Enhancing the visibility of blood vessels in colour images

An image processing device for enhancing the visibility of blood vessels in a colour image, said image processing device comprising a processing unit operationally connectable to an image capturing device of a medical device, wherein said processing unit is configured to receive a colour image having a plurality of colour channels including a red colour channel, a green colour channel, and a blue colour channel from said image capturing device, said colour image has a plurality of pixels and said processing unit further is configured to, for at least some of said plurality of pixels, perform the steps of:

• (a) process data obtained from the red colour channel together with data obtained from the green colour channel to create a value of a first sub parameter, process data obtained from the red colour channel together with data obtained from the blue colour channel to create a value of a second sub parameter;
• process said value of said first sub parameter together with said value of said second sub parameter to create a value of a first parameter indicative of the intensity in a red spectrum relative to a total intensity of said pixel;
• (b) using said value of said first parameter to alter said pixel,
• wherein said first parameter has at least three possible values, and wherein the strength of the alteration is dependent on the value of said first parameter.