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