Fig. 1. Flow charts of (a) dictionary learning algorithm and (b) photoacoustic signal reconstruction algorithm based on dictionary learning

Fig. 2. Schematic of simulation

Fig. 3. (a) Simulated photoacoustic data; (b) signal at where marked with white line in Fig. 3 (a)

Fig. 4. (a) Initial random dictionary; (b) learned dictionary from sample set

Fig. 5. (a) Original image; (b) photoacoustic image reconstructed by measurement with 160 detector locations; (c) photoacoustic image reconstructed by measurement with 40 detector locations; (d) photoacoustic image reconstructed by measurement with 40 detector locations based on proposed algorithm in this paper

Table 1. Selected key parameters in algorithm implementation

Table 2. PSNR and SSIM obtained with different algorithms under the conditions of different sampled points and SNRs