Light source driving device, light source device, and image capturing device
The configuration of a light source driving device, which drives a plurality of light sources that emit light to an object to measure the distance to the object, is simplified. A light source device drives a plurality of light sources provided in a system that measures the distance to the object. The light source driving device is provided in the light source device. The light source driving device includes a light source control unit that individually controls emission of light from a plurality of light sources that emit the light to an object to measure a distance to the object.
1 . A light source driving device, comprising:
a light source information obtainment unit that obtains light source information about an amount of light emitted by, and an amount of ambient light in, a plurality of light sources; and
a light source control unit that transmits a light emission control signal constituting a plurality of bit strings to the plurality of light sources to individually control emission of the light from the plurality of light sources to an object to measure a distance to the object, wherein
the light source control unit controls the emission of the light based on the light source information and light emission conditions for emitting the light from the plurality of light sources, and
the light emission conditions are provided by a bit string stored in memory accessible by the light source control unit, the bit string representing the light emission conditions.
2 . The light source driving device according to claim 1 , wherein each light source of the plurality of light sources includes a laser diode.
3 . The light source driving device according to claim 1 , further comprising a light-emitting element drive unit for the plurality of light sources, wherein the light source information obtainment unit controls the light-emitting element drive unit and causes the plurality of light sources to emit light.
4 . The light source driving device according to claim 3 , wherein the light source control unit calculates a light emission current based on the light source information and outputs a light emission current as the light emission control signal to the light-emitting element drive unit.
5 . The light source driving device according to claim 3 , wherein the light emission conditions include an emission range of the light in the plurality of light sources.
6 . The light source driving device according to claim 1 , wherein the light source information obtainment unit obtains information about a light emission current as the light source information, the light emission current being current that causes the plurality of light sources to emit light.
7 . The light source driving device according to claim 6 , wherein the light source information obtainment unit obtains information about a threshold of the light emission current in the plurality of light sources as the light source information.
8 . The light source driving device according to claim 6 , wherein the light source information obtainment unit obtains, as the light source information, information about a linearity of the light emission current that causes light emitting elements of the plurality of light sources to emit light.
9 . The light source driving device according to claim 1 , wherein the light source information obtainment unit obtains damage to the plurality of light sources as the light source information.
10 . The light source driving device according to claim 1 , further comprising a light emission condition holding unit, wherein
the light source control unit causes the light source information obtainment unit to obtain the light source information based on the light emission conditions held in the light emission conditions holding unit; and
in response to the light emission conditions being held in the light emission condition holding unit specifying obtainment of the light source information:
the light source control unit causes the light source obtainment unit to obtain the light source information; and
the light source information obtainment unit holds the obtained light source information in a light source information holding unit.
11 . The light source driving device according to claim 1 , wherein the light source information obtainment unit obtains the light source information based on a detection result from a light-receiving unit that detects light.
12 . The light source driving device according to claim 1 , wherein light emission conditions include information as to whether or not to obtain the light source information.
13 . The light source driving device according to claim 1 , wherein the light source control unit controls the plurality of light sources to emit the light simultaneously.
14 . The light source driving device according to claim 1 , further comprising the plurality of light sources.
15 . A light source device comprising:
a plurality of light sources that emit light to an object to measure a distance to the object;
a light source information obtainment unit that obtains light source information about an amount of light emitted by, and an amount of ambient light in, a plurality of light sources; and
a light source control unit that transmits a light emission control signal constituting a plurality of bit strings to the plurality of light sources to individually control emission of the light from the plurality of light sources, wherein
the light source control unit controls the emission of the light based on the light source information and light emission conditions for emitting the light from the plurality of light sources, and
the light emission conditions are provided by a bit string stored in memory accessible by the light source control unit, the bit string representing the light emission conditions.
16 . The light source device according to claim 15 , further comprising a light emission condition holding unit, wherein
the light source control unit causes the light source information obtainment unit to obtain the light source information based on the light emission conditions held in the light emission conditions holding unit; and
in response to the light emission conditions being held in the light emission condition holding unit specifying obtainment of the light source information:
the light source control unit causes the light source obtainment unit to obtain the light source information; and
the light source information obtainment unit holds the obtained light source information in a light source information holding unit.
17 . An image capturing device comprising:
a plurality of light sources that emit light to an object;
a light source information obtainment unit that obtains light source information about an amount of light emitted by. and an amount of ambient light in. a plurality of light sources:
a light source control unit that transmits a light emission control signal constituting a plurality of bit strings to the plurality of light sources to individually control emission of the light from the plurality of light sources, wherein
the light source control unit controls the emission of the light based on the light source information and light emission conditions for emitting the light from the plurality of light sources, and
the light emission conditions are provided by a bit string stored in memory accessible by the light source control unit, the bit string representing the light emission conditions;
a sensor that detects reflected light that has been emitted and reflected by the object; and
a processing circuit that performs processing of detecting a distance to the object by measuring a time from when the light is emitted to when the reflected light is detected.
18 . The image capturing device according to claim 17 , further comprising a light emission condition holding unit, wherein
the light source control unit causes the light source information obtainment unit to obtain the light source information based on the light emission conditions held in the light emission conditions holding unit; and
in response to the light emission conditions being held in the light emission condition holding unit specifying obtainment of the light source information:
the light source control unit causes the light source obtainment unit to obtain the light source information; and
the light source information obtainment unit holds the obtained light source information in a light source information holding unit.