  The IHS sharpening technique is one of the most commonly used techniques for
sharpening. Different transformations have been developed to transfer a color
image from the RGB space to the IHS space. Through literature, it appears that,
various scientists proposed alternative IHS transformations and many papers
have reported good results whereas others show bad ones as will as not those
obtained which the formula of IHS transformation were used. In addition to
that, many papers show different formulas of transformation matrix such as IHS
transformation. This leads to confusion what is the exact formula of the IHS
transformation?. Therefore, the main purpose of this work is to explore
different IHS transformation techniques and experiment it as IHS based image
fusion. The image fusion performance was evaluated, in this study, using
various methods to estimate the quality and degree of information improvement
of a fused image quantitatively.
