The minimum and maximum attenuation coefficients obtained for each tissue type are presented in Fig. 3. Based on these ranges, thresholding was performed to generate a custom color map for segmenting tissue type and the resulting en face parametric image of attenuation is shown in Fig. 2(C).
It has been observed that among the selected concretes, steel magnetite offers maximum value for linear attenuation coefficient, mass attenuation coefficient, equivalent atomic number and least values in terms of penetration depth equivalent to mean free path and exposure buildup factors.
All these quantities are characterized by regularly spaced minima and maxima, depending on the attenuation coefficient and the target-receiver distance.
The transmission data, together with a blank scan of the source without object, can be reconstructed to obtain an attenuation coefficient distribution, for instance, by a maximum likelihood reconstruction of the transmission data (MLTR) [80] (Fig. 8).
The transmission image shows the distribution of the linear attenuation coefficient (cm−1), which was reconstructed using a maximum a posteriori reconstruction.
Step 1: Set the basic parameters: population size (PS), attenuation coefficient of loudness (delta ), increasing coefficient of pulse emission (gamma ), the maximum loudness (A^{0}) and maximum pulse emission (r^{0}) and the maximum number of iterations T. Step 2: Define objective function (f(x_{i}),i=1,2,ldots,text {PS}).
After 12 FT cycles the electric signal's energy attenuation coefficient increases by about 40 45%, and the maximum signals' spectrum centroid increasing reaches about 8 kHz.
The ability to attenuate accelerations through the upper body was quantified using the attenuation coefficient.
The plot of channel attenuation as the signal frequency is varied is known as the attenuation spectrum, while the average attenuation over the entire frequency range of a transmitted signal is defined as the attenuation coefficient.
