Top: 1d cut along the x-axis (solid line) and the y-axis (dashed line) of the measured intensity of QSO SDSS J015339.60-001104.8. We analyzed the area within the two dotted lines. Bottom: we show the measured intensity (red line), the interpolated function F (solid blue line), the intensity of the reconstructed image (dashed blu line), and the residuals (dotted blue line) of the 1d cut along the x-axis (left) and the y-axis (right) of the central area (3 × 3 pixels).