Busca de feijoes em imagem

feijoes.php

<?php

	use function CV\imread;
	use function CV\imwrite;
	use function CV\threshold;
	use function CV\findContoursWithoutHierarchy;
	use function CV\boundingRect;
	use function CV\rectangleByRect;
	use function CV\cvtColor;

	use const CV\THRESH_BINARY_INV;
	use const CV\RETR_EXTERNAL;
	use const CV\RETR_FLOODFILL;
	use const CV\CHAIN_APPROX_SIMPLE;
	use const CV\IMREAD_GRAYSCALE;
	use const CV\COLOR_GRAY2RGB;

	use CV\Scalar;

	$binary = null;
	$image  = imread('feijao.jpg', IMREAD_GRAYSCALE);
	threshold($image, $binary, 80, 255, THRESH_BINARY_INV);

	imwrite('feijao_bw.jpg', $binary);

	$contours = null;
	findContoursWithoutHierarchy($binary, $contours, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE);

	$boxes = array_map(function ($contour) {
		return boundingRect($contour);
	}, $contours);

	$color = cvtColor($binary, COLOR_GRAY2RGB);

	foreach ($boxes as $box) {
		rectangleByRect($color, $box, new Scalar(0, 255, 255));
	}

	imwrite('feijao_bbox.jpg', $color);

	$boxes = array_filter($boxes, function ($box) {
		return $box->width > 20 && $box->height > 20;
	});

	echo 'Encontrados ' . count($boxes) . ' feijões na foto.';
?>