Halcon表面缺陷檢測-劃痕檢測

對應示例程式：
surface_scratch.hdev

目標：通過影像預處理和形態學處理提取劃痕

思路為：
      1.讀取影像
      2.自動閾值分割
      3.連通域分割，提取出面積最大的區域
      4.形態學處理，得到乾淨的目標影像
      5.進行顯示

影像：

程式碼：

dev_update_off ()
dev_close_window ()
* 
* Step 1: Acquire image   讀取影像
* 
read_image (Image, 'surface_scratch')
get_image_size (Image, Width, Height)
dev_open_window_fit_image (Image, 0, 0, Width, Width, WindowID)
set_display_font (WindowID, 16, 'mono', 'true', 'false')
dev_set_draw ('margin')
dev_set_line_width (4)
dev_display (Image)
Message := 'This program shows the extraction of'
Message[1] := 'surface scratches via local thresholding'
Message[2] := 'and morphological post-processing'
disp_message (WindowID, Message, 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowID, 'black', 'true')
stop ()
* 
* Step 2: Segment image  影像分割
* 
* Using a local threshold
mean_image (Image, ImageMean, 7, 7)
dyn_threshold (Image, ImageMean, DarkPixels, 5, 'dark')
* 
* Extract connected components
connection (DarkPixels, ConnectedRegions)
dev_set_colored (12)
dev_display (Image)
dev_display (ConnectedRegions)
Message := 'Connected components after image segmentation'
Message[1] := 'using a local threshold.'
disp_message (WindowID, Message, 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowID, 'black', 'true')
stop ()
* 
* Step 3: Process regions  提取區域
* 
* Select large regions
select_shape (ConnectedRegions, SelectedRegions, 'area', 'and', 10, 1000)
dev_display (Image)
dev_display (SelectedRegions)
disp_message (WindowID, 'Large Regions', 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowID, 'black', 'true')
stop ()
* 
* Visualize fractioned scratch  劃痕視覺化 重新開了一個視窗
open_zoom_window (0, round(Width / 2), 2, 303, 137, 496, 3, WindowHandleZoom)
dev_set_color ('blue')
dev_display (Image)
dev_display (SelectedRegions)
set_display_font (WindowHandleZoom, 16, 'mono', 'true', 'false')
disp_message (WindowHandleZoom, 'Fractioned scratches', 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowHandleZoom, 'black', 'true')
stop ()
* 
* Merge fractioned scratches via morphology  通過形態學合併破碎的劃痕
union1 (SelectedRegions, RegionUnion)
dilation_circle (RegionUnion, RegionDilation, 3.5)
dev_display (Image)
dev_display (RegionDilation)
Message := 'Region of the scratches after dilation'
disp_message (WindowHandleZoom, Message, 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowHandleZoom, 'black', 'true')
stop ()
skeleton (RegionDilation, Skeleton)
connection (Skeleton, Errors)
dev_set_colored (12)
dev_display (Image)
dev_display (Errors)
Message := 'Fractioned scratches merged via morphology'
disp_message (WindowHandleZoom, Message, 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowHandleZoom, 'black', 'true')
stop ()
* 
* Distinguish small and large scratches  區分大的 和小的 劃痕 進行顯示
close_zoom_window (WindowHandleZoom, Width, Height)
select_shape (Errors, Scratches, 'area', 'and', 50, 10000)
select_shape (Errors, Dots, 'area', 'and', 1, 50)
dev_display (Image)
dev_set_color ('red')
dev_display (Scratches)
dev_set_color ('blue')
dev_display (Dots)
Message := 'Extracted surface scratches'
Message[1] := 'Not categorized as scratches'
disp_message (WindowID, Message, 'window', 440, 310, ['red','blue'], 'true')

用到的幾個運算元：
      dyn_threshold—使用區域性閾值分割影像
      dilation_circle–圓形膨脹
      skeleton–計算區域的骨架
      select_shape–藉助形狀特徵選擇區域
      connection–根據連通域分割影像