Developments in video surveillance have always been concerned with producing higher quality images to enable better footage and therefore improved surveillance. Recent years have seen a dramatic improvement in megapixel and high definition cameras with high quality lenses, which has significantly improved image quality and zoom ability. However, it is not just a case of developing high definition cameras to improve image quality; there are other factors that can result in low quality images, ineffective footage or poor visibility, particularly for outdoor cameras.
This post is part of a series of short articles that we will be publishing regarding superior image quality in challenging and changing environments. Factors such as poor or no lighting, difficult lighting scenarios, vibration and weather and environmental issues can result in poor CCTV image quality which, in extreme cases, may make the footage unusable. This in turn can have adverse effects on your ability to keep a safe and secure environment through CCTV surveillance. We will therefore take a look at these challenging scenarios and the solutions available to ensure the best in image quality and clarity at all times.
CCTV solutions for fog, haze, smoke and rain
Instances of heavy fog, haze, smoke, dust and rain can pose as a serious challenge to CCTV cameras. As a result of particles in the air, whether tiny water droplets or ice crystals, airborne dust, smoke particles or chemicals, our vision, and therefore CCTV images too, can be obscured. Loss of contrast in objects and shifts in hue, due to the effect of light scattering through these airborne particles, produces this deteriorated vision and image clarity. Where the atmospheric particles are large, they can also block pixel imaging in cameras resulting in a loss of detail in images.
Severe pollution in Beijing
In China, where air pollution is becoming increasingly serious and increasingly common (especially in large cities), pollution hazes caused by airborne dust particles, acids and chemicals can severely limit visibility. For example, China’s northern city of Harbin hit a visibility low of 10 meter earlier this year when hit with severe pollution.
Whether caused by pollution, weather or other factors, fog, haze and smoke can result in poor quality CCTV footage with obscured images, a limited field of vision and often the inability to identify objects clearly or for cameras to perform regular functions such as license plate recognition. This poses as a challenge, limiting the ability of CCTV cameras to provide useable footage which can in turn inhibit the end user’s ability to effectively maintain a secure environment.
There is therefore an increasing market demand for technology that can solve this problem (especially in China), as end users seek cameras with features that can effectively reverse or eliminate image obscurity from fog and haze so that CCTV surveillance can still be used effectively. Such technology has been developed for CCTV in the past, but solutions have generally been extremely expensive or not particularly effective.
This is, however, changing. One of the leading solutions is one that has been developed by VisionClear (by Seeways) who have released a high definition optical zoom camera with a ‘de-fog image processing feature’ which improves visibility and image clarity for obscured objects in challenging environments.
The de-fog feature works through a complex algorithm which first determines the fog destiny of the scene, then analyses the obscured image before applying contrast and sharpness adjustments to the video in real-time to produce image enhancement. The technology is built in to the camera as a function that can be turned on and off.
Hitachi, Hikvision, Fujifilm and Skyworth are among other CCTV camera providers that offer cameras with effective de-fog functions, although such features are becoming increasingly more widespread.
De-fog function off
De-fog function on
Effective solutions
Fog or haze can be particularly damaging to video surveillance monitoring traffic or highways where it is often vital to be able to monitor vehicles or track traffic flow over a large area. Installing cameras with de-fog features for traffic monitoring could increase the effectiveness of CCTV surveillance by reducing the inability to collect important data, such as license plates numbers and vehicle or people tracking, as well as reducing the risk being unable to see dangerous or illegal driving.
Security solutions at factories, ports, airports, and other sites or logistic centers covering a large area, especially those that are situated in locations prone to fog or haze, may also benefit from employing cameras with a de-fog function for increased reliability for outdoor CCTV surveillance and to reduce the risk of being blind to significant breaches of security.
Large expansive areas where there may be extreme weather conditions could also benefit from de-fog cameras. Surveillance at large parks and border monitoring could be enhanced, and the de-fog function could also be used to help prevent the spreading of forest fires due to the feature’s ability to reduce image obscurity caused by smoke.
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