Analysis of Ancient Mosaic Images for Dedicated ... - Institut Fresnel

Analysis of Ancient Mosaic Images for Dedicated Applications 467
Algorithm 1cms format coding.
Require: Mosaic image I.
Ensure: Tessera-oriented coding of I in filef.
Tessera extraction (cf. Section 16.3).
for n = 1, . . . , N do
Write the number of contour pixels Nn ←f.
Write the mean color value Vn ←f.
Write the first contour pixel coordinates ln, cn ←f.
for i = 2, . . . , Nn do
Compute chain code direction for pixel i.
Write direction ←f.
end for
end for
Algorithm 2cms format decoding.
Require: Compressed filef.
Ensure: Tessera-oriented decoding of filefinto image I.
Read file header → L, C, N, Rb, Gb, Bb.
Create an image I with dimensions L × C and background color (Rb, Gb, Bb).
for n = 1, . . . , N do
Read tessera header → Nn, Rn, Gn, Bn, ln, cn.
Set pixel (ln, cn) with color (Rn, Gn, Bn).
for i = 2, . . . , Nn do
Compute coordinates (li, ci).
Set pixel (li, ci) with color (Rn, Gn, Bn).
end for
Fill in the closed contour with color (Rn, Gn, Bn).
end for
FIGURE 16.14
Result of coding/decoding of the Deer image in Figure 16.10(a).