Object Detection
Upload an image and see how a pre-trained AI model detects objects using bounding boxes and confidence scores.
Upload an image
Choose an image for detection
Supported formats: .png, .jpg, .jpeg, .webp.
Preview
Image + overlay
Results
Detected objects
Confidence is the model’s estimate. Filtering helps you see how thresholds change what is shown.
Model status
Idle — Loading COCO-SSD model...
Confidence threshold: 50%
Lower threshold shows more detections (and more mistakes). Higher threshold shows fewer detections (usually more reliable).
Count
0
Confidence meaning
What does confidence mean?
A confidence score of 92% means the model strongly favours that label, but it does not guarantee correctness. Adjusting the threshold helps you see filtering trade-offs.
Step-by-step pipeline
How object detection works
Object detection finds what objects are present and where they are located.
Image input
You upload an image (kept local in the browser).
Resize / preprocess
The model expects images in a consistent format and size.
Model scans features
The neural network looks for learned visual patterns.
Predict object class
It predicts categories from the COCO dataset.
Generate bounding box
For each object, it estimates a rectangle location.
Assign confidence
Each prediction includes a confidence score.
Display detections
The UI draws boxes and shows the filtered results.
Detection table
Bounding box coordinates
COCO-SSD outputs \((x, y, width, height)\) boxes in image pixel coordinates.
| Object | Confidence | X | Y | Width | Height |
|---|---|---|---|---|---|
| No detections to display. | |||||
How the model makes predictions
Pre-trained visual patterns
The model has already been trained on many labelled images. It does not “understand” the image like a human.
It detects visual patterns learned during training and predicts object categories from the COCO dataset.
Each prediction includes a class label, a bounding box, and a confidence score.
Understanding the output
Labels, boxes, thresholds, and mistakes
Class label: the predicted object name.
Confidence score: how sure the model is.
Bounding box: the rectangle around the object.
Threshold: the minimum confidence needed to show a result.
False positive: when the model detects something incorrectly.
False negative: when the model misses an object.
Limitations and ethics
Use detection responsibly
- The model can make mistakes.
- It may perform worse on unusual images, poor lighting, occlusion, or objects outside its training dataset.
- Confidence is not the same as truth.
- Object detection should be used carefully in surveillance, identity-related, or high-stakes contexts.
- This demo is for learning, not clinical, forensic, or safety-critical decision-making.
Student learning outcomes
What you will learn
- Understand what object detection means.
- Understand the difference between classification and detection.
- Interpret confidence scores.
- Understand bounding boxes.
- Understand why AI models can make mistakes.
- Learn how pre-trained models can run in the browser.
Privacy note
This demo runs COCO-SSD in the browser and does not upload your image to a server.