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Dear all, Hi! I am doing some research about the steganography in BPCS way created by a Japanese professor. BPCS means Bit Plane Complexity Segementation.It needs calculating the complexity of an image in advance. The concept of Complexity is defined as the following: ********************************************************************* The length of black-and-white border in a binary image is a good measure for an image complexity. If the border is long, the image is complex, otherwise it is simple. The total length of black-and-white border equals to the summation of the number of color-changes along the rows and columns in an image. For example, a single black pixel surrounded by white background pixels has the boarder length of 4. We will define the image complexity by the following. = k/(The max possible B-W changes in the image) Where, k is the total length of black-and-white border in the image. So, the value ranges over: 0<=lt;=1 Notice:B-W changes means black to white change image format is BMP ********************************************************************* if we define "nccc" as the total number of color change along row and "nccc" as the total number of color change along column and the size for the BMP image is width*height,then we can easily get the complexity of an image as: (nccc+nccr)/[ 2*width*height-(width+height)].I have finished this computation in C language.To continue this research I have to compute the complexities of local areas in an image.Generally the size of a local area means a 8*8 block of that image. Instead of C language,I would like to use Matlab to wtite this program. Clearly I should use blkproc function(B=blkproc(A,[8 8],fun)).However I am not familiar with Matlab and do not know how to write the fun here.Could you give me your help? Thanks all! Maya |
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SOS!!!problem about the complexity of local area of an image
Started by ●May 28, 2003
Reply by ●June 3, 20032003-06-03
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Hi, Use bwmorph function (images toolbox) options to detect borders and thin it. then find the the number of border pixels using nnz function. Joe BSTeX- Equation viewer for Matlab http://www.geocities.com/bstex2001 --- uestcgao <> wrote: > Dear all, > > Hi! I am doing some research about the steganography > in BPCS way created by a Japanese professor. BPCS > means Bit Plane Complexity Segementation.It needs > calculating the complexity of an image in advance. > The concept of Complexity is defined as the > following: ********************************************************************* > The length of black-and-white border in a binary > image is a good > measure for an image complexity. If the border is > long, the image is > complex, otherwise it is simple. The total length of > black-and-white > border equals to the summation of the number of > color-changes along > the rows and columns in an image. For example, a > single black pixel > surrounded by white background pixels has the > boarder length of 4. > We will define the image complexity by the > following. > = k/(The max possible B-W changes in the > image) > Where, k is the total length of black-and-white > border in the image. > So, the value ranges over: 0<=lt;=1 > Notice:B-W changes means black to white change > image format is BMP > ********************************************************************* > > > if we define "nccc" as the total number of color > change along row > and "nccc" as the total number of color change along > column and the > size for the BMP image is width*height,then we can > easily get the > complexity of an image as: > (nccc+nccr)/[ 2*width*height-(width+height)].I have > finished this > computation in C language.To continue this research > I have to > compute the complexities of local areas in an > image.Generally the > size of a local area means a 8*8 block of that > image. > > Instead of C language,I would like to use Matlab to > wtite this > program. Clearly I should use blkproc > function(B=blkproc(A,[8 > 8],fun)).However I am not familiar with Matlab and > do not know how > to write the fun here.Could you give me your help? > > Thanks all! > > Maya __________________________________ |
