JPH06121209A - Visual line detector - Google Patents

Abstract

PURPOSE:To prevent the generation of smear and to improve the accuracy of visual line detection by controlling a light shielding means to close an optical path when an image pickup element makes a charge read processing so as to avoid the image pickup element from receiving the light. CONSTITUTION:A light source 6 is extinguished by a signal from a control circuit 3 and a liquid crystal shutter 14. Simultaneously a signal is sent from a solid-state image pickup element driving circuit 2 to a solid-state image pickup element 1 to implement the charge read processing. When the read of the charge is finished, the control circuit 3 lights the light source 6 and a liquid crystal shutter 14 reaches a light transmission enable state to allow the light receiving section of the solid-state image pickup element 1 to form an image. That is, in this case, while the charge stored in the solid-state image pickup element 1 is being transferred, since the optical path of the light made incident on the solid-state image pickup element 1 is closed by the liquid crystal shutter 14, no light strikes on the light receiving section of the solid-state image pickup element 1 during the read processing of the picked-up charge and the generation of the smear is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual axis detecting device using a solid-state image pickup device as means for detecting the visual axis of a photographer.

[0002]

2. Description of the Related Art Up to now, the present applicant has proposed some video cameras using a visual axis detecting means. An example thereof will be described with reference to FIGS. 6 and 7.

FIG. 6 is a block diagram of a main part of a line-of-sight detecting part of a video camera provided with a line-of-sight detecting means proposed by the present applicant in a viewfinder. FIG. 7 is a timing chart showing the operation of the control circuit 3 of FIG.

In FIG. 6, reference numeral 1 denotes a solid-state image pickup device, which is composed of a light receiving portion, a vertical transfer portion, a horizontal transfer portion, and the like. Reference numeral 2 is a solid-state image sensor drive circuit for driving the solid-state image sensor 1, and 6 is a light source such as a light emitting diode, which is usually an infrared light emitting diode. Reference numeral 5 is a light source drive circuit for blinking the light source 6, and 3 is a control circuit for moving the solid-state imaging device drive circuit 2 and the light source drive circuit 5 at a timing described later. Reference numerals 7 and 8 are half mirrors, 9 is a finder lens, and 10 is a CRT for monitoring a shooting state. And 12 is
It is a gaze point detection circuit that calculates a gaze point on the finder screen of the photographer based on the image of the solid-state image sensor 1. The solid-state imaging device 1, the imaging lens 4, the half mirror 7, and the finder lens 9 form an imaging optical system of a visual axis detection system.

The operation of the line-of-sight detecting means having the above structure will be described. Light emitted from the blinking light source 6 controlled by the control circuit 3 and driven by the light source drive circuit 5 is reflected by the half mirror 8, transmitted through the half mirror 7, and converted into a parallel light flux by the finder lens 9 to the eye 11 of the photographer. Irradiate. The reflected light from the irradiated eye is reflected by the half mirror 7 and forms an image on the solid-state image sensor 1 by the imaging lens 4.
Under the control of the control circuit 3, the solid-state image pickup device drive circuit 2 reads out the image signal of the eye captured by the solid-state image pickup device 1, and the gaze point detection circuit 12 performs a predetermined calculation to determine the gaze point of the photographer. Ask. The present invention is not directly related to the content of the eye gaze detection calculation, and thus the description thereof is omitted.

Next, the operation of the control circuit 3 will be described with reference to the timing chart of FIG.

While the light source 6 is on, the solid-state image sensor 1
The image of the eye reflected on the light receiving unit (not shown) is accumulated in the light receiving unit as electric charge according to the brightness of the light. At the same time when the light source 6 is turned off by the signal from the t ₁ control circuit 3,
The solid-state image sensor 1 is controlled by the solid-state image sensor drive circuit 2.
Then, electric charges are successively transferred from the light receiving portion by a vertical transfer line and a horizontal transfer line (not shown), and then sent to the gazing point detection circuit 12 to perform signal processing to obtain an image.
When the transfer of the t ₂ charges is completed, the control circuit 3 sends a command to the light source drive circuit to turn on the light source 6 and start accumulating new charges in the solid-state imaging device. ··· t ₃

[0008]

The solid-state image pickup device used in the conventional visual axis detection device performs the charge reading process when the light source 1 is turned off. During this period, the solid-state image pickup device shields light. It wasn't done. Therefore, during the charge reading process, external light passes through the finder and hits the light receiving part of the solid-state image sensor, and the charge generated in the light receiving part leaks into the vertical transfer part and smears with a white tail in the vertical direction. It was the cause of the phenomenon. The occurrence of smear is a troublesome problem that makes it difficult to detect the line of sight.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a visual axis detection device which improves the visual axis detection accuracy by preventing the occurrence of smear. To do.

[0010]

Therefore, in the visual axis detecting device according to the present invention, a light-shielding means for opening and closing the optical path which is provided on the optical path of the image pickup element for picking up an image of the eye, and the image pickup charge of the image pickup element. It is intended to achieve the above-mentioned object by a configuration characterized in that the light shielding means is closed during the transfer of the image data, and a control means is provided for blocking the light beam incident on the image pickup device.

[0011]

With the above construction, when the image pickup device is performing the charge reading process, the control means controls the light shielding means to close the optical path so that the image pickup device is not exposed to the light. To the vertical transfer section during the transfer,
It is possible to prevent the occurrence of smear caused by the generation of photocharges in the light receiving portion during the transfer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The visual axis detection device according to the present invention will be described below with reference to embodiments.

1 and 2 are views for explaining a first embodiment of the present invention, and FIG. 1 is a block diagram of a main part of a video camera equipped with a visual axis detecting means. FIG. 2 is a timing chart showing the operation of the control circuit 3 shown in FIG. In addition,
In FIG. 1, the same or corresponding parts as those of the conventional example shown in FIG.

A liquid crystal shutter 14 is arranged in front of the light receiving portion of the solid-state image pickup device 1 so as to cover the light receiving portion. A liquid crystal shutter drive circuit 13 drives the liquid crystal shutter 14, and is connected to the control circuit 3 and operated by a signal from the control circuit 3. The control circuit 3 controls the liquid crystal shutter drive circuit 13, the solid-state image sensor drive circuit 2, and the light source drive circuit 5 at the timing described later.

Reference numeral 15 is an optical system, 16 is a shutter for controlling exposure, 17 is an image pickup device such as a CCD for converting an image formed by the optical system 15 into an electric signal, and 18 is signal processing for performing predetermined signal processing. A circuit, 19 is a recording processing circuit for performing a predetermined process for recording a video signal, 20 is a magnetic head, 2
1 is a magnetic tape for recording video signals, 22 is an optical system 15
Is a motor for driving the focus lens.

Reference numeral 23 denotes A for controlling the drive of the motor 22 according to the output of the gazing point detection circuit 12 and the output of the image pickup device 17.
This is an F control circuit, and specifically controls so as to focus on the gazing point of the photographer detected by the gazing point detection circuit 12.

Reference numeral 24 is an AE control circuit for adjusting the shutter 16 in accordance with the output of the image pickup device 17, and 25 is a view in which a video signal output from the signal processing intelligent circuit 18 and predetermined information (shooting time etc.) are combined. The display processing circuit performs signal processing for displaying on the CRT 10 of the finder.

The first main feature of the present invention having the above-mentioned structure
The visual axis detection operation of the embodiment will be described. The light emitted from the blinking light source 6 driven by the light source drive circuit 5 controlled by the control circuit 3 is reflected by the half mirror 8, transmitted through the half mirror 7, and becomes a parallel light flux by the finder lens 9 to the photographer's eye. Irradiate 11. The reflected light from the irradiated eye is reflected by the half mirror 7, is collected by the imaging lens 4, and is transmitted through the liquid crystal shutter 14 which is in a state in which the light can be transmitted according to the command of the control circuit 3 and is thus solid. An image is formed on the image sensor 1. The solid-state image sensor drive circuit 2 is a control circuit 3
The solid-state image sensor 1 is driven under the control of 1) to read out an image signal. The read image signal is the gazing point detection circuit 1
2, the gazing point detection circuit 12 performs a predetermined calculation from the image of the eye 11 captured by the solid-state image sensor 1 to obtain the gazing point (gaze position) of the photographer.

Next, the operation of the control circuit 3 will be described with reference to the timing chart of FIG.

While the light source 6 is on, the liquid crystal shutter drive circuit 13 that receives the command from the control circuit 3 makes the liquid crystal shutter 14 in a state in which light can pass through. The image of the eye reflected on the light receiving portion (not shown) of the solid-state image pickup device 1 is accumulated in the light receiving portion as electric charges according to the brightness of the light. ... At the same time as turning off the light source 6 by a signal from the T ₁ control circuit 3,
The liquid crystal shutter 14 is closed. At the same time, a signal is sent from the solid-state image sensor drive circuit 2 to the solid-state image sensor 1, and the charge reading process is performed. When the reading of the T ₂ charges is completed, the control circuit 3 turns on the light source 6, the liquid crystal shutter 14 becomes a state in which light can be transmitted, and an image is formed again on the light receiving portion of the solid-state image sensor 1. Then, the solid-state image sensor 1 starts accumulating new charges.・
.. T _{3 With the} above configuration and control, the liquid crystal shutter 14 closes the optical path incident on the solid-state image sensor 1 during transfer of the charges accumulated in the solid-state image sensor 1, so that during the process of reading the image charge, The light-receiving portion of the solid-state image sensor 1 is not exposed to light, and smear can be prevented.

(Second Embodiment) FIG. 3 is a block diagram of an essential part of a video camera provided with a second embodiment of the present invention, in which the same or corresponding portions as those of the first embodiment are designated by the same reference numerals and will be described repeatedly. Is omitted.

In the second embodiment, the liquid crystal shutter 14 is arranged behind the half mirror 7 in the image forming optical system for detecting the line of sight. The light source 6 is constantly turned on by the light source drive circuit 5 and is overlapped with the optical axis of the imaging optical system via the half mirror 8.

The control circuit 3 of the second embodiment controls the solid-state image pickup device drive circuit 2 and the liquid crystal shutter drive circuit 13. That is, the liquid crystal shutter 14 is set in a state in which light can be transmitted for a certain period of time. In the meantime, the light from the light source 6 is reflected by the half mirror 8 and transmitted through the liquid crystal shutter 14, and is reflected again by the half mirror 7 to be a parallel light flux by the finder lens 9 to illuminate the eye 11 of the photographer. The light reflected from the eye is reflected by the half mirror 7, passes through the half mirror 8, and forms an image on the solid-state image sensor 1 by the imaging lens 4.

The image of the eye reflected on the light receiving portion (not shown) of the solid-state image pickup device 1 is accumulated in the light receiving portion as electric charge according to the brightness of the light. At the same time when the liquid crystal shutter 14 is closed by a signal from the control circuit 3, a signal is sent from the solid-state image pickup device drive circuit 2 to the solid-state image pickup device 1 to perform charge reading processing. When the charge reading is completed, the control circuit 3 again
The liquid crystal shutter 14 is set in a light transmissive state, and accumulation of new charges by the solid-state image sensor is started.

With the above configuration and control, the same effect as that of the first embodiment can be exhibited while the light source 6 is kept lit without blinking.

(Third Embodiment) FIG. 4 is a block diagram of the essential parts of a video camera provided with a third embodiment of the present invention.
FIG. 17 is an explanatory diagram of a rotary plate indicated by 17 in FIG. The third embodiment has the same structure as that of the second embodiment except for the light-shielding means that can be opened and closed. The same or corresponding parts as those of the second embodiment are designated by the same reference numerals, and a duplicate description will be omitted.

In the third embodiment, a rotating plate 28 rotated by a motor 27 is provided instead of the liquid crystal shutter 14 as a light-shielding means that can be opened and closed, and 26 is a motor 27.
It is a motor drive circuit that controls the rotation of the. The control circuit 3 includes a motor drive circuit 26, an image pickup element drive circuit 2
To control.

As shown in FIG. 5, the rotary plate 28 is provided with a notch 29 in a part of the disk. While the imaging optical system is opened by the notch 29 of the rotary plate 28, the eye is illuminated by the light source 6, and the solid-state imaging device 1 starts to accumulate electric charges.
When the rotary plate 28 rotates and the imaging optical system is blocked, the solid-state imaging device 1 starts reading out electric charges. The control circuit 3 controls the motor drive circuit 26 so that the imaging optical system is opened by the notch 29 of the rotary plate 28 when the solid-state image pickup device 1 finishes reading the electric charges.

With the above structure, the rotary plate 28 can be used instead of the liquid crystal shutter 14 to achieve the same effect as that of the second embodiment.

[0030]

As described above, according to the present invention,
A light blocking means that can be opened and closed is arranged in the middle of the optical path incident on the image sensor, and the light blocking means is controlled by the control means so that the image sensor transfers light while the charge is being transferred. In addition, it is possible to provide a line-of-sight detection device in which line-of-sight detection is always easy, because photo-electric charges are not generated in the light-receiving unit and the smear does not leak into the vertical transfer unit during transfer of electric charges.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a video camera according to a first embodiment.

FIG. 2 is a control circuit timing chart of the first embodiment.

FIG. 3 is a block diagram of a main part of a video camera according to a second embodiment.

FIG. 4 is a block diagram of a main part of a video camera according to a third embodiment.

FIG. 5 is an explanatory view of a rotary plate of a third embodiment.

FIG. 6 is a block diagram of a conventional visual line detection device.

FIG. 7 is a timing chart of a control circuit of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid-state image sensor 2 Solid-state image sensor drive circuit 3 Control circuit 4 Imaging lens 5 Light source drive circuit 6 Light source 7,8 Half mirror 9 Finder lens 10 CRT 11 Eye 12 Gazing point detection circuit 13 Liquid crystal shutter drive circuit 14 Liquid crystal shutter 26 Motor Drive circuit 27 Motor 28 Rotating plate 29 Notch

Claims (1)

[Claims] 1. A light-shielding device that is provided in the optical path of an image-pickup element that images an eye and opens and closes the optical path, and the light-shielding means that is closed while the image-capturing element is transferring image-forming charges. A line-of-sight detection device comprising: