Mask Visualization¶
Class: MaskVisualizationBlockV1
Source: inference.core.workflows.core_steps.visualizations.mask.v1.MaskVisualizationBlockV1
Fill segmentation masks with semi-transparent color overlays, creating solid color fills that precisely follow the shape of detected objects from instance segmentation predictions.
How This Block Works¶
This block takes an image and instance segmentation predictions (with masks) and fills the mask regions with colored overlays. The block:
- Takes an image and instance segmentation predictions (with masks) as input
- Extracts segmentation masks for each detected object from the predictions
- Applies color styling to each mask based on the selected color palette, with colors assigned by class, index, or track ID
- Fills the mask regions with solid colors using Supervision's MaskAnnotator
- Blends the colored mask overlays with the original image using the specified opacity level
- Returns an annotated image where mask regions are filled with semi-transparent colors, while non-masked areas remain unchanged
The block fills the exact shape of each object's segmentation mask with colored overlays, creating solid color fills that precisely follow object boundaries. Unlike polygon visualization (which draws outlines) or bounding box visualizations (which use rectangular regions), mask visualization fills the entire mask area with color, providing clear visual indication of the segmented regions. The opacity parameter controls how transparent the mask overlay is, allowing you to see the original image details through the colored mask (lower opacity) or create more opaque fills (higher opacity) that better obscure background details. This block requires instance segmentation predictions with mask data, as it specifically works with segmentation masks to create precise, shape-following color fills.
Common Use Cases¶
- Instance Segmentation Visualization: Visualize instance segmentation results by filling mask regions with colors to clearly show segmented objects, validate segmentation quality, or highlight detected regions in analysis workflows
- Precise Shape-Following Overlays: Fill objects with colors that exactly match their segmented shapes, useful for applications requiring accurate region visualization such as medical imaging, quality control, or precise object identification
- Mask-Based Object Highlighting: Highlight segmented objects with colored overlays that follow exact object boundaries, providing clear visual distinction between different objects or object classes
- Segmentation Model Validation: Visualize segmentation predictions with colored mask fills to verify model performance, identify segmentation errors, or validate mask accuracy in model development and debugging workflows
- Medical and Scientific Imaging: Display segmented regions in medical imaging, microscopy, or scientific analysis applications where colored mask overlays help visualize tissue boundaries, cell regions, or measured areas
- Mask Quality Inspection: Use colored mask fills to inspect segmentation quality, verify mask boundaries, or identify areas where segmentation may need improvement in training data or model outputs
Connecting to Other Blocks¶
The annotated image from this block can be connected to:
- Other visualization blocks (e.g., Label Visualization, Polygon Visualization, Bounding Box Visualization) to combine mask fills with additional annotations (labels, outlines) for comprehensive visualization
- Data storage blocks (e.g., Local File Sink, CSV Formatter, Roboflow Dataset Upload) to save images with mask overlays for documentation, reporting, or analysis
- Webhook blocks to send visualized results with mask fills to external systems, APIs, or web applications for display in dashboards or monitoring tools
- Notification blocks (e.g., Email Notification, Slack Notification) to send annotated images with mask overlays as visual evidence in alerts or reports
- Video output blocks to create annotated video streams or recordings with mask fills for live monitoring, segmentation visualization, or post-processing analysis
Type identifier¶
Use the following identifier in step "type" field: roboflow_core/mask_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.. | ✅ |
color_palette |
str |
Select a color palette for the visualised elements.. | ✅ |
palette_size |
int |
Specify the number of colors in the palette. This applies when using custom or Matplotlib palettes.. | ✅ |
custom_colors |
List[str] |
Define a list of custom colors for bounding boxes in HEX format.. | ✅ |
color_axis |
str |
Choose how bounding box colors are assigned.. | ✅ |
opacity |
float |
Opacity of the mask overlay, ranging from 0.0 (fully transparent) to 1.0 (fully opaque). Controls the transparency of the colored mask fill. Lower values (e.g., 0.3-0.5) create semi-transparent overlays that allow original image details to show through, while higher values (e.g., 0.7-1.0) create more opaque fills that better obscure background details. Typical values range from 0.4 to 0.7 for balanced visualization where both the mask and underlying image are visible.. | ✅ |
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 Mask Visualization in version v1.
- inputs:
Keypoint Visualization,Twilio SMS/MMS Notification,OPC UA Writer Sink,Qwen 3.6 API,SIFT Comparison,Grid Visualization,SAM 3,PLC Writer,Llama 3.2 Vision,JSON Parser,Absolute Static Crop,Distance Measurement,Roboflow Visual Search Classifier,Velocity,Image Threshold,Polygon Zone Visualization,CogVLM,BoT-SORT Tracker,MQTT Writer,Contrast Equalization,Google Gemini,Detections List Roll-Up,OCR Model,GLM-OCR,Background Subtraction,Contrast Enhancement,Reference Path Visualization,Twilio SMS Notification,Mask Edge Snap,Instance Segmentation Model,Google Gemma API,PTZ Tracking (ONVIF),Detections Filter,Detections Classes Replacement,VLM As Detector,Florence-2 Model,Dynamic Crop,Halo Visualization,Image Blur,SAM 3 Interactive,LMM,Seg Preview,SAM 3,Ellipse Visualization,OpenAI,Florence-2 Model,Line Counter,LMM For Classification,Time in Zone,Semantic Segmentation Model,Instance Segmentation Model,Event Writer,Path Deviation,OpenAI,Time in Zone,Keypoint Detection Model,Google Gemma,Buffer,Slack Notification,Heatmap Visualization,SORT Tracker,Semantic Segmentation Model,Email Notification,Circle Visualization,Perspective Correction,Camera Focus,Crop Visualization,Polygon Visualization,Detections Consensus,Line Counter,ByteTrack Tracker,Multi-Label Classification Model,Detections Combine,Stability AI Inpainting,OpenAI-Compatible LLM,SAM 3,VLM As Classifier,Object Detection Model,PLC ModbusTCP,Image Slicer,Google Gemini,Roboflow Vision Events,Detections Transformation,Size Measurement,Local File Sink,SAM3 Video Tracker,Dot Visualization,Line Counter Visualization,Time in Zone,Instance Segmentation Model,Depth Estimation,Stitch OCR Detections,PP-OCR,Blur Visualization,EasyOCR,Clip Comparison,Anthropic Claude,PLC EthernetIP,Segment Anything 2 Model,CSV Formatter,Color Visualization,Per-Class Confidence Filter,Dynamic Zone,Image Convert Grayscale,Motion Detection,Stitch OCR Detections,Single-Label Classification Model,Qwen 3.5 API,Trace Visualization,Icon Visualization,Current Time,PLC Reader,Model Comparison Visualization,Camera Focus,QR Code Generator,Google Gemini,Detections Stitch,Image Stack,Instance Segmentation Model,Qwen-VL,Mask Visualization,MoonshotAI Kimi,Microsoft SQL Server Sink,Text Display,Stability AI Image Generation,Google Vision OCR,Webhook Sink,OpenAI,VLM As Detector,Identify Outliers,Pixelate Visualization,Stitch Images,Detection Offset,S3 Sink,Classification Label Visualization,MoonshotAI Kimi,Polygon Visualization,Anthropic Claude,Dimension Collapse,Roboflow Dataset Upload,Morphological Transformation,Detection Event Log,Bounding Box Visualization,Template Matching,VLM As Classifier,Image Contours,Image Slicer,Stability AI Outpainting,Anthropic Claude,Roboflow Custom Metadata,SAM2 Video Tracker,Camera Calibration,Roboflow Asset Library Attributes,Morphological Transformation,Detections Stabilizer,Path Deviation,Relative Static Crop,Mask Area Measurement,Background Color Visualization,Model Monitoring Inference Aggregator,Clip Comparison,Corner Visualization,GeoTag Detection,SIFT,Track Class Lock,Roboflow Visual Search,OpenRouter,Identify Changes,Bounding Rectangle,Llama 3.2 Vision,Qwen3.5-VL,Email Notification,Triangle Visualization,OpenAI,Roboflow Dataset Upload,OC-SORT Tracker,Pixel Color Count,Image Preprocessing,SIFT Comparison,Halo Visualization,Label Visualization - outputs:
Keypoint Visualization,Twilio SMS/MMS Notification,Keypoint Detection Model,Perception Encoder Embedding Model,Qwen 3.6 API,Object Detection Model,SAM 3,Llama 3.2 Vision,Absolute Static Crop,Roboflow Visual Search Classifier,Image Threshold,Polygon Zone Visualization,CogVLM,BoT-SORT Tracker,Contrast Equalization,Google Gemini,OCR Model,GLM-OCR,Background Subtraction,Contrast Enhancement,Reference Path Visualization,Google Gemma API,Instance Segmentation Model,Mask Edge Snap,VLM As Detector,Florence-2 Model,Halo Visualization,Dynamic Crop,SAM 3 Interactive,LMM,Image Blur,Seg Preview,SAM 3,Ellipse Visualization,OpenAI,Florence-2 Model,LMM For Classification,Time in Zone,Semantic Segmentation Model,Instance Segmentation Model,OpenAI,Event Writer,Single-Label Classification Model,Google Gemma,Keypoint Detection Model,Buffer,Heatmap Visualization,Semantic Segmentation Model,SORT Tracker,Email Notification,Circle Visualization,Perspective Correction,Camera Focus,Byte Tracker,Crop Visualization,Keypoint Detection Model,Polygon Visualization,ByteTrack Tracker,Multi-Label Classification Model,Stability AI Inpainting,SAM 3,Object Detection Model,VLM As Classifier,Google Gemini,Image Slicer,Roboflow Vision Events,Multi-Label Classification Model,Qwen3.5,Object Detection Model,SAM3 Video Tracker,Dot Visualization,QR Code Detection,Line Counter Visualization,Instance Segmentation Model,Depth Estimation,PP-OCR,Blur Visualization,EasyOCR,Clip Comparison,Anthropic Claude,Segment Anything 2 Model,Color Visualization,Qwen2.5-VL,Qwen3-VL,Image Convert Grayscale,Motion Detection,Single-Label Classification Model,Qwen 3.5 API,Trace Visualization,Icon Visualization,Model Comparison Visualization,Camera Focus,Google Gemini,Detections Stitch,Image Stack,Instance Segmentation Model,Qwen-VL,Mask Visualization,MoonshotAI Kimi,Text Display,Gaze Detection,Stability AI Image Generation,Google Vision OCR,OpenAI,VLM As Detector,Pixelate Visualization,Stitch Images,Classification Label Visualization,MoonshotAI Kimi,Polygon Visualization,Anthropic Claude,Roboflow Dataset Upload,Morphological Transformation,Bounding Box Visualization,SmolVLM2,Template Matching,VLM As Classifier,Image Contours,Image Slicer,Stability AI Outpainting,Anthropic Claude,Multi-Label Classification Model,SAM2 Video Tracker,Barcode Detection,Camera Calibration,Morphological Transformation,Detections Stabilizer,Relative Static Crop,Background Color Visualization,Clip Comparison,GeoTag Detection,Corner Visualization,SIFT,Track Class Lock,Dominant Color,Moondream2,Roboflow Visual Search,OpenRouter,Qwen3.5-VL,Llama 3.2 Vision,CLIP Embedding Model,Single-Label Classification Model,Triangle Visualization,OpenAI,Pixel Color Count,OC-SORT Tracker,Roboflow Dataset Upload,Image Preprocessing,SIFT Comparison,YOLO-World Model,Halo Visualization,Label Visualization
Input and Output Bindings¶
The available connections depend on its binding kinds. Check what binding kinds
Mask 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[semantic_segmentation_prediction,rle_instance_segmentation_prediction,instance_segmentation_prediction]): Segmentation predictions containing masks for detected objects. The block uses segmentation masks to create colored fills that precisely follow object or class boundaries. Requires segmentation model outputs with mask data, which may be RLE-encoded..color_palette(string): Select a color palette for the visualised elements..palette_size(integer): Specify the number of colors in the palette. This applies when using custom or Matplotlib palettes..custom_colors(list_of_values): Define a list of custom colors for bounding boxes in HEX format..color_axis(string): Choose how bounding box colors are assigned..opacity(float_zero_to_one): Opacity of the mask overlay, ranging from 0.0 (fully transparent) to 1.0 (fully opaque). Controls the transparency of the colored mask fill. Lower values (e.g., 0.3-0.5) create semi-transparent overlays that allow original image details to show through, while higher values (e.g., 0.7-1.0) create more opaque fills that better obscure background details. Typical values range from 0.4 to 0.7 for balanced visualization where both the mask and underlying image are visible..
-
output
image(image): Image in workflows.
Example JSON definition of step Mask Visualization in version v1
{
"name": "<your_step_name_here>",
"type": "roboflow_core/mask_visualization@v1",
"image": "$inputs.image",
"copy_image": true,
"predictions": "$steps.instance_segmentation_model.predictions",
"color_palette": "DEFAULT",
"palette_size": 10,
"custom_colors": [
"#FF0000",
"#00FF00",
"#0000FF"
],
"color_axis": "CLASS",
"opacity": 0.5
}