Enhancing the Visibility of Blood Vessels in Colour Images

1. A method of operating an image processing device for enhancing the visibility of blood vessels in a colour image captured by an image capturing device of a medical device, said colour image having a plurality of colour channels including a red colour channel, a green colour channel, and a blue colour channel and having a plurality of pixels, wherein said method comprises, for at least some of said plurality of pixels, the steps of: (a) processing 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, and processing 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, wherein said processing comprises subtracting said data obtained from the green colour channel from said data obtained from the red colour channel; processing 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; and (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.

2. The method according to claim 1, wherein step (a) comprises: processing data obtained from the blue colour channel to determine the value of said first parameter.

3. The method according to claim 1, wherein both said value of said first sub parameter and said value of said second sub parameter are indicative of the intensity in the red spectrum relative to the total intensity of said pixel.

4. The method according to claim 1, wherein parts of the colour image having no blood vessels are substantially unaltered and displayed with normal colours.

5. The method according to claim 1, wherein said method further comprises: determining a value of a second parameter indicative of the intensity of said pixel and wherein said value of said first parameter together with said value of said second parameter are used to alter said pixel.

6. The method according to claim 1, wherein said plurality of colour channels are normalized prior to being processed together.

7. The method according to claim 6, wherein a low pass filtered image is created for each of said plurality of colour channels indicating a local average for each pixel, and wherein each colour channel is normalized using its low pass filtered image.

8. The method according to claim 7, wherein a value of a third parameter is created based on user input, and wherein the alteration is dependent on both said value of said first parameter and said value of said third parameter, whereby the user may control the strength of the alteration.

9. The method according to claim 1, wherein a high value of the first parameter indicates a high intensity in the red spectrum relative to the total intensity of said pixel and a low value of the first parameter indicates a low intensity in the red spectrum relative to the total intensity of said pixel, wherein values of the first parameter that are among the 50% highest of all possible values results in alterations that are more significant than the alterations that result from values of the first parameter that are among the 50% lowest of all possible values.

10. The method according to claim 9, wherein for at least 50% of the possible values of said first parameter an increase in the value of the first parameter results in an increase in the strength of the alteration.

11. 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, and 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, wherein said process data comprises subtracting said data obtained from the green colour channel from said data obtained from the red colour channel; 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; and (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.

12. The image processing device according to claim 11, wherein step (a) comprises: processing data obtained from the blue colour channel to determine the value of said first parameter.

13. The image processing device according to claim 11, wherein both said value of said first sub parameter and said value of said second sub parameter are indicative of the intensity in the red spectrum relative to the total intensity of said pixel.

14. The image processing device according to claim 11, wherein parts of the colour image having no blood vessels are substantially unaltered and displayed with normal colours.

15. The image processing device according to claim 11, wherein said image processing device is operationally connectable to an input unit for receiving user input and further configured to receive a user selected value of a third parameter from said input unit and wherein the alteration is dependent on both said value of said first parameter and said value of said third parameter, whereby the user may control the strength of the alteration.

16. A display unit for displaying images obtained by an image capturing device of a medical device, wherein said display unit comprises: the image processing device according to claim 11.

17. An endoscope system comprising: an endoscope; and the image processing device according to claim 11, wherein said endoscope has an image capturing device and said processing unit of said image processing device is operationally connectable to said image capturing device of said endoscope.

18. The endoscope system according to claim 17, wherein the endoscope system further comprises a display unit, wherein said display unit is operationally connectable to said image capturing device of said endoscope and configured display said captured images.

19. A method of operating an image processing device for enhancing the visibility of blood vessels in a colour image captured by an image capturing device of a medical device, said colour image having a plurality of colour channels including a red colour channel, a green colour channel, and a blue colour channel and having a plurality of pixels, wherein said method comprises, for at least some of said plurality of pixels, the steps of: (a) processing 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, and processing 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; processing 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; and (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, and wherein prior to step (a): a low pass filtered image is created for each of said plurality of colour channels indicating a local average for each pixel, and each colour channel of said plurality of colour channels is normalized using its low pass filtered image.

20. The method according to claim 19, wherein step (a) comprises: processing data obtained from the blue colour channel to determine the value of said first parameter.

21. The method according to claim 19, wherein step (a) comprises subtracting said data obtained from the green colour channel from said data obtained from the red colour channel.

22. The method according to claim 19, wherein said method further comprises: determining a value of a second parameter indicative of the intensity of said pixel and wherein said value of said first parameter together with said value of said second parameter are used to alter said pixel.

23. The method according to claim 19, wherein a value of a third parameter is created based on user input, and wherein the alteration is dependent on both said value of said first parameter and said value of said third parameter, whereby the user may control the strength of the alteration.

24. The method according to claim 19, wherein a high value of the first parameter indicates a high intensity in the red spectrum relative to the total intensity of said pixel and a low value of the first parameter indicates a low intensity in the red spectrum relative to the total intensity of said pixel, wherein values of the first parameter that are among the 50% highest of all possible values results in alterations that are more significant than the alterations that result from values of the first parameter that are among the 50% lowest of all possible values.

25. A method of operating an image processing device for enhancing the visibility of blood vessels in a colour image captured by an image capturing device of a medical device, said colour image having a plurality of colour channels including a red colour channel, a green colour channel, and a blue colour channel and having a plurality of pixels, wherein said method comprises, for at least some of said plurality of pixels, the steps of: (a) processing 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, and processing 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; processing 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; and (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, and wherein a high value of the first parameter indicates a high intensity in the red spectrum relative to the total intensity of said pixel and a low value of the first parameter indicates a low intensity in the red spectrum relative to the total intensity of said pixel, wherein values of the first parameter that are among the 50% highest of all possible values results in alterations that are more significant than the alterations that result from values of the first parameter that are among the 50% lowest of all possible values.

26. The method according to claim 25, wherein step (a) comprises: processing data obtained from the blue colour channel to determine the value of said first parameter.

27. The method according to claim 25, wherein step (a) comprises subtracting said data obtained from the green colour channel from said data obtained from the red colour channel.

28. The method according to claim 25, wherein said method further comprises: determining a value of a second parameter indicative of the intensity of said pixel and wherein said value of said first parameter together with said value of said second parameter are used to alter said pixel.

29. The method according to claim 25, wherein a low pass filtered image is created for each of said plurality of colour channels indicating a local average for each pixel, and wherein each colour channel is normalized using its low pass filtered image.

30. The method according to claim 25, wherein a value of a third parameter is created based on user input, and wherein the alteration is dependent on both said value of said first parameter and said value of said third parameter, whereby the user may control the strength of the alteration.

31. 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, wherein said image processing device is operable to receive a user selected value of a third parameter, and wherein the alteration is dependent on both said value of said first parameter and said value of said third parameter, whereby the user may control the strength of the alteration with the user selected value.

32. The image processing device according to claim 31, wherein step (a) comprises: processing data obtained from the blue colour channel to determine the value of said first parameter.

33. The image processing device according to claim 31, wherein both said value of said first sub parameter and said value of said second sub parameter are indicative of the intensity in the red spectrum relative to the total intensity of said pixel.

34. The image processing device according to claim 31, wherein step (a) comprises subtracting said data obtained from the green colour channel from said data obtained from the red colour channel.

35. The image processing device according to claim 31, wherein step (a) comprises subtracting said data obtained from the green colour channel from said data obtained from the red colour channel to create the value of the first sub parameter; subtracting said data obtained from the blue colour channel from said data obtained from the red colour channel to create the value of the second sub parameter; averaging the value of the first sub parameter and the value of the second sub parameter to create the value of the first parameter.