Understanding How Mobotix Person Detection Works
Mobotix cameras are equipped with powerful, intelligent video analytics that can distinguish between general motion and specific objects, such as people. However, if you're being inundated with false alerts, it can quickly become frustrating and undermine your trust in the system. This guide will help you understand why your person detection might be inaccurate and how to fine-tune the settings for reliable, precise alerts.
The Difference Between Motion Detection and AI Analytics
It's important to understand the two main types of detection:
- Pixel-Based Motion Detection (VMD): This is the traditional method. The camera simply looks for changes in pixels from one frame to the next. It's effective but can be easily fooled by anything that moves, such as shadows, rain, insects, or swaying trees.
- Object-Based Analytics (AI): This is a more advanced method. The camera's processor has been trained to recognise the specific shapes, sizes, and movement patterns of people. It actively analyses the scene to identify human figures. While much more accurate, it still requires proper calibration to work effectively. Mobotix's ActivitySensor is an advanced form of this, designed to filter out irrelevant motion.
Common Reasons for Incorrect Person Detection
If you're getting too many false alerts or the camera is missing people, it's likely due to one of these common issues.
Environmental Factors
The camera's surroundings play a huge role in its accuracy.
- Busy Backgrounds: Trees, bushes, and flags that move in the wind are a primary source of false alerts.
- Lighting Changes: Fast-moving shadows from clouds or flashing car headlights can be misinterpreted as motion.
- Camera Position: If a person is too far away and appears too small in the frame, the camera may not have enough detail to identify them correctly.
Incorrect Configuration
The default settings are rarely perfect for every scene.
- Detection Area is Too Broad: Monitoring an entire scene, including a busy street or a neighbour's garden, will inevitably lead to unwanted alerts.
- Sensitivity is Too High: A sensitivity level set to maximum will cause the camera to flag even very small or distant movements as potential events.
- Object Size is Not Defined: Failing to tell the camera the minimum and maximum size of a person in the frame can lead to it misidentifying other objects.
How to Calibrate and Improve Mobotix Person Detection
Follow these steps within your Mobotix camera's web interface to dramatically reduce false positives.
Step 1: Defining the Correct Detection Area (Masking)
This is the most critical step. You need to tell the camera exactly where to look.
- Navigate to the Event Settings or Video Analytics section.
- Create a new detection window or polygon.
- Carefully draw the zone to cover only the areas you are interested in, such as your walkway, garden, or doorway.
- Crucially, exclude areas with known sources of false motion. Do not include the public pavement, the road, or the large tree that sways in the wind.
Step 2: Adjusting Sensitivity and Object Size Parameters
Fine-tune how the camera interprets motion within your defined zone.
- Sensitivity: Start with a medium sensitivity setting. If you are still getting false alerts, lower it. If it's missing real events, increase it slightly.
- Object Size: Many analytics platforms allow you to draw a box representing the smallest and largest a person will appear in the detection zone. This helps the camera ignore things like cats or passing cars.
Step 3: Using ActivitySensor to Reduce False Positives
Mobotix's ActivitySensor is specifically designed to combat environmental false alarms.
- In the event logic settings, choose ActivitySensor as your trigger instead of standard VMD.
- Configure the ActivitySensor by telling it the direction of travel you're interested in. For example, you can set it to only trigger if an object moves towards your door, ignoring people just walking past.
- Adjust the ActivitySensor's sensitivity independently to find the right balance for your scene.
By taking the time to properly calibrate the detection zones, sensitivity, and advanced features like ActivitySensor, you can transform your Mobotix camera from a source of annoying notifications into a highly accurate and reliable security tool.