Recent Patents on Signal Processing (Discontinued) - Volume 1, Issue 2, 2011

Signal processing is a field of expertise applicable for a large variety of applications with high industrial impact and feasibility. This is why many patents in signal processing were initiated during the last few decades for large variety of data manipulation, image processing applications as well as for optimization of various devices and sub systems for communication. A large variety of applications that can benefit from the recent advances in signal processing capabilities and which are presented in this issue of the journal on recent patents on signal processing involve image processing, processing of voice signals, detection of speech impairments using mobile devices, video compression and video error resilience/concealment, optics communications, optimization of optical components such as MUX/DEMUX, distortion mitigation in transmitter systems and detection of handwriting impairment.

In this paper we present two image processing techniques allowing improving the recognition quality of remote optically recorded voice signals (the first technique) and of images taken under varied illumination conditions (the second technique). Regarding the first approach dealing with the processing of voice signals that were recorded by a patented optical technology, we present a concept that improves the quality of the recording and the classification of the characteristics of the recording while the proposed signal processing operations are applied over the spectrogram of the optically recorded signals. Regarding the second approach dealing with the illumination varied conditions, we present a new technique based upon combination between spectral (of colors) manipulation called the HSV and spatial transformation called the K-factor that is applied over the HSV components. Such manipulation allows composing image which is both insensitive to illumination and contains the significant spatial details of the originally imaged object.

Research and development in the area of image and video compression are actively being done for over 25 years now. New algorithms and systems have been proposed by researchers to further improve the picture quality and compression ratio. This is an effort to compile some of the latest work done by the researchers in the field of image and video compression. In this paper, compression algorithm for Computed Tomography (CT) images by Wegner is discussed where image is classified into more significant and less significant samples. Another patent by Vetra and Yedidia is discussed where less significant samples are compressed more to achieve desired bit rate. Coding of correlated images is explained using a syndrome bit. A luminance based image compression method by Alekis et al. is also dealt with. The paper concentrates more on video coding techniques, where an object based video compression method is discussed for video conference and video blogging applications. Wireless transmission of high definition multimedia interface (HDMI) digital video signal by Bertonis and Giese is discussed where the system adjusts video compression rate and modulation index to maintain constant symbol rate. Non-linear quantization and modular arithmetic computation based video compression by Waertdt is elaborated where differential encoding is performed on multiple blocks of video data to generate a code word. A lossless video compression method for H.264 codec by Gajeong-dong et al. is also discussed. To improve the quality of the predicted frames, a video compression method by gray A. demos is discussed here that uses interpolation with unequal weighting. General discussion on image and video compression is also discussed in the paper.

In this paper, we have proposed a novel technique to electronically post-compensate fiber nonlinearity in 40 Gb/s long-haul WDM transmission systems on which a patent application has recently been filed to USPTO. We have analyzed this technique for both intensity and phase modulated WDM transmission system using two different dispersion maps. Our analysis shows that the proposed technique can increase the overall system margin by 1.5 dB in intensity modulated and 1.0 dB in phase modulated 40 Gb/s long-haul WDM transmission systems.

Router buffer overflow and random bit errors have always been a problem in the Internet. The growth in multimedia applications in mobile extensions of the Internet has increased the threat from error bursts, random errors, and packet erasures that are a manifestation of wireless channels. Source-coded error resilience has come to prominence in the H.264/AVC codec standard, and this paper reviews such innovations surrounding this codec. Some innovations are new variants of an existing technique such as data-partitioning and some are entirely new such as the powerful dispersed-mode flexible macroblock ordering. Other techniques, such as reversible variable length coding, were not transferred to H.264/AVC from earlier codecs and, hence, innovations are proposed to still provide robust entropy coding. Other variants such as adaptive intra-refresh are still being experimented with. When error resilience or other protection methods fail to present an adequate video frame then error concealment can be brought to bear. This paper reviews error concealment which is important to commercial companies as they are able to distinguish their codec from others. The paper considers spatial, temporal and hybrid error concealment methods. Though this paper contains over one hundred references and relevant patents have been discussed, it can only provide a slice through this rich field.

Recent research in communication is inclined towards modulation and assesses techniques that are more spectrally efficient to support more users per base station to reduce overall network costs and make the services affordable to subscribers. However, these signals are highly envelope varying that invokes distortion in transmitted signal due to transmitter nonlinearity and other linear impairments. Therefore, to extract optimum benefits in terms of cost and performance, transmitter linearization solutions are constantly evolving. This patent review highlights developments in this arena from past decade to current and futuristic trends, focusing on the evolution from bulky analogue to reconfigurable digital predistortion and from memoryless nonlinearity based distortion mitigation to recent trends to compensate for memory and other transmitter line-up imperfections.

The advantages of Multi-valued logic (MVL) systems and circuits have drawn a significant interest as a coming generation technology that can be viewed as an alternative approach to solve many problems in transmission, storage and processing of large amount of information in digital signal processing. The paper presents an all-optical circuit for designing ternary (three-valued) multiplexer & demultiplexer with the help of polarization encoded basic ternary logic gates (ternary min and ternary delta literal). It focuses on recent patents / publications in relevant field and future scope of works in the fascinating field of optical multi-valued logic.

Fine motor dysfunction in patients with movement disorders, such as Parkinson's disease, is characterized by slowness of movements, decrease of reaction time and involuntary movements. In this article, recent patents on detecting and assessing the said dysfunction are reviewed; their implementation in telemedicine settings, design considerations and ability to assist in dose and time adjustments are discussed. These patents explain application of signal processing techniques in analysis and interpretation of digitized handwriting/drawing information of individuals based on data gathered using touch screens. The study reveals that measures concerning forces, accelerations and radial displacements are the most relevant measurements to detect fine movement anomalies. These findings demonstrate that digitized analysis of handwriting/drawing movements may be useful in clinical trials evaluating fine motor control. This review further depicts the role of employing event-based data acquisition and signal processing techniques suitable for nonstationary signals, such as Wavelet transform, in systems for patient home-monitoring.

Speech impairment is an important symptom of Parkinson's disease (PD). This paper presents a detailed systematic literature review on speech impairment assessment through mobile devices. A two-tier review methodology is utilized. The first tier focuses on real-time problems in speech detection. In the second tier, acoustics features that respond to medication changes in Levodopa responsive PD patients are investigated for recognition of speech symptoms. The investigation of the patents reveals that speech disorder assessment can be made by a comparative analysis between pathological acoustic patterns and the normal acoustic patterns saved in a database. The review depicts that vowel and consonant formants are the most relevant acoustic parameters to reflect PD medication changes. Since consonants have high zero-crossing rate (ZCR) whereas vowels have low ZCR, enhancements in voice segmentation can be done by inducing ZCR. Our synthesis further suggests that wavelet transforms have potential for being useful in real-time voice analysis for detection and quantification of symptoms at home.

The patents annotated in this section have been selected from various patent databases. These recent patents are relevant to the articles published in this journal issue, categorized by the processes and technologies related to various disciplines of signal processing sciences....