List of Figures

• A dark current CCD exposure with cosmic ray events which are removed with non-linear filters. (A) original, (B) 5*5 median filter, (C) 5*1 median filter, and (D) 5*1 recursive filter.
• Removal of cosmic ray events on a CCD spectral exposure with different techniques: (A) original, (B) $5 \times 1$ median filter, (C) $5 \times 1$ recursive filter and (D) stack comparison.
• Removal of artifacts on CCD exposures (A,B,C) of the galaxy A0526-16 by stacking the frames yielding the combined image (D).
• A density-intensity transformation curve for a photographic emulsion using normal densities (A) and Backer densities (B).
• A dispersion curve (A) for an IDS spectrum with the linear term omitted. The spectrum rebinned to wavelength is shown with (B1) and without the Jacobian determinant correction (B2).
• Different digital filters applied on a CCD image: (A) original, (B) block filter, (C) smooth filter, and (D) Laplacian filter.
• Removal of stars from a CCD frame of Comet Halley: (A) original, (B) $5 \times 5$ median filter, (C) $5 \times 1$ recursive filter, and (D) both recursive $5 \times 1$ filter and a $1 \times 3$ median filter.
• Background fitting with an iterative $\kappa \sigma$ technique: (A) original, (B) mask of included areas, and (C) fitted background.
• The radial profile of an elliptical galaxy shown with linear steps (A) and rebinned to r^1/4 increments (B).
• Azimuthal profile in the inner parts of a spiral galaxy A0526-16 across the spiral arms (A). The amplitude of the Fourier transform (B) of this profile shows the strong even frequencies.
• Deconvolution a photographic image with the Lucy method: (A) original and (B) restored image after 3 iterations.
• Two normalized early type spectra used as template (A1) and object (A2) yield the cross-correlation function (B).
• Correlation between two measures of the inclination angle of galaxies: (A) with angle i as variable, and (B) with $\cos(i)$.
• Romafot reduction scheme
• Romafot procedure to determine accuracy and degree of completeness
• Romafot procedure to transfer inputs to other program frames
• Echelle Reduction Scheme
• Images BARS, OFFBARS, BARS30 and BARS60.
• Images RINGS and OFFRINGS.
• Plot of sky brightness as a function of time
• Schematic flowchart for reductions
• Sample drift plot
• Morlet's wavelet: real part at left and imaginary part at right.
• Mexican Hat
• The filter bank associated with the multiresolution analysis
• Wavelet transform representation of an image
• linear interpolation $\phi$
• Wavelet $\psi$
• Passage from c₀ to c₁, and from c₁ to c₂.
• Passage from C₁ to C₀.
• Pyramidal Structure
• Wavelet Interpolation Functions
• On left, the filter $\hat{\tilde{h}}$, and on right the filter $\hat{\tilde{g}}$.
• Galaxy NGC2297
• Superposition of all the scales. This image is obtained by the command visual/cube.
• Superposition of all the scales. Each scale is plotted in a 3 dimensional representation. This image is obtained by the command visual/pers.
• Synthesis image (command visual/synt). Each scale is binarized, and represented by one gray level.
• One contour per scale is plotted (command visual/cont).
• Superposition of all the scales. This image is obtained by the command visual/cube.
• Superposition of all the scales. Each scale is plotted in a 3 dim. representation. This image is obtained by the command visual/pers.
• Synthesis image (command visual/synt).
• Synthesis image (command visual/synt). Each scale is normalized.
• Correlation.
• Signal to noise ratio.
• Trend analysis of the detector mean temperature with Modified Julian Date
• Association of DARK exposures with scientific frames
• Association of FF exposures with scientific frames
• Response/Echelle
• Reduce/Echelle (1)
• Reduce/Echelle (2)
• Main window of the GUI XEchelle
• Sky Background window
• Main window of the GUI XLong
• Panels for Open and Save As... options of the menu File
• Search Window
• Lines Identification Window
• Wavelength Calibration window
• Resampling Window
• Spectrum Extraction window
• Flux Calibration window
• Batch Reduction window
• IR Data Reduction