for some military aplications and some departments of the security forces. The ranges obtained at 940nm are half the ranges obtained at 850nm.

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Dalgaboyu (nm = nanometre)

WHAT IS THE RELATION OF RANGE AND THE ANGLE?

Range  is inversly proportional to angle. If angle decreases range increases.

WHAT ARE THE RADIATION ANGLES OF UNI INFRARED ILLUMINATORS?

Standard radiation angles are 25⁰, 45⁰, 90⁰ and 120⁰.

HOW SHOULD WE SELECT THE ANGLE OF THE IR ILLUMINATOR?

For fixed cameras the  angles should be selected according the approximate angle of the camera. For speed domes generally 120⁰ radiation angle is preferred. By using 3 ir illuminators a night vision of 360⁰ can be achieved.

WHAT ARE THE APPLICATION AREAS OF mini robust, UNI 100 & UNI 200?

Mini Robust, our smallest outdoor model is ideal for any fixed camera as well as Car
Plate Reading or on vehicle applications……

UNI 200, is ideal for Driver Identification, Extreme long range (1000m+) applications,
special military applications……..etc.

WHAT IS THE ADVANTAGE OF ACTIVE INFRARED NIHGT VISION OVER THERMAL CAMERAS?

Thermal Cameras show a kind of thermal map. The scene is defined by temperature differences. It is not possible to identify persons by the wiev taken by this method. Besides this a lot of details (e.g. road lanes) can not be seen by thermal cameras. At night vision provided by UNIVERSAL  INFRARED ILLUMINATORS all details can be seen and human beings and animals can be identified very clearly.