Abstract: An image not subjected to color correction, gamma correction, MTF correction and others is used as an image to be subjected to Retinex image processing. Thus, a RAW image prepared only by converting an electric signal of a CCD image sensor by an A/D converter into a digital form is used as an image to be subjected to the Retinex processing. Predetermined gamma correction is performed after the Retinex processing. Thereby, Retinex algorithm substantially modeling functions of a retina and a cortex of a living body exhibits its original performance. The resolution of the original image is lowered, and processing is performed on an image thus produced to produce a blurred image. Then, the resolution of the blurred image is restored to the same resolution as that of the original image, and the Retinex processing is performed. Thereby, the Retinex processing can be performed without increasing memory consumption and extremely lowering an operation speed.

Abstract: An object is illuminated sequentially with light of wavelengths in respective narrow bands through a light guide in an electronic endoscope provided with an imaging device. The picture images are photoelectrically converted by the imaging device and are temporarily stored respectively in memories. The spectral distribution characteristics of the object are calculated by using spectral distribution calculating data and are displayed on a display.

Abstract: A method and image processing system is for reconstruction of an input image. The method for reconstruction of an input image includes a step of inputting image data (for example, densities) of at least two pixels nearest to a position of an additional pixel to be added to the input image and those of neighbor pixels located on extension lines of segments drawn between the position of the additional pixel and that of each of the nearest pixels of which the image data were inputted, and a step of estimating the value of the image data of the additional pixel on the basis of the inputted image data of at least two pair of the nearest and corresponding neighbor pixels by using an improved and simple algorithm which is newly proposed herein and called "linear extrapolation and average method".