# US 10,484,626 B2 · Gain adjustment unit, recording medium holding gain adjustment program, endoscope and endoscope apparatus

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- Number: US 10,484,626 B2
- Document ID: US10484626B2
- Status: Granted
- Kind: B2
- Application number: 15/678,259
- Filed: 2017-08-16
- Published: 2017-12-28
- Granted: 2019-11-19
- Earliest claimed: 2016-01-12
- Assignees: Olympus Corporation
- Applicants: Olympus Corporation
- Inventors: Yasunori Matsui; Shinji Yamashita; Yuzuru Tanabe; Yuta Matsuno
- Web page: https://patentgrep.com/patent/US10484626B2

## CPC

- A61B 1/000095: {for image enhancement}
- A61B 1/045: Control thereof
- G02B 23/24: Instruments {or systems} for viewing the inside of hollow bodies, e.g. fibrescopes
- H04N 25/51: Control of the gain
- H04N 25/671: for non-uniformity detection or correction
- H04N 25/75: Circuitry for providing, modifying or processing image signals from the pixel array
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A gain adjustment unit calculates a total sum of analog gains on a way from photoelectric conversion output of an image pickup device to input of an analog/digital conversion circuit with use of picked-up images provided from the analog/digital conversion circuit, the analog/digital conversion circuit being configured to convert an output of an analog processing section into a digital signal, the analog processing section being configured to transmit and amplify an image pickup signal from the image pickup device, the image pickup device being provided at an insertion portion of an endoscope, and determines, as an adjustment gain, a difference between a target value of a total sum of gains and the total sum of the analog gains, and output information.

## Claims

### Claim 1

A gain adjustment unit, comprising:
an analog total gain calculation section configured to calculate a total sum of analog gains on a way from photoelectric conversion output of an image pickup device to input of an analog/digital conversion circuit with use of picked-up images provided from the analog/digital conversion circuit, the analog/digital conversion circuit being configured to convert an output of an analog processing section into a digital signal, the analog processing section being configured to transmit and amplify an image pickup signal from the image pickup device, the image pickup device being provided at an insertion portion of an endoscope;
an adjustment gain calculation section configured to determine, as an adjustment gain, a difference between a target value of a total sum of gains on the way from the photoelectric conversion output of the image pickup device to the input of the analog/digital conversion circuit and the total sum of the analog gains, and output information of the adjustment gain to adjust an analog gain of the endoscope; and
a memory section configured to take in the picked-up image from the analog/digital conversion circuit,
wherein the analog total gain calculation section calculates the total sum of the analog gains with use of the picked-up image based on an output of the image pickup device at bright time and the picked-up image based on an output of the image pickup device at dark time, among the picked-up images held by the memory section.

### Claim 2 (depends on 1)

The gain adjustment unit according to claim 1, wherein the analog total gain calculation section determines light shot noise of the image pickup device on a basis of statistics of the picked-up bright-time images and statistics of the picked-up dark-time images, determines a level of the picked-up bright-time image on a basis of an average value of the picked-up bright-time images and an average value of the picked-up dark-time images, and calculates the analog total gain on a basis of the determined light shot noise and the level of the picked-up image.

### Claim 3 (depends on 2)

The gain adjustment unit according to claim 2, wherein the statistics are standard deviation or dispersion values.

### Claim 4 (depends on 1)

The gain adjustment unit according to claim 1, wherein
the memory section holds the picked-up images of two frames or more at the bright time and the picked-up images of two frames or more at the dark time, and
the analog total gain calculation section removes fixed pattern noise with use of a difference between the picked-up images of two frames or more at the bright time, and removes the fixed pattern noise with use of a difference between the picked-up images of two frames or more at the dark time.

### Claim 5 (depends on 1)

An endoscope, comprising:
a recording section configured to record information of the adjustment gain that is provided from the gain adjustment unit according to claim 1; and
a digital amplifier configured to add the adjustment gain to an output of the analog/digital conversion circuit, on a basis of the information of the adjustment gain.

### Claim 6 (depends on 5)

The endoscope according to claim 5, further comprising a gain adjustment unit that includes an analog total gain calculation section and an adjustment gain calculation section, the analog total gain calculation section being configured to calculate a total sum of analog gains on a way from photoelectric conversion output of an image pickup device to input of an analog/digital conversion circuit with use of picked-up images provided from the analog/digital conversion circuit, the analog/digital conversion circuit being configured to convert an output of an analog processing section into a digital signal, the analog processing section being configured to transmit and amplify an image pickup signal from the image pickup device, the image pickup device being provided at an insertion portion of an endoscope, and the adjustment gain calculation section being configured to determine, as an adjustment gain, a difference between a target value of a total sum of gains on the way from the photoelectric conversion output of the image pickup device to the input of the analog/digital conversion circuit and the total sum of the analog gains, and to output information of the adjustment gain to adjust an analog gain of the endoscope.

### Claim 7 (depends on 5)

An endoscope apparatus, comprising:
the endoscope according to claim 5; and
a video processor configured to receive an output of the endoscope and to perform predetermined image processing on the output, wherein
the video processor includes a gain adjustment unit that includes an analog total gain calculation section and an adjustment gain calculation section, the analog total gain calculation section being configured to calculate a total sum of analog gains on a way from photoelectric conversion output of an image pickup device to input of an analog/digital conversion circuit with use of picked-up images provided from the analog/digital conversion circuit, the analog/digital conversion circuit being configured to convert an output of an analog processing section into a digital signal, the analog processing section being configured to transmit and amplify an image pickup signal from the image pickup device, the image pickup device being provided at an insertion portion of an endoscope, and the adjustment gain calculation section being configured to determine, as an adjustment gain, a difference between a target value of a total sum of gains on the way from the photoelectric conversion output of the image pickup device to the input of the analog/digital conversion circuit and the total sum of the analog gains, and to output information of the adjustment gain to adjust an analog gain of the endoscope.

### Claim 8 (depends on 1)

An endoscope, comprising:
a recording section configured to record information of the adjustment gain that is provided from the gain adjustment unit according to claim 1; and
an analog gain control section configured to control a gain of the analog processing section to add the adjustment gain to the total sum of the analog gains, on a basis of the information of the adjustment gain.