Heatmap Visualization

Class: HeatmapVisualizationBlockV1

Source: inference.core.workflows.core_steps.visualizations.heatmap.v1.HeatmapVisualizationBlockV1

Draw heatmaps on an image based on provided detections. Heat accumulates over time and is drawn as a semi-transparent overlay of blurred circles.

How This Block Works

This block takes an image and detection predictions and draws a heatmap. The block:

1. Takes an image and predictions as input.
2. Accumulates heat based on the position of detections.
3. Draws a semi-transparent overlay of blurred circles representing the heat.

Common Use Cases

• Density Analysis: Visualize the density of objects in a scene.
• Traffic Monitoring: Identify high-traffic areas.
• Retail Analytics: Analyze foot traffic in stores.

Type identifier

Use the following identifier in step "type" field: roboflow_core/heatmap_visualization@v1to add the block as as step in your workflow.

Properties

Name	Type	Description	Refs
name	str	Enter a unique identifier for this step..	❌
copy_image	bool	Enable this option to create a copy of the input image for visualization, preserving the original. Use this when stacking multiple visualizations..	✅
position	str	The position of the heatmap relative to the detection..	✅
opacity	float	Opacity of the overlay mask, between 0 and 1..	✅
radius	int	Radius of the heat circle..	✅
kernel_size	int	Kernel size for blurring the heatmap..	✅
top_hue	int	Hue at the top of the heatmap. Defaults to 0 (red)..	✅
low_hue	int	Hue at the bottom of the heatmap. Defaults to 125 (blue)..	✅
ignore_stationary	bool	If True, only moving objects (based on tracker ID) will contribute to the heatmap..	✅
motion_threshold	int	Minimum movement in pixels required to consider an object as moving..	✅

The Refs column marks possibility to parametrise the property with dynamic values available in workflow runtime. See Bindings for more info.

Available Connections

Compatible Blocks

Check what blocks you can connect to Heatmap Visualization in version v1.

• inputs: Triangle Visualization, Detections Stitch, Ellipse Visualization, Detections Classes Replacement, Florence-2 Model, Blur Visualization, Anthropic Claude, Google Gemini, Motion Detection, Keypoint Visualization, Pixelate Visualization, Image Slicer, SIFT Comparison, Line Counter, Keypoint Detection Model, Dynamic Zone, Distance Measurement, SAM 3, Image Slicer, EasyOCR, CSV Formatter, Object Detection Model, Anthropic Claude, Detections Combine, Google Gemini, Pixel Color Count, Background Color Visualization, Image Convert Grayscale, Camera Calibration, Time in Zone, Image Preprocessing, Byte Tracker, VLM As Detector, PTZ Tracking (ONVIF).md), Detections Transformation, SIFT, Stability AI Outpainting, Moondream2, Stitch OCR Detections, Detection Offset, Trace Visualization, OpenAI, YOLO-World Model, Icon Visualization, Dot Visualization, Time in Zone, Email Notification, Instance Segmentation Model, Path Deviation, Camera Focus, Contrast Equalization, Segment Anything 2 Model, Text Display, Detections Filter, Reference Path Visualization, Image Threshold, Perspective Correction, Image Contours, Multi-Label Classification Model, Detection Event Log, Local File Sink, Identify Changes, Byte Tracker, Google Vision OCR, Crop Visualization, Detections List Roll-Up, Google Gemini, Webhook Sink, Classification Label Visualization, VLM As Classifier, Seg Preview, OpenAI, Gaze Detection, Stability AI Image Generation, Roboflow Dataset Upload, Morphological Transformation, LMM, Halo Visualization, Camera Focus, Llama 3.2 Vision, Model Comparison Visualization, VLM As Detector, Stitch OCR Detections, Roboflow Dataset Upload, Line Counter Visualization, Label Visualization, SIFT Comparison, QR Code Generator, Email Notification, Slack Notification, Detections Stabilizer, Object Detection Model, Path Deviation, Corner Visualization, Florence-2 Model, SAM 3, OpenAI, Bounding Box Visualization, Keypoint Detection Model, Anthropic Claude, Background Subtraction, Polygon Visualization, Image Blur, VLM As Classifier, Relative Static Crop, Clip Comparison, Detections Merge, Heatmap Visualization, CogVLM, Mask Visualization, Twilio SMS Notification, Instance Segmentation Model, OpenAI, OCR Model, Stitch Images, Dynamic Crop, Model Monitoring Inference Aggregator, Circle Visualization, Byte Tracker, Color Visualization, Cosine Similarity, Velocity, Twilio SMS/MMS Notification, Depth Estimation, Roboflow Custom Metadata, LMM For Classification, Bounding Rectangle, Grid Visualization, Polygon Zone Visualization, Polygon Visualization, Halo Visualization, JSON Parser, SAM 3, Stability AI Inpainting, Time in Zone, Identify Outliers, Detections Consensus, Template Matching, Overlap Filter, Absolute Static Crop, Single-Label Classification Model, Line Counter
• outputs: Triangle Visualization, Detections Stitch, Roboflow Dataset Upload, Ellipse Visualization, Morphological Transformation, LMM, Florence-2 Model, Blur Visualization, CLIP Embedding Model, Anthropic Claude, Halo Visualization, Google Gemini, Camera Focus, Llama 3.2 Vision, Motion Detection, Model Comparison Visualization, VLM As Detector, Keypoint Visualization, Qwen3-VL, Pixelate Visualization, Image Slicer, Roboflow Dataset Upload, Line Counter Visualization, Keypoint Detection Model, SmolVLM2, Label Visualization, SIFT Comparison, Clip Comparison, Buffer, SAM 3, Detections Stabilizer, Object Detection Model, EasyOCR, Image Slicer, Corner Visualization, Florence-2 Model, Object Detection Model, SAM 3, QR Code Detection, Anthropic Claude, OpenAI, Google Gemini, Perception Encoder Embedding Model, Bounding Box Visualization, Keypoint Detection Model, Anthropic Claude, Pixel Color Count, Background Subtraction, Background Color Visualization, Image Convert Grayscale, Camera Calibration, Polygon Visualization, Image Blur, VLM As Classifier, Relative Static Crop, Clip Comparison, Heatmap Visualization, CogVLM, Mask Visualization, Image Preprocessing, VLM As Detector, Instance Segmentation Model, OpenAI, OCR Model, SIFT, Stitch Images, Single-Label Classification Model, Moondream2, Stability AI Outpainting, Dynamic Crop, Circle Visualization, Byte Tracker, OpenAI, Trace Visualization, Color Visualization, Qwen2.5-VL, Icon Visualization, YOLO-World Model, Dot Visualization, Time in Zone, Email Notification, Instance Segmentation Model, Camera Focus, Twilio SMS/MMS Notification, Contrast Equalization, Depth Estimation, Segment Anything 2 Model, LMM For Classification, Text Display, Dominant Color, Reference Path Visualization, Image Threshold, Perspective Correction, Multi-Label Classification Model, Image Contours, Polygon Zone Visualization, Polygon Visualization, Halo Visualization, Google Vision OCR, SAM 3, Stability AI Inpainting, Crop Visualization, Template Matching, Google Gemini, Barcode Detection, VLM As Classifier, Classification Label Visualization, Seg Preview, OpenAI, Absolute Static Crop, Multi-Label Classification Model, Single-Label Classification Model, Gaze Detection, Stability AI Image Generation

Input and Output Bindings

The available connections depend on its binding kinds. Check what binding kinds Heatmap Visualization in version v1 has.

Bindings

• input

  • image (image): The image to visualize on..
  • copy_image (boolean): Enable this option to create a copy of the input image for visualization, preserving the original. Use this when stacking multiple visualizations..
  • predictions (Union[object_detection_prediction, instance_segmentation_prediction, keypoint_detection_prediction, rle_instance_segmentation_prediction]): Model predictions to visualize..
  • metadata (video_metadata): Video metadata containing video_identifier to maintain separate state for different videos..
  • position (string): The position of the heatmap relative to the detection..
  • opacity (float): Opacity of the overlay mask, between 0 and 1..
  • radius (integer): Radius of the heat circle..
  • kernel_size (integer): Kernel size for blurring the heatmap..
  • top_hue (integer): Hue at the top of the heatmap. Defaults to 0 (red)..
  • low_hue (integer): Hue at the bottom of the heatmap. Defaults to 125 (blue)..
  • ignore_stationary (boolean): If True, only moving objects (based on tracker ID) will contribute to the heatmap..
  • motion_threshold (integer): Minimum movement in pixels required to consider an object as moving..

• output

  • image (image): Image in workflows.

Example JSON definition of step Heatmap Visualization in version v1

{
    "name": "<your_step_name_here>",
    "type": "roboflow_core/heatmap_visualization@v1",
    "image": "$inputs.image",
    "copy_image": true,
    "predictions": "$steps.object_detection_model.predictions",
    "metadata": "$inputs.video_metadata",
    "position": "BOTTOM_CENTER",
    "opacity": 0.2,
    "radius": 40,
    "kernel_size": 25,
    "top_hue": 0,
    "low_hue": 125,
    "ignore_stationary": true,
    "motion_threshold": 25
}