A computer implemented method and apparatus for processing images comprises obtaining two or more images acquired by ultrasound. One or more operating parameters of the ultrasound probe (transducer) are varied so that the resulting images of a material or object under investigation differ with respect to intensity. Examples of parameters which may be varied include probe angle, frequencies, and even the time and/or resolution of the respective images. The method further comprises creating a new image by selectively subtracting one or more images from one or more others. In an embodiment, there are two images and one is partially subtracted from the other. If negative values are obtained as a result of the subtraction, such values are set to zero.