Welcome to the
Claudio Rocchini's Research
claudiorockini.name

CMYK to RGB conversion...

... It's not an easy task! References are poor and difficult to find even on the web.

A very good paper is: Digital simulation of offset colour printing and calculation of four-color printing plates K. I Zelianeos, N. G Theofanous - ITC Journal, 1998-1, pp. 15-24. The first part of following code is based on this paper, wicht defines a stimulus equation simulating the four-color printing.

Applying the Zelianeos-Theofanous stimulus equation and comparing the results with scanned real printing, some residual error remains. We have attempted to model this residual error with a quadratic formula based on the original cmyk value. The parameters of quadratic correction are obtained by best-fitting of scanned real data.

Below the code wich implements out cmyk2rgb transformation.

The code

The following source C++ source code implementes our conversion. The code contains two functions:

  void cmyk2rgb( const byte cmyk[], byte rgb[] );
  void dcmyk2rgb( const double cmyk[], double rgb[] );
The first function accepts interger values from 0 to 255, the second one accepts double values from 0 to 1.

Download the C++ source code:

Download an example of image conversione using TIFFLIB:

Examples

Some examples of software application. On the left the original image (tif cmyk + png rgb obained from commercial software), on the center the GIMP conversion, on the right our conversion.
Original (Converted using Commercial software)

Download original CMYK tif
Converted using GIMP

 
Converted using our software
Original (Converted using Commercial software)

Download original CMYK tif
Converted using GIMP

 
Converted using our software
© Photo from the author: Mostra dei Fiori a Firenze, Cascate Austriache


Sliders from the Past:

  1. My Master Thesis (1997)
  2. A General Method for Preserving Attributes Values on Simplified Meshes (1998 - Granada)
  3. Attivita' (1998)
  4. Acquisizioni (1999)
  5. Acquisizione del colore (1999)
  6. Un prototipo di 3D scanner (1999 - Pisa)
  7. Multiple Textures Stitching and Blending on 3D Objects (1999)
  8. Marching Intersections: an Efficient Resampling Algorithm for Surface Management (2000 - Genova)
  9. 3D Scanning a basso costo con luce strutturata (2000 - Pisa)
  10. Attivita' (2001)
  11. Oggetti artistici tridimensionali e range scanning (2001, Bressanone)
  12. A low cost 3D scanner based on structured light (Eurographics 2001)
  13. Derivazione IGM - ASITA 2012
Posters
  1. Rilievo Tridimensionale della Minerva di Arezzo
  2. 3D Scanning and Cultural Heritage
  3. 3D Scanning


Selected publications:

  1. C. Rocchini, G. Ciacci, A. Baldi, M. V. De Vita, T. Bianchi. Il Collaudo del DB Topografico della Puglia. VIII Workshop Beni Ambientali e Culturali e GIS - Firenze 19 Novembre 2009.
  2. C. Rocchini. I sistemi informativi geografici orientati alla rete dell'Istituto Geografico Militare. Convegno Nazionale Associazione Italiana di Cartografia. Firenze, 6-8 maggio 2009.
  3. C. Rocchini. Il trattamento della toponomastica nella cartografia digitale. Convegno Nazionale Associazione Italiana di Cartografia: "Luoghi e Tempo nella Cartografia", Trieste, 20-22 aprile 2005.
  4. C. Rocchini. Un Metodo per la Generalizzazione Automatica di Aree. 8° Conferenza Nazionale ASITA "GEOMATICA standardizzazione, interoperanbilità e nuove tecnologie", Roma, 14-17 dicembre 2004.
  5. C. Rocchini. Simbolizzazione Automatica di Oggetti Areali e Lineari. 8° Conferenza Nazionale ASITA "GEOMATICA standardizzazione, interoperanbilità e nuove tecnologie", Roma, 14-17 dicembre 2004.
  6. C. Rocchini, P. Cignoni, F. Ganovelli, C. Montani, P. Pingi, and R. Scopino. The Marching Intersections Algorithm for Merging Range Images. The Visual Computer, 20 (2-3), May 2004, 149 – 164.
  7. C. Rocchini. Nuovi sviluppi nel processo di produzione dei plastici dell’IGM. Convegno Nazionale Associazione Italiana di Cartografia: "Cartografia della Montagna". Trento, maggio 2003.
  8. F. Ganovelli, F. Ponchio, C. Rocchini. Fast Tetrahedron-Tetrahedron overlap Algorithm. ACM Journal of Graphics Tools, Volume 7, number 2 (2003).
  9. P. Cignoni, C. Rocchini, C. Montani, R. Scopigno. External Memory Management and Simplification of Huge Meshes. IEEE Trans. on Visualization and Computer Graphics, vol. 9(4),Oct-Dic 2003, pp.525-537.
  10. C. Rocchini, P. Cignoni, C. Montani and R. Scopino. Acquiring, Stitching and Blending Appearance Attributes on 3D Models. The Visual Computer, Springer International, 18 (2002) 3, 186-204, 2002.
  11. Fontana, R. Greco, M. Materazzi, M. Pampaloni, E. Pezzati, L. Rocchini, C. Scopino. Three-dimensional modelling of statues: the Minerva of Arezzo. Cultural Heritage Journal, Vol. 3, n. 4, 2002, pp. 325-331.
  12. M. Tarini, M. Callieri, C. Montani, C. Rocchini, K. Olsson, and T. Persson. Marching Intersections: An Efficient Approach to Shape-from-Silhouette. 7th Int.l Fall Workshop on Vision, Modeling, and Visualization 2002, Erlangen (D), Nov. 20 - 22, 2002.
  13. Marco Callieri, Paolo Cignoni, Claudio Rocchini, Roberto Scopino. Weaver, an automatic texture builder. 3D Data Processing, Visualization and Transmission, Int. Conf., Padova, June 19-21, 2002.
  14. P. Cignoni, C. Montani, C. Rocchini, C. Scopigno. Acquisition and management of digital 3D models of statues. 3rd International Congress on "Science and Technology for the Safeguard of Cultural Heritage in the Mediterranean Basin". Alcalà de Henares (Spain) 9-14 July 2001, Proceedings Vol. II, 1159-1164. A. Guarino ed.. Universidad de Alcalá and Consiglio Nazionale delle Ricerche, 2002.
  15. F. Guerra, C. Balletti , L. Pezzati, R. Fontana, E. Pampaloni, R. Scopigno, C. Rocchini. Laser scanning for shape measurements. 3D Digital Imaging and Modeling Applications of: Heritage, Industry, Medicine & Land. Workshop Proc., Padua (I), 3-4 April, 2001.
  16. C. Rocchini, P. Cignoni. Generating Random Points in a Tetrahedron. Journal of Graphics Tools, A.K. Peters Ltd., 5 (4), 9-12, 2000.
  17. C. Rocchini, P. Cignoni, C. Montani, P. Pingi and R. Scopigno. A low cost optical 3D scanner. Computer Graphics Forum, , Blackwell Publishers, (in press), Febr. 2001.
  18. C. Rocchini, P. Cignoni, F. Ganovelli, C. Montani, P. Pingi and R. Scopigno. Marching Intersections: an Efficient Resampling Algorithm for Surface Management. International Conference on Shape Modeling and Applications (SMI 2001), Genova, Italy, 7-11 May 2001.
  19. C. Rocchini and R. Scopigno. A low-cost Optical 3D scanner. ERCIM News, (44)17-18, January 2001.
  20. C. Rocchini, P. Cignoni, C. Montani, P. Pingi, R. Scopigno, L. Pezzati, M. Cygielman, R. Giachetti, G. Gori, M. Miccio, R. Pecchioli. 3D Scanning the Minerva of Arezzo; ICHIM 2001 Cultural Heritage and Technology in the Third Millennium, Milano (Italy), Jan. 2001.
  21. C. Rocchini, P. Cignoni, C. Montani, P. Pingi, R. Scopigno. A suite of tools for the management of 3D scanned data. 3D Digital Imaging and Modeling Applications of: Heritage, Industry, Medicine & Land, Workshop Proc., Padua (I), 3-4 April, 2001.
  22. M. Tarini, P. Cignoni, C. Rocchini, and R. Scopigno. Real time, accurate, multi-featured rendering of bump mapped surfaces. Computer Graphics Forum, Blackwell Publishers, 19(3):119-130, august 2000.
  23. P. Cignoni, C. Costanza, C. Montani, C. Rocchini, R. Scopigno. Simplification of tetrahedral meshes with accurate error evaluation. In IEEE Visualization, pages 85-92, Salt Lake City, Utah, USA, October 9-13 2000. ACM Press.
  24. P. Cignoni, C. Montani, C. Rocchini, R. Scopigno, and M. Tarini. Preserving attribute values on simplified meshes by re-sampling detail textures. The Visual Computer, Springer International, 10(15):519-539, 2000.
  25. P. Cignoni, C. Montani, C. Rocchini, R. Scopigno, and P. Pingi. 3D scanning and rendering cultural heritage artifacts on a low budget. In High Performance Graphics Systems and Applications European Workshop, pages 11-14, Palazzo Marescotti, Bologna, Italy, October 16-17 2000. CINECA.
  26. M. Tarini, P. Cignoni, C. Rocchini, and R. Scopigno. Computer assisted reconstruction of buildings from photographic data. In B. Girod, H. Niemann, and H.-P. Seidel, editors, Vision, Modeling and Visualization 2000, Saarbrucken, Germany, November 22 - 24 2000. IOS Press, pp. 213-220.
  27. M. Tarini, P. Cignoni, C. Rocchini, and R. Scopigno. Real time, accurate, multi-featured rendering of bump mapped surfaces. Technical Report IEI:B4-01-00, IEI, CNR, Pisa, March 2000.
  28. P. Cignoni, C. Montani, C. Rocchini, and R. Scopigno. External memory simplification of huge meshes. Technical Report IEI:B4-02-00, IEI, CNR, Pisa, March 2000.
  29. P. Cignoni, F. Ganovelli, C. Montani, P. Pingi, C. Rocchini, and R. Scopigno. Virtual marching cubes: Simple and effcient topological simplification. Technical Report IEI:B4-03-00, IEI, CNR, Pisa, March 2000.
  30. C. Rocchini, P. Cignoni, C. Montani, and R. Scopigno. Multiple textures stitching and blending on 3d objects. In G. Ward and D. Lischinsky, editors, 10th Eurographics Workshop on Rendering, pages 127-138, Granada (E), Hune 21-23 1999. EuroGraphics.
  31. P. Cignoni, C. Montani, C. Rocchini, and R. Scopigno. Zeta: a resolution modeling system. GMIP: Graphical Models and Image Processing, 60(5):305-329, September 1998.
  32. P. Cignoni, C. Montani, C. Rocchini, and R. Scopigno. Texture detail acquisition and zippering. Technical Report IEI:B4-34-98, IEI-CNUCE, CNR, Pisa, November 1998.
  33. P. Cignoni, C. Montani, C. Rocchini, R. Scopigno, and M. Tarini. Preserving attribute values on simplified meshes by resampling detail textures. Technical Report IEI:B4-35-98, IEI-CNUCE, CNR, Pisa, November 1998.
  34. P. Cignoni, C. Montani, C. Rocchini, and R. Scopigno. High quality pictorial detail acquisition and patching on 3d objects. Technical Report IEI:B4-35-98, IEI, CNR, Pisa, December 1998.
  35. P. Cignoni, C. Rocchini, and R. Scopigno. Metro: measuring error on simplified surfaces. Computer Graphics Forum, Blackwell Publishers, 17(2):167-174, June 1998.
  36. P. Cignoni, C. Montani, C. Rocchini, and R. Scopigno. A general method for recovering attribute values on simplifed meshes. In H. Hagen D. Ebert and H. Rushmeier, editors, IEEE Visualization '98 Conference Proceedings, pages 59-66, Research Triangle Park (NC), October 18-23 1998. IEEE, ACM Press.
On the top (from left to right): Me and my Low Cost 3D scanner, Virtual MC 3D algorithm at work, Low Cost 3D Scanner pattern over Tutankhamon, Zeta Resolution Editing on a body model. On the bottom (from left to right). Virtual MC 2D algorithm at work, Patterns on Stanford Bunny, folding a cube into a tetrahedron, Digital Minerva of Arezzo, Digital Roberto's Vase, Metro on handle and Paolo's Math Handle triangle stripped.
Support Wikipedia