1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a computer readable recording device for processing an in-vivo intraluminal image formed of a plurality of wavelength components.
2. Description of the Related Art
As image processing performed on an image that is captured by a medical observation apparatus, such as an endoscope or a capsule endoscope, inside a lumen of a living body (hereinafter, the image is described as an intraluminal image or simply described as an image), there is a known technology for extracting a specific region, such as an abnormal area, based on a distribution of feature data in the image (for example, Japanese Laid-open Patent Publication No. 2010-113616).
The endoscope or the capsule endoscope captures an image that covers from a near view to a distant view through a content fluid (a digestive fluid, such as bile) inside the lumen; therefore, color information in the image varies depending on the amount of the content fluid through which light passes. Specifically, in a feature space based on the color information, a boundary used for discriminating whether an imaging object is a normal area or a lesion area varies depending on a distance from a capsule endoscope or the like to the imaging object. Therefore, in the technology disclosed in Japanese Laid-open Patent Publication No. 2010-113616, an image is divided into regions based on the value of a specific wavelength component (specifically, a R component), which is specified according to the degree of absorption or scattering in a living body from among a plurality of wavelength components contained in the image, and a target of interest in each of the divided regions is specified by using a discrimination criterion set for each of the regions. Consequently, it becomes possible to accurately discriminate a lesion area irrespective of the distance to the imaging object.