A number of impairments, resulting from the nature of cDNA microarray technology, affect the cDNA microarray image formation. Therefore, microarray images exhibit variations in intensity attributed mainly to variations in the image background, variations in the spot sizes and positions, artifacts caused by laser light reflection and dust on the glass slide, and photon and electronic noise introduced during scanning.

	Acquired cDNA image	=	Ideal cDNA image	+	Noise signal
Due to numerous noise sources in cDNA microarray technology, the microarray image formation is a complicated, nonlinear process influenced by many factors. The various image impairments can be represented by a noise signal with the vectorial samples considered random in nature. The acquired cDNA image can be modeled using the additive noise model with ideal and noise signals considered as the input. The noise signal is considered either impulsive in nature or it can be modeled as mixed noise, i.e. white additive Gaussian noise followed by impulsive noise.