TopTechnical DictionaryMinimum temperature

Minimum temperature

Minimum operating temperature of the camera is a temperature at which the manufacturer guarantees the correct image quality. The image quality should be identical to the one observed at room temperature. What are the limits for the camera itself? At what temperature the camera simply stops working? We couldn't find a straight answer and we’ve decided to test the cameras in a climatic test chamber simulating the conditions that can be found in nature.

 

An extreme low temperature in Poland was recorded in Siedlce on 11 January 1941 at - 41°C and in Europe, it was recorded in Russia in Ust-Shchuger and was -58.1°C on 31 December 1978.

 

The test conditions were as follows: 

  • Eight (8) camera models where installed in the climatic test chamber, the power supply was switched on and the video was recorded throughout the test.
  • An initial relative humidity, usually observed in winter, was set at 30%.
  • The temperature was reduced to -50°C and the image was monitored.
  • The power supply of all cameras was shut down (power failure simulation) after the lowest temperature was reached.
  • After 3 hours, all cameras were switched on again.
  • The temperature was gradually increased from - 50 degrees Celsius to + 10 degrees.

    • The test results are shown below.

     

    The study was conducted in the Euro Centrum Science and Technology Park in Katowice. The picture shows the climatic test chambers.

     

    Eight Gemini AHD series camera models with different enclosures and image sensors were tested. The cameras with vandal-proof (dome) enclosures, compact type enclosure as well as plastic enclosure, which due to lack of protection are for indoors only were tested.

     

    Two additional light sources where installed inside the chamber to disable the IR Illuminators of the cameras. The cameras feature light sensors and at low light enable IR illuminators. The illuminators are an additional source of heat and to prevent falsified results were disabled for the test. No IR illuminators were enabled during the test.

     

    Power supply and BNC connectors remained inside the chamber; the recorder with the display device operated at room temperature. The cables were led through a special penetration in the chamber wall.

     

    The image from the cameras throughout the test was observed on the display and recorded on the recorder’s HDD.

     

    The conditions inside the climatic test chamber where remotely monitored.

     

    First, the relative air humidity was established.

     

    After the humidity check (yellow), the main test has started by reducing the temperature to - 50°C. 

    X - Time

    Y - Temperature

    Z - Relative humidity

    1 - Temperature and humidity stabilization periods

    2 - Humidity monitoring end period.

    3 - Temperature reduced to -10°C

    The graph shows the results of changes in temperature in time. Two measurements with different temperature decrease period were carried out. 

    X - Time

    Y - Temperature

    The recorder has recorded changes in the camera image throughout the entire test. Up to -30°C all cameras performed as expected and did not show any differences in image quality. After that, some cameras lost focus to a certain degree.

     

    To our surprise, the images from all tested cameras were correct up to -50°C. The picture shows the moment when the temperature dropped to - 44.8°C. However, conditions like that are extremely rare.

     

    At -50°C, the cameras were shut down (power failure simulation), since the probability of failure at low temperature is relatively high. The cameras were left for 3 hours, and turned on again after that time. The picture shows a frozen water vapour on the dome as due to cooling.

     

    The moment, the cameras were turned on again at -50°C was recorded. 

     

    The test showed that all the cameras resumed normal operation at - 50°C. The picture shows images from all the cameras immediately after switching the power supply back on.

     

    The last phase of the test was a gradual increase in temperature. The quality of the image has improved with the increase in temperature. 

    X - Time

    Y - Temperature

    Final conclusions: 


    1. All cameras performed as expected without failure, also at –50°C.


    2. Although a single series of (Gemini) cameras with different enclosures was tested, we can safely assume that cameras offered by other manufacturers will perform in a similar way.


    3. No Speed Dome type cameras were tested which due to mechanical parts can produce different results.


    4. The test result can be considered positive.