JPS6399679A - Automatic focussing controller - Google Patents

Abstract

PURPOSE:To detect a focusing position in a short time by selecting a horizontal scan line whose high frequency component of a video signal is maximum among plural scan lines corresponding to the video signal and finding the position of a TV camera. CONSTITUTION:A differentiation circuit 9 differentiates the video signal and its maximum amplitude within horizontal scan time is detected in an amplitude detecting circuit 10, whereby the signal is stored in a storage circuit 11 during a horizontal retrace. A motor control circuit 12 detects the position of the TV camera when the horizontal scan line scans from a position detecting circuit 14, and successively stores in the storage circuit 11. A control circuit 8 finds the maximum value among amplitude data stored in the storage circuit 11, detects the horizontal scan line whose maximum value has been obtained, and transmits position data of the TV camera 6 whose horizontal scan line is obtained to the motor control circuit 12 as a focusing position data. Thus, focus position information which is the largest and which is equal to the number of horizontal scan lines can be obtained in one screen, whereby focusing position detecting time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to TV
The present invention relates to an automatic focus adjustment device that detects the focal point position of a camera and controls the position of a TV camera.

2. Description of the Related Art A conventional fΦ automatic focusing device is disclosed in, for example, Japanese Patent Application Laid-open No. 5
2-28340-Bow gazette; 1-8 and 11 seem to be 2
′・−, the structure was as shown in Figure 2.

That is, the sample 17 is illuminated by an epi-illumination lamp 20, and an image is focused on the imaging surface of a TV camera 28 via an objective lens 18, a focusing lens 23, and an eyepiece lens 19. The video signal is differentiated by a differentiating circuit 31 and then rectified by a rectifying circuit 32. The integrating circuit 33 integrates the rectified signal of the specified scanning line at the sampling period specified by the control circuit 3.

The output signal of the integrating circuit 33 is sent to the holding circuit 34 and the comparing circuit 35.
and is sent to the level detection circuit 39. The contents of the holding circuit 34 are updated after the comparison circuit 35 completes the comparison operation. When the output of the integrating circuit 33 is larger than the content of the holding circuit 34, the motor control circuit 36 controls the motor drive circuit 38.
The motor 25 is driven in the same direction as before, and in the opposite case, the rotation direction of the motor 25 is reversed. In this way, the motor 25 is driven five times so that the amplitude of the output signal of the integrating circuit 33 is maximized, and the position of the TV camera is automatically set to the in-focus position.

Problems to be Solved by the Invention However, with the above configuration, it takes one screen's worth of time to capture the video signal to obtain the high frequency component of the video signal at a certain focal position. There is a problem in that the calculation requires at least as much video signal acquisition time as the number of times the motor is driven.

In consideration of the above-mentioned problems, the present invention makes it possible to control the high frequency components of the video signal at a certain focal position. To provide an automatic focus adjustment device that does not require the time required to capture video signals for one side.

Means for Solving the ProblemsSecondly, the automatic focus adjustment device of the present invention has a driving means for moving the TV camera near and far from the subject in synchronization with the video signal 23. , means for selecting a horizontal scanning line having the maximum high frequency component of video reliability from among a plurality of horizontal scanning lines corresponding to the video signal obtained from the TV camera;
Based on the selected horizontal scan line, the horizontal scan line is obtained T
The camera is equipped with means for determining the position of the V camera.

Operation According to the present invention, each horizontal scanning line signal of the video signal corresponds to the position of the TV camera due to the above-described configuration. In other words, up to the same number of focus position information as the number of horizontal scanning lines can be obtained on one screen, which is different from the conventional automatic focus position adjustment devices that can only obtain focus position information on one point on one screen. The in-focus position can be detected in a shorter time than it would have required processing multiple screens.

EXAMPLE Hereinafter, an automatic focus adjustment device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of an automatic focus adjustment device in one embodiment of the present invention. In Figure 1, the sample (
Subject) 1 is illuminated by an epi-illumination lamp 4 through a condensing lens 3 and a mirror 2, and a TV lens 5
An image is focused on the imaging surface of the TV camera 6 via the TV camera 6. After the video signal is differentiated by the differentiation circuit 9, the maximum amplitude within the horizontal scanning time is detected by the amplitude detection circuit 1o, and is stored in the storage circuit 11 during the horizontal retrace period. The motor control circuit 12 is
A synchronization signal is received from the synchronization signal detection circuit 7 to rotate the motor 15 via the motor drive circuit 13, and the TV camera 6 is moved up and down by the TV camera feed device 16. Further, the motor control circuit 12 detects the position of the TV camera 6 when the horizontal A scan line is being scanned by the position detection circuit 14, and sequentially stores it in the storage circuit 11. Control 1 "11 road 8I" 1,
The maximum value of the amplitude data stored in the storage circuit 11 is determined, the horizontal scanning line where the maximum value is obtained is detected, and the position data of the TV camera 6 from which the horizontal scanning line is obtained is determined.
The data is sent to the motor control circuit 12 as in-focus position data, and the motor 15 is driven to automatically set the TV lens 5 to the in-focus position.

Effects of the Invention As described above, the present invention provides a driving means for moving a TV camera toward and away from a subject in synchronization with a video image signal, and a driving means for moving a TV camera toward and away from a subject in synchronization with a video image signal, and a drive means for moving a TV camera toward and away from a subject in synchronization with a video image signal, and a drive means for moving a TV camera toward and away from a subject in synchronization with a video image signal. , by providing means for selecting the horizontal scanning line with the maximum high frequency component of the video signal, and means for determining the position of the TV camera from which the horizontal scanning line was obtained based on the selected horizontal scanning line. Since the same number of focal point position information as the number of horizontal scanning lines can be obtained on one screen, the time for detecting the focal point position can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an automatic focus adjustment device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional automatic focus adjustment device. 1... Sample (subject), 5... Lens, 6... TV camera.

Claims (1)

[Claims] A driving means for moving the TV camera toward and away from the subject in synchronization with the video signal, and a horizontal scanning line in which the high frequency component of the video signal is the largest among the plurality of horizontal scanning lines corresponding to the video signal obtained from the TV camera. and means for determining, based on the selected horizontal scanning line, the position of the TV camera from which the horizontal scanning line was obtained.