Biomedical Engineering Reference
In-Depth Information
X
X
N
M
1
MN
2
I
ð
x
;
y
Þ
I
0
ð
x
;
y
Þ
MSE
¼
½
y
¼
1
x
¼
1
• Peak Signal to Noise Ratio: the peak error between the original and the com-
pressed image is shown by PSNR
¼
20 log
10
p
MAX
i
MSE
MAX
I
MSE
PSNR
¼
10 log
10
System Implementation
Matlab Software Version 7.0.1 consists of various modules:
1. The input module to retrieve the medical image as input.
2. Provide security feature by changing the DICOM unique identifier (UID).
3. Wavelet
decomposition
module
to
provide
wavelet
compression
using
Daubechies wavelet of order 2.
4. Compression module to compress the input image by applying run length
encoding.
5. Reconstruct original image from compressed image data applying run length
decoding.
6. Wavelet reconstruction to decompress the image and extract the original image.
Compression Algorithm
General flow of the various modules of Matlab Software is shown by the algorithm
below. Source code of this program is given in Appendix-A.
• Read an image from a DICOM file into the MATLAB workspace.
• Read the metadata from the same DICOM file.
• Remove all the text from the image.
• Generate a new DICOM UID using the dicomuid function.
• Set the value of the SeriesInstanceUID field in the metadata associated with the
original DICOM file to the generated value.
• Write the modified image to a new DICOM file, specifying the modified
metadata structure, info, as an argument.
• Apply wavelet decomposition and run length encoding to provide lossless
compression of image.
• To verify this operation, view the SeriesInstanceUID metadata field in the new
file.
• Apply run length decoding and wavelet reconstruction to decompress the Image.
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