关于Python 的简单栅格图像边界提取方法

a=[[0 for col in range(Raster.width)]for row in range(Raster.height)]
 
for i in range(0,Raster.width):
... for j in range(0,Raster.height):
...  if(myRaster[j][i]!=0 and myRaster[j-1][i]==0):
...    a[j][i]=myRaster[j][i]
...  if(myRaster[j][i]==0 and myRaster[j-1][i]!=0):
...    a[j-1][i]=myRaster[j-1][i]
...    
 
 
for i in range(0,myRaster.height):
... for j in range(0,myRaster.width):
...  if(arr[i][j]!=0 and arr[i][j-1]==0):
...    a[i][j]=arr[i][j]
...  if(arr[i][j]==0 and arr[i][j-1]!=0):
...    a[i][j-1]=arr[i][j-1]