ACEEE-SIPG Director: Dr. Gylson Thomas (Professor, MES College of Engineering, Kerala, India)

Signal processing is the analysis, interpretation, and manipulation of signals. Signals of interest include: sound, images, time-varying measurement values and sensor data, for example biological data such as electrocardiograms, control system signals, telecommunication transmission signals such as radio signals, and many others.
Processing of such signals includes

•           filtering (for example in tone controls, equalizers and image enhancement software)
•           adaptive filtering (for example for echo-cancellation in a conference telephone, or separation of information from noise for aircraft identification by radar)
•           digitalization, reconstruction and compression (for example, image compression, sound coding)
•           feature extraction (for example speech-to-text conversion)
•           spectrum analysis (for example in magnetic resonance imaging and OFDM modulation)
•           wavetable synthesis (in modems and music synthesizers), and
•           storage (in digital delay lines and reverb).

Signals are analog or digital electrical representations of time-varying or spatial-varying physical quantities. In the context of signal processing, arbitrary binary data streams and on-off signals are not considered as signals, but only analog and digital signals that are representations of analog physical quantities.

In communication systems, signal processing occurs at OSI layer 1, the Physical Layer (modulation, equalization, multiplexing, radio transmission, etc) in the seven layer OSI model, as well as at OSI layer 6, the Presentation Layer (source coding, including analog-to-digital conversion and data compression). Categories of signal processing includes:

•           Analog signal processing — for signals that have not been digitized, as in classical radio, telephone, radar, and television systems. This involves linear electronic circuits such as passive filters, active filters, additive mixers, integrators and delay lines. It also involves non-linear circuits such as compandors, multiplicators (frequency mixers and voltage-controlled amplifiers), voltage-controlled filters, voltage-controlled oscillators and phase-locked loops.
•           Discrete time signal processing — for sampled signals that are considered as defined only at discrete points in time, and as such are quantized in time, but not in magnitude. Analog discrete-time signal processing is a technology based on electronic devices such as sample and hold circuits, analog time-division multiplexers, analog delay lines and analog feedback shift registers. This technology was a predecessor of digital signal processing, see below, and is still used in advanced processing of gigahertz signals. The concept of discrete-time signal processing also refers to a theoretical discipline that establishes a mathematical basis for digital signal processing, without taking quantization error into consideration.
•           Digital signal processing — for signals that have been digitized. Processing is done by general-purpose computers or by digital circuits such as ASICs, field-programmable gate arrays or specialized digital signal processors (DSP chips). Typical arithmetical operations include fixed-point and floating-point, real-valued and complex-valued, multiplication and addition. Other typical operations supported by the hardware are circular buffers and look-up tables. Examples of algorithms are the Fast Fourier transform (FFT), finite impulse response (FIR) filter, Infinite impulse response (IIR) filter, Wiener filter and Kalman filter.

Image processing is any form of signal processing for which the input is an image, such as photographs or frames of video; the output of image processing can be either an image or a set of characteristics or parameters related to the image. Most image-processing techniques involve treating the image as a two-dimensional signal and applying standard signal-processing techniques to it.

Image processing usually refers to digital image processing, but optical and analog image processing are also possible. This article is about general techniques that apply to all of them. The acquisition of images (producing the input image in the first place) is referred to as imaging.

ACEEE-SIPG (Signal & Image Processing Group) has formed to tap the potential in Signal & Image Processing. The research group has also proposed International Journal of Signal & Image Processing (IJSIP) to cover the following broad topics.

•           image enhancement
•           adaptive filtering
•           digitalization,
•           reconstruction and compression
•           feature extraction
•           spectrum analysis
•           wavetable synthesis
•           Digital storage and retrieval
•           digital image processing
•           signal processing
•           Video processing
•           Sound processing
•           Signal restoration
•           Adaptive processing
•           biomedical signal processing
•           multimedia signal processing
•           communication signal processing
•           non-linear signal processing
•           array processing
•           statistical signal processing
•           modeling & filtering
•           multi-resolution
•           segmentation
•           restoration & enhancement
•           colour and multi-spectral processing
•           interpolation
•           motion detection and estimation
•           stereoscopic processing

Original contributions which are not submitted and not under consideration in any other conferences/journals are solicited on topics covered under the above broad areas (but not limited to). Prospective authors are invited to submit full papers electronically in PDF double column format to: aceee.sipg AT engineersnetwork.org