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: Multi-Label Classification Model, Dimension Collapse, Classification Label Visualization, Background Color Visualization, Dynamic Crop, Clip Comparison, Segment Anything 2 Model, Absolute Static Crop, LMM For Classification, Image Blur, Roboflow Dataset Upload, CogVLM, Circle Visualization, OCR Model, Clip Comparison, Template Matching, SIFT Comparison, Multi-Label Classification Model, Path Deviation, OpenAI, Stitch OCR Detections, Detections Stitch, QR Code Detection, Pixel Color Count, Detections Stabilizer, Path Deviation, Line Counter, VLM as Classifier, Time in Zone, Model Comparison Visualization, Stitch Images, Bounding Box Visualization, Keypoint Detection Model, Moondream2, Continue If, Color Visualization, Slack Notification, LMM, Llama 3.2 Vision, Instance Segmentation Model, VLM as Detector, Time in Zone, Byte Tracker, Detections Filter, YOLO-World Model, Barcode Detection, Grid Visualization, SmolVLM2, Stability AI Inpainting, Cosine Similarity, Keypoint Detection Model, Dot Visualization, Google Gemini, Detections Merge, CLIP Embedding Model, Dynamic Zone, Size Measurement, Property Definition, Roboflow Custom Metadata, Data Aggregator, VLM as Classifier, Detections Classes Replacement, Gaze Detection, Object Detection Model, Corner Visualization, Roboflow Dataset Upload, Image Preprocessing, Image Slicer, Byte Tracker, Line Counter, Label Visualization, Bounding Rectangle, Identify Outliers, Single-Label Classification Model, First Non Empty Or Default, Webhook Sink, Cache Get, Mask Visualization, Delta Filter, Google Vision OCR, Twilio SMS Notification, Buffer, Detection Offset, Model Monitoring Inference Aggregator, Florence-2 Model, Stability AI Image Generation, Cache Set, Identify Changes, Crop Visualization, JSON Parser, VLM as Detector, Velocity, OpenAI, Dominant Color, Perspective Correction, SIFT Comparison, Relative Static Crop, Ellipse Visualization, Reference Path Visualization, Anthropic Claude, Blur Visualization, Pixelate Visualization, Email Notification, Expression, CSV Formatter, Keypoint Visualization, Camera Focus, Single-Label Classification Model, Qwen2.5-VL, Florence-2 Model, Detections Transformation, Image Convert Grayscale, Image Threshold, Trace Visualization, Detections Consensus, Polygon Visualization, Triangle Visualization, Environment Secrets Store, Halo Visualization, Polygon Zone Visualization, Local File Sink, Rate Limiter, Instance Segmentation Model, Camera Calibration, SIFT, Image Contours, Line Counter Visualization, Image Slicer, Byte Tracker, Distance Measurement, Object Detection Model
• 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"
}