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. Author manuscript; available in PMC: 2017 Oct 23.
Published in final edited form as: J Ultrasound Med. 2016 Aug 29;35(10):2165–2177. doi: 10.7863/ultra.15.09059

Figure 6.

Figure 6

Example of power spectrum analysis on a single photoacoustic A-line signal. A, C-scan photoacoustic image of the excised prostate specimen shown in Figure 5A. B, Photoacoustic A-line signal generated by the tissue corresponding to the blue pixel in A. C, Windowed photoacoustic signal: ie, the photoacoustic signal in B was multiplied with a Hamming window of the same length. D, Amplitude spectrum of the windowed photoacoustic (PA) A-line signal along with the 1-way amplitude spectrum of the transducer (both normalized) in the useable bandwidth region (2.4–7.4 MHz). E, Calibrated power spectrum fitted to the linear model. The red line in E is the best fit straight line to the power spectrum of the windowed photoacoustic A-line, which is shown by the blue line. AU indicates arbitrary unit.