Image processing 非常简单的边缘检测_Image Processing_Edge Detection

Image processing 非常简单的边缘检测

image-processing

Image processing 非常简单的边缘检测,image-processing,edge-detection,Image Processing,Edge Detection,我有一个简单的、高对比度的黑白视频图像，我需要在上面找到垂直边的X值和水平边的Y值。我还需要知道边的方向（白色->黑色或黑色->白色）将有：零或一条水平边零或一条垂直边边缘非常直边缘将通过从黑色到白色或从白色到黑色的锐利（浅）过渡来定义我一直在阅读有关边缘检测算法的书籍，但对其了解甚少，但我真正了解的是，它们都比我的要求复杂得多。它们都是为了从复杂图像生成简单边缘的图像而设计的。我的要求（我的图像）要简单得多，我只需要X和Y值为零到两条边如果我在一张图上画一行像素（X=像素指数，Y

我有一个简单的、高对比度的黑白视频图像，我需要在上面找到垂直边的X值和水平边的Y值。我还需要知道边的方向（白色->黑色或黑色->白色）

将有：

零或一条水平边

零或一条垂直边

边缘非常直

边缘将通过从黑色到白色或从白色到黑色的锐利（浅）过渡来定义

我一直在阅读有关边缘检测算法的书籍，但对其了解甚少，但我真正了解的是，它们都比我的要求复杂得多。它们都是为了从复杂图像生成简单边缘的图像而设计的。我的要求（我的图像）要简单得多，我只需要X和Y值为零到两条边

如果我在一张图上画一行像素（X=像素指数，Y=像素强度），我会得到一条直线，一个上升的斜率和另一条直线。斜坡的中心点就是我需要的。但台词并不完美。它们很吵，可能会有小的凸起或凹陷，或者如果看不到边缘，可能（大部分）是平坦的

那么，有没有一个简单的算法来平滑该图并生成“坡度”的方向和中心点

如果要平滑边缘，OpenCV中的过滤器可以帮助您。我不知道您是否已经在使用OpenCV库。这是图像处理中最有用的库之一

如果要填补行中的空白，可以再次使用OpenCV中的

要使用边缘检测算法，您不需要了解它们。优点是你可以简单地测试它，看看它是否能给你想要的结果。我个人使用Canny边缘检测来检测黑白X射线图像中的边缘

包括“opencv2/imgproc/imgproc.hpp” 这就是我使用开口过滤器来填充边缘的小间隙的地方

int blurSize = 3;
    cv::blur(imageVector, imageVector, cv::Size(blurSize,blurSize));

我只是用了平滑滤镜模糊

    bool L2gradient = false;
    cv::Canny(imageVector , imageVector, lower, upper, kernelSize, L2gradient);

我想到的对于这个特殊的应用程序非常有效，所以我想我会与大家分享

首先，我用一个可调的阈值对图像进行二值滤波

然后我运行一个“平滑”操作。我肯定有一个专业术语我不知道。我检查每个像素的邻居（邻居的数量是可调的），以决定该像素是黑色还是白色

然后我抓取一个矩形区域（用于图像的每个顶部、底部、左侧和右侧部分），并注意每行（垂直）/列（水平）的第一个过渡（黑色到白色或白色到黑色）

如果找到的转换数明显小于区域中的行/列数，则没有行

我生成这些转换的平均值和总体标准偏差

如果偏差大于某个可调值，则没有直线。

如果偏差较小，则使用平均值作为行的位置。

我将直接从命令行使用ImageMagick来处理此问题-它安装在大多数Linux发行版上，也可用于OSX和Windows

所以，首先，我会去灰度和正常化的对比度，这样你就不太容易受到曝光或照明的变化。然后我将阈值设置为50%，这样所有像素都将被强制为黑色或白色

convert line.png -colorspace gray -normalize -threshold 50% result.png

然后我会运行一个又高又细的中值滤波器（比如说100像素高，1像素宽），在垂直方向上平滑图像（这样我就可以找到水平边缘）

然后我会将图像的大小调整为1像素宽和100像素高，以减少输出的体积，因为我会说，在图像高度的1%范围内找到边缘是这样一个嘈杂的图像所能期望的

convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 1x100 -resize 1x100! txt:

# ImageMagick pixel enumeration: 1,100,255,srgb
0,0: (32496,32496,32496)  #7E7E7E  srgb(126,126,126)
0,1: (32969,32969,32969)  #808080  srgb(128,128,128)
0,2: (33498,33498,33498)  #828282  srgb(130,130,130)
0,3: (32632,32632,32632)  #7F7F7F  srgb(127,127,127)
0,4: (32708,32708,32708)  #7F7F7F  srgb(127,127,127)
0,5: (32787,32787,32787)  #808080  srgb(128,128,128)
0,6: (32615,32615,32615)  #7F7F7F  srgb(127,127,127)
0,7: (33186,33186,33186)  #818181  srgb(129,129,129)
0,8: (33786,33786,33786)  #838383  srgb(131,131,131)
0,9: (33610,33610,33610)  #838383  srgb(131,131,131)
0,10: (32577,32577,32577)  #7F7F7F  srgb(127,127,127)
0,11: (33159,33159,33159)  #818181  srgb(129,129,129)
0,12: (33578,33578,33578)  #838383  srgb(131,131,131)
0,13: (33276,33276,33276)  #818181  srgb(129,129,129)
0,14: (33259,33259,33259)  #818181  srgb(129,129,129)
0,15: (32620,32620,32620)  #7F7F7F  srgb(127,127,127)
0,16: (32624,32624,32624)  #7F7F7F  srgb(127,127,127)
0,17: (33131,33131,33131)  #818181  srgb(129,129,129)
0,18: (33278,33278,33278)  #818181  srgb(129,129,129)
0,19: (32680,32680,32680)  #7F7F7F  srgb(127,127,127)
0,20: (33136,33136,33136)  #818181  srgb(129,129,129)
0,21: (32707,32707,32707)  #7F7F7F  srgb(127,127,127)
0,22: (33051,33051,33051)  #818181  srgb(129,129,129)
0,23: (33794,33794,33794)  #838383  srgb(131,131,131)
0,24: (33704,33704,33704)  #838383  srgb(131,131,131)
0,25: (33028,33028,33028)  #818181  srgb(129,129,129)
0,26: (33605,33605,33605)  #838383  srgb(131,131,131)
0,27: (33785,33785,33785)  #838383  srgb(131,131,131)
0,28: (33290,33290,33290)  #828282  srgb(130,130,130)
0,29: (33079,33079,33079)  #818181  srgb(129,129,129)
0,30: (33430,33430,33430)  #828282  srgb(130,130,130)
0,31: (33246,33246,33246)  #818181  srgb(129,129,129)
0,32: (33102,33102,33102)  #818181  srgb(129,129,129)
0,33: (33248,33248,33248)  #818181  srgb(129,129,129)
0,34: (33823,33823,33823)  #848484  srgb(132,132,132)
0,35: (33678,33678,33678)  #838383  srgb(131,131,131)
0,36: (33497,33497,33497)  #828282  srgb(130,130,130)
0,37: (33960,33960,33960)  #848484  srgb(132,132,132)
0,38: (33520,33520,33520)  #828282  srgb(130,130,130)
0,39: (33235,33235,33235)  #818181  srgb(129,129,129)
0,40: (32655,32655,32655)  #7F7F7F  srgb(127,127,127)
0,41: (32825,32825,32825)  #808080  srgb(128,128,128)
0,42: (32847,32847,32847)  #808080  srgb(128,128,128)
0,43: (33214,33214,33214)  #818181  srgb(129,129,129)
0,44: (32966,32966,32966)  #808080  srgb(128,128,128)
0,45: (33262,33262,33262)  #818181  srgb(129,129,129)
0,46: (33178,33178,33178)  #818181  srgb(129,129,129)
0,47: (32501,32501,32501)  #7E7E7E  srgb(126,126,126)
0,48: (32499,32499,32499)  #7E7E7E  srgb(126,126,126)
0,49: (31982,31982,31982)  #7C7C7C  srgb(124,124,124)
0,50: (32564,32564,32564)  #7F7F7F  srgb(127,127,127)
0,51: (32336,32336,32336)  #7E7E7E  srgb(126,126,126)
0,52: (30311,30311,30311)  #767676  srgb(118,118,118)
0,53: (27119,27119,27119)  #6A6A6A  srgb(106,106,106)
0,54: (13002,13002,13002)  #333333  srgb(51,51,51)
0,55: (1855,1855,1855)  #070707  srgb(7,7,7)
0,56: (187,187,187)  #010101  srgb(1,1,1)           <--- This is your edge at 56% of the image height down from the top
0,57: (72,72,72)  #000000  srgb(0,0,0)
0,58: (0,0,0)  #000000  black
0,59: (0,0,0)  #000000  black
0,60: (0,0,0)  #000000  black
0,61: (0,0,0)  #000000  black
0,62: (0,0,0)  #000000  black
0,63: (0,0,0)  #000000  black
0,64: (0,0,0)  #000000  black
0,65: (0,0,0)  #000000  black
0,66: (0,0,0)  #000000  black
0,67: (0,0,0)  #000000  black
0,68: (0,0,0)  #000000  black
0,69: (0,0,0)  #000000  black
0,70: (0,0,0)  #000000  black
0,71: (0,0,0)  #000000  black
0,72: (0,0,0)  #000000  black
0,73: (0,0,0)  #000000  black
0,74: (0,0,0)  #000000  black
0,75: (0,0,0)  #000000  black
0,76: (0,0,0)  #000000  black
0,77: (0,0,0)  #000000  black
0,78: (0,0,0)  #000000  black
0,79: (0,0,0)  #000000  black
0,80: (0,0,0)  #000000  black
0,81: (0,0,0)  #000000  black
0,82: (0,0,0)  #000000  black
0,83: (0,0,0)  #000000  black
0,84: (0,0,0)  #000000  black
0,85: (0,0,0)  #000000  black
0,86: (0,0,0)  #000000  black
0,87: (0,0,0)  #000000  black
0,88: (0,0,0)  #000000  black
0,89: (0,0,0)  #000000  black
0,90: (0,0,0)  #000000  black
0,91: (0,0,0)  #000000  black
0,92: (0,0,0)  #000000  black
0,93: (0,0,0)  #000000  black
0,94: (0,0,0)  #000000  black
0,95: (0,0,0)  #000000  black
0,96: (0,0,0)  #000000  black
0,97: (0,0,0)  #000000  black
0,98: (0,0,0)  #000000  black
0,99: (0,0,0)  #000000  black

总之，在终端中运行的两个命令（无需编写、编译和链接任何代码）如下所示：

# Find horizontal edges
convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 1x100 -resize 1x100! txt:

# Find vertical edges
convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 100x1 -resize 100x1! txt:

如果您向我们展示了一些示例图像，并说明了您计划使用的操作系统和工具，这将非常有帮助……如果您展示了您实际正在做的事情的图像，那会更好！您可能也会受益于潜在的更健壮或更快的方法…@MarkSetchell我已经添加了一个示例图像。我希望我之前发布了一个图像！谢谢你，我的荣幸。我希望这些想法能很好地适用于您的其他图像。如果出现任何问题，请记住，问题是免费的，所以请直接提问：-）祝您的项目好运！

convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 1x100 result.png

convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 1x100 -resize 1x100! txt:

# ImageMagick pixel enumeration: 1,100,255,srgb
0,0: (32496,32496,32496)  #7E7E7E  srgb(126,126,126)
0,1: (32969,32969,32969)  #808080  srgb(128,128,128)
0,2: (33498,33498,33498)  #828282  srgb(130,130,130)
0,3: (32632,32632,32632)  #7F7F7F  srgb(127,127,127)
0,4: (32708,32708,32708)  #7F7F7F  srgb(127,127,127)
0,5: (32787,32787,32787)  #808080  srgb(128,128,128)
0,6: (32615,32615,32615)  #7F7F7F  srgb(127,127,127)
0,7: (33186,33186,33186)  #818181  srgb(129,129,129)
0,8: (33786,33786,33786)  #838383  srgb(131,131,131)
0,9: (33610,33610,33610)  #838383  srgb(131,131,131)
0,10: (32577,32577,32577)  #7F7F7F  srgb(127,127,127)
0,11: (33159,33159,33159)  #818181  srgb(129,129,129)
0,12: (33578,33578,33578)  #838383  srgb(131,131,131)
0,13: (33276,33276,33276)  #818181  srgb(129,129,129)
0,14: (33259,33259,33259)  #818181  srgb(129,129,129)
0,15: (32620,32620,32620)  #7F7F7F  srgb(127,127,127)
0,16: (32624,32624,32624)  #7F7F7F  srgb(127,127,127)
0,17: (33131,33131,33131)  #818181  srgb(129,129,129)
0,18: (33278,33278,33278)  #818181  srgb(129,129,129)
0,19: (32680,32680,32680)  #7F7F7F  srgb(127,127,127)
0,20: (33136,33136,33136)  #818181  srgb(129,129,129)
0,21: (32707,32707,32707)  #7F7F7F  srgb(127,127,127)
0,22: (33051,33051,33051)  #818181  srgb(129,129,129)
0,23: (33794,33794,33794)  #838383  srgb(131,131,131)
0,24: (33704,33704,33704)  #838383  srgb(131,131,131)
0,25: (33028,33028,33028)  #818181  srgb(129,129,129)
0,26: (33605,33605,33605)  #838383  srgb(131,131,131)
0,27: (33785,33785,33785)  #838383  srgb(131,131,131)
0,28: (33290,33290,33290)  #828282  srgb(130,130,130)
0,29: (33079,33079,33079)  #818181  srgb(129,129,129)
0,30: (33430,33430,33430)  #828282  srgb(130,130,130)
0,31: (33246,33246,33246)  #818181  srgb(129,129,129)
0,32: (33102,33102,33102)  #818181  srgb(129,129,129)
0,33: (33248,33248,33248)  #818181  srgb(129,129,129)
0,34: (33823,33823,33823)  #848484  srgb(132,132,132)
0,35: (33678,33678,33678)  #838383  srgb(131,131,131)
0,36: (33497,33497,33497)  #828282  srgb(130,130,130)
0,37: (33960,33960,33960)  #848484  srgb(132,132,132)
0,38: (33520,33520,33520)  #828282  srgb(130,130,130)
0,39: (33235,33235,33235)  #818181  srgb(129,129,129)
0,40: (32655,32655,32655)  #7F7F7F  srgb(127,127,127)
0,41: (32825,32825,32825)  #808080  srgb(128,128,128)
0,42: (32847,32847,32847)  #808080  srgb(128,128,128)
0,43: (33214,33214,33214)  #818181  srgb(129,129,129)
0,44: (32966,32966,32966)  #808080  srgb(128,128,128)
0,45: (33262,33262,33262)  #818181  srgb(129,129,129)
0,46: (33178,33178,33178)  #818181  srgb(129,129,129)
0,47: (32501,32501,32501)  #7E7E7E  srgb(126,126,126)
0,48: (32499,32499,32499)  #7E7E7E  srgb(126,126,126)
0,49: (31982,31982,31982)  #7C7C7C  srgb(124,124,124)
0,50: (32564,32564,32564)  #7F7F7F  srgb(127,127,127)
0,51: (32336,32336,32336)  #7E7E7E  srgb(126,126,126)
0,52: (30311,30311,30311)  #767676  srgb(118,118,118)
0,53: (27119,27119,27119)  #6A6A6A  srgb(106,106,106)
0,54: (13002,13002,13002)  #333333  srgb(51,51,51)
0,55: (1855,1855,1855)  #070707  srgb(7,7,7)
0,56: (187,187,187)  #010101  srgb(1,1,1)           <--- This is your edge at 56% of the image height down from the top
0,57: (72,72,72)  #000000  srgb(0,0,0)
0,58: (0,0,0)  #000000  black
0,59: (0,0,0)  #000000  black
0,60: (0,0,0)  #000000  black
0,61: (0,0,0)  #000000  black
0,62: (0,0,0)  #000000  black
0,63: (0,0,0)  #000000  black
0,64: (0,0,0)  #000000  black
0,65: (0,0,0)  #000000  black
0,66: (0,0,0)  #000000  black
0,67: (0,0,0)  #000000  black
0,68: (0,0,0)  #000000  black
0,69: (0,0,0)  #000000  black
0,70: (0,0,0)  #000000  black
0,71: (0,0,0)  #000000  black
0,72: (0,0,0)  #000000  black
0,73: (0,0,0)  #000000  black
0,74: (0,0,0)  #000000  black
0,75: (0,0,0)  #000000  black
0,76: (0,0,0)  #000000  black
0,77: (0,0,0)  #000000  black
0,78: (0,0,0)  #000000  black
0,79: (0,0,0)  #000000  black
0,80: (0,0,0)  #000000  black
0,81: (0,0,0)  #000000  black
0,82: (0,0,0)  #000000  black
0,83: (0,0,0)  #000000  black
0,84: (0,0,0)  #000000  black
0,85: (0,0,0)  #000000  black
0,86: (0,0,0)  #000000  black
0,87: (0,0,0)  #000000  black
0,88: (0,0,0)  #000000  black
0,89: (0,0,0)  #000000  black
0,90: (0,0,0)  #000000  black
0,91: (0,0,0)  #000000  black
0,92: (0,0,0)  #000000  black
0,93: (0,0,0)  #000000  black
0,94: (0,0,0)  #000000  black
0,95: (0,0,0)  #000000  black
0,96: (0,0,0)  #000000  black
0,97: (0,0,0)  #000000  black
0,98: (0,0,0)  #000000  black
0,99: (0,0,0)  #000000  black

convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 100x1 -resize 100x1! txt:

# ImageMagick pixel enumeration: 100,1,255,srgb
0,0: (0,0,0)  #000000  black
1,0: (0,0,0)  #000000  black
2,0: (0,0,0)  #000000  black
3,0: (0,0,0)  #000000  black
4,0: (0,0,0)  #000000  black
5,0: (0,0,0)  #000000  black
6,0: (0,0,0)  #000000  black
7,0: (0,0,0)  #000000  black
8,0: (0,0,0)  #000000  black
9,0: (0,0,0)  #000000  black
10,0: (0,0,0)  #000000  black
11,0: (0,0,0)  #000000  black
12,0: (0,0,0)  #000000  black
13,0: (0,0,0)  #000000  black
14,0: (0,0,0)  #000000  black
15,0: (0,0,0)  #000000  black
16,0: (0,0,0)  #000000  black
17,0: (0,0,0)  #000000  black
18,0: (0,0,0)  #000000  black
19,0: (0,0,0)  #000000  black
20,0: (0,0,0)  #000000  black
21,0: (0,0,0)  #000000  black
22,0: (0,0,0)  #000000  black
23,0: (0,0,0)  #000000  black
24,0: (0,0,0)  #000000  black
25,0: (0,0,0)  #000000  black
26,0: (0,0,0)  #000000  black
27,0: (0,0,0)  #000000  black
28,0: (0,0,0)  #000000  black
29,0: (0,0,0)  #000000  black
30,0: (0,0,0)  #000000  black
31,0: (0,0,0)  #000000  black
32,0: (0,0,0)  #000000  black
33,0: (0,0,0)  #000000  black
34,0: (0,0,0)  #000000  black
35,0: (0,0,0)  #000000  black
36,0: (0,0,0)  #000000  black
37,0: (0,0,0)  #000000  black
38,0: (0,0,0)  #000000  black
39,0: (0,0,0)  #000000  black
40,0: (0,0,0)  #000000  black
41,0: (0,0,0)  #000000  black
42,0: (0,0,0)  #000000  black
43,0: (0,0,0)  #000000  black
44,0: (0,0,0)  #000000  black
45,0: (7,7,7)  #000000  srgb(0,0,0)
46,0: (87,87,87)  #000000  srgb(0,0,0)
47,0: (342,342,342)  #010101  srgb(1,1,1)
48,0: (3623,3623,3623)  #0E0E0E  srgb(14,14,14)
49,0: (16943,16943,16943)  #424242  srgb(66,66,66)      <-- This is your vertical edge, 49% of the image width across from the left side
50,0: (29779,29779,29779)  #747474  srgb(116,116,116)
51,0: (33852,33852,33852)  #848484  srgb(132,132,132)
52,0: (34745,34745,34745)  #878787  srgb(135,135,135)
53,0: (35643,35643,35643)  #8B8B8B  srgb(139,139,139)
54,0: (35893,35893,35893)  #8C8C8C  srgb(140,140,140)
55,0: (35932,35932,35932)  #8C8C8C  srgb(140,140,140)
56,0: (35934,35934,35934)  #8C8C8C  srgb(140,140,140)
57,0: (36041,36041,36041)  #8C8C8C  srgb(140,140,140)
58,0: (36095,36095,36095)  #8C8C8C  srgb(140,140,140)
59,0: (35975,35975,35975)  #8C8C8C  srgb(140,140,140)
60,0: (35937,35937,35937)  #8C8C8C  srgb(140,140,140)
61,0: (35937,35937,35937)  #8C8C8C  srgb(140,140,140)
62,0: (36042,36042,36042)  #8C8C8C  srgb(140,140,140)
63,0: (36094,36094,36094)  #8C8C8C  srgb(140,140,140)
64,0: (36148,36148,36148)  #8D8D8D  srgb(141,141,141)
65,0: (36409,36409,36409)  #8E8E8E  srgb(142,142,142)
66,0: (36409,36409,36409)  #8E8E8E  srgb(142,142,142)
67,0: (36375,36375,36375)  #8E8E8E  srgb(142,142,142)
68,0: (36252,36252,36252)  #8D8D8D  srgb(141,141,141)
69,0: (36214,36214,36214)  #8D8D8D  srgb(141,141,141)
70,0: (36176,36176,36176)  #8D8D8D  srgb(141,141,141)
71,0: (36274,36274,36274)  #8D8D8D  srgb(141,141,141)
72,0: (36406,36406,36406)  #8E8E8E  srgb(142,142,142)
73,0: (36366,36366,36366)  #8E8E8E  srgb(142,142,142)
74,0: (36128,36128,36128)  #8D8D8D  srgb(141,141,141)
75,0: (36004,36004,36004)  #8C8C8C  srgb(140,140,140)
76,0: (35900,35900,35900)  #8C8C8C  srgb(140,140,140)
77,0: (35872,35872,35872)  #8C8C8C  srgb(140,140,140)
78,0: (35855,35855,35855)  #8C8C8C  srgb(140,140,140)
79,0: (35779,35779,35779)  #8B8B8B  srgb(139,139,139)
80,0: (35777,35777,35777)  #8B8B8B  srgb(139,139,139)
81,0: (35664,35664,35664)  #8B8B8B  srgb(139,139,139)
82,0: (35774,35774,35774)  #8B8B8B  srgb(139,139,139)
83,0: (35785,35785,35785)  #8B8B8B  srgb(139,139,139)
84,0: (35753,35753,35753)  #8B8B8B  srgb(139,139,139)
85,0: (35671,35671,35671)  #8B8B8B  srgb(139,139,139)
86,0: (35675,35675,35675)  #8B8B8B  srgb(139,139,139)
87,0: (35694,35694,35694)  #8B8B8B  srgb(139,139,139)
88,0: (35621,35621,35621)  #8B8B8B  srgb(139,139,139)
89,0: (35819,35819,35819)  #8B8B8B  srgb(139,139,139)
90,0: (36080,36080,36080)  #8C8C8C  srgb(140,140,140)
91,0: (36300,36300,36300)  #8D8D8D  srgb(141,141,141)
92,0: (36550,36550,36550)  #8E8E8E  srgb(142,142,142)
93,0: (36561,36561,36561)  #8E8E8E  srgb(142,142,142)
94,0: (36425,36425,36425)  #8E8E8E  srgb(142,142,142)
95,0: (36268,36268,36268)  #8D8D8D  srgb(141,141,141)
96,0: (36317,36317,36317)  #8D8D8D  srgb(141,141,141)
97,0: (36409,36409,36409)  #8E8E8E  srgb(142,142,142)
98,0: (36521,36521,36521)  #8E8E8E  srgb(142,142,142)
99,0: (36568,36568,36568)  #8E8E8E  srgb(142,142,142)

convert line.png -stroke red -draw "line 0,268 640,268" -draw "line 313,0 313,480" result.png

# Find horizontal edges
convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 1x100 -resize 1x100! txt:

# Find vertical edges
convert line.png -colorspace gray -normalize -threshold 50% -virtual-pixel mirror -statistic median 100x1 -resize 100x1! txt: