如何裁剪圖像，使用imagemagick圖像中的顏色邊框

Question

我想知道如何裁剪一個圖像的8部分不等於 和尺寸不知道（我可以嘗試一些，但def不等於尺寸）。

實施例：http://i.imgur.com/YG92jJH.jpg

通過使用灰色框之間的空白。

基本上要打開例如（原版右上角）：http://i.imgur.com/swKDTnn.jpg

Answer 1

您應該首先玩multicrop的imagemagick腳本的開關。

 
$ bash multicrop 


multicrop: 
Revised by Anthony Thyssen to add -b option ... revised 8/24/2010 
Developed by Fred Weinhaus 1/30/2010 .......... revised 7/7/2010 

USAGE: multicrop [-c coords] [-b bcolor] [-f fuzzval] [-g grid] [-u unrotate] [-m mask] infile outfile 
USAGE: multicrop [-h or -help] 

OPTIONS: 

-c   coords   pixel coordinate to extract background color; 
          may be expressed as gravity value (NorthWest, etc) 
          or as "x,y" value; default is NorthWest=(0,0) 
-b   bcolor   background color to use instead of option -c; 
          any valid IM color; default is to use option -c 
-f   fuzzval  fuzz value for separating background color; 
          expressed as (integer) percent 0 to 100; 
          default=0 (uniform color) 
-g   grid   grid spacing in both x and y as percent of 
          image width and height; used to locate images; 
          integer>0; default=10;                                       
-u   unrotate  unrotate method; choices are 1 for -deskew,                                  
          2 for unrotate script and 3 for no unrotate;                                  
          default=1                                          
-m   mask   mask presentation method; choices are view,                                  
          save (to file) or output mask only; default                                  
          is none of the above, just output the images                                  



NAME: MULTICROP                                                

PURPOSE: To crop and unrotate multiple images from a scanned image.                                   

DESCRIPTION: MULTICROP crops and unrotates multiple images from a scanned image.                               
The images must be well separated so that background color shows between them.                                
The process uses a floofill technique based upon a seed coordinate and a fuzz                                
value to separate the individual images from the background of the scan.                                 
The correct choice of fuzz factor is very important. If too small, the images                                
will not be separate. If too larger, parts of the outer area of the image                                 
containing similar colors will be lost and the image may be separated into                                 
multiple parts. There are two unrotate methods. The first uses the IM deskew 
function, but is limited to 5 degrees of rotate or less. The second uses my 
unrotate script. It allows much larger rotations, but will be slower. If 
using the second method, my unrotate script must be downloaded and installed. 

IMPORTANT: The images in the scanned file must be well separated in x and y 
so that their bounding boxes do not overlap. This is especially important 
if the images have a significant rotation. 

The output images will be named from the specified outfile and -0, -1, 
etc, will be appended before the .suffix. 

Arguments: 

-c coords ... COORDS is any location within the background (non-image) area 
for the algorithm to find the background color. It may be specified in terms 
of gravity parameters (NorthWest, North, NorthEast, East, SouthEast, South, 
SouthWest or West) or as a pixel coordinate "x,y". The default is the 
upper left corner = NorthWest = "0,0". 

-b bcolor ... BCOLOR is the background color to use for flood fill instead 
of extracting this color from the image. This is useful when an image has 
no borders with sub-images hard against the edges. Any valid IM color is 
allowed. The default is to use option -c. 

-f fuzzval ... FUZZVAL is the fuzz amount specified as an integer percent 
value between 0 to 100 (without the % sign). The correct choice of fuzz 
factor is very important. If too small, the images will not be separate. 
If too larger, parts of the outer area of the image containing similar 
colors will be lost and the image may be separated into multiple parts. 
Typical values are probably between 5 and 20 percent. The default=10 

-g grid ... GRID is the grid spacing for testing points in the input image 
to see if they are background or image. The grid value is specified as an 
integer percent greater than 0 and less than 100 of the width and height 
of the input image. The default=10. 

-u unrotate ... UNROTATE is the unrotation method. Choices are: 1, 2 or 3. 
The default is unrotate=1, which is fast and uses the IM -deskew function, 
but is limited to images that are rotated no more than 5 degrees in the scan. 
Option unrotate=2 uses my unrotate script. It can handle larger rotations, 
but is slower. If using the latter method, my unrotate script must be 
downloaded and also installed so that it is available for this script to use. 
Option unrotate=3 makes no attempt to unrotate the images. 

-m mask ... MASK provides several options for reviewing the initial mask that 
is generated by the fuzz value. The choices are: view (display to X11 window), 
save (to disk) along with the images, or output (without processing the images). 
The default is to simply process the images without showing or saving the mask. 
If using the view mode, then processing will stop until the image is closed. 
But this allows you to then kill the script if the mask is not appropriate. 
A good approach is to use the output mode repeatedly with various fuzzvals 
until a reasonable mask is created. Note that the mask must separate the 
images, but the background can "eat" a little into the images so long as no 
full edge is lost or the images is split into multiple parts. 

NOTE: If using unrotate method 2, then my script, unrotate, is required 
as well. 

CAVEAT: No guarantee that this script will work on all platforms, 
nor that trapping of inconsistent parameters is complete and 
foolproof. Use At Your Own Risk.