All Figures

$\begin{figure} \par\includegraphics[width=16.7cm,clip]{3480fig1.eps} \end{figure}$ Figure 1: Reconstruction of aperture-synthesis images from computer-simulated LBT raw data (all images are shown on the same scale). a) test object (based on the HST image of NGC 3504); b) object from panel a) convolved with the PSF of a simulated diffraction-limited 22.8 m telescope; c), d) computer-simulated LBT raw images of the object (simulated total magnitude $J=17.0^{\rm m}$ , sky background $J=16.0^{\rm m}$ per arcsec square, read-out noise of 11 e^- rms, pupil position angles 0 $^\circ$ and 30 $^\circ$ ); e), f) LBT PSFs for position angles 0 $^\circ$ and 30 $^\circ$ These PSFs are derived from four unresolved stars in the vicinity of the target (see text and Fig. 2). The brightness of these reference stars ranges from $J=20.0^{\rm m}$ to $21.0^{\rm m}$ ; g), h), i) diffraction-limited images reconstructed from 6 LBT raw images (taken with pupil position angles of 0 $^\circ$ , 30 $^\circ$ , 60 $^\circ$ , 90 $^\circ$ , 120 $^\circ$ ,and 150 $^\circ$ , two of which are shown in panels c) and d) and the corresponding 6 LBT PSFs (two of which are shown in panels e) and f) using the RL g), the OSEM h), and the BB i) methods; the faint star-like structure in the upper left corner of panels a and b has a brightness of $J=25.2^{\rm m}$ (marked by an arrow in panel b). The restoration errors are 5.37% g), 5.61% h), and 5.20% i) (see text for details). The typical computing (PC) times for the RL, OSEM, and BB methods were 6 min, 3 min, and 12 min, respectively.
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In the text

$\begin{figure} \par\includegraphics[width=17cm,clip]{3480fig2.eps} \end{figure}$ Figure 2: a) One of six computer-simulated LBT raw images with the field-of-view (FOV) of the LINC-NIRVANA instrument of 10 arcsec corresponding to $2048\times 2048$ pixel (total magnitude of the galaxy $J=17^{\rm m}$ , sky background $J=16^{\rm m}$ per arcsec square, J magnitudes of the four reference stars: 20.0 $^{\rm m}-21.0^{\rm m}$ , distances of the four reference stars to the galaxy: 2.6 $\hbox {$^{\prime \prime }$ }{-} 5.8\hbox {$^{\prime \prime }$ }$ ; see Table 1 and Fig. 1). b) One of six LBT PSFs (pupil position angle 30 $^\circ$ , Strehl ratio $\sim$ 30%) derived from the computer-simulated LBT raw image a) by adding up the PSFs of the four re-centered reference stars (256 $\times$ 256 pixel FOV). c) One of six LBT raw images of the target used for the deconvolution process.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{3480fig3.eps} \end{figure}$ Figure 3: a) Modulus of the Fourier transform of a single computer-simulated LBT raw image of a point source (pupil position angle 30 $\circ$ ). b) Same as a), but with all Fourier elements outside the uv-coverage set to zero (see text).
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{3480fig4.ps} \end{figure}$ Figure 4: Intensity cuts along a line through the nucleus and the faint star-like object (upper left corner in Fig. 1b) for the test object (Fig. 1b; red), the RL reconstruction (Fig. 1g; green), the OSEM reconstruction (Fig. 1h; blue), and the BB reconstruction (Fig. 1i; pink).
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In the text

$\begin{figure} \par\includegraphics[width=15.7cm,clip]{3480fig5.eps} \end{figure}$ Figure 5: Laboratory simulation of LINC-NIRVANA and image reconstruction from laboratory data using the RL, OSEM, and BB methods. a) Test object (galaxy) used for the laboratory experiment (simulated resolution corresponding to a diffraction-limited 22.8 m single-dish telescope). b), c) Laboratory LBT raw images and PSFs for pupil position angles 0 $^\circ$ and 60 $^\circ$ . d), e), f) Diffraction-limited reconstructions derived from 6 LBT raw images (total magnitude $H = 16.2^{\rm m}$ ) using the RL d), OSEM e), and BB methods f). The restoration errors are 6.85% d), 6.76% e), and 6.23% f). The typical computing (PC) times for the RL, OSEM, and BB methods were 6 min, 4 min, and 3 min, respectively.
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In the text

$\begin{figure} \par\includegraphics[width=8.6cm,clip]{3480fig6.ps} \end{figure}$ Figure 6: Intensity cuts along a horizontal line through the nucleus for the test object (Fig. 5a; red), the RL reconstruction (Fig. 5d; green), the OSEM reconstruction (Fig. 5e; blue), and the BB reconstruction (Fig. 5f; pink).
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In the text

$\begin{figure} \par\includegraphics[width=13.4cm,clip]{3480fig7.eps} %\end{figure}$ Figure 7: Image reconstruction from computer-simulated LBT data with space-variant PSFs using the space-variant BB method. a) Computer-generated object convolved with the PSF corresponding to a single-dish 22.8 m pupil: the object is a cluster of 7 stars (5 stars have magnitude J = 22.21 $^{\rm m}$ , the 2 fainter stars have J = 22.97 $^{\rm m}$ ). b) One of the simulated LBT raw images (position angle 60 $^\circ$ ): Poisson noise corresponding to an average number of $8\times 10^5$ photons, detector noise of 11 e^- rms, and a sky background brightness of J = 16 $^{\rm m}$ per arcsec square. The three reference stars are located at the top left, bottom left and at the right-hand side; c)-e) PSFs of the 3 reference stars magnified by a factor of $\sim$ 2.5 and displayed without photon noise to visualize their space-variant Strehl ratios of 92 $\%$ , 60 $\%$ , and 17 $\%$ (from left to right); f), g) diffraction-limited images reconstructed from 3 LBT raw images recorded with pupil position angles 0 $^\circ$ , 60 $^\circ$ , and 120 $^\circ$ obtained with the space-variant f) and space-invariant g) version of the Building Block method. The restoration errors of the two reconstructions are 5.55% f); space-variant BB method) and 21.67% g); space-invariant BB method). The typical computing (PC) times for the space-variant and space-invariant BB methods were 5 min and 5 min, respectively.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{3480fig3.eps} \end{figure}$	Figure 3: a) Modulus of the Fourier transform of a single computer-simulated LBT raw image of a point source (pupil position angle 30 $\circ$ ). b) Same as a), but with all Fourier elements outside the uv-coverage set to zero (see text).
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$\begin{figure} \par\includegraphics[width=8.4cm,clip]{3480fig4.ps} \end{figure}$	Figure 4: Intensity cuts along a line through the nucleus and the faint star-like object (upper left corner in Fig. 1b) for the test object (Fig. 1b; red), the RL reconstruction (Fig. 1g; green), the OSEM reconstruction (Fig. 1h; blue), and the BB reconstruction (Fig. 1i; pink).
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$\begin{figure} \par\includegraphics[width=8.6cm,clip]{3480fig6.ps} \end{figure}$	Figure 6: Intensity cuts along a horizontal line through the nucleus for the test object (Fig. 5a; red), the RL reconstruction (Fig. 5d; green), the OSEM reconstruction (Fig. 5e; blue), and the BB reconstruction (Fig. 5f; pink).
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