Test drive of the MVK-8152c DVI in the dark.
Color video cameras with a day-night function and IR illumination are very popular now. But how effective are these technologies in reality? We decided to conduct a «test drive» of such a video camera model MVK-8152c DVI in real conditions of complete darkness, in order, as they say, to dot the i's and cross the t's and make sure of the capabilities of this video camera.
Surprisingly, it turned out to be quite difficult to find complete darkness. Summer nights are bright, and the first attempt to conduct this test drive away from the city, at the dacha, did not take place, as it was not dark enough. Then we found a radical solution. We rented a long and completely dark room — a shooting range 50 m long and about 20 m wide. In such conditions, we were able to conduct a truly honest test of a video camera with IR illumination.
First, a few words about the video camera itself. When developing the MVK-8152ts DVI, we tried to take into account all the nuances and use the best technologies available today in the new product. At the same time, we retained the main principle of the MVK outdoor video cameras — readiness for installation without additional settings and operability in any climatic zones of Russia.
As a result, we created a video camera with the following characteristics:
a new generation SONY Super HAD CCD II matrix with improved sensitivity and color rendering;
a mechanical IR filter, thanks to which the video camera switches to black and white mode in low light;
resolution — 550 TVL;
operating temperature range -45– +45 °C (long-term tests in a heat and cold chamber confirmed this characteristic, the mechanical elements of the video camera — a sliding IR filter and an automatic lens diaphragm operate stably at both minimum and maximum temperatures);
IR-corrected varifocal ARD lens (f = 2.8–11 mm) (thanks to the special design of the lens, image sharpness is maintained both in the «day» mode under normal lighting, and when switching to the «night» mode and IR lighting);
external lens adjustments (to adjust the viewing angle and focus, we placed the adjustment knobs outside the housing, so that focusing is done without depressurizing the video camera).
When developing the IR illuminator unit, many subtleties were also taken into account:
the unit, consisting of 2 IR illuminators with a common bracket, is placed outside the housing, and the structure itself is removable. Thus, cooling is better implemented and service is simplified;
small housings house diode matrices with 24 diodes (with a wavelength of 850 nm) each with a total power of 8 W. Similar housings of spotlights of other video cameras house only 12 individual diodes, naturally, the power of IR radiation is 2 times less;
the use of a common lens made it possible to make it replaceable, therefore each spotlight unit is equipped with two sets of lenses — 30° and 60° for individual adjustment of the radiation angle;
As you know, the power of IR radiation depends heavily on voltage, so our floodlights have built-in voltage stabilizers and the power of IR radiation does not change when the voltage changes within 10.5–24 V.
So, we decided to try out the new video camera in action.
During the test, we used:
MVK-0852tsDVI video camera;
PC with a digital video surveillance system to record the results;
power supply with the ability to adjust the output voltage;
tape measure;
distance marks of 10, 15, 20, 30, 40 and 50 m;
a completely dark room and a flashlight to move around in complete darkness.
The method was not strict and verified, in fact, we took screenshots of the resulting image, changing the settings of the camera viewing angle and the lens in the IR spotlights.
Here is what we got:
1) MVK-8152ts DVI, focus set to 11 mm (viewing angle — 24 °), lenses 30 ° in the IR spotlights:
the human figure is clearly distinguishable at a distance of 30 m and closer, the IR radiation provides uniform illumination throughout the entire field of view of the video camera (Fig. 1).
Fig. 1.
2) MVK-8152c DVI, focus set to 2.8 mm (viewing angle – 97°), lenses – 60° in IR illuminators:
a human figure is clearly visible at a distance of 20 m and closer, IR radiation provides uniform illumination over most of the video camera’s field of view.
As a result of the test, we were convinced that the MVK-8152c DVI in complete darkness with the IR illuminator unit turned on provides an image sufficient to detect a person on an object at a distance of up to 30 m with 30° lenses in IR illuminators and up to 20 m with 60° lenses in IR illuminators, which is a very worthy, and most importantly — confirmed result. Now the MVK-8152c DVI video camera can be safely recommended for surveillance in closed, absolutely dark rooms and at any objects with insufficient lighting.