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