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