Image quality in surveillance cameras: an overview of the technology

The quality of surveillance video is crucial to the effectiveness of a security system. Important technologies affecting image quality include resolution, lighting, night vision, image compression formats, and image enhancement technologies such as WDR (Wide Dynamic Range) i DNR (Digital Noise Reduction). Choosing the right surveillance camera depends on many factors, such as the size of the monitored area, lighting conditions, resolution requirements and budget. These factors should be carefully evaluated to get the best possible image quality from the surveillance system.

What is image quality in surveillance?

Image quality in surveillance refers to the sharpness, clarity and detail of the images captured by cameras. The high image quality enables easier recognition of faces, vehicle registrations and other relevant details.

What technologies affect image quality?

Key technologies affecting image quality include resolution, lighting, night vision, image compression formats and image enhancement technologies.

Types of resolution in surveillance cameras

Resolution is the number of pixels of which an image is composed. The more pixels, the higher the image quality. Popular resolutions include:

VGA (640×480)

HD (1280×720)

Full HD (1920×1080)

4K (3840×2160)

The choice of the appropriate resolution depends on the size of the monitored area and the requirements of the system.

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Effect of lighting on image quality

Lighting affects image quality by reducing noise and increasing contrast. Good lighting allows better recognition of objects and details. Optimum illumination can be achieved by using LED spotlights or other light sources.

Night vision in surveillance cameras

Night vision in surveillance cameras allows recording images in low-light conditions. Cameras equipped with infrared (Infra Red) in the 850nm to 940nm band use diodes that emit light invisible to the human eye, allowing them to recognize objects in the dark. The choice of a camera with night vision depends on the lighting conditions of the monitored area. Nowadays, ever-improving sensor technology makes it possible to produce cameras that can work efficiently even in minimal light without an illuminator built into the camera itself. Thermal imaging cameras built on the basis of uncooled microbolometer. These cameras work effectively in total darkness as well as in fog. However, the limitation of these cameras is still the low resolution which somewhat limits their capabilities.

Image compression formats

The choice of the appropriate compression format depends on the requirements for image quality, data transmission speed and storage capacity. Format H.265 offers better compression than H.264, which allows for smaller file size and faster transmission while maintaining good image quality.

Image enhancement technologies

Image enhancement technologies such as wide dynamic range (WDR) or digital noise reduction (DNR), improve image quality by increasing contrast, reducing noise and adjusting exposure. WDR helps produce better images when there are large differences in lighting, while DNR reduces noise produced in low-light conditions.

How to choose the right surveillance camera in terms of image quality?

Choosing the right surveillance camera depends on many factors, such as:

• Size of the monitored area
• Lighting conditions
• Resolution requirements
• Sensitivity expressed in Lux
• Budget

Carefully evaluate these factors before deciding on a surveillance camera to get the best possible image quality.