Exposure control apparatus, image capturing apparatus and method of controlling exposure

An exposure control apparatus, comprising:

• a photometry amount acquisition unit for acquiring a measured light amount as a photometry amount;
• a light emission amount control unit for increasing a light emission amount of a light emission unit when the photometry amount is within a certain light amount range;
• a gain control unit for increasing a gain to an output signal of an image sensor when the photometry amount is not within the light amount range and setting the gain to a constant value when the photometry amount is within the light amount range;
• an exposure time control unit for controlling an exposure time of the image sensor by synchronizing with a timing signal having a frequency provided by multiplying a reference frequency;
• and
• a pulse signal generation unit for generating a pulse signal having a frequency provided by multiplying the reference frequency,
• wherein the light emission unit emits light depending on a pulse width of the pulse signal.

An exposure control apparatus, comprising:

• a photometry amount acquisition unit for acquiring a measured light amount as a photometry amount;
• a light emission amount control unit for increasing a light emission amount of a light emission when the photometry amount is within a certain light amount range;
• a gain control unit for increasing a gain to an output signal of an image sensor when the photometry amount is not within the light amount range and setting the gain to a constant value when the photometry amount is within the light amount range;
• an exposure time control unit for controlling an exposure time of the image sensor by synchronizing with a timing signal having a frequency provided by multiplying a reference frequency;
• and
• a pulse signal generation unit for generating a pulse signal having a frequency provided by multiplying the reference frequency, wherein
• the light emission unit emits light depending on a pulse width of the pulse signal,
• the exposure time control unit starts to expose the image sensor by synchronizing with the timing signal, and
• the light emission amount control unit starts to emit light in the light emission unit by synchronizing with the timing signal.

An image capturing apparatus, comprising:

• a photometry amount acquisition unit configured to acquire a measured light amount as a photometry amount;
• a light emission amount control unit configured to increase a light emission amount of a light emission unit when the photometry amount is between a first threshold value and a second threshold value;
• and
• a gain control unit configured to increase the gain to the output signal of the image sensor when the photometry amount is less than a third threshold value;
• and
• the gain control unit configured to set the gain to a constant value when the photometry amount is between the third threshold value and a fourth threshold value;
• and
• an image capturing unit for image capturing an image including the output signal.

A method of controlling exposure, comprising:

• acquiring a measured light amount as a photometry amount;
• controlling a light emission amount by increasing a light emission amount of a light emission unit when the photometry amount is between a first threshold value and a second threshold value;
• and
• controlling a gain by increasing the gain to the output signal of the image sensor when the photometry amount is less than a third threshold value and setting the gain to a constant value when the photometry amount is between the third threshold value and a fourth threshold value.