from __future__ import print_function
import cv2 as cv
import numpy as np
import argparse
from matplotlib import pyplot as plt

parser = argparse.ArgumentParser(description='Code for Feature Detection tutorial.')
parser.add_argument('--input', help='Path to input image.', default='data/1.jpg')
args = parser.parse_args()

src = cv.imread(cv.samples.findFile(args.input), cv.IMREAD_GRAYSCALE)
if src is None:
	print('Could not open or find the image:', args.input)
	exit(0)

# -- Step 1: Detect the keypoints using SURF Detector
minHessian = 400
detector = cv.xfeatures2d.HarrisLaplaceFeatureDetector.create()
keypoints = detector.detect(src)

# -- Draw keypoints
img_keypoints = np.empty((src.shape[0], src.shape[1], 3), dtype=np.uint8)
cv.drawKeypoints(src, keypoints, img_keypoints)

# -- Show detected (drawn) keypoints
cv.imshow('SURF Keypoints', img_keypoints)

corners = cv.goodFeaturesToTrack(src, 25, 0.01, 10)

# Draw corners detected
print('** Number of corners detected:', corners.shape[0])
radius = 4
for i in range(corners.shape[0]):
	cv.circle(src, (int(corners[i, 0, 0]), int(corners[i, 0, 1])), radius, (0, 0, 255))

cv.imshow('goodFeaturesToTrack', src)

cv.waitKey()