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