A study of attentional effects of intensity transforms for mammograms

This paper presents a study of the attentional effects of two types of intensity distribution variations upon observer behaviour when viewing mammograms: equalisation (to a uniform image intensity histogram) and normalisation (to match an industry best practice image intensity histogram). For untrained observers, some consistent attraction of attention towards the strongest intensity regions of the images for the more highly contrasting equalised images as compared with the unprocessed images was detected. For the normalised images, this effect was even more marked. For a trained observer, no substantial disruption of attentional patterns during viewing was detected for equalised images, but was for normalised images. The nature and extent of the changes in the attentional behaviour for both untrained and trained observers indicates potential value in further studies and emphasizes the need to conduct clinically related studies with trained observers.