Dynamic Range Compression

Several different systems have been proposed for two-channel dynamic-range compression. The most common approach is independent operation of the two channels [Villchur, 1973], Commercial products incorporating adjustable gains, compression... 

Blesser, 1969] Blesser, B. (1969). Audio dynamic range compression for minimum perceived distortion. IEEE Trans. Audio and Electroacoustics, Vol. AU- 17(1) 22— 32. 

Dynamic Range Compression. In the next application, dynamic range compression, phase coherence is again required to control sine-wave phase relations. Here however the original phase relation is not preserved, but rather intentionally modified to yield a response with a minimum peak-to-rms value relying on a phase design technique derived in a radar signal context. 

Rahman et al. (1999) extended the algorithm of Moore et al. They use a Gaussian to compute the blurred image and perform color correction on multiple scales. This method is not only used for color constancy but also for dynamic range compression. Output color o, is computed as... 

Figure 9 Data path of architecture for dynamic range compression system consisting of a MPY unit of reduced size and two ALUs The routing blocks at the EX U inputs take care of signal alignment.

The data can be visualized in several formats. In a gel image, the optical density at each point is related to the fluorescence intensity false color images can be used to improve the dynamic range of visualization. We usually employ a logarithmic compression to help visualize the wide dynamic range of the data the image can be processed to saturate the most intense components, allowing observation of less intense components. 

The dynamic range of OSME and GC-SNIFF data is generally less than a factor of ten, whereas dilution analysis frequently yields data that cover three or four powers of ten. It has been determined, however, that compressive transforms (log, root 0.5, and so on) of dilution analysis data are needed to produce statistics with normally distributed error (Acree and Barnard, 1994). Odor Spectrum Values (OSVs) were designed to transform dilution analysis data, odor units, or any potency data into normalized values that are comparable from study to study and are appropriate for normal statistics. The OSV is determined from the equation ... 

For recruitment compensation, on the other hand, longer release times are desired to minimize any deleterious effects of the compression on the speech envelope[Plomp, 1988] [Boothroyd et al., 1988] or in modulating the background noise[Cole, 1993] [Neuman et al., 1995], Low compression ratios are often chosen to match the dynamic range of the impaired ear to that of a normal ear, and a low compression threshold is often chosen so that speech sounds at any level of presentation can be perceived above the impaired auditory threshold [Waldhauer and Villchur, 1988][Killion, 1993],... 

Waldhauer and Villchur, 1988] Waldhauer, F. and Villchur, E. (1988). Full dynamic range multiband compression in a hearing aid. Hear. Journal, 41 29—32. 

Some press sensors may have a rather narrow dynamic range not necessarily correlated with accuracy. For example, a very accurate compression roll pin designed to measure 50 kN force may not detect 5kN signal. 

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