If you were born between the 80s and the 90s, you’d probably remember the time before DVDs and good old VHS.
Given the standard of VHS video quality back then, pretty much of every video from the past was blurry; from movies, security camera footage and even conspiracy theory ‘evidence’. With the production of VHS ceasing last year, let’s go back to the future.
Last month, around Valentine’s Day, a North Korean named Kim Jong-nam, believed to be the half-brother of North Korean dictator Kim Jong-un, was assassinated at KLIA2.
Less than a week later, Japanese broadcaster Fuji TV released a grainy CCTV footage showing a woman covering the victim’s face with something from behind before she hurriedly left the scene. Within a short timeframe, the perpetrator was identified and then detained with much praise to the local authorities.
Now, this begs the question: why are CCTV footages always so grainy and in low quality?
With the advancement in mobile phone camera technology - dual lens, optical zoom, 41 megapixels - can't we just replace CCTV cameras with mobile phones?
Though many question the poor quality of security footage in an age of 4K video cameras, we must first address the biggest misconception that mobile phone cameras are better than CCTV cameras.
Sure, colours and vividness of pictures from our smartphones are pretty but in the context of surveillance, prettiness isn’t at the top of the list of important factors.
Here are four main reasons why we will never replace common CCTV cameras with smartphone cameras:
CCTV CAMERA SENSORS ARE SOPHISTICATED
You might’ve seen them in shopping malls, banks and cinemas; CCTV cameras with cute LEDs around the lens. Surveillance cams these days are equipped with infrared (IR) illuminators designed to capture video in low or no light environments. Powered by banks or arrays of IR LEDs, the environment is flooded with IR light (invisible to the naked eye) and details are then picked up by special sensors in the camera unit.
CCTV CAMERAS HAVE A MUCH MORE POWERFUL OPTICAL ZOOM
Depending on the complexity and cost, many modern CCTV cameras have very powerful optical zoom. Traditionally, smartphone cameras only have a single prime lens (iPhones have two) where users will have to rely on digital zoom to get the picture they want. With digital zoom, pictures get noisy and grainy.
IT REQUIRES A LOT OF MEMORY SPACE
The storage system in the CCTV is also very complex. With a multitude of cameras feeding footage into the central system, videos from A DAY’S worth of surveillance in decent resolution can easily chew through 1TB of storage! CCTVs record and store videos and images directly to Digital Video Recorders (DVRs). Meanwhile, we’re deleting our pictures to make space on our smartphones to snap your OOTD pictures.
SMARTPHONES DO NOT HAVE THE PROCESSING POWER
With many video feeds from different cameras, computers work around the clock alongside cameras to compress videos, timestamp them and sometimes even directly feeding footage live via network connections.
So, the big reveal is this: contrary to popular belief, smartphone cameras are actually not better than CCTV cameras!
So why are we still seeing blurry CCTV footage if they’re so much better than smartphone cameras, you ask?
This is because of image/video cropping on low resolution video.
Yes, that cropping. Just like what you do on Instagram.
Selecting an area of a HD picture. The resulting cropped picture will have a resolution lesser than 1080p
Cropping an area in a low resolution video like 320 X 240 with low frames per second (FPS) affects the quality of the video as you are only selecting a low ‘X’ number of pixels in that area.
So, when you crop a certain footage from a low resolution video, what you will get is a very noisy picture like this:
Image: Daily Mail
According to an article on Quora
, if an establishment uses a low quality CCTV camera, only 25% of the image's resolution is recorded. Add cropping into the equation and you'll get a super grainy, low quality footage.
Also, there are other factors that affect a CCTV footage, such as compression when the recording is fed into a DVR set to be stored.
So, in case you TL;DR, CCTV footages are not bad quality in nature, it only happens when you want to crop a certain area out of the footage.
Oh, and in case you're wondering: noise is a type of visual distortion produced either by low light, pixel density, exposure and sensor size. Blur, on the other hand, happens when the sample video is recorded in low FPS and still image is captured from a frozen image frame.