Question

如何使此代码打印超过200的亮像素总数：

 vi es.log 

2017.11.27 21:20:51 ERROR es[][o.e.b.Bootstrap] Exception
java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:195) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:342) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:132) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:123) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:70) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.cli.Command.main(Command.java:90) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) [elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) [elasticsearch-5.6.3.jar:5.6.3]
2017.11.27 21:20:51 WARN  es[][o.e.b.ElasticsearchUncaughtExceptionHandler] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:123) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:70) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) ~[elasticsearch-5.6.3.jar:5.6.3]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:195) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:342) ~[elasticsearch-5.6.3.jar:5.6.3]
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:132) ~[elasticsearch-5.6.3.jar:5.6.3]
        ... 6 more

现在它在新线上打印每个单个像素超过200，但我只想要一行打印总数如下：

from PIL import Image
img = input("File name: ")
img = Image.open(img);
for y in range(img.height):
  for x in range(img.width):
    pixel = img.getpixel((x, y))
    if pixel >= 200:
      print(pixel,"pixels are bright.")

Answer 1

您可以使用PIL图像中的getcolors（）函数，该函数返回一个元组列表，其中包含在图像中找到的颜色以及每个颜色的数量。我正在使用以下函数返回以颜色为键，以计数器为值的字典。

from PIL import Image

def getcolordict(im):
    w,h = im.size
    colors = im.getcolors(w*h)
    colordict = { x[1]:x[0] for x in colors }
    return colordict

im = Image.open('image.jpg')
colordict = getcolordict(im)

# get the amount of black pixels in image
# in RGB black is 0,0,0
black_pixels_count = colordict.get((0,0,0))

# get the amount of white pixels in image
# in RGB white is 255,255,255
white_pixels_count = colordict.get((255,255,255))

Answer 2

你也可以试试这个（Python 3）：

from PIL import Image

imgFile = input("File name: ")
img = Image.open(imgFile);
pixels = img.getdata()
total = len(list(filter(lambda i: i >= (200,200,200), pixels)))
print("There are %d bright pixels" % total)

您可以使用getdata()方法一次性获取所有像素，然后您可以过滤高于所需值的像素。在Python 2中，您只需编写i >= 200。

如何计算图像中的亮像素？

2 个答案: