颜色跟踪中颜色阈值获取标红代码的意思与原理,该方法与histogram.get_threhsold()的区别是?
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主要是不太明白这里边的表述,相如计算直方图频道的CDF,返回一个传递 percentile (0.0 - 1.0) (浮点数)中的直方图的值,我知道是通过累加到一定百分数对应的阈值的值,但是不知道累加到的这个百分数是什么东西,如果调整的话怎么调整。
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把所有的像素从小到大排起来,
get_percentile(0.1)就是10%位置上的灰度值。
get_percentile(0.9)就是90%位置上的灰度值。
get_percentile(0.5)就是50%位置上的灰度值,也就是中位数。# Image Histogram Info Example # # This script computes the histogram of the image and prints it out. import sensor, image, time sensor.reset() sensor.set_pixformat(sensor.GRAYSCALE) # or RGB565. sensor.set_framesize(sensor.QVGA) sensor.skip_frames(time = 2000) sensor.set_auto_gain(False) # must be turned off for color tracking sensor.set_auto_whitebal(False) # must be turned off for color tracking clock = time.clock() while(True): clock.tick() img = sensor.snapshot() # Gets the grayscale histogram for the image into 8 bins. # Bins defaults to 256 and may be between 2 and 256. hist = img.get_histogram(bins=8) print(hist) print(hist.get_percentile(0.1)) print(clock.fps()) # You can also pass get_histogram() an "roi=" to get just the histogram of that area. # get_histogram() allows you to quickly determine the color channel information of # any any area in the image.