Articles
FAQ
FREQUENTLY ASKED QUESTION
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. But all details can be seen and human beings and animals can be identified very clearly at night vision provided by UNI INFRARED ILLUMINATORS.
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. UNI 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, all kinds of details can be seen at the view taken by the CCD camera supported by UNI 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.
FROM RED TO VIOLET
Graphical Expressions ofSun Emission – Human Eye - CCD Cameras
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. In case the scene is illuminated by appropriate infrared they give very clear pictures at absolute darkness.
WHAT IS THE INFRARED EXPERIENCE OF UNIVERSAL?
UNIVERSAL has imported infrared illuminators from Europe since 1995 and used them in several facilities for night vision. Since 2005 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. UNI 100 and 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.
WHAT IS THE RELATION OF RANGE AND THE ANGLE?
Range is inversly proportional to angle. If angle decreases range increases.
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.
WHAT ARE THE STANDARD ANGLES OF UNI INFRARED ILLUMINATORS?
Standard radiation angles are 15⁰, 30⁰, 50⁰ and 120⁰. As special production for large quantities (100+pcs) additionally 10⁰, 20⁰, 45⁰, 60⁰ options are possible.
HOW SHOULD WE SELECT THE ANGLE OF THE UNI 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 UNI 100 & UNI 200?
UNI 100 is ideal for all kinds of fixed camera applications as well as motorized Pan/Tilt/Zoom applications. At motorized applications 1 or 2 UNI 100 illuminators can be coupled with the motor. In case of 2 illuminators one of them may be medium angle (30⁰ or 50⁰ ) and the other 15⁰ to support zooming in. This application is very effective and can provide night vision for very large areas. (70000 to 120000 sqm)per PT motorized camera.