FIGURE 7 The MAP image of ex-vivo colorectal tissues reconstructed from: (a) raw data, (b) de-noised data by sqtwolog threshold method, (c) de-noised data by 4-order Butterworth low pass filter, (d) de-noised data by our proposed de-noising method (gaWD). (e) the calculated SNR of (a)-(d).
We also plot the 3D volumetric PA image of the ex-vivo colorectal tissues, after de-noising processing by the above three methods, respectively. The results are displayed in FIGURE 8 . Same with the de-noising results in FIGURE 7 , the 3D volumetric PA image reconstructed by our proposed gaWD method shows cleaner in background, achieving higher image contrast and more detailed texture.