How to ease the motion blur (ghost) from a security IP camera?

"Why the image look so fuzzy from my new CCTV camera at night? When people approach in, it looks like ghost walking in my garden." The HD security IP camera or analog (TVI/AHD/CVI) are equipped with CMOS sensor which can do an excellent job during the day. However it doesn't perform well in low light condition. People choose CMOS sensor basing on the performance at day for the cost. CMOS is cheaper than CCD. Eventually, the performance at night is compromised.

To improve the night vision, adding the Infrared LEDs to the camera is the first step. However, it doesn't help much, the infrared is still too weak to generate the fair image at night, then activating the frame accumulation (or slow shutter). This is the main reason cause the image fuzzy or (ghost). "Shutter speed can have a dramatic impact on the appearance and quality of photographs, especially when moving objects are involved" (Wikipedia) Let's take a example, when you walk from your garden to the living room, the camera should take 80 pictures, now the camera only takes 40 pictures in order to accumulated more illumination for each picture. The detail should be stay two separate picture, mix into one. The picture looks very good and bright if everything stay still. As long as you walk, you lost the details and see the ghost on the monitor. How can we fix it? After all, the criminal is not going to stand still and say hello to your camera.

Firstly, don't choose the camera with low cost sensor. Even the low cost sensor can perform pretty well at day. The difference is the night vision capability. Pick up the camera with 1/3 inch even bigger size sensor. The bigger the size is, the better the night vision will be. Like human eyes, one person can see clearly if he or she has better vision capability.

Disable the slow shutter. This can tell how well your camera performs at night. Find the camera setting. Disable the slow shutter. The image will become darker and higher frame per second (fps). Don't complain the darkness. No criminals will stand still under your camera. The ghost image doesn't deliver useful information for identification at all.

Add extra illuminators. It could be Infrared or visible lamp. The infrared can project further distance than visible light, however, you have to scarify the image's color details, because the infrared always affects the color reproduction of the camera, making the image looks over purple. Most of the camera will eliminate the color when it sees Infrared. The PIR lamp is another option especially when you have some existed street light. It can pop up unexpectedly and generates the deterrence when the criminal approach in. 

SONY have release new sensor which increase the sensitivity. It calls Starvis. People name this technology as moonlight, light fighter, starlight, or super low lux. This technology allocates the components to the button of the sensor in order to reserve more space for sensor in front. Most of these starvis camera are equipped with Infrared leds, which can ease the fuzzy issue, because the sensor just has better night vision capability. With IR illumination, it requires less slow shutter or frame accumulation to achieve the same performance. You will find the difference when you walk around in front the camera. Actually, the starvis can do even better than that, it can produce the color night vision if some of your installation spot has street light such as front door. The color image delivers much more information than black and white image. The camera is still equipped with Infrared LEDs in case it is too dark. However, it needs to postpone the switch point of Infrared and keep the camera working under color mode when the installation location has some street light. Normally, the regular IR camera just switch to black and white even it has significant light at night. The color night vision camera not only can deliver color image in low light conditions, but also can extend the use lift of the camera, because the camera has less time with Infrared on (heat issue). The below is compare between SONY starvis 291 and SONY EXMOR 322.

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3 Komentar

Great post.. keep it up


Your shutter speed is very low if you are getting ghosting.. Just up the shutter speed until this goes away, its a compromise. to faster a shutter & not enough light gets in & image is too dark, too slow shutter & contrast is very nice but everything that moves ghosts. thanks, Nadia.. Read more here >