One - dimensional image reconstruction by exponential filtering in infrared stellar speckle interferometry : application to IRC + 10216

Exponential filtering, together with an improved version of the iterative Fourier-transform algorithm, is applied to image reconstruction from one-dimensional infrared stellar speckle interferometry data. The performance of the method is checked first by computer simulations with both noiseless and noisy data and then with a realistic simulation of one-dimensional infrared stellar speckle interferometry. We have seen no problems with convergence. The only problem that we found was an expected noisy appearance of the results when noisy data were simulated. Finally, the method was applied to observational specklegrams of the infrared source IRC +10216, in two standard photometric bands: K and M (2.2 and 5 m, respectively). The reconstruction in K of a north-south scan clearly shows three components inside a circumstellar shell. On the other hand, in the M band only a wing on the north side of the main component is resolvable.