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80 lines
2.6 KiB
Python
Executable File
80 lines
2.6 KiB
Python
Executable File
#!/usr/bin/python
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import cv
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import sys
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import urllib2
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hist_size = 64
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range_0 = [0, 256]
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ranges = [ range_0 ]
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class DemHist:
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def __init__(self, src_image):
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self.src_image = src_image
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self.dst_image = cv.CloneMat(src_image)
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self.hist_image = cv.CreateImage((320, 200), 8, 1)
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self.hist = cv.CreateHist([hist_size], cv.CV_HIST_ARRAY, ranges, 1)
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self.brightness = 0
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self.contrast = 0
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cv.NamedWindow("image", 0)
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cv.NamedWindow("histogram", 0)
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cv.CreateTrackbar("brightness", "image", 100, 200, self.update_brightness)
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cv.CreateTrackbar("contrast", "image", 100, 200, self.update_contrast)
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self.update_brightcont()
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def update_brightness(self, val):
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self.brightness = val - 100
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self.update_brightcont()
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def update_contrast(self, val):
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self.contrast = val - 100
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self.update_brightcont()
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def update_brightcont(self):
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# The algorithm is by Werner D. Streidt
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# (http://visca.com/ffactory/archives/5-99/msg00021.html)
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if self.contrast > 0:
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delta = 127. * self.contrast / 100
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a = 255. / (255. - delta * 2)
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b = a * (self.brightness - delta)
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else:
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delta = -128. * self.contrast / 100
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a = (256. - delta * 2) / 255.
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b = a * self.brightness + delta
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cv.ConvertScale(self.src_image, self.dst_image, a, b)
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cv.ShowImage("image", self.dst_image)
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cv.CalcArrHist([self.dst_image], self.hist)
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(min_value, max_value, _, _) = cv.GetMinMaxHistValue(self.hist)
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cv.Scale(self.hist.bins, self.hist.bins, float(self.hist_image.height) / max_value, 0)
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cv.Set(self.hist_image, cv.ScalarAll(255))
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bin_w = round(float(self.hist_image.width) / hist_size)
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for i in range(hist_size):
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cv.Rectangle(self.hist_image, (int(i * bin_w), self.hist_image.height),
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(int((i + 1) * bin_w), self.hist_image.height - cv.Round(self.hist.bins[i])),
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cv.ScalarAll(0), -1, 8, 0)
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cv.ShowImage("histogram", self.hist_image)
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if __name__ == "__main__":
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# Load the source image.
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if len(sys.argv) > 1:
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src_image = cv.GetMat(cv.LoadImage(sys.argv[1], 0))
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else:
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url = 'https://code.ros.org/svn/opencv/trunk/opencv/samples/c/baboon.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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src_image = cv.DecodeImageM(imagefiledata, 0)
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dh = DemHist(src_image)
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cv.WaitKey(0)
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