Hoya Corporation

Go Matsui

Kohei Iketani

Mitsufumi Fukuyama

An image-signal processing unit comprising a first and second luminance calculation block, a correction-value calculation block, and a subtraction block, is provided. The first luminance calculation block calculates a first luminance corresponding to the sum of a plurality of primary color light components. Each of them is multiplied by a coefficient from a first coefficient combination. The second luminance calculation block calculates a second luminance corresponding to the sum of a plurality of the primary color light components. Each of them is multiplied by a coefficient from a second coefficient combination. The correction-value calculation block calculates a luminance correction value according to the second luminance if the first luminance is greater than a threshold value. The subtraction block calculates a corrected luminance by subtracting the luminance correction value from the first luminance.

Image-signal processing unit

An endoscope processor including a light source controller, an imaging device driver, and a gamma-correction block, is provided. The light source controller can order first and second light sources to alternately emit first and second lights, respectively. The imaging device driver orders an imaging device to generate first and second image signals by capturing an optical image of a subject while the firs and the second light are shone on the subject, respectively. The gamma-correction block carries out gamma correction on the first and second image signals using first and second color gamma coefficients, respectively. The first and second color gamma coefficients are predetermined according to the wavelength band of the first and second lights.

Endoscope processor executing gamma correction on image signals using gamma coefficients

An electronic endoscope system comprises a video-scope, an imaging device, and a black balance processor. The imaging device, which is provided on the video-scope, is exposed at a normal shutter speed so as to generate an image signal corresponding to an optical image that is formed thereon. The black balance processor generates a black balance value for adjusting the black balance of the image signal, based on a black image signal corresponding to a black image. The black image signal is generated by exposing the imaging device at a high shutter speed that is faster than the normal shutter speed.

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Saitama, Japan

Go Matsui