JPH04304405A - Automatic zooming and tracking camera device - Google Patents

Abstract

PURPOSE:To put a camera which has the automatic zooming and tracking device in invariably optimum zooming operation even if photographic conditions are changed. CONSTITUTION:An infrared range finding part 20a in a microcomputer 27 finds data on a display by an infrared system. A video signal processing AF part 16a in the microcomputer 27 finds the data on the distance by a video signal processing system. Those data are compared by an AF system selection part 17 to select one better range finding system and a stepping motor driving part 18 performs focusing operation and an automatic frame arithmetic circuit 19 performs the automatic zooming and tracking operation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in cameras such as video cameras and still cameras having automatic zooming and tracking devices.

0002

2. Description of the Related Art An automatic zooming tracking camera device is a camera that controls zooming so that the sizes of objects at different distances displayed on the screen are constant. The method of control is to first find the distance to the subject, then use that value to calculate the angle of view at which the subject appears on the screen at a certain size, and then move the zoom to achieve that angle of view. It is something. Therefore, the accuracy of zoom control depends on the accuracy of distance measurement of the subject.

[0003] Automatic zooming and tracking camera devices usually employ distance measuring means based on the principle of triangulation using an infrared method. In this method, an infrared light emitting element is installed on the camera side, and the infrared light emitted from the light emitting element is reflected from the subject, and the light is received by a light receiving element placed a predetermined distance from the light emitting element to measure the distance. It is. This method is
It has the advantage of being able to measure distances in dark places and regardless of the subject's brightness or contrast. Furthermore, since it is independent from the imaging system, it is possible to operate the focus without hunting, regardless of the depth of field of the lens. This is suitable for precise, natural, and smooth zoom control in automatic zoom tracking, which is why the infrared method is generally used as a distance measuring method.

By the way, there is another type of distance measuring means called a video signal processing method. In this method, incident light from the subject passes through the photographic lens and is guided to the solid-state image sensor for recording. The increase in the number of high-frequency components is used to detect increases and decreases in the high-frequency components, and the distance is measured based on the degree of increase or decrease in the high-frequency components. This method has the advantage that since the distance measuring section and the imaging section are the same, parallax does not occur and distance measurement can be performed regardless of the distance to the subject.

[0005]

[Problem to be solved by the invention] However, due to its principle, the infrared method makes it difficult to measure the distance of distant objects, and it is also difficult to measure the distance of objects that absorb infrared rays, such as hair or black clothing. There is a drawback. Additionally, in this method, a distance measurement unit is often provided outside the camera.
Therefore, there is also the problem that parallax occurs. Therefore, under the above-mentioned photographing conditions, the accuracy of automatic zooming and tracking may decrease or its operation may become unstable.

[0006] In the video signal processing method, it is not possible to determine whether the focus shift is occurring in the front or the rear, and the master lens is moved once in a certain direction and information on the direction of the shift is obtained. Because the focus is adjusted, a phenomenon may occur where the object is out of focus by a large amount and then comes back into focus. Another disadvantage is that it is weak in dark places, and the accuracy of distance measurement decreases depending on the brightness and contrast of the subject. Furthermore, the distance measurement accuracy is affected by the depth of field, and hunting is relatively common in the operation of the master lens, so it is not suitable for automatic zoom tracking, and this method is not normally used alone.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a distance measuring means using an infrared method, a distance measuring means using a video signal processing method, and a distance measuring means using a video signal processing method. A means for selecting a distance measuring means with higher distance accuracy, and a means for controlling zoom using object distance information obtained by the selected distance measuring means are provided.

[0008]

[Operation] As described above, since the present invention is provided with a means for selecting a distance measuring method, when it is determined that the distance measuring accuracy has decreased when distance measuring is performed using the infrared method, , switch from the infrared method to the video signal processing method. On the other hand, if it is determined that the distance measurement accuracy has decreased while distance measurement is being performed using the video signal processing method, the method is switched to the infrared method. Then, distance information of the subject is obtained from the selected distance measuring means, and zooming can be controlled so that the sizes of subjects located at different distances displayed on the screen are constant.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below according to an embodiment shown in the drawings.

FIG. 1 is a block diagram of a camera having an automatic zooming tracking device according to the present invention. In the following description, arrows indicate signal paths or control directions.

[0011] A camera lens system usually consists of several parts. For example, front lens 1, zoom lens 2
, a compensator 3, an aperture 4, a relay lens 5, a master lens 6, etc. The zoom lens 2 is driven by a zoom motor 8a, which is driven by a zoom motor driver 8b. The zoom position is detected by a potentiometer 9a attached to the outer ring of the zoom lens 2, and its output is converted by a zoom position detection circuit 9b into a form that can be input to a microcomputer (hereinafter referred to as microcomputer) 27. The position of the aperture 4 is detected by the Hall element 10.
The aperture is adjusted based on the brightness of the subject. The master lens 6 is driven by a stepping motor 11a, and the stepping motor 11a is driven by a stepping motor driver 11b. The position of the master lens 6 is detected by a photointerrupter 12a and a master lens position detection circuit 12b.

First, a distance measuring section using a video signal processing method in the microcomputer 27 will be explained.

The light passing through the lens is imaged on the solid-state image pickup device 7, and its output is outputted from the output terminal 14 as a video signal by the video signal processing circuit 13. This video output is branched and the AF signal processing circuit 15 extracts high frequency components. The output of the AF signal processing circuit 15 is
The signal is input to the video signal processing AF section 16a of the microcomputer 27. The video signal processing AF section 16a includes a focus area gate 16b, a data integration section 16c, a focus determination calculation section 16d, and the like. Therefore, after the integration range of the data integration section 16c is controlled by the focus area gate 16b, the imaging information is sent to the focus determination calculation section 16d, and the in-focus state is determined. Signals from the Hall element 10 and the potentiometer 9a are also sent to the focus determination calculation section 16d.

Next, the infrared distance measuring section within the microcomputer 27 will be explained. The infrared distance measuring section 20a includes an infrared LED driving section 20b, a distance measuring calculation section 20c, and the like. In order to pulse-drive the infrared LED 24 provided on the outside of the camera, a pulse is output from the infrared LED drive section 20b. In response to the pulse, the infrared LED driver 23 drives the infrared LED 24. Projection lens 26
The infrared light is focused and projected onto the subject. The light reflected by the object is focused onto the light receiving element 22 by the light receiving lens 25. The output of the light receiving element 22 is amplified and noise removed by the distance measuring circuit 21, and the distance to the subject is calculated by the distance measuring calculation section 20c.

The selection of the AF method is performed as follows. The calculation results of the video signal processing AF section 16a and the infrared distance measuring section 20a are sent to the AF method selection section 17. The AF method selection section 17 determines, based on the results of the video signal processing AF section 16a and the infrared distance measuring section 20a, whether the subject is far or close, whether the infrared reflectance is high or low, and whether the contrast is low or high. Determine. Further, the signals from the Hall element 10 and the potentiometer 9a are also transmitted to the AF method selection section 17 and the focus judgment calculation section 16.
d, and the brightness and darkness of the subject, the zoom position, and the depth of field of the lens are determined. Based on these imaging information, the AF method selection unit 17 selects either the video signal processing method or the infrared method as the distance measuring method, whichever is considered to have higher distance measuring accuracy. For example, when performing infrared distance measurement, if the distance measurement circuit 21 has difficulty detecting a signal because the infrared light reflected by the subject is weak, the distance measurement calculation section 21
If 0c, it is determined that the reflectance of infrared rays of the subject is low or that the subject is far away, and the result is sent to the AF method selection section 17. The AF method selection section 17 receives the result and switches the distance measuring means to the video signal processing method. Conversely, when distance measurement is performed using video signal processing, if the contrast of the subject is low, the subject is dark, or the zoom is on the wide side and the depth of field is deep, the focus judgment calculation section 16d determines that the measurement accuracy has decreased and sends the result to the AF method selection section 17. The AF method selection section 17 switches the distance measuring means to the infrared method based on the result.

The AF method selection section 17 receives distance data from the distance measuring means considered to be optimal, and issues a command for focusing to the stepping motor drive section 18 based on the data. In the stepping motor drive section 18, a photo interrupter 12a, a master lens position detection circuit 12b
The moving amount of the master lens 6 is calculated based on the position data of the master lens 6, and based on the result, a drive pulse is sent to the stepping motor driver 11b to drive the stepping motor 11a, resulting in focusing.

The auto frame calculation circuit 19 is a means for controlling zoom, and is a means for controlling zoom.
Based on the distance data, the zoom focal length at which the subject becomes a certain size is calculated. It also receives the position data of the zoom lens 2 from the zoom position detection circuit 9b, calculates the difference from the calculated value, and calculates the amount of zoom movement. Based on the calculated value, the zoom motor driver 8b drives the zoom motor 8a, and as a result, automatic zoom tracking is performed.

[0018]

According to the present invention, since the distance measuring means can be switched depending on the photographing conditions of the subject, the accuracy of distance measuring can be improved compared to the case where only the infrared method is used. Therefore, when automatic zoom tracking is performed, the accuracy of zoom control is improved and the operation is stabilized. In addition, focusing accuracy is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

[Explanation of symbols]

13 Video signal processing circuit 15 AF signal processing circuit 16a Video signal processing AF section 16d Focus determination calculation unit 17 AF method selection section 18 Stepping motor drive section 19 Auto frame calculation circuit 20a Infrared distance measuring section 27 Microcomputer

Claims (1)

[Claims] [Claim 1] A distance measuring means using an infrared method, a distance measuring means using a video signal processing method, and means for selecting a distance measuring method with higher distance measuring accuracy according to photographing conditions of a subject; An automatic zooming tracking camera device comprising: means for controlling zoom using distance information of a subject obtained by a distance measuring means.