Dome-type camera and aperture control method
View Patent ↗A dome-type camera includes a camera lens capable of rotating in a tilt direction, a dome cover for covering the camera lens, and an aperture control unit for controlling the amount of aperture of the camera lens. The amount of aperture is set to become smaller from an open value toward a closed value in accordance with the tilt angle of the camera lens becoming smaller from a zenith direction of the dome cover toward a horizontal direction. According to this dome-type camera, a desirable low tilt angle image with a reduced blur may be obtained even with a megapixel dome camera.
1. A dome-type camera comprising:
a hemispherical dome cover;
a lens unit arranged at a position offset from a spherical center of the dome cover in a zenith direction;
an aperture controller that controls an aperture amount of a camera lens; and
a zoom controller that controls a zoom factor of the camera lens,
wherein a first reference value used as a reference for the aperture amount is set to become smaller from an open value toward a closed value in accordance with an angle of the camera lens in a tilt direction becoming smaller from a zenith direction of the dome cover toward a horizontal direction,
wherein a second reference value used as a reference for the aperture amount is set to become smaller from the open value toward the closed value in accordance with an increase in the zoom factor, and
wherein the aperture amount is set using the first reference value and the second reference value.
2. The dome-type camera according to claim 1 , further comprising:
an illuminance meter that measures an illuminance of light entering the camera lens,
wherein a third reference value used as a reference for the aperture amount is set to become greater from the closed value toward the open value in accordance with a decrease in the illuminance, and
wherein a value that is set using the first reference value and the second reference value is compared with the third reference value, and the aperture amount is set to a greater of the value that is set using the first reference value and the second reference value, and the third reference value.
3. The dome-type camera according to claim 1 , wherein the lens unit includes the camera lens.
4. An aperture control method used by a dome-type camera including a hemispherical dome cover, a lens unit arranged at a position offset from a spherical center of the dome cover in a zenith direction, an aperture controller that controls an aperture amount of a camera lens, and a zoom controller that controls a zoom factor of the camera lens, the aperture control method comprising:
detecting an angle of the camera lens in a tilt direction;
determining a first reference value used as a reference for the aperture amount, to become smaller from an open value toward a closed value in accordance with the detected angle in the tilt direction becoming smaller from the zenith direction of the dome cover toward a horizontal direction;
detecting a zoom factor;
determining a second reference value used as a reference for the aperture amount, to become smaller from the open value toward the closed value in accordance with an increase in the zoom factor; and
determining the aperture amount using the first reference value and the second reference value.
5. The aperture control method according to claim 4 , further comprising:
measuring an illuminance of light entering the camera lens;
determining a third reference value used as a reference for the aperture amount, to become greater from the closed value toward the open value in accordance with a decrease in the illuminance;
comparing a value determined using the first reference value and the second reference value with the third reference value; and
determining the aperture amount as a greater of the value determined using the first reference value and the second reference value, and the third reference value.
6. The aperture control method according to claim 4 , wherein the lens unit includes the camera lens.