无法从图像中提取准确的眼睛对象

Question

我试图从图像中提取出准确的眼睛大小，而该图像没有显示人的确切眼睛大小，然后我必须准确计算出该眼睛对象的高度和宽度。

我使用的代码：

# import the necessary packages
from imutils import face_utils
import numpy as np
import argparse
import imutils
import dlib
import cv2

# construct the argument parser and parse the arguments
ap = argparse.ArgumentParser()
ap.add_argument("-p", "--shape-predictor", required=True,
    help="path to facial landmark predictor")
ap.add_argument("-i", "--image", required=True,
    help="path to input image")
args = vars(ap.parse_args())

# initialize dlib's face detector (HOG-based) and then create
# the facial landmark predictor
detector = dlib.get_frontal_face_detector()
predictor = dlib.shape_predictor(args["shape_predictor"])

# load the input image, resize it, and convert it to grayscale
image = cv2.imread(args["image"])
image = imutils.resize(image, width=500)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

# detect faces in the grayscale image
rects = detector(gray, 1)
FACIAL_LANDMARKS_IDXS = [
    ("Right Eye", (36, 42)),
        ("Left Eye", (42, 48))
]

# loop over the face detections
for (i, rect) in enumerate(rects):
    # determine the facial landmarks for the face region, then
    # convert the landmark (x, y)-coordinates to a NumPy array
    shape = predictor(gray, rect)
    shape = face_utils.shape_to_np(shape)

    # loop over the face parts individually
    for (name, (i, j)) in FACIAL_LANDMARKS_IDXS:
        # clone the original image so we can draw on it, then
        # display the name of the face part on the image
        clone = image.copy()
        cv2.putText(clone, name, (10, 30), cv2.FONT_HERSHEY_SIMPLEX,
            0.7, (0, 0, 255), 2)

        # loop over the subset of facial landmarks, drawing the
        # specific face part
        for (x, y) in shape[i:j]:
            cv2.circle(clone, (x, y), 1, (0, 0, 255), -1)

        # extract the ROI of the face region as a separate image
        (x, y, w, h) = cv2.boundingRect(np.array([shape[i:j]]))
        roi = image[y:y + h, x:x + w]
        roi = imutils.resize(roi, width=250, inter=cv2.INTER_CUBIC)

        # show the particular face part
        cv2.imshow("Extracted image", roi)
        cv2.imshow("Image", clone)

        cv2.waitKey(0)
        cv2.imwrite("/Users/User/Downloads/detect-face-parts/images/new.jpg", roi);

预期：图像中的全眼物体

实际：

还有其他方法可以使用OpenCV通过适当的增强技术来提取眼睛吗？