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The process or image compression in a practical Picture Archiving and Communication System (PACS) was discussed with detail. To fully reduce the inter-slice correlation existing in the volumetric image sets generated by CT and MR, 3D Discrete Wavelet Transformation (DWT) was introduced in our applica-tion. Iustead or using a fixed quantizer of lossless low rrequency and distinct loss of high frequency, an adap-tive quantizer was devised taking MSE as the performance index. In the low frequency subband, DPCM was replaced with S+P trans form to facilitate coding computation. Compared with JPEG or 2D DWT, our method is 20 %-50% more erricient. Furthermore, preliminary tests showed that 33 dB may be the maximal distortion threshold for CT images.
To fully reduce the inter-slice correlation existing in the volumetric image sets generated by CT and MR, 3D Discrete Wavelet Transformation (DWT) was introduced in our applica- tion. Iustead or using a fixed quantizer of lossless low rrequency and distinct loss of high frequency, an adap-tive quantizer was devised taking MSE as the performance index. In the low frequency subband, DPCM was replaced with S + P Compared with JPEG or 2D DWT, our method is 20% -50% more erricient. Furthermore, preliminary tests showed that 33 dB may be the maximal distortion threshold for CT images.