To provide an image processing device, an image processing method, and an image processing program capable of performing image processing beneficial for producing an image having high visibility without giving a sense of incongruity to a user such as a doctor. An image processing device is provided, the image processing device being provided with a weighting determination unit and a brightness calculation unit, wherein: when a region made up of a plurality of pixels, which is at least one portion of an input image input to the image processing device, is defined as a noted region, and this input image, either originally or as a result of an operation after being input, is an image expressed in an RGB color space, that is, each pixel is made up of an R component configuring red, a G component configuring green, and a B component configuring blue, and these are collectively defined as RGB components.
