Delta Filter

Class: DeltaFilterBlockV1

Source: inference.core.workflows.core_steps.flow_control.delta_filter.v1.DeltaFilterBlockV1

The Delta Filter is a flow control block that triggers workflow steps only when an input value changes. It avoids redundant processing and optimizes system efficiency.

+----------------+      (value changes)       +----------------+
| Previous Value |  ----------------------->  |   Next Steps    |
+----------------+                           +----------------+

Key Features:

Change Detection: Tracks input values and only proceeds when a change is detected. Dynamic Value Support: Handles various input types (e.g., numbers, strings). Context-Aware Caching: Tracks changes on a per-video basis using video_identifier.

Usage Instructions: Input Configuration: Set "Input Value" to reference the value to monitor (e.g., counter). Next Steps Setup: Define steps to execute on value change.

Example Use Case:

A video analysis workflow counts people in the zone. When the count changes, Delta Filter triggers downstream steps (e.g., setting variable in OPC), minimizing redundant processing.

Type identifier

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

Properties

Name	Type	Description	Refs
name	str	Enter a unique identifier for this step..	❌

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 Delta Filter in version v1.

• inputs: Identify Changes, Relative Static Crop, Background Color Visualization, First Non Empty Or Default, Line Counter Visualization, Barcode Detection, Detections Stabilizer, Detections Transformation, Object Detection Model, Cache Set, Camera Focus, Color Visualization, Roboflow Dataset Upload, Expression, Detections Filter, SmolVLM2, CSV Formatter, Object Detection Model, Bounding Box Visualization, OCR Model, Rate Limiter, Path Deviation, JSON Parser, Clip Comparison, Identify Outliers, Model Comparison Visualization, Anthropic Claude, Corner Visualization, Line Counter, Multi-Label Classification Model, Qwen2.5-VL, QR Code Detection, Keypoint Visualization, Mask Visualization, Image Threshold, Florence-2 Model, VLM as Detector, Data Aggregator, Polygon Zone Visualization, Google Gemini, Bounding Rectangle, Image Preprocessing, Twilio SMS Notification, Roboflow Custom Metadata, Reference Path Visualization, Blur Visualization, Detections Classes Replacement, Image Contours, Keypoint Detection Model, Ellipse Visualization, Byte Tracker, Crop Visualization, Stitch Images, Line Counter, Stitch OCR Detections, LMM, Webhook Sink, Email Notification, Size Measurement, Dimension Collapse, Velocity, Image Blur, Image Convert Grayscale, Stability AI Inpainting, Triangle Visualization, Classification Label Visualization, Keypoint Detection Model, Path Deviation, Time in Zone, VLM as Classifier, Detections Merge, Local File Sink, OpenAI, Roboflow Dataset Upload, Grid Visualization, Gaze Detection, LMM For Classification, Llama 3.2 Vision, Instance Segmentation Model, Pixel Color Count, Label Visualization, YOLO-World Model, Environment Secrets Store, Moondream2, Dot Visualization, Byte Tracker, Overlap Filter, Detections Consensus, Template Matching, Single-Label Classification Model, Google Vision OCR, Dynamic Crop, Depth Estimation, SIFT Comparison, SIFT Comparison, Byte Tracker, Cosine Similarity, Camera Calibration, Detection Offset, Halo Visualization, Clip Comparison, Polygon Visualization, Instance Segmentation Model, SIFT, Dynamic Zone, CLIP Embedding Model, VLM as Detector, Pixelate Visualization, Dominant Color, Detections Stitch, Property Definition, OpenAI, CogVLM, Florence-2 Model, Image Slicer, Delta Filter, Perspective Correction, Cache Get, Multi-Label Classification Model, Stability AI Image Generation, Time in Zone, Model Monitoring Inference Aggregator, Distance Measurement, Trace Visualization, Single-Label Classification Model, Buffer, VLM as Classifier, Segment Anything 2 Model, Absolute Static Crop, Continue If, Circle Visualization, Slack Notification, Image Slicer
• outputs: None

Input and Output Bindings

The available connections depend on its binding kinds. Check what binding kinds Delta Filter in version v1 has.

Bindings

• input

  • image (image): not available.
  • value (*): Flow will be allowed to continue only if this value changes between frames..
  • next_steps (step): Steps to execute when the value changes..

• output

Example JSON definition of step Delta Filter in version v1

{
    "name": "<your_step_name_here>",
    "type": "roboflow_core/delta_filter@v1",
    "image": "<block_does_not_provide_example>",
    "value": "$steps.line_counter.count_in",
    "next_steps": "$steps.write_to_csv"
}