Crate corrmatch 

CorrMatch is a CPU-first template matching library for grayscale images.

It provides a coarse-to-fine matcher with optional rotation search and two metrics: ZNCC and SSD. The primary entry points are Template, CompiledTemplate, and Matcher.

Quick start

use corrmatch::{
    CompileConfig, MatchConfig, Matcher, RotationMode, Template, ImageView,
};

let template = Template::new(tpl, tw, th)?;
let compiled = template.compile(CompileConfig::default())?;
let matcher = Matcher::new(compiled).with_config(MatchConfig {
    rotation: RotationMode::Enabled,
    ..MatchConfig::default()
});
let image_view = ImageView::from_slice(image, width, height)?;
matcher.match_image(image_view)

Concepts

• Template: owned template pixels.
• CompiledTemplate: precomputed template pyramid and (optionally) angle banks.
• Matcher: runs the coarse-to-fine search and returns the best match.
• CompiledTemplate::compile_unrotated: lightweight assets for translation-only matching.

Data model

• Images and templates are grayscale u8 buffers in row-major order.
• ImageView supports explicit row stride; results report top-left coordinates at level 0.
• Scores: ZNCC in roughly [-1, 1], SSD reported as negative SSE (higher is better).

Determinism

Matching is deterministic; enabling rayon via MatchConfig.parallel keeps results stable.

Feature flags

• rayon: parallel search execution.
• simd: SIMD-accelerated kernels (currently: unmasked translation-only path).
• image-io: file I/O helpers via the image crate.

Low-level API

Advanced building blocks are available under corrmatch::lowlevel.

CLI

A JSON-driven CLI lives in the corrmatch-cli workspace crate.

Modules

lowlevel

Low-level building blocks for custom matching pipelines.

Structs

CompileConfig

Configuration for compiling template assets with rotation support.

CompileConfigNoRot

Configuration for compiling template assets without rotation support.

ImagePyramid

Owned image pyramid built from a base level.

ImageView

Borrowed 2D image view with an explicit stride.

Match

Match result for the finest pyramid level.

MatchConfig

Configuration for the coarse-to-fine matcher pipeline.

Matcher

Matcher that runs coarse-to-fine search using a compiled template.

OwnedImage

Owned contiguous grayscale image buffer.

Template

Owned template image in contiguous grayscale format.

Enums

CompiledTemplate

Compiled template assets for rotated or unrotated matching.

CorrMatchError

Errors that can occur when running corrmatch operations.

Metric

Matching metric selector.

RotationMode

Controls whether rotation is searched.

Type Aliases

CorrMatchResult

Result alias for corrmatch operations.