320 lines
11 KiB
Python
320 lines
11 KiB
Python
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# author: Adrian Rosebrock
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# website: http://www.pyimagesearch.com
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# import the necessary packages
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import numpy as np
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import cv2
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import sys
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# import any special Python 2.7 packages
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if sys.version_info.major == 2:
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from urllib import urlopen
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# import any special Python 3 packages
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elif sys.version_info.major == 3:
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from urllib.request import urlopen
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def translate(image, x, y):
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# define the translation matrix and perform the translation
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M = np.float32([[1, 0, x], [0, 1, y]])
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shifted = cv2.warpAffine(image, M, (image.shape[1], image.shape[0]))
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# return the translated image
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return shifted
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def rotate(image, angle, center=None, scale=1.0):
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# grab the dimensions of the image
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(h, w) = image.shape[:2]
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# if the center is None, initialize it as the center of
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# the image
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if center is None:
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center = (w // 2, h // 2)
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# perform the rotation
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M = cv2.getRotationMatrix2D(center, angle, scale)
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rotated = cv2.warpAffine(image, M, (w, h))
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# return the rotated image
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return rotated
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def rotate_bound(image, angle):
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# grab the dimensions of the image and then determine the
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# center
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(h, w) = image.shape[:2]
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(cX, cY) = (w / 2, h / 2)
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# grab the rotation matrix (applying the negative of the
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# angle to rotate clockwise), then grab the sine and cosine
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# (i.e., the rotation components of the matrix)
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M = cv2.getRotationMatrix2D((cX, cY), -angle, 1.0)
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cos = np.abs(M[0, 0])
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sin = np.abs(M[0, 1])
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# compute the new bounding dimensions of the image
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nW = int((h * sin) + (w * cos))
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nH = int((h * cos) + (w * sin))
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# adjust the rotation matrix to take into account translation
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M[0, 2] += (nW / 2) - cX
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M[1, 2] += (nH / 2) - cY
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# perform the actual rotation and return the image
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return cv2.warpAffine(image, M, (nW, nH))
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def resize(image, width=None, height=None, inter=cv2.INTER_AREA):
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# initialize the dimensions of the image to be resized and
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# grab the image size
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dim = None
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(h, w) = image.shape[:2]
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# if both the width and height are None, then return the
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# original image
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if width is None and height is None:
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return image
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# check to see if the width is None
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if width is None:
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# calculate the ratio of the height and construct the
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# dimensions
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r = height / float(h)
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dim = (int(w * r), height)
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# otherwise, the height is None
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else:
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# calculate the ratio of the width and construct the
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# dimensions
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r = width / float(w)
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dim = (width, int(h * r))
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# resize the image
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resized = cv2.resize(image, dim, interpolation=inter)
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# return the resized image
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return resized
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def skeletonize(image, size, structuring=cv2.MORPH_RECT):
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# determine the area (i.e. total number of pixels in the image),
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# initialize the output skeletonized image, and construct the
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# morphological structuring element
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area = image.shape[0] * image.shape[1]
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skeleton = np.zeros(image.shape, dtype="uint8")
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elem = cv2.getStructuringElement(structuring, size)
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# keep looping until the erosions remove all pixels from the
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# image
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while True:
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# erode and dilate the image using the structuring element
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eroded = cv2.erode(image, elem)
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temp = cv2.dilate(eroded, elem)
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# subtract the temporary image from the original, eroded
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# image, then take the bitwise 'or' between the skeleton
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# and the temporary image
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temp = cv2.subtract(image, temp)
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skeleton = cv2.bitwise_or(skeleton, temp)
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image = eroded.copy()
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# if there are no more 'white' pixels in the image, then
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# break from the loop
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if area == area - cv2.countNonZero(image):
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break
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# return the skeletonized image
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return skeleton
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def opencv2matplotlib(image):
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# OpenCV represents images in BGR order; however, Matplotlib
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# expects the image in RGB order, so simply convert from BGR
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# to RGB and return
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return cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
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def url_to_image(url, readFlag=cv2.IMREAD_COLOR):
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# download the image, convert it to a NumPy array, and then read
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# it into OpenCV format
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resp = urlopen(url)
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image = np.asarray(bytearray(resp.read()), dtype="uint8")
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image = cv2.imdecode(image, readFlag)
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# return the image
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return image
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def auto_canny(image, sigma=0.33):
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# compute the median of the single channel pixel intensities
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v = np.median(image)
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# apply automatic Canny edge detection using the computed median
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lower = int(max(0, (1.0 - sigma) * v))
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upper = int(min(255, (1.0 + sigma) * v))
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edged = cv2.Canny(image, lower, upper)
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# return the edged image
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return edged
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def grab_contours(cnts):
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# if the length the contours tuple returned by cv2.findContours
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# is '2' then we are using either OpenCV v2.4, v4-beta, or
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# v4-official
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if len(cnts) == 2:
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cnts = cnts[0]
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# if the length of the contours tuple is '3' then we are using
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# either OpenCV v3, v4-pre, or v4-alpha
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elif len(cnts) == 3:
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cnts = cnts[1]
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# otherwise OpenCV has changed their cv2.findContours return
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# signature yet again and I have no idea WTH is going on
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else:
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raise Exception(("Contours tuple must have length 2 or 3, "
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"otherwise OpenCV changed their cv2.findContours return "
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"signature yet again. Refer to OpenCV's documentation "
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"in that case"))
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# return the actual contours array
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return cnts
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def is_cv2(or_better=False):
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# grab the OpenCV major version number
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major = get_opencv_major_version()
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# check to see if we are using *at least* OpenCV 2
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if or_better:
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return major >= 2
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# otherwise we want to check for *strictly* OpenCV 2
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return major == 2
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def is_cv3(or_better=False):
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# grab the OpenCV major version number
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major = get_opencv_major_version()
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# check to see if we are using *at least* OpenCV 3
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if or_better:
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return major >= 3
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# otherwise we want to check for *strictly* OpenCV 3
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return major == 3
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def is_cv4(or_better=False):
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# grab the OpenCV major version number
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major = get_opencv_major_version()
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# check to see if we are using *at least* OpenCV 4
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if or_better:
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return major >= 4
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# otherwise we want to check for *strictly* OpenCV 4
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return major == 4
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def get_opencv_major_version(lib=None):
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# if the supplied library is None, import OpenCV
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if lib is None:
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import cv2 as lib
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# return the major version number
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return int(lib.__version__.split(".")[0])
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def check_opencv_version(major, lib=None):
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# this function may be removed in a future release as we now
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# use the get_opencv_major_function to obtain the current OpenCV
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# version and then perform the actual version check *within* the
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# respective function
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import warnings
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message = """
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The check_opencv_version function is deprecated and may be
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removed in a future release. Use at your own risk.
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"""
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warnings.warn(message, DeprecationWarning, stacklevel=2)
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# if the supplied library is None, import OpenCV
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if lib is None:
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import cv2 as lib
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# return whether or not the current OpenCV version matches the
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# major version number
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return lib.__version__.startswith(major)
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def build_montages(image_list, image_shape, montage_shape):
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"""
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---------------------------------------------------------------------------------------------
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author: Kyle Hounslow
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---------------------------------------------------------------------------------------------
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Converts a list of single images into a list of 'montage' images of specified rows and columns.
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A new montage image is started once rows and columns of montage image is filled.
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Empty space of incomplete montage images are filled with black pixels
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---------------------------------------------------------------------------------------------
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:param image_list: python list of input images
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:param image_shape: tuple, size each image will be resized to for display (width, height)
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:param montage_shape: tuple, shape of image montage (width, height)
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:return: list of montage images in numpy array format
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---------------------------------------------------------------------------------------------
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example usage:
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# load single image
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img = cv2.imread('lena.jpg')
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# duplicate image 25 times
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num_imgs = 25
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img_list = []
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for i in xrange(num_imgs):
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img_list.append(img)
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# convert image list into a montage of 256x256 images tiled in a 5x5 montage
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montages = make_montages_of_images(img_list, (256, 256), (5, 5))
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# iterate through montages and display
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for montage in montages:
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cv2.imshow('montage image', montage)
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cv2.waitKey(0)
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----------------------------------------------------------------------------------------------
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"""
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if len(image_shape) != 2:
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raise Exception('image shape must be list or tuple of length 2 (rows, cols)')
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if len(montage_shape) != 2:
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raise Exception('montage shape must be list or tuple of length 2 (rows, cols)')
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image_montages = []
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# start with black canvas to draw images onto
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montage_image = np.zeros(shape=(image_shape[1] * (montage_shape[1]), image_shape[0] * montage_shape[0], 3),
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dtype=np.uint8)
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cursor_pos = [0, 0]
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start_new_img = False
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for img in image_list:
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if type(img).__module__ != np.__name__:
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raise Exception('input of type {} is not a valid numpy array'.format(type(img)))
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start_new_img = False
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img = cv2.resize(img, image_shape)
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# draw image to black canvas
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montage_image[cursor_pos[1]:cursor_pos[1] + image_shape[1], cursor_pos[0]:cursor_pos[0] + image_shape[0]] = img
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cursor_pos[0] += image_shape[0] # increment cursor x position
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if cursor_pos[0] >= montage_shape[0] * image_shape[0]:
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cursor_pos[1] += image_shape[1] # increment cursor y position
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cursor_pos[0] = 0
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if cursor_pos[1] >= montage_shape[1] * image_shape[1]:
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cursor_pos = [0, 0]
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image_montages.append(montage_image)
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# reset black canvas
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montage_image = np.zeros(shape=(image_shape[1] * (montage_shape[1]), image_shape[0] * montage_shape[0], 3),
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dtype=np.uint8)
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start_new_img = True
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if start_new_img is False:
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image_montages.append(montage_image) # add unfinished montage
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return image_montages
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def adjust_brightness_contrast(image, brightness=0., contrast=0.):
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"""
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Adjust the brightness and/or contrast of an image
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:param image: OpenCV BGR image
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:param contrast: Float, contrast adjustment with 0 meaning no change
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:param brightness: Float, brightness adjustment with 0 meaning no change
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"""
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beta = 0
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# See the OpenCV docs for more info on the `beta` parameter to addWeighted
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# https://docs.opencv.org/3.4.2/d2/de8/group__core__array.html#gafafb2513349db3bcff51f54ee5592a19
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return cv2.addWeighted(image,
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1 + float(contrast) / 100.,
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image,
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beta,
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float(brightness))
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