Nonlocal Noise Removal Technique to Improve the Electromagnetic Field Pattern in Near-Field Scanning of a Device

A nonlocal noise removal technique, known as block-matching 3-D (BM3D), is introduced to improve the quality of a blurry electromagnetic pattern generated from near field of a device. Noise distribution in electromagnetic pattern is analyzed. Taking the nonlocal self-similarity into account, the BM3D technique removes the noise of the pattern in a 3-D transformation domain based on sparse representation. First, the noise removal technique was validated well on the profile recovery of weak emission of a microstrip line driven by a square wave. Then, the BM3D technique is applied to improve source localization in a field programmable gate array (FPGA) and also to improve pattern clustering in a double data rate (DDR) synchronous dynamic random access memory (SDRAM) integrated circuit (IC). Both the applications demonstrate the effectiveness of the BM3D noise removal technique in the near-field scanning patterns of a device.