Endoscope system, control device, method of controlling light source, and computer-readable recording medium
An endoscope system includes: a light source configured to emit a pulse light; an imager configured to capture an image on a frame by frame basis; a processor configured to: determine a first Duty target value representing a Duty ratio of the pulse light to make an image that is captured in a next imaging frame have intended brightness; based on a frequency of vocal cords, determine a light emission period at a time when the pulse light is emitted; based on the first duty target value and the light emission period, determine a pulse width of the pulse light that is emitted next; and based on the light emission period and the pulse width, control the light source in light emission.
1 . An endoscope system comprising:
a light source configured to emit a pulse light;
an imager configured to capture an image on a frame by frame basis; and
a processor configured to:
determine a first duty target value representing a duty ratio of the pulse light to make an image that is captured in a next imaging frame have intended brightness;
based on a frequency of vocal cords, determine a light emission period for a time when the pulse light is emitted;
based on the first duty target value and the light emission period, determine a pulse width of the pulse light that is emitted next; and
based on the light emission period and the pulse width, control the light source in light emission,
wherein, as for the first duty target value,
in a case of a first pulse in the imaging frame, the first duty target value is determined based on brightness of an image that is previously acquired, and
in a case of a different pulse after the first pulse in the imaging frame, the first duty target value is determined based on:
a second duty target value; and
a carry over error,
wherein the carry over error is a difference between the second duty target value of a pulse of light that is emitted one time before a current pulse and a duty control value representing an actual duty ratio of the pulse of light that is emitted one time before the current pulse.
2 . The endoscope system according to claim 1 , wherein the processor is configured to calculate the pulse width in a step size of an integral multiple of a line period of the imager.
3 . The endoscope system according to claim 1 , further comprising:
an audio input portion configured to receive an input of a sound that is made by a living organism and thus generate an audio signal; and
a detector configured to detect a frequency of vibrations of the vocal cords based on the audio signal that is generated by the audio input portion.
4 . A control device configured to control a light source configured to emit a pulse light, the control device comprising:
a processor configured to:
determine a first duty target value representing a duty ratio of the pulse light to make an image that is captured in a next imaging frame have intended brightness;
based on a frequency of vocal cords, determine a light emission period for a time when the pulse light is emitted;
based on the first duty target value and the light emission period, determine a pulse width of the pulse light that is emitted next; and
based on the light emission period and the pulse width, control the light source in light emission,
wherein, as for the first duty target value,
in a case of a first pulse in the imaging frame, the first duty target value is determined based on brightness of an image that is previously acquired,
in a case of a different pulse after the first pulse in the imaging frame, the first duty target value is determined based on:
a second duty target value; and
a carry over error,
wherein the carry over error is a difference between the second duty target value of a pulse of light that is emitted one time before a current pulse and a duty control value representing an actual duty ratio of the pulse of light that is emitted one time before the current pulse.
5 . A method of controlling a light source configured to emit a pulse light, the method comprising:
determining a first duty target value representing a duty ratio of the pulse light to make an image that is captured in a next imaging frame have intended brightness;
based on a frequency of vocal cords, determining a light emission period for a time when the pulse light is emitted;
based on the first duty target value and the light emission period, determining a pulse width of the pulse light that is emitted next; and
based on the light emission period and the pulse width, controlling the light source in light emission,
wherein, as for the first duty target value,
in a case of a first pulse in the imaging frame, the first duty target value is determined based on brightness of an image that is previously acquired, and
in a case of a different pulse after the first pulse in the imaging frame, the first duty target value is determined based on:
a second duty target value; and
a carry over error,
wherein the carry over error is a difference between the second duty target value of a pulse of light that is emitted one time before a current pulse and a duty control value representing an actual duty ratio of the pulse of light that is emitted one time before the current pulse.
6 . A non-transitory computer-readable recording medium with an executable program stored thereon, the program causing a processor to execute:
determining a first duty target value representing a duty ratio of a pulse light to make an image that is captured in a next imaging frame have intended brightness;
based on a frequency of vocal cords, determining a light emission period for a time when the pulse light is emitted;
based on the first duty target value and the light emission period, determining a pulse width of the pulse light that is emitted next; and
based on the light emission period and the pulse width, controlling a light source in light emission,
wherein, as for the first duty target value,
in a case of a first pulse in the imaging frame, the first duty target value is determined based on brightness of an image that is previously acquired, and
in a case of a different pulse after the first pulse in the imaging frame, the first duty target value is determined based on:
a second duty target value, and
a carry over error,
wherein the carry over error is a difference between the second duty target value of a pulse of light that is emitted one time before a current pulse and a duty control value representing an actual duty ratio of the pulse of light that is emitted one time before the current pulse.