Its impossible for a chameleon to match a background like that, some of there natural colors and shape help them blend in in there natural habitates but most of the time if a chameleon is changing its colors its to attact attention, for example males fire up when seeing females, females will show if they are ready to mate or not with there colors, if a cham is mad, excited ect this will all change its color but not to match the backgroung. As far as i know the only things that can do that are cuttle fish/octopus there are probably more but thats all i know of,
Chameleons color changing abilities are tied to two things. One they attempt to better thermoregulate their body temperatures with color changes. Dark colors absorb more light this means more heat. Bright colors reflect more light meaning less heat. As their blood pressure is playing a role in these different color changes it can also be tied to their moods. Only an experienced chameleon owner can begin to understand what all the variables are that can effect these changes and the behavior that maybe associated with them. The attitude of the chameleon itself can throw off peoples best attempts to explain these changes in colors in reference to moods as they will change from chameleon to chameleon.
Brandy is right. Memember of the Octi group are the only genre of animals that have been noted to legitimittly use color changing abilities as camoflauge. Some octopuses will take this to another level by imitating the shape and color patterns of other ocean animals and objects. They have been seen imitating sea snakes with two arms while the rest is hide in a hole. No animal in the ocean wants to mess with a sea snake. This provides them with a good nites sleep. They will also flatten out and swim like a flounder. A lot of bigger fish will not eat these as they taste bad to them.
I am not laughing at you, but it makes me think of the statement that if a chameleon is placed on plaid material it will die b/c it cannot match the pattern - lol!! This is not an attack on your original inquiry, just something that makes me chuckle :E