locateimage (Go)

Performs an (exact or fuzzy) search of a sample image within a larger image, returning the coordinates and similarity scores of the matches.

Installation

This package contains a Go module, so in Go 1.11+ module mode you can import it directly. Otherwise do:

go get -u github.com/andreyvit/locateimage

Example

See godoc.org/github.com/andreyvit/locateimage for a full reference.

All locates all matches:

mm, err := locateimage.All(context.Background(), canvas, sample, 0.04)
if err != nil {
    log.Fatal(err)
}
log.Print(mm)

Find locates a single match:

m, err := locateimage.Find(context.Background(), canvas, sample, 0, locateimage.Fastest)
if err != nil {
    log.Print(err)
} else {
    log.Printf("sample found at %v, similarity = %.*f%%", m.Rect, locateimage.SimilarityDigits-2, 100*m.Similarity)
}

Find returns ErrNotFound if no match is found. Available selection modes are Fastest, Best and Only.

Foreach invokes a callback for each match:

err = locateimage.Foreach(context.Background(), canvas, sample, 0.04, func(m locateimage.Match) error {
    log.Print(m)
    return nil
})
if err != nil {
    log.Fatal(err)
}

Caveats

The package currently only deals with image.RGBA-encoded images. You can use Convert to convert any image to this format. (Note that reading a PNG file returns an NRGBA format, so the conversion will be required. It makes sense to add support for formats like NRGBA in the future.)

The search is currently slow, taking tens or hundreds of milliseconds on large images (screenshots of a 27" screen). This can likely be improved, and contributions are welcome.

Versions

None currently.