Adaptive threshold (cv::adaptiveThreshold). The per-pixel threshold comes from the neighborhood mean (or Gaussian-weighted mean) minus a constant C — right for document scans and shadowed scenes with lighting gradients.

Module：OpenCV color & threshold · Task type：opencv_adaptive_threshold

Ports

Inputs

PortTypeRequired
inImage / cv::Mat✓

Outputs

PortTypeRequired
outcv::Mat✓

Parameters

参数类型默认值范围 / 选项说明
max_valuefloat255[0, 255]
block_sizeint11[3, 99]neighborhood edge length (positive odd)
Cfloat2[-50, 50]
adaptive_methodenum0MEAN_C / GAUSSIAN_C
threshold_typeenum0BINARY / BINARY_INV

Example graph

A minimal runnable pipeline (read → process → write). Drag it into GraphStudio or open via --open; replace data/test.png with a real path.

{
  "version": "2.0",
  "tasks": [
    {
      "id": "read",
      "type": "opencv_image_read",
      "params": {
        "file_path": "data/test.png"
      }
    },
    {
      "id": "node",
      "type": "opencv_adaptive_threshold",
      "params": {
        "max_value": 255,
        "block_size": 11,
        "C": 2,
        "adaptive_method": 0,
        "threshold_type": 0
      }
    },
    {
      "id": "save",
      "type": "opencv_image_write",
      "params": {
        "file_path": "out_out.png"
      }
    }
  ],
  "edges": [
    {
      "from": "read",
      "from_port": "out",
      "to": "node",
      "to_port": "in"
    },
    {
      "from": "node",
      "from_port": "out",
      "to": "save",
      "to_port": "in"
    }
  ]
}

Part of the GraphStudio node guide series; parameters reflect the latest release.