Motion detection in cameras: more convenient than human presence sensors or continuous recording?

Network camera functions improve every year, and you can now easily record high-quality video and images even at home. Along with higher image quality, new additional functions keep appearing. One of them is motion detection. It makes it easier to check for suspicious persons, so many users will find it appealing.

If you want to set up network cameras such as security cameras, you need to consider whether you really need motion detection, weighing its advantages, disadvantages, and cost. Let’s look at what motion detection is and how useful it is by comparing it with similar functions.

What is motion detection?

Motion detection is a function that detects when an object in the video moves. In security cameras, it works with a video recorder to record video only when the movement of a suspicious person is detected, which greatly reduces recording time.

By linking motion detection with sensor lights, you can also use it to deter intruders and as a substitute for garage or entrance lights at night.

How motion detection works

There are several ways to detect motion. Motion detection in security cameras detects moving objects in recorded video. Video uses an illusion: like a flip book, it switches many images quickly so that things appear to move to the human eye.

If the video captures a suspicious person entering, the images change as they switch, and a large change makes it possible to detect a moving object.

Early motion detection often gave false alarms, for example reacting to tree branches moving in the wind. In recent years, better software, including AI known as deep learning, and better hardware have reduced false alarms so that the system reacts only to human movement.

Products with motion detection

Several types of cameras have motion detection.

Security cameras

Security cameras have roles besides preventing intrusions, and motion detection is considered necessary for them.

Dashcams

A dashcam records the area around a car or motorcycle, such as the view ahead. It can be used not only to verify traffic accidents, such as pedestrians suddenly stepping out or the movements of other cars while driving.

Some models also have security functions for when the vehicle is parked, so some dashcams have motion detection.

Compact cameras

With a large camera such as a security camera, suspicious persons may notice where it is. For this reason, palm-sized compact cameras are sold.

Some of these compact cameras have motion detection to make up for their short maximum continuous operating time.

Advantages and disadvantages of motion detection

Motion detection is useful for detecting suspicious persons, but it has advantages and disadvantages.

Advantages of motion detection

The biggest advantage is that it greatly reduces recording time on the video recorder. Continuous recording records video 24 hours a day, 365 days a year, so it needs huge storage.
Motion detection records only when a suspicious person moves, so it needs less storage. When checking recorded video, you only need to check the times when a suspicious person moved, which saves time.

Disadvantages of motion detection

Motion detection relies on changes in the video caused by moving objects, so changes in light can cause false detections. It is useful in parking lots and entrances where few people pass, but in a busy shopping street it reacts constantly, so the length of recorded video is not much different from continuous recording.

Motion detection or similar functions: which is more convenient?

Let’s compare motion detection with human presence sensors and continuous recording to see how useful it is.

Compared with human presence sensors

Human presence sensors detect the temperature of people and animals using infrared or reflected ultrasound. Their disadvantages are that in hot seasons such as summer, the small difference between air temperature and body temperature makes people hard to detect, and that they also react to animals.

On the other hand, human presence sensors react to body heat, so there is no time lag as with motion detection. Used with sensor lights, they can be expected to help prevent crime.

Compared with continuous recording

As mentioned above, the difference between continuous recording and motion detection is the recording time. Where few people pass by, such as parking lots and factories, motion detection reduces recording time and is very effective. On the other hand, in busy places such as shopping streets, there is little difference between motion detection and continuous recording.

Summary

A security camera with motion detection, which helps prevent intrusions by suspicious persons, is convenient. However, which functions a camera needs depends on each user’s purpose and installation location. Budgets also matter, so consult an expert and buy only what you need.