Abstract: In an electronic endoscope of the present invention, an edge detection circuit detects a down edge section and an up edge section of both ends of a blood vessel in a width direction based on a G signal output from an RGB color conversion circuit, an R coefficient selector and a B coefficient selector select, for example, a coefficient smaller than 1 for the detected down edge section and select, for example, a coefficient larger than 1 for the up edge section, and a multiplier multiplies an R signal and a B signal by these coefficients. As a result, both ends of the blood vessel are highlighted with a left end part expressed blackish and a right end part expressed reddish, making it possible to clearly display blood vessels in mucous membranes on a monitor.

Abstract: The apparatus according to the present invention includes a level adjusting circuit that increases a gain of a G (or B) signal output from a color conversion circuit, a binarization circuit that forms a binarized image from this G signal and an edge detection circuit that extracts blood vessel position signals through edge detection based on this binarized signal. Then, the apparatus extracts RGB color signals making up a blood vessel image by using the above-described blood vessel position signals, increases the gains of these blood vessel color signals and then adds the blood vessel color signals to the color signals of an original image. This allows blood vessels to be displayed in high contrast to mucous membranes, etc. Furthermore, the apparatus can also amplify the R signal and B signal by using a signal obtained by differentiating the above-described G signal as a gain signal to highlight blood vessels.

Abstract: In an electronic endoscope using an imaging element comprising a colour filter for pixel binning, it is possible to carry out outline enhancement processing, zoom processing, and the like, to a high degree of detail. An optical chopper 36 in the form of a semi-circular plate is caused to rotate at {fraction (1/30)}th second per revolution, and images are captured in time periods of {fraction (1/60)}th second separated by light shielding intervals of {fraction (1/60)}th second. An imaging signal for the odd-numbered lines and the even-numbered lines is read out successively from the imaging element at {fraction (1/60)}th second intervals, and stored in memories 23 and 24, respectively.

Abstract: In a first signal suppressing process, in cases where a signal level of a certain color signal among color signals obtained from an image sensing operation is higher than a predetermined signal level, the certain color signal is suppressed. An image sensing operation with a comparatively large exposure quantity and an image sensing operation with a comparatively small exposure quantity are performed alternately. It is detected that suppression of a certain color signal is performed in the first signal suppressing process when the image sensing operation with a comparatively large exposure quantity is performed. A calculation is made to find composition ratios of the color signals, which are obtained from the image sensing operation with a comparatively small exposure quantity. A second signal suppressing process is performed for suppressing at least one color signal other than the certain color signal such that the composition ratios become identical with the calculated composition ratios.

Abstract: In an electronic endoscope of the present invention, an edge detection circuit detects a down edge section and an up edge section of both ends of a blood vessel in a width direction based on a G signal output from an RGB color conversion circuit, an R coefficient selector and a B coefficient selector select, for example, a coefficient smaller than 1 for the detected down edge section and select, for example, a coefficient larger than 1 for the up edge section, and a multiplier multiplies an R signal and a B signal by these coefficients. As a result, both ends of the blood vessel are highlighted with a left end part expressed blackish and a right end part expressed reddish, making it possible to clearly display blood vessels in mucous membranes on a monitor.

Abstract: The apparatus according to the present invention includes a level adjusting circuit that increases a gain of a G (or B) signal output from a color conversion circuit, a binarization circuit that forms a binarized image from this G signal and an edge detection circuit that extracts blood vessel position signals through edge detection based on this binarized signal. Then, the apparatus extracts RGB color signals making up a blood vessel image by using the above-described blood vessel position signals, increases the gains of these blood vessel color signals and then adds the blood vessel color signals to the color signals of an original image. This allows blood vessels to be displayed in high contrast to mucous membranes, etc. Furthermore, the apparatus can also amplify the R signal and B signal by using a signal obtained by differentiating the above-described G signal as a gain signal to highlight blood vessels.

Abstract: With an electronic endoscope, a wide band video signal is output to connected instruments without giving electric shocks to a body even when the connected instruments are not insulated. The video signal V is converted to differential signals V1, V2 by a differential amp 31 and input to buffers 42, 43 via capacitors 32, 33. The clamp signal CP generated by the clamp signal output means 44 is input to the end terminals of the switches SW1, SW2 via the photocoupler 46. The differential signals V1, V2 undergo pulse clamping in the buffers 42, 43 and the DC components are restored. The video signal restoring portion 49 restores the video signal V on the basis of the differential signals V1, V2 having undergone DC restoration and outputs the video signals to the connected instruments.