Resolving Noise on Camera Image

Noise on a video image is a way to refer to any unwanted artifacts or lines on the camera image that affects its clarity. In an ideal scenario, all camera images would be clear of noise to provide the best picture. Noise can appear on an image in many ways, such as fuzzy areas of the image, rolling horizontal lines, rolling vertical lines, or "ghosting" (the appearance of another image floating over the camera image).

Potential Causes/Resolutions:

  1. Power Line Noise:
    The leading cause of noise on a camera image is from interference coming from the vehicle power supply. Vehicles use alternators to charge the vehicle batteries with the engine power. Alternators generate electricity through spinning magnets creating Alternating Current (AC) power and then converting that power to direct current (DC) to charge the battery using a rectifier. Sometimes the rectifier does not completely remove the AC from the DC power output and this causes noise on the vehicle power supply that is visible on the camera image.
    • To determine if noise is the cause of this problem:
      • Turn the vehicle on but do not start the engine.
        If the noise is not present, then the alternator is the cause.
        If the noise is still present, continue testing for other potential causes.
      • To resolve this type of noise.
        The simplest solution is to install a noise filter inline on the power line of the video system.
        A noise filter such as the "Workman NF-20 Noise Filter" (available through multiple vendors online), isolates the power line noise providing cleaner power to the system and reducing or eliminating camera image noise. The noise filter will have a power and ground input and a power and ground output that will be installed inline on the red battery power and black ground wires of the monitor or multiplexer as shown in the upper diagram below. If using a monitor, the ignition power supply should also be filtered, to use a noise filter for battery power and ignition, a relay will need to be used as shown in the lower diagram below.
  2. RF Noise:
    Radio Frequency (RF) interference can affect the video signal, this is often caused when installing video system components near two-way radio equipment/antennas or other complex electronic devices.
    • To determine if this type of noise is the cause:
      • Turn off all two-way radio equipment or other electronic systems.
        Check if the noise is no longer present in the image.
        If the noise is still present, continue testing for other potential causes.
      • To resolve this type of noise.
        Reroute cables away from the antenna and power cables from the electronic components, and/or move the video system components away from two-way radios or the other electronic components causing the noise.
  3. Coupling Noise:
    If a video cable is not properly shielded and it is routed next to other wiring or cables, sometimes the signals of the adjacent cables can cause noise to appear on the camera image in the form of "ghosting". This occurs most commonly when two improperly shielded video cables are routed next to each other.
    • To determine if this type of noise is the cause:
      • If using a multi-camera system, disconnect all but one camera and see if the noise goes away.
        If the noise is still present, continue testing for other potential causes.
      • To resolve this type of noise.
        Ensure that properly shielded video cables are being used. If using AHD cameras, AHD cables must be used because they have increased shielding to protect the AHD video signal. Reusing older SD video cables when upgrading a system may be easier, but the SD cables do not have the same shielding as the AHD cables and can be affected by interference and coupling.
        In other cases, routing the video cables so there is at least 3 inches of space between them can also reduce the presence of this type of noise.
Was this article helpful?
0 out of 0 found this helpful

Comments

0 comments

Please sign in to leave a comment.

Articles in this section

See more
Our helpline hours:
8:00am - 7:00pm EDT Monday to Friday
Follow us on LinkedIn
Get the latest news and updates first