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:
PLC Writer,Image Blur,Track Class Lock,Mask Edge Snap,Path Deviation,Crop Visualization,VLM As Detector,Polygon Visualization,Roboflow Visual Search Classifier,Detections Stabilizer,Image Slicer,Qwen3.5-VL,Image Convert Grayscale,Webhook Sink,Semantic Segmentation Model,VLM As Classifier,Motion Detection,SAM 3 Interactive,Clip Comparison,Buffer,SIFT,OC-SORT Tracker,Slack Notification,Label Visualization,MoonshotAI Kimi,PLC Reader,Stitch OCR Detections,Label Visualization,Instance Segmentation Model,S3 Sink,Email Notification,Velocity,BoT-SORT Tracker,Detection Event Log,Pixel Color Count,Background Subtraction,Ellipse Visualization,Stitch Images,OPC UA Writer Sink,Path Deviation,Corner Visualization,CSV Formatter,Triangle Visualization,Detection Offset,Qwen-VL,JSON Parser,Bounding Rectangle,Distance Measurement,Camera Calibration,Seg Preview,Google Gemini,Polygon Zone Visualization,Roboflow Custom Metadata,LMM For Classification,Camera Focus,PP-OCR,SIFT Comparison,Trace Visualization,Color Visualization,Local File Sink,Llama 3.2 Vision,SAM3 Video Tracker,Llama 3.2 Vision,Morphological Transformation,Dynamic Zone,SAM2 Video Tracker,Google Vision OCR,Google Gemma API,Detections Filter,Google Gemma,Microsoft SQL Server Sink,Polygon Visualization,Icon Visualization,PLC ModbusTCP,Detections Transformation,Rich Label Visualization,Identify Changes,Twilio SMS/MMS Notification,Keypoint Visualization,Image Slicer,OpenAI,Clip Comparison,OpenAI,Keypoint Detection Model,Object Detection Model,Qwen 3.6 API,Instance Segmentation Model,Single-Label Classification Model,Mask Visualization,Nearest Neighbor Detection Match,OpenAI,OpenAI-Compatible LLM,Instance Segmentation Model,Roboflow Visual Search,VLM As Detector,Stability AI Outpainting,Blur Visualization,Frame Delay,Bounding Box Visualization,Absolute Static Crop,Roboflow Dataset Upload,Reference Path Visualization,OpenAI,Anthropic Claude,Google Gemini,Detections Stitch,Event Writer,Stitch OCR Detections,CogVLM,Time in Zone,VLM As Classifier,Email Notification,Contrast Enhancement,Current Time,Template Matching,Mask Area Measurement,Perspective Correction,Detections List Roll-Up,Halo Visualization,Semantic Segmentation Model,Dimension Collapse,Multi-Label Classification Model,Dynamic Crop,OpenRouter,Detections Consensus,PLC EthernetIP,OCR Model,GeoTag Detection,Per-Class Confidence Filter,Halo Visualization,Line Counter Visualization,Time in Zone,Time in Zone,Roboflow Asset Library Attributes,Size Measurement,LMM,Relative Static Crop,Depth Estimation,SIFT Comparison,Detections Combine,SAM 3,Dot Visualization,ByteTrack Tracker,GLM-OCR,Florence-2 Model,EasyOCR,Background Color Visualization,Google Gemini,Image Contours,Roboflow Dataset Upload,Segment Anything 2 Model,Qwen 3.5 API,MoonshotAI Kimi,Stability AI Inpainting,Contrast Equalization,Morphological Transformation,Image Threshold,Camera Focus,SAM 3,Line Counter,Stability AI Image Generation,Instance Segmentation Model,Circle Visualization,QR Code Generator,Google Gemini,Detections Classes Replacement,Model Monitoring Inference Aggregator,Roboflow Vision Events,Heatmap Visualization,Twilio SMS Notification,Auto Rotate on Edges,Cosmos 3,MQTT Writer,SAM 3,Anthropic Claude,SORT Tracker,Image Preprocessing,Line Counter,Anthropic Claude,Text Display,Image Stack,Grid Visualization,Model Comparison Visualization,PTZ Tracking (ONVIF),Identify Outliers,Florence-2 Model,Classification Label Visualization,Pixelate Visualization - outputs:
Image Blur,Track Class Lock,Mask Edge Snap,Crop Visualization,VLM As Detector,Object Detection Model,Polygon Visualization,Roboflow Visual Search Classifier,Detections Stabilizer,Image Slicer,Qwen3.5-VL,Image Convert Grayscale,CLIP Embedding Model,Semantic Segmentation Model,VLM As Classifier,Motion Detection,SAM 3 Interactive,Keypoint Detection Model,Clip Comparison,YOLO-World Model,Buffer,SIFT,OC-SORT Tracker,Label Visualization,MoonshotAI Kimi,Label Visualization,Instance Segmentation Model,Perception Encoder Embedding Model,Email Notification,Keypoint Detection Model,BoT-SORT Tracker,Pixel Color Count,Single-Label Classification Model,Background Subtraction,Ellipse Visualization,Stitch Images,Corner Visualization,Triangle Visualization,Qwen-VL,Camera Calibration,Seg Preview,Google Gemini,Polygon Zone Visualization,LMM For Classification,Camera Focus,PP-OCR,SIFT Comparison,Trace Visualization,Object Detection Model,Color Visualization,Llama 3.2 Vision,Llama 3.2 Vision,SAM3 Video Tracker,Dominant Color,Morphological Transformation,SAM2 Video Tracker,Google Vision OCR,Google Gemma API,Google Gemma,Polygon Visualization,Icon Visualization,Rich Label Visualization,Qwen2.5-VL,Twilio SMS/MMS Notification,Keypoint Visualization,OpenAI,Image Slicer,OpenAI,Keypoint Detection Model,Clip Comparison,Object Detection Model,Qwen 3.6 API,Instance Segmentation Model,Single-Label Classification Model,Mask Visualization,Moondream2,OpenAI,Byte Tracker,Instance Segmentation Model,Roboflow Visual Search,VLM As Detector,Stability AI Outpainting,Blur Visualization,Multi-Label Classification Model,Frame Delay,Bounding Box Visualization,Absolute Static Crop,Roboflow Dataset Upload,OpenAI,Anthropic Claude,Reference Path Visualization,Google Gemini,Detections Stitch,Event Writer,CogVLM,VLM As Classifier,Barcode Detection,Contrast Enhancement,Template Matching,QR Code Detection,Perspective Correction,Semantic Segmentation Model,Halo Visualization,Multi-Label Classification Model,Dynamic Crop,OpenRouter,OCR Model,GeoTag Detection,Halo Visualization,Line Counter Visualization,Time in Zone,Multi-Label Classification Model,LMM,Relative Static Crop,Depth Estimation,SAM 3,ByteTrack Tracker,Dot Visualization,GLM-OCR,Florence-2 Model,EasyOCR,Background Color Visualization,Qwen3.5,Google Gemini,Image Contours,Roboflow Dataset Upload,MoonshotAI Kimi,Segment Anything 2 Model,Qwen 3.5 API,Stability AI Inpainting,Contrast Equalization,Morphological Transformation,Image Threshold,Camera Focus,SAM 3,Stability AI Image Generation,Instance Segmentation Model,Circle Visualization,Google Gemini,Roboflow Vision Events,Single-Label Classification Model,Heatmap Visualization,Cosmos 3,Auto Rotate on Edges,SAM 3,Anthropic Claude,SORT Tracker,Image Preprocessing,Qwen3-VL,Gaze Detection,Anthropic Claude,Text Display,Image Stack,Grid Visualization,Model Comparison Visualization,Florence-2 Model,Classification Label Visualization,SmolVLM2,Pixelate 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[instance_segmentation_prediction,rle_instance_segmentation_prediction,semantic_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
}