While we shop for a camera for a home security system, we essentially want our camera to capture images and videos with good clarity and sharpness. The technical term is resolution measured in pixels per inch(PPI) or dots per inch (DPI). You will get a more detailed view of an image with more dots per inch. In the case of printers and scanners, the resolution is measured in dots per minute (DPI).
What are Primary colours?
While we were in kindergarten, we were taught about primary colours – Red, Yellow, and Blue!!! But then why does the Colour-picker take the Red, Green, and Blue (RGB) combination?
Do you know what light is? Light is a colour reflected in our eyes either directly from the source or reflected from an object.
How do you identify the colour of an object?
Unlike Sun, torch, or flashlight, the colour of objects is non-emissive. The reflected colour from the object is a subtractive mix – which is CMYK – Cyan, Magenta, Yellow, and K for Black. Printers and Publishers use CMYK colours for printing.
Light from some direct source uses an additive colour system – Red, Green, and Blue, a mix of which results in white colour. Our television and computer monitor screen emits light hence follows the RGB system.
How camera captures an image?
Sensors collect light from an object and convert it into photoelectrons in digital cameras. The object’s colour is captured based on the intensity of red, green, or blue pixels. The camera’s resolution depends on the size of a pixel, the aperture of a lens, magnification, and other factors.
720p vs 1080p cameras
The 720p camera captures the smallest area and resolution – 1280 x 720 – an HD-ready camera. If you are focusing on a small area with adequate lights and a clear field of vision, then 720p may serve the purpose.
1080p camera – 1920 x 1080, known as Full HD resolution, will be required to accommodate larger space in the image and recognise objects at a distance.
With a 720p camera, streaming real-time video onto your mobile will be quicker than a high resolution 1080p camera with frequent lag and buffering due to its lower bandwidth. You would require more memory and storage with a high-resolution camera if you frequent business travel or vacation. A one-hour video captured from a 720p camera will consume one-third of space compared to the same length video captured from a 1080p camera.
Surveillance cameras are installed for the safety of our property and our loved ones at our home. For an event, investigation agencies require you to recognise the occupant of your home and identify an intruder. You recognise an occupant and know you have seen them before, need at least a 20-pixel comprehensive picture. Identifying an intruder, you will be required to confidently point out someone when seen in person during an investigation and need to capture images between 40 and 80 pixels.
4K vs 5MP cameras
4k cameras are ultra HD security cameras with resolutions up to 3840 x 2160 with over 8 million pixels suitable for capturing images of someone at the doorstep in close-up and full body. 4K cameras require lots of internal storage and consume a lot of battery and power.
5 MegaPixel cameras can be used in surveillance systems when you don’t want to compromise image quality and look for fast streaming of captured images even at low internet speed. You want to install the camera at the main entrance to identify who has arrived.
The only drawback with a 5MP camera is that the captured media files may take more storage even after compression, and they are costly.
With high-resolution cameras, you will get smaller images on your screen if you watch captured images over your mobile device. The text from the image will not be readable. You can easily view high-resolution images with larger monitor screens unless the monitor has limitations with pixel density or aspect ratio.
This article discussed how light from objects gets converted into coloured images by camera. CMYK colour method for printing and RGB for capturing an image and comparing 720p, 1080p, 4K, and 5K cameras for good resolution of pictures and videos in home security to help you analyse your situation and make an informed decision.