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Filtering resulting data based on value delta change

Below you can find example workflows you can use as inspiration to build your apps.

Saving Workflow results into file, but only if value changes between frames

This Workflow was created to achieve few ends:

  • getting predictions from object detection model

  • filtering out predictions found outside of zone

  • counting detections in zone

  • if count of detection in zone changes save results to csv file

Run on video to produce meaningful results

This workflow will not work using the docs preview. You must run it on video file. Copy the template into your Roboflow app, start inference server and use video preview to get the results.

Workflow definition 
{
    "version": "1.0",
    "inputs": [
        {
            "type": "WorkflowImage",
            "name": "image"
        },
        {
            "type": "WorkflowParameter",
            "name": "target_directory"
        },
        {
            "type": "WorkflowParameter",
            "name": "model_id",
            "default_value": "yolov8n-640"
        }
    ],
    "steps": [
        {
            "type": "roboflow_core/roboflow_object_detection_model@v2",
            "name": "model",
            "images": "$inputs.image",
            "model_id": "$inputs.model_id"
        },
        {
            "type": "roboflow_core/detections_filter@v1",
            "name": "detections_filter",
            "predictions": "$steps.model.predictions",
            "operations": [
                {
                    "type": "DetectionsFilter",
                    "filter_operation": {
                        "type": "StatementGroup",
                        "operator": "and",
                        "statements": [
                            {
                                "type": "BinaryStatement",
                                "left_operand": {
                                    "type": "DynamicOperand",
                                    "operand_name": "_",
                                    "operations": [
                                        {
                                            "type": "ExtractDetectionProperty",
                                            "property_name": "center"
                                        }
                                    ]
                                },
                                "comparator": {
                                    "type": "(Detection) in zone"
                                },
                                "right_operand": {
                                    "type": "StaticOperand",
                                    "value": [
                                        [
                                            0,
                                            0
                                        ],
                                        [
                                            0,
                                            1000
                                        ],
                                        [
                                            1000,
                                            1000
                                        ],
                                        [
                                            1000,
                                            0
                                        ]
                                    ]
                                },
                                "negate": false
                            }
                        ]
                    }
                }
            ],
            "operations_parameters": {}
        },
        {
            "type": "roboflow_core/property_definition@v1",
            "name": "property_definition",
            "data": "$steps.detections_filter.predictions",
            "operations": [
                {
                    "type": "SequenceLength"
                }
            ]
        },
        {
            "type": "roboflow_core/delta_filter@v1",
            "name": "delta_filter",
            "value": "$steps.property_definition.output",
            "image": "$inputs.image",
            "next_steps": [
                "$steps.csv_formatter"
            ]
        },
        {
            "type": "roboflow_core/csv_formatter@v1",
            "name": "csv_formatter",
            "columns_data": {
                "Class Name": "$steps.detections_filter.predictions"
            },
            "columns_operations": {
                "Class Name": [
                    {
                        "type": "DetectionsPropertyExtract",
                        "property_name": "class_name"
                    }
                ]
            }
        },
        {
            "type": "roboflow_core/local_file_sink@v1",
            "name": "reports_sink",
            "content": "$steps.csv_formatter.csv_content",
            "file_type": "csv",
            "output_mode": "append_log",
            "target_directory": "$inputs.target_directory",
            "file_name_prefix": "csv_containing_changes"
        }
    ],
    "outputs": [
        {
            "type": "JsonField",
            "name": "csv",
            "coordinates_system": "own",
            "selector": "$steps.csv_formatter.csv_content"
        }
    ]
}