Fast implementation of connected-component labelling in Swift. Currently only 4-connectivity is supported.

In CcLabel, call the labelImageFast function to label your image. Optionally, the bounding boxes of the components can be computed by passing-in true for the calculateBoundingBoxes parameter.

NOTE: Before processing, the image must first be binarized (all pixels must be either black or white). To binarize an image using the GPUImage library:

class func binarizeImage(image: UIImage) -> UIImage {
    let start = NSDate()
    let stillImageFilter = GPUImageAdaptiveThresholdFilter()
    stillImageFilter.blurRadiusInPixels = 4.0
    let filteredImage = stillImageFilter.imageByFilteringImage(image)
    let end = NSDate();
    print("Binarized image in " + String(end.timeIntervalSinceDate(start)) + " seconds")
    return filteredImage
}

• Automated tests
• Better documentation
• Code tidy-up (break long methods up a bit)
• Performance results
• 8-connectivity

CCLabel is licensed under the Apache License, Version 2.0