Threshold Module Reference

Provides thresholding operations for image binarization and segmentation.

Threshold Types

pub enum ThresholdType {
    Binary,
    BinaryInv,
    Trunc,
    ToZero,
    ToZeroInv,
}

Type	Description
Binary	pixel > thresh ? maxval : 0
BinaryInv	pixel > thresh ? 0 : maxval
Trunc	pixel > thresh ? thresh : pixel
ToZero	pixel > thresh ? pixel : 0
ToZeroInv	pixel > thresh ? 0 : pixel

Adaptive Methods

pub enum AdaptiveMethod {
    MeanC,
    GaussianC,
}

Method	Description
MeanC	Mean of the blockSize x blockSize neighborhood.
GaussianC	Gaussian-weighted sum of the neighborhood.

Operations

impl<B: Backend> Image<B> {
    pub fn threshold(&self, thresh: f32, maxval: f32, thresh_type: ThresholdType) -> Result<Self>;
    pub fn threshold_otsu(&self, maxval: f32) -> Result<Self>;
    pub fn threshold_triangle(&self, maxval: f32) -> Result<Self>;
    pub fn adaptive_threshold(
        &self,
        maxval: f32,
        method: AdaptiveMethod,
        block_size: usize,
        c: f32,
    ) -> Result<Self>;
}

Example

use iris::prelude::*;
use burn::backend::wgpu::Wgpu;

type Backend = Wgpu;
let device = Default::default();
let img = Image::<Backend>::open("input.jpg", &device)?;

// Fixed binary threshold
let binary = img.threshold(0.5, 1.0, ThresholdType::Binary)?;

// Automatic Otsu threshold
let otsu = img.threshold_otsu(1.0)?;

// Triangle method
let triangle = img.threshold_triangle(1.0)?;

// Adaptive threshold
let adaptive = img.adaptive_threshold(1.0, AdaptiveMethod::MeanC, 11, 2.0)?;