# US 2017/0366730 A1 · Imaging apparatus, flicker detection method, and flicker detection program > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0366730 A1 - Document ID: US20170366730A1 - Status: Published application - Kind: A1 - Application number: 15/693,921 - Filed: 2017-09-01 - Published: 2017-12-21 - Earliest claimed: 2015-03-02 - Assignees: FUJIFILM Corporation - Applicants: FUJIFILM Corporation - Inventors: Tatsuo ONODERA - Web page: https://patentgrep.com/patent/US20170366730A1 ## CPC - H04N 23/745: Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination - H04N 23/76: by influencing the image signals - H04N 25/531: by controlling rolling shutters in CMOS SSIS - H04N 25/60: Noise processing, e.g. detecting, correcting, reducing or removing noise - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An imaging apparatus includes: an imaging element; an imaging element driving unit that directs the imaging element to alternately perform imaging operations at a first frame rate and a second frame rate being different from the first frame rate; and a flicker detection unit that detects whether a first flicker of a light source with a first frequency is present and whether a second flicker of a light source with a second frequency is present, based on a first captured image signal obtained by an imaging operation at the first frame rate and a second captured image signal obtained by an imaging operation at the second frame rate as defined herein, and a sum of a duration of a first frame period based on the first frame rate and a duration of a second frame period based on the second frame rate is a value as defined herein ## Claims ### Claim 1 An imaging apparatus comprising: an imaging element; an imaging element driving unit that directs the imaging element to alternately perform imaging operations at a first frame rate and a second frame rate being different from the first frame rate; and a flicker detection unit that detects whether a first flicker of a light source with a first frequency is present and whether a second flicker of a light source with a second frequency is present, based on a first captured image signal obtained by an imaging operation at the first frame rate and a second captured image signal obtained by an imaging operation at the second frame rate, wherein a sum of a duration of a first frame period based on the first frame rate and a duration of a second frame period based on the second frame rate is a value obtained by multiplying a reciprocal of the first frequency or the second frequency by a natural number, and the flicker detection unit detects whether the first flicker is present and whether the second flicker is present, based on a first coincidence between a set of the first captured image signals or a set of the second captured image signals and a second coincidence between the first captured image signal obtained for the first frame period in the imaging operation at the first frame rate and the second captured image signal obtained for the second frame period following the first frame period. ### Claim 2 (depends on 1) The imaging apparatus according to claim 1, wherein, in a case in which the sum is a value obtained by multiplying the reciprocal of the first frequency by a natural number, the flicker detection unit detects that the second flicker is present in a case in which the first coincidence is equal to or less than a first threshold value, detects that the first flicker is present in a case in which the first coincidence is greater than the first threshold value and the second coincidence is equal to or less than a second threshold value, and detects that there is no flicker in a case in which the first coincidence is greater than the first threshold value and the second coincidence is greater than the second threshold value. ### Claim 3 (depends on 2) The imaging apparatus according to claim 2, wherein, in a case in which the sum is a value obtained by multiplying the reciprocal of the second frequency by a natural number, the flicker detection unit detects that the first flicker is present in a case in which the first coincidence is equal to or less than the first threshold value, detects that the second flicker is present in a case in which the first coincidence is greater than the first threshold value and the second coincidence is equal to or less than the second threshold value, and detects that there is no flicker in a case in which the first coincidence is greater than the first threshold value and the second coincidence is greater than the second threshold value. ### Claim 4 (depends on 1) The imaging apparatus according to claim 1, wherein the first frame rate is a value other than a value obtained by dividing the second frequency by a natural number, and in a case in which the sum is a value obtained by multiplying the reciprocal of the first frequency by a natural number, the flicker detection unit detects that there is no flicker in a case in which the second coincidence is greater than a second threshold value, detects that the second flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is equal to or less than a first threshold value, and detects that the first flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is greater than the first threshold value. ### Claim 5 (depends on 4) The imaging apparatus according to claim 4, wherein the first frame rate is a value other than a value obtained by dividing the first frequency by a natural number, and in a case in which the sum is a value obtained by multiplying the reciprocal of the second frequency by a natural number, the flicker detection unit detects that there is no flicker in a case in which the second coincidence is greater than the second threshold value, detects that the first flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is equal to or less than the first threshold value, and detects that the second flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is greater than the first threshold value. ### Claim 6 (depends on 1) The imaging apparatus according to claim 1, wherein, in a case in which the flicker detection unit detects that the first flicker or the second flicker is present, the imaging element driving unit drives the imaging element under a driving condition for preventing deterioration of image quality due to the detected flicker. ### Claim 7 (depends on 2) The imaging apparatus according to claim 2, wherein, in a case in which the flicker detection unit detects that the first flicker or the second flicker is present, the imaging element driving unit drives the imaging element under a driving condition for preventing deterioration of image quality due to the detected flicker. ### Claim 8 (depends on 1) The imaging apparatus according to claim 1, wherein the first frequency is 100 Hz and the second frequency is 120 Hz. ### Claim 9 (depends on 2) The imaging apparatus according to claim 2, wherein the first frequency is 100 Hz and the second frequency is 120 Hz. ### Claim 10 A flicker detection method comprising: an imaging element driving step of directing an imaging element to alternately perform imaging operations at a first frame rate and a second frame rate being different from the first frame rate; and a flicker detection step of detecting whether a first flicker of a light source with a first frequency is present and whether a second flicker of a light source with a second frequency is present, based on a first captured image signal obtained by an imaging operation at the first frame rate and a second captured image signal obtained by an imaging operation at the second frame rate, wherein a sum of a duration of a first frame period based on the first frame rate and a duration of a second frame period based on the second frame rate is a value obtained by multiplying a reciprocal of the first frequency or the second frequency by a natural number, and in the flicker detection step, whether the first flicker is present and whether the second flicker is present are detected, based on a first coincidence between a set of the first captured image signals or a set of the second captured image signals and a second coincidence between the first captured image signal obtained for the first frame period in the imaging operation at the first frame rate and the second captured image signal obtained for the second frame period following the first frame period. ### Claim 11 (depends on 10) The flicker detection method according to claim 10, wherein, in a case in which the sum is a value obtained by multiplying the reciprocal of the first frequency by a natural number, in the flicker detection step, it is detected that the second flicker is present in a case in which the first coincidence is equal to or less than a first threshold value, that the first flicker is present in a case in which the first coincidence is greater than the first threshold value and the second coincidence is equal to or less than a second threshold value, and that there is no flicker in a case in which the first coincidence is greater than the first threshold value and the second coincidence is greater than the second threshold value. ### Claim 12 (depends on 11) The flicker detection method according to claim 11, wherein, in a case in which the sum is a value obtained by multiplying the reciprocal of the second frequency by a natural number, in the flicker detection step, it is detected that the first flicker is present in a case in which the first coincidence is equal to or less than the first threshold value, that the second flicker is present in a case in which the first coincidence is greater than the first threshold value and the second coincidence is equal to or less than the second threshold value, and that there is no flicker in a case in which the first coincidence is greater than the first threshold value and the second coincidence is greater than the second threshold value. ### Claim 13 (depends on 10) The flicker detection method according to claim 10, wherein the first frame rate is a value other than a value obtained by dividing the second frequency by a natural number, and in a case in which the sum is a value obtained by multiplying the reciprocal of the first frequency by a natural number, in the flicker detection step, it is detected that there is no flicker in a case in which the second coincidence is greater than a second threshold value, that the second flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is equal to or less than a first threshold value, and that the first flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is greater than the first threshold value. ### Claim 14 (depends on 13) The flicker detection method according to claim 13, wherein the first frame rate is a value other than a value obtained by dividing the first frequency by a natural number, and in a case in which the sum is a value obtained by multiplying the reciprocal of the second frequency by a natural number, in the flicker detection step, it is detected that there is no flicker in a case in which the second coincidence is greater than the second threshold value, that the first flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is equal to or less than the first threshold value, and that the second flicker is present in a case in which the second coincidence is equal to or less than the second threshold value and the first coincidence is greater than the first threshold value. ### Claim 15 (depends on 10) The flicker detection method according to claims 10, further comprising: a driving step of, in a case in which the flicker detection step detects that the first flicker or the second flicker is present, driving the imaging element under a driving condition for preventing deterioration of image quality due to the detected flicker. ### Claim 16 (depends on 11) The flicker detection method according to claims 11, further comprising: a driving step of, in a case in which the flicker detection step detects that the first flicker or the second flicker is present, driving the imaging element under a driving condition for preventing deterioration of image quality due to the detected flicker. ### Claim 17 (depends on 10) The flicker detection method according to claim 10, wherein the first frequency is 100 Hz and the second frequency is 120 Hz. ### Claim 18 (depends on 11) The flicker detection method according to claim 11, wherein the first frequency is 100 Hz and the second frequency is 120 Hz. ### Claim 19 A computer readable medium storing a flicker detection program that causes a computer to perform: an imaging element driving step of directing an imaging element to alternately perform imaging operations at a first frame rate and a second frame rate different from the first frame rate; and a flicker detection step of detecting whether a first flicker of a light source with a first frequency is present and whether a second flicker of a light source with a second frequency is present, based on a first captured image signal obtained by an imaging operation at the first frame rate and a second captured image signal obtained by an imaging operation at the second frame rate, wherein a sum of a duration of a first frame period based on the first frame rate and a duration of a second frame period based on the second frame rate is a value obtained by multiplying a reciprocal of the first frequency or the second frequency by a natural number, and in the flicker detection step, whether the first flicker is present and whether the second flicker is present are detected, based on a first coincidence between a set of the first captured image signals or a set of the second captured image signals and a second coincidence between the first captured image signal obtained for the first frame period in the imaging operation at the first frame rate and the second captured image signal obtained for the second frame period following the first frame period.