image-js/lib/morphology/bottomHat.js

Image processing and manipulation in JavaScript

import { Image } from '../Image.js';
import { subtract } from '../compare/index.js';
import { checkKernel } from '../utils/validators/checkKernel.js';
import checkProcessable from '../utils/validators/checkProcessable.js';
/**
 * This function is the black top hat (also called bottom hat).
 * In mathematical morphology and digital image processing,
 * top-hat transform is an operation that extracts small elements and details from given images.
 * The black top-hat transform is defined dually as the difference between the closed and the input image.
 * Top-hat transforms are used for various image processing tasks, such as feature extraction, background equalization,
 * image enhancement, and others. (Wikipedia)
 * @see {@link http://docs.opencv.org/2.4/doc/tutorials/imgproc/opening_closing_hats/opening_closing_hats.html}
 * @param image - Image to process.
 * @param options - Bottom hat options.
 * @returns The bottom-hatted image.
 */
export function bottomHat(image, options = {}) {
    const { kernel = [
        [1, 1, 1],
        [1, 1, 1],
        [1, 1, 1],
    ], iterations = 1, } = options;
    if (image instanceof Image) {
        checkProcessable(image, {
            bitDepth: [1, 8, 16],
            components: 1,
            alpha: false,
        });
    }
    checkKernel(kernel);
    let newImage = image;
    for (let i = 0; i < iterations; i++) {
        const openImage = newImage.close({ kernel });
        newImage = subtract(openImage, newImage, { absolute: true });
    }
    return newImage;
}
//# sourceMappingURL=bottomHat.js.map