In the IP security camera world, manufacturers often highlight how many megapixels (MP) a camera has. More megapixels, or higher resolution, often mean a significant increase in camera prices as well. So what are megapixels, and should you really pay up for them?
Let’s start off with just the pixel. All digital screens display images that are broken up into tiny little squares called pixels. Each pixel is a specific color and all those colors together make up an image. It is a lot like the painting style, pointillism, best exemplified by Georges Seurat’s A Sunday Afternoon on the Island of La Grande Jatte.
If you look closely, you will see tiny dots of color that form a larger picture when you step back. Digital screens are just like that, except with way more dots or, pixels - so many that you cannot see each individual square.
Megapixels
A megapixel is 1 million pixels. So cameras that boast a 5MP resolution are really saying their images are broken up into 5 million tiny squares. The idea is that the more pixels you have, the higher the quality of your image.
Manufacturers advertise camera resolution in many different ways. Sometimes, they use the MP, sometimes the vertical pixel number, and sometimes the horizontal pixel number. It can be confusing. The table below gives insight into what manufacturers mean with different names.
If you’re curious where 4K fits into all this, it’s the horizontal pixel name for 8MP, because 3840 pixels is roughly 4000.
IP Cameras
As related to IP security cameras, more MP mean the more detail you can see on your images. It may mean the difference between seeing a red car drove into the parking lot before you got robbed, versus seeing a red Toyota Camry with the license plate, "STEALN," that drove in.
So how many MP do you need?
A good way to determine your MP needs is by first calculating your pixels per feet (PPF) in a certain shot.
To do this, take the horizontal number of pixels in your camera divided by how wide a field of view is in a single shot. So if your shot of the parking lot is 70 ft and you are using a 2MP camera, you would take 1920/70 which comes to 27.4 ppf.
To determine your ppf needs, use the Army’s convenient abbreviation, DCRT: Detection Classification, Recognition, Identification.
- 20 ppf = Detection. You can see something in the field of view
- 40 ppf = Classification. You can see what type of object it is. Example: a car versus a person
- 60 ppf = Recognition. You can see some characteristics of the object. Example: that is a person in a hat
- 100 ppf = Identification. You can see individual distinguishing features about the object. Example: that is Bob wearing a Milwaukee Bucks hat.
What works best for you
The idea behind resolution in IP security is to only get as high of resolution as you need to save money on cameras, bandwidth, and storage. For example, if you have an area where you do not need to catch as much detail, like a back parking lot where the dumpster is, you can opt for a lower resolution camera. If you have a large, high-traffic area, maybe opt for a higher resolution camera.
Overall, you should consult with experts to figure out what works best to meet your security needs and fits within your budget.