Table 2. Final study design that describes the structure of the 10 images for the experiment. N represents normal background, D represents dark background (70% opacity). The colours of the left and right tumour are as stated in Figure 1 with the contrast being the luminance contrast between the two tumours.
| Image | Background | Left tumour | Right tumour | Contrast |
|---|---|---|---|---|
| 1 | N | G_L1 | G_L2 | 30% |
| 2 | N | G_L3 | G_L2 | 30% |
| 3 | N | G_L3 | G_L1 | 60% |
| 4 | N | Y_L1 | G_L1 | 0% |
| 5 | N | G_L2 | Y_L2 | 0% |
| 6 | N | Y_L2 | Y_L1 | 30% |
| 7 | N | Y_L2 | Y_L3 | 30% |
| 8 | N | Y_L1 | Y_L3 | 60% |
| 9 | D | Y_L1 | G_L1 | 0% |
| 10 | D | G_L2 | Y_L2 | 0% |