Motion Detection Explained

Motion Detection

YI Home Camera can do many great things. Motion detection is a feature that many people rely on. When the camera detects movement (motion) in the front of the camera, the system will send a push notification to the user’s mobile phone, alerting the user that something has happened. In the meantime, the camera captures a picture, and 6s motion video to the cloud for safe record. User can look at view the alert picture and videos from the YI Home Camera alert tab. Those alerts (along with the pictures/videos) are stored in the cloud for 7 days and deleted automatically after that.

Motion detection algorithm

The camera determines that there are movements in the video, by comparing the adjacent video frames. If there are significant changed between those frames, a motion is detected.

Why 6s for the video length

This is a compromise for the alert notification delay. The longer we choose for the video, the longer the delay will be for the user to receive the notification. 6s seems a good compromise, that the alert won’t be delayed for long, while user can still see what happened.

Advanced motion detection features

More advanced motion detection features are available to different camera models, depending on the camera’s processing capabilities. Examples including, but not limited to: Detection Zone, motion sensitivity, human detection, baby crying detection.

Today, the detection zone feature, is only available to non-rotating cameras. The justification was, for rotating cameras, the viewing angle is moving around, thus the detection zone is not well defined.

Alert Reporting algorithm

One of frequently asked questions is, when does the camera reports a moving event?

Obviously, if the camera reports every movements detection, user will be notified too many times, thus consider it abusive. To avoid this, the system introduces two parameters to control when to report a motion.

The first parameter is called motion block grace period threshold.

Continuous movements are considered as a moving block. A moving block is counted as one reportable event. The system will only report once, for the whole block.

The window between the end time of the last moving block, and the start time of the next moving block, is the motion block grace period.

If the motion block grace period is longer than a pre-defined threshold, the new moving block is considered as report candidate.

The motion block grace period threshold, is set at 60s by default. It is configurable by the server.

The second parameter is called motion report minimum interval.

A report candidate will be reported, only if last report happened before the motion report minimum internal ago.

The internal is set to 10minutes by default and is configurable by the server.

Let’s use a few examples to illustrate the algorithms above.

Say, at 8:00:00am, the camera detected movement, and reported the event to the user. The movement stopped at 8:01:00am.

The second movement is detected at 8:01:30am and stopped at 8:02:00am.

The motion block grace period is 30s (between 8:01:00am and 8:01:30), which is less than the 60s threshold. This moving block is not considered as report candidate, thus will not be reported.

The third movement is detected at 8:05:00am, lasted for 30s. The grace period is 3minutes (8:02:00am to 8:05:00am), which is longer than 60s. This is a report candidate.

However, this event will not be reported. The last event report happened at 8:00:00am. This report candidate happened only 5 minutes later (8:00:00am to 8:05:00am), which is less than the 10 minutes internal.

The fourth movement is detected at 8:15:00am, lasted for 30s. This is a report candidate and will be reported.

12 thoughts on “Motion Detection Explained

  1. ➡️ Please suggest me that … How to download entire video clips from timeline ❓❓❓
    ➡️ Here in YI 720p camera give the permission to download only few second videos in mobile device which have been detected by motion detect feature but it wouldn’t be evidence of any serious incident.
    ➡️ Please improve your software feature and UI features which can be possible to download the entire video from timeline into mobile/ tab memory card.

  2. I get frequently reports of movements when I switch the camera on. It’s sometimes showing the right time and sometimes seem to refer to an alert from previous days. It also doesn’t record a movie even though it reports.
    Second issue I have after the recent updates is I have to go to settings screen twice to ‘refresh’ camera status. Especially visible when trying to switch the camera off. The first entry always shows camera as off even though I know it’s on. The second entry lets me switch it off. It’s a big, can you fix it please?

  3. I care for an alzheimer’s parent in my home. I need to review all of the alerts each day and night, but do not want them alerting and buzzing my phone constantly. The alerts are driving me crazy! I need it to record all alerts, but not beep my cell phone for each. How can this be,accomplished?

  4. Why i can’t play my video when it’s already save cause caught movement?
    What the problem?
    The problem comes from the camera or SD card?

  5. hello, it’s possible to implement in” human detection” features the possibility to see the dot-line around human body shapes? in this way we can see in real time if human detection function is working well or not. thanks

      1. Yes.customer service is very bad. product is good. in my dream it will be Open source and we can tune alone.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s