def edgelinking(img_original):
    plt.subplot(1, 2, 1)
    plt.title("Original")
    MAX_X = len(img_original)
    MAX_Y = len(img_original[0])

    im2 = img_original.copy()
    im2[:, :, 0] = img_original[:, :, 2]
    im2[:, :, 2] = img_original[:, :, 0]
    plt.imshow(im2)
    plt.xticks([])
    plt.yticks([])

    gray = cv2.cvtColor(img_original, cv2.COLOR_BGR2GRAY)
    ret, thresh = cv2.threshold(gray, 115, 255, 0)
    contournImg = zero_image(gray)

    img = thresh
    orderStd = [(-1,0), (-1,1), (0,1), (1,1), (1,0), (1,-1), (0,-1), (-1,-1)]
    lastValue = img[0][0]
    lastC = 0
    for x, i in enumerate(thresh):
        for y, pixel in enumerate(i):
            if (x < MAX_X - 1 and x > 0) and (y < MAX_Y - 1 and y > 0):
                if thresh[x][y] == lastValue:
                    continue
                if contournImg[x][y]:
                    continue
                lastValue = img[x][y]
                contournImg[x][y] = 255
                while True:
                    foundNeighboor = False
                    for c in orderStd[0:lastC] + orderStd[lastC:len(orderStd)]:
                        if img[x + c[0]][y + c[1]] != lastValue and not contournImg[x + c[0]][y + c[1]]:
                            lastValue = img[x + c[0]][y + c[1]]
                            lastC = orderStd.index(c) - 1
                            if lastC < 0:
                                lastC = 7
                            foundNeighboor = True
                            contournImg[x + c[0]][y + c[1]] = 255
                            break
                    if not foundNeighboor:
                        break

    plt.subplot(1, 2, 2)
    plt.title("Contornada")
    plt.imshow(contournImg, cmap="gray")
    plt.xticks([])
    plt.yticks([])
    plt.show()

    return contournImg