IEICE Information and Communication Technology Forum
Linear Interpolation in Time Domain for Improved Audio or Image Signal Reconstruction
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An extremely low cost and complexity hardware linear interpolator is presented in this paper used for the improved reconstruction of audio or image signals like the ones produced by surveillance optic or infrared cameras, X-ray images, sound detectors, microphones etc. Real time compression can also be performed if the audio or image signal has long sequences of identical values. A set of appropriate correction rules for exponential or logarithmic curves that are based on simple operations like shifts and comparisons can be employed since several parts of a signal can be approximated by such exponential or logarithmic curves. Applications in the Internet of Things (IoT) area can benefit from such an interpolator-compressor since lower resolution/power Analog Digital Converters (ADCs) can be used in lighter transceivers that exchange information with lower data rate. An improvement of about 15% in the Mean Square Error (MSE) has been measured using real signals. An interpolator with 9-bit input resolution can be implemented with only 583 Logic Elements (LE) i.e., less than 3% of an Altera Cyclone III EP3C25N Field Programmable Gate Array (FPGA) resources.