33. A readable matrix code image fusing an input image and a message based on a readable matrix coding specification, comprising: function patterns areas readable to comply with a function patterns specification; code word area readable to comply with a code word specification, the code word area including a free cells area and a derived cells area in an extent which is in compliance with the code word specification, wherein the free cells area represents free cells' whose appearance, when compared to respective areas of the input image, complies with a visual perceptual similarity criterion, and wherein the derived cells area forms, together with the free cells area, a valid code word.
33. A readable matrix code image fusing an input image and a message based on a readable matrix coding specification, comprising: function patterns areas readable to comply with a function patterns specification; code word area readable to comply with a code word specification, the code word area including a free cells area and a derived cells area in an extent which is in compliance with the code word specification, wherein the free cells area represents free cells' whose appearance, when compared to respective areas of the input image, complies with a visual perceptual similarity criterion, and wherein the derived cells area forms, together with the free cells area, a valid code word. 42. The readable matrix code image according to claim 33 , wherein one or more portions of the free cells area are associated with one or more of the following: padding cells, border cells and metadata cells.