JPH042280A - Automatic focusing device - Google Patents

Abstract

PURPOSE:To attain focusing immediately to an object in the modes other than the recording mode by varying timing entering focusing with the video recording mode of the object and in the other modes. CONSTITUTION:A video image of an object caught by a lens 2 is subject to photoelectric conversion by a video camera section 1 and information as to whether or not a lens 2 is focused to the object is extracted from the video information and the information is outputted to a microcomputer 4. The microcomputer 4 drives a focus motor 3 based on the information as to whether or not the focusing is taken to apply focus control of the lens 2. Moreover, the video information subject to photoelectric conversion is subject to picture processing by the video camera section 1 and outputted to a VTR section 5. The VTR section 5 records the video information inputted from the video camera section 1 onto a magnetic tape. Thus, the focusing is immediately entered to the object in the modes other than the recording mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an automatic focusing device for automatically focusing a lens of a video camera on a subject.

(Prior art) Modern still cameras and camera-integrated video tape recorders (VTRs) generally have a built-in automatic focusing device that automatically focuses the lens on the subject. It has become. Still cameras are required to be in focus the moment the shutter is released, and the time from when the camera lens is pointed at the subject to when it is in focus is required to be short.

On the other hand, since video cameras used in combination with a VTR, such as a camera-integrated VTR, record continuous images, the automatic focusing device becomes sensitive when the video camera is moved or the subject moves during recording. There was a problem that when the camera operated in response, the captured image became unnatural. For example, when a person passes in front of the video camera, a more natural image can be obtained by maintaining the already in-focus state without entering automatic focusing operation. On the other hand, when moving the video camera to move to another subject, it is desirable to immediately start focusing and focus on the subject on that side in a short time. However, even in such a case, it is undesirable for the lens to bounce due to the inertia of the motor during the focusing operation.

After all, if the automatic focusing device operates while the video camera is shooting, the focusing process at that time will also be recorded, so it is necessary to take this into consideration when setting the focusing timing of the automatic focusing device. . Therefore, an automatic focusing device for a video camera used in combination with a VTR is required to perform contradictory operations as described above. However, conventional automatic focusing devices such as camera-integrated VTRs automatically stop focusing when a control device such as a microcomputer recognizes that the focus has been out of focus for more than a certain period of time, for example 0.5 seconds or more. This prevents the automatic focusing device from operating even if the subject is temporarily out of focus due to someone passing in front of the camera or due to camera shake.

By the way, even with the video camera used in combination with the above-mentioned VTR, the process of focusing is not recorded unless the subject is being recorded, so in this case, the camera must be pointed at the subject and focused in the same way as a still camera. The shorter the time it takes, the better. With this setting, you can start recording immediately after pointing the camera at the subject. However, in such cases, conventional automatic focusing devices of this type take 0.5 seconds to focus on the subject.
The drawback was that there was a delay of about seconds.

(Problems to be Solved by the Invention) In the automatic focusing device installed in a video camera used in combination with a conventional VTR, the focusing process is recorded while recording the subject. Focusing is performed only when the subject is out of focus, so that natural-looking images are captured. However, if such settings are made for all modes, the focusing operation will be delayed for the specified period of time, such as when pointing the camera at the subject and starting recording, making it impossible to immediately capture the subject in focus. There was a drawback.

Therefore, the present invention aims to eliminate the above-mentioned drawbacks by changing the timing of starting the focusing operation when recording the image of the subject and in other modes, and immediately starting the focusing operation on the subject in the mode other than the recording mode. The aim is to provide an automatic focusing device that can be

[Structure of the invention]

(Means for Solving the Problems) The present invention relates to a video camera used in combination with a video tape recorder that records video information of a subject, and in which a lens mounted on the video camera is out of focus on the subject. In this case, an automatic focusing device that automatically focuses the lens includes a determining means for determining whether or not the video tape recorder is in a recording operation; and a control means for controlling the lens to immediately enter an operation to focus the lens when it is determined that the recording operation is not in progress and the lens is not focused on the subject. .

(Function) In the automatic focusing device of the present invention, the determining means determines whether the video tape recorder is in recording operation. Control means: control for immediately starting an operation for focusing the lens when the determination means determines that the video tape recorder is not in recording operation and the lens is not focused on the subject; I do.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing an embodiment of an automatic focusing device of the present invention. 1 is a video camera section; 2 is a lens mounted on the video camera section 1; 3 is a focus motor that drives the lens to focus the lens; 4 is a control for controlling the focus motor 3 to focus the lens 2 on the subject. 5 is a VTR section that records video information obtained by the video camera section 1 on a magnetic tape (not shown).

Here, the microcomputer 4 constitutes a determination means and a control means.

Next, the operation of this embodiment will be explained. The image of the subject captured by the lens 2 is photoelectrically converted by the video camera unit 1. Information on whether the lens 2 is focused on the subject is extracted from this photoelectrically converted video information and is output to the microcomputer 4. The microcomputer 4 drives the focus motor 3 based on the information as to whether or not the lens is in focus, thereby controlling the focus of the lens 2. Further, the video information photoelectrically converted by the video camera section 1 is outputted to the VTR section 5 after being subjected to image processing.

The VTR unit 5 records video information input from the video camera unit 1 on a magnetic tape. Incidentally, the VTR section 5 provides the microcomputer 4 with information as to whether or not a video signal is currently being recorded.

FIG. 2 is a flowchart showing the focusing operation of the microcomputer 4 shown in FIG. First, in step 201, the VTR section 5 receives information from the VTR section 5.
It is determined whether or not recording is in progress, and if it is in progress, the process proceeds to step 202, and if it is not in progress, step 20
Proceed to step 8. In step 208, it is determined whether or not the lens 2 is in focus based on the information from the video camera section 1. If it is, the process returns to step 201, and if it is not, the process proceeds to step 207. In step 207, the operation of driving the focus motor 3 to focus the lens 2 continues until the information that the focus is achieved is obtained from the video camera section 1, and then, when the focus is achieved, the operation of the focus motor 3 is stopped. , return to step 201.

On the other hand, if the process proceeds to step 202, first N is set to 0, and then in step 203 it is determined whether or not the lens 2 is in focus based on information from the video camera section. Return to step 201, and if they do not match, proceed to step 204. 0, 1 in step 204
After waiting for a second, the process proceeds to step 205, where the N is increased by +1.
Step 206 with the incremented value as the new N
Proceed to. In step 206, it is determined whether the value of N has become 5 or not, and if it has not become 5, the process returns to step 203.
If the number is 5, the process advances to step 207.

According to this embodiment, when the VTR unit 5 is not recording,
When the lens 2 is out of focus, the microcomputer 4 can immediately drive the focus motor 3 to start a focusing operation. Therefore, when the lens 2 is directed toward a subject and the VTR section 5 starts a recording operation, the VTR section 5 can immediately record the subject that is in focus. Also, when the VTR unit 5 is recording, the microcomputer 4 starts focusing the lens 2 only when the lens 2 is out of focus for 0.5 seconds continuously. Video can be recorded.

〔Effect of the invention〕

As described above, according to the automatic focusing device of the present invention, the timing of starting the focusing operation is changed when recording an image of a subject and in other modes, and the subject is immediately focused in a mode other than the recording mode. can go into action.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the automatic focusing device of the present invention, and FIG. 2 is a flowchart 1 to 1 showing the focusing operation of the microcomputer shown in FIG. 1...Video camera section 2...Lens 3...Focus motor 4...Microcomputer 5...VTR department representative Patent attorney Noriyuki Chika Yudo Hiroshi UjiFigure 2

Claims (1)

[Claims] In a video camera used in combination with a video tape recorder for recording video information of a subject, when the lens mounted on the video camera is out of focus on the subject, the lens is automatically focused. In the automatic focusing device that operates, a determining means for determining whether or not the video tape recorder is in a recording operation, and when the determining means determines that the video tape recorder is not in a recording operation, and . An automatic focusing device comprising: a control means for immediately starting an operation of focusing the lens when the lens is out of focus with respect to the subject.