JP2010136250A5 - - Google Patents

Description

FIG. 1 is a schematic diagram of Embodiment 1 of the present invention. In the embodiment of FIG. 1, the photographing apparatus 103 having the photographing optical system 107 is installed in a hemispherical dome (clear dome) (dome-shaped protective case) 102 and used as the monitoring camera 101.

2 and 3, reference numeral 1 denotes a photographing optical system, which includes a four-group rear focus zoom lens (hereinafter referred to as "RFZ lens") including four lens groups. The RFZ lens 1 includes a fixed first lens unit L1, a second lens unit L2 having a variable power function, a fixed third lens unit L3 composed of an afocal system, a focus function, and an image plane associated with variable power. The fourth lens unit L4 has a function of correcting the fluctuation.

That is, it is the trajectory information of the fourth lens unit L4 stored in the storage unit in the control unit 7 when performing the zooming operation while keeping the image plane position constant.

In FIG. 5, curves a, c, and b indicate the movement trajectory of the fourth lens unit L4 during zooming when focusing on an object at infinity, an object at an intermediate distance, and an object at a close distance in order.

c (n + 1) = | c (n) −a (n) | / | b (n) −a (n) |
× | b (n + 1) −a (n + 1) | + a (n + 1) (1)
According to the equation (1), for example, in FIG. 5, when the fourth lens unit L4 is at the point c0, the ratio of the internal division from the point c0 to the line segment b0-a0 is obtained. Then, the zoom position Z is obtained from the position of the second lens group 102 on the optical axis. When the zoom position is Z1, the point c1 is a position on the optical axis of the fourth lens unit L4 that internally divides the line segment b1-a1 according to this ratio.

A position (zoom position) Z on the optical axis of the second lens unit L2 is obtained by a position sensor. When the zoom position Z is obtained, the movement locus (curve C) of the fourth lens unit L4 at each zoom position is obtained using the internal ratio described above.

Assume that the current focus position of the fourth lens unit L4 is Fpos and the zoom position is Zpos.

FIG. 6 is a diagram showing that the following locus of the fourth lens unit L4 changes when focusing on an infinite subject depending on the presence or absence of a dome. As can be seen from this figure, the fourth lens unit L4, for example, takes a trace trace obtained from the calculation described above when a dome is mounted. Also, when zooming is performed using the trajectory information with a dome when there is no dome, the shape of the movement trajectory is different, so the image plane position cannot be made constant and the focus is blurred.

Zpos: current zoom position FposTarget: preset focus position (position on the optical axis of the fourth lens unit L4 )
FposTarget A: Nearest locus position obtained from the storage locus number at the current zoom position Z FposTargetB: Infinite locus position Zpos0 obtained from the storage locus number at the current zoom position Z: Tele zoom position Zpos with storage locus data 1: There is storage locus data Wide-side zoom position FposTarget A0: Storage locus position FposTarget A1 obtained from the closest-side storage locus number at the tele-side zoom position Zpos0: Storage locus position FposTargetB0 obtained from the nearest-side storage locus number at the wide-side zoom position Zpos1 From the infinite-side storage locus number at Zpos0 Obtained memory trajectory position FposTargetB1: Memory trajectory position obtained from infinite memory trajectory number in Zpos1 α: internal ratio numerator β: internal ratio denominator FposTarget etA = FposTargetA0 + (FposTargetA1−FposTargetA0) × (Zpos−Zpos1) / (Zpos0−Zpos1)
FposTargetB = FposTargetB0 + (FposTargetB1-FposTargetB0) × (Zpos−Zpos1) / (Zpos0−Zpos1)
FposTarget = FposTargetB +
(FposTargetA-FposTargetB) × (α / β)
When the zoom operation is performed with the dome mounted, driving from the current focus position to the preset focus position FposTarget may be performed. Then, the subject distance position when stored can be reproduced even if the zoom position is changed.

Claims (5)

A photographic device detachable in a hemispherical dome-shaped protective case, the photographic device is a photographic optical system and mounting means for detachably mounting on the dome-shaped protective case;
An imaging apparatus comprising: focal length information changing means for changing focal length information of the imaging optical system when mounted in the dome-shaped protective case.   The photographing apparatus according to claim 1, wherein the focal length information changing unit is driven by vibration or remote operation by a switching unit provided in the photographing apparatus.   The photographing apparatus includes a detecting unit that detects whether or not the dome-shaped protective case is mounted, and the focal length information changing unit is configured to detect a focal length of the photographing optical system based on a signal from the detecting unit. The photographing apparatus according to claim 1, wherein the information is changed. The photographing apparatus has detection means for detecting whether or not the dome-shaped protective case is mounted, and the detecting means detects a dome shape of the dome-shaped protective case to which the photographing apparatus is mounted; 4. The photographing apparatus according to claim 1, wherein the focal length information changing unit changes focal length information of the photographing optical system based on a signal from the detecting unit. 5. . The imaging optical system imaging apparatus according to any one of claims 1 to 4, characterized in that consists of a zoom lens that performs focusing by the lens unit on the image side of the part or scaling of the scaling unit.