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. Author manuscript; available in PMC: 2020 May 1.
Published in final edited form as: Proc SPIE Int Soc Opt Eng. 2014 Mar 11;9037:90370P. doi: 10.1117/12.2043335

Figure 1. Phantom used for the human and model observers and sample 4 Alternate Forced Choice trials.

Figure 1.

(Left) The simulated phantom has twelve cylindrical signals at varied diameters and contrasts. Signals appear circular in the axial slice. Starting from 12 o’clock and moving clockwise, they are pin #1 (4mm 0.3%), pin #2 (6mm 0.3%), pin #3 (8mm 0.3%), pin #4 (15mm 0.3%), pin #5 (4mm 0.5%), pin #6 (6mm 0.5%), pin #7 (8mm 0.5%), pin #8 (15mm 0.5%), pin #9 (4mm 1.0%), pin #10 (6mm 1.0%), pin #11 (8mm 1.0%), and pin #12 (15mm 1.0%). (Center) A 4AFC trial for FBP is shown with one signal image and three noise images. (Right) A 4AFC trial for IMR is shown. All 4AFC experiments used a window of 100 and level of 0 HU. Contrast has been enhanced in these images for display purposes.