Many folks rely on security cameras for protecting their homes and workplaces. However, varying lighting conditions can pose significant challenges, but innovations like BLC, HLC, and WDR offer effective solutions.
I’ll discuss how these technologies boost security camera footage quality.
Key takeaways about Security Camera Technologies
- BLC (Backlight Compensation): Essential for enhancing image clarity in shadowed areas by adjusting exposure selectively.
- HLC (Highlight Compensation): Reduces glare from bright objects like headlights, making key details like license plates more visible.
- WDR (Wide Dynamic Range): Balances exposure across the scene, combining multiple frames to ensure all areas, light or dark, are clear.
- DWDR/HDR: Software-based methods similar to WDR but applied after image capture; commonly used in consumer electronics for better color and detail.
- Practical Use: Most modern security cameras incorporate these features, ensuring balanced, clear footage regardless of lighting conditions, crucial for surveillance accuracy.
What is BLC?
BLC stands for “Backlight Compensation.” Security cameras use this setting to enhance the clarity of shadows or backlights in an image.
Most modern cameras can automatically balance contrast to improve image clarity. In low light, the camera opens up to collect more light. In bright conditions, it reduces light intake.
Thanks to this feature, it’s easy to make cameras under-expose parts of an image by shining a light on them. To prevent this, security cameras now include the BLC feature.
When the BLC feature is activated, it splits the image into sections and adjusts the exposure for each part separately. This helps to clarify darker regions without over-exposing the entire image. Highlights may become brighter, but the overall balance remains intact.
What is HLC?
HLC stands for Highlight Compensation. It helps reduce over-exposure of bright and reflective objects.
Reflective surfaces and light sources, like shiny objects and vehicle headlights, can cause “glare” in security camera footage, reducing image clarity.
With HLC, the image is divided into sections, and the exposure of each is separately reduced. This substantially eliminates glare and improves image readability.
HLC is great for reducing headlight glare from passing vehicles. With HLC on, the darker parts of the image stay clear, and the glare is confined to the headlights, making it easier to capture number plates and faces.
What is WDR?
After covering HLC and BLC, you might wonder how security cameras balance these two. That’s where WDR (Wide Dynamic Range) comes in.
WDR is an advanced and balanced setting for both BLC and HLC. It enhances the exposure of low-light areas like backlights and shadows while keeping over-exposed regions clear.
For example, if a security camera is placed inside a room with windows that need monitoring, the BLC setting will enhance the interior view. However, it will over-brighten the incoming light from the windows, making it unreadable.
With WDR technology, the camera uses two sensors to capture images at different exposure levels and combines them. This results in a clear image that shows both the interior and exterior details with the same level of accuracy. There’s no over-exposed or under-exposed parts, ensuring no vital information is lost.
Therefore, the image has a wider dynamic range. The images it captures show higher intensity levels and can display a broader range of colors.
Why is WDR measured in decibels?
WDR is a crucial feature found in most modern security cameras. It provides clear images despite changing exposure levels.
Experts have enhanced WDR technology in cameras, focusing on light sensors and hardware. As a result, some cameras now have better hardware capabilities, letting them capture more nuanced colors and brightness levels.
Experts evaluated this by the maximum radiance a camera can capture. They then created a logarithmic ratio comparing the maximum and minimum radiance captured from a scene.
Since this was a logarithmic ratio, the unit of measurement was decibels (dB). Decibels are commonly used for various signal-related applications.
The most common WDR value was 60dB, indicating the camera had a ratio of 1000:1. Higher values (like 120dB, 140dB) meant an even wider dynamic range. This spec evaluates security cameras — a higher HDR dB value means a better camera.
What is DWDR/HDR?
Although the WDR feature needs hardware (specifically two light sensors), DWDR and HDR are software-based technologies that enhance image clarity and color variety.
DWDR and HDR serve the same function. However, HDR became popular as an enhancement feature advertised for smartphones. Before smartphones had the quick processing power for real-time HDR algorithms, it was used in photo editing software to enhance colors and make images more vibrant.
As software algorithms, these “post-processing” techniques, though not as strong as hardware-based WDR, are still useful in TVs, monitors, smartphones, and other entertainment devices.
The difference between DWDR/HDR and WDR
WDR technology requires specific hardware, whereas DWDR/HDR is a software feature that can be applied to any image after capturing.
Experts consider WDR or “True WDR” superior because it enhances the photo at the hardware stage. This captures images with better colors and intensity levels from the start. Images with WDR showcase a “wider” range of colors and brightness, making them more accurate. Simply put, WDR images contain more details and information, regardless of DWDR/HDR processing.
Benefits of these features for camera surveillance
While BLC and HLC are basic technologies compared to WDR, they still help enhance the clarity and detail of your security camera’s footage.
With BLC, the brighter regions won’t ruin the darker parts of a scene. HLC ensures you catch details that might get lost due to intense brightness or reflections.
And finally, there’s WDR. This technology enhances image details without over-exposing or under-exposing any area. With WDR technology, you can see clearly inside and outside, even through windows.
Conclusion
For beginners, grasping these image processing technologies can be challenging. If you’re unsure about choosing an expensive security camera with high-end features, think about where you’ll install it and what information you need. Most modern security cameras have these features, so don’t worry unless you’re handling it yourself.