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updated links in cheatsheet renamed directory for Mat tutorial changed links from willow docs to opencv.itseez.com, from Trac to current Redmine
105 lines
3.5 KiB
Python
Executable File
105 lines
3.5 KiB
Python
Executable File
#!/usr/bin/python
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"""
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This program is a demonstration of ellipse fitting.
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Trackbar controls threshold parameter.
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Gray lines are contours. Colored lines are fit ellipses.
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Original C implementation by: Denis Burenkov.
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Python implementation by: Roman Stanchak, James Bowman
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"""
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import sys
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import urllib2
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import random
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import cv2.cv as cv
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def contour_iterator(contour):
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while contour:
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yield contour
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contour = contour.h_next()
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class FitEllipse:
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def __init__(self, source_image, slider_pos):
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self.source_image = source_image
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cv.CreateTrackbar("Threshold", "Result", slider_pos, 255, self.process_image)
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self.process_image(slider_pos)
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def process_image(self, slider_pos):
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"""
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This function finds contours, draws them and their approximation by ellipses.
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"""
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stor = cv.CreateMemStorage()
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# Create the destination images
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image02 = cv.CloneImage(self.source_image)
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cv.Zero(image02)
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image04 = cv.CreateImage(cv.GetSize(self.source_image), cv.IPL_DEPTH_8U, 3)
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cv.Zero(image04)
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# Threshold the source image. This needful for cv.FindContours().
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cv.Threshold(self.source_image, image02, slider_pos, 255, cv.CV_THRESH_BINARY)
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# Find all contours.
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cont = cv.FindContours(image02,
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stor,
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cv.CV_RETR_LIST,
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cv.CV_CHAIN_APPROX_NONE,
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(0, 0))
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for c in contour_iterator(cont):
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# Number of points must be more than or equal to 6 for cv.FitEllipse2
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if len(c) >= 6:
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# Copy the contour into an array of (x,y)s
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PointArray2D32f = cv.CreateMat(1, len(c), cv.CV_32FC2)
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for (i, (x, y)) in enumerate(c):
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PointArray2D32f[0, i] = (x, y)
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# Draw the current contour in gray
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gray = cv.CV_RGB(100, 100, 100)
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cv.DrawContours(image04, c, gray, gray,0,1,8,(0,0))
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# Fits ellipse to current contour.
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(center, size, angle) = cv.FitEllipse2(PointArray2D32f)
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# Convert ellipse data from float to integer representation.
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center = (cv.Round(center[0]), cv.Round(center[1]))
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size = (cv.Round(size[0] * 0.5), cv.Round(size[1] * 0.5))
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# Draw ellipse in random color
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color = cv.CV_RGB(random.randrange(256),random.randrange(256),random.randrange(256))
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cv.Ellipse(image04, center, size,
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angle, 0, 360,
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color, 2, cv.CV_AA, 0)
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# Show image. HighGUI use.
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cv.ShowImage( "Result", image04 )
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if __name__ == '__main__':
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if len(sys.argv) > 1:
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source_image = cv.LoadImage(sys.argv[1], cv.CV_LOAD_IMAGE_GRAYSCALE)
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else:
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url = 'http://code.opencv.org/svn/opencv/trunk/opencv/samples/c/stuff.jpg'
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filedata = urllib2.urlopen(url).read()
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imagefiledata = cv.CreateMatHeader(1, len(filedata), cv.CV_8UC1)
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cv.SetData(imagefiledata, filedata, len(filedata))
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source_image = cv.DecodeImage(imagefiledata, cv.CV_LOAD_IMAGE_GRAYSCALE)
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# Create windows.
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cv.NamedWindow("Source", 1)
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cv.NamedWindow("Result", 1)
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# Show the image.
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cv.ShowImage("Source", source_image)
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fe = FitEllipse(source_image, 70)
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print "Press any key to exit"
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cv.WaitKey(0)
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cv.DestroyWindow("Source")
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cv.DestroyWindow("Result")
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