JPH04242626A - Visual axis detector - Google Patents

Abstract

PURPOSE:To provide a visual axis detector capable of detecting the visual axis of one's eyeball with high accuracy by obtaining the positional coordinate of a first Purkinje image based on reflected light from one's eyeball and that of the pupil by the use of an image sensor and properly controlling the integrating time of the image sensor and a projected light amount from a projector. CONSTITUTION:A light flux from a projecting means 7 is incident on one's eyeball 201, and the positional coordinate of a Purkinje image based on the reflected ray from the eyeball and that of the pupil are detected by a detecting means 4 having an image sensor 4a. When the visual axis of eyeball is obtained by the use of these positional coordinates detected by the detecting means 4, the integrating time of the image sensor 4a is changed by an integrating time control means 9 on the basis of the output signal from a photometric sensor 8 for photometry of brightness near the front of the eyeball, while a luminescent amount from the projecting means 7 is changed by a luminescence control means 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line-of-sight detection device, and more particularly, the present invention relates to a line-of-sight detection device, and in particular, a device that irradiates the eyeball of an observer (photographer) with a light beam from a light projecting means, and uses the first Purkinje image (corneal reflection image) based on the light reflected from the eyeball. ) and a pupil on the image sensor surface, and the line of sight of the eyeball is detected using the position coordinates of each image on the image sensor surface.The integration time and light projection when detecting the light flux with the image sensor. The amount of light emitted from the device is appropriately controlled to enable highly accurate line-of-sight detection.

0002

2. Description of the Related Art FIG. 9 is a block diagram of main parts of a conventional line of sight detection device.

Reference numeral 91 in the figure represents a microprocessing unit (M.P.U.), which performs various calculation processes such as line of sight calculations using Purkinje's first image and pupil position information. 92 is a memory, and 93 is an interface circuit, which has an A/D conversion function. Reference numeral 97 denotes a light projecting means, which causes infrared light emitted from an infrared light emitting diode 97a, which is insensitive to the viewer, to enter the viewer's eyeball (not shown) via a light projecting lens 97b. 95 is a light emission control circuit;
The light emission of the infrared light emitting diode 97a is controlled. Reference numeral 96 denotes a position sensor, which detects the vertical and horizontal directions of the camera when the line of sight detection device is applied to the camera.

Reference numeral 94 denotes a detection means, which includes an image sensor 94a, a drive circuit 94b, a light-receiving lens 94c, etc., and transmits the Purkinje first image based on the reflected light from the eyeball and the pupil to the image sensor through the light-receiving lens 94c. 9
The image is formed on the 4a plane.

A method for detecting the line of sight of the eyeball in the figure is disclosed in, for example, Japanese Patent Laid-Open No. 2-209125 and Japanese Patent Laid-Open No. 2-26463.
This is proposed in Publication No. 2, etc. In the same publication, the light projecting means 97
The line of sight is detected using two pieces of information: the first Purkinje image (corneal reflection image) based on the reflected light from the eyeball among the infrared light emitted from the eye, and the positional information of the pupil center calculated from a plurality of pupillary limbus.

That is, infrared light from the light projecting means is illuminated from the front onto the observer's eyeball, and at this time, the position where the so-called Purkinje first image, which is a virtual image of the infrared light emitting diode generated by reflection on the front surface of the cornea, is generated is determined. Detected with an image sensor. At this time, the position where the Purkinje first image is generated coincides with the position of the pupil center when the rotation angle of the eyeball is zero (however, the optical axis of the eyeball), and as the eyeball rotates, the position with respect to the pupil center shifts.

[0007] At this time, the deviation (distance) between the first Purkinje image and the center of the pupil is approximately proportional to the sine of the rotation angle of the eyeball. For this purpose, from the positional information of the Purkinje first image and the center of the pupil, the positional interval is determined, the rotation angle of the eyeball, and calculations such as visual axis correction are performed to determine the line of sight of the photographer.

[0008] At this time, the integration time of the image sensor when the image sensor receives the light flux depends on the luminance of the infrared light emitting diode, the sensitivity of the image sensor, the S/N ratio, and the external light normally expected during shooting. A reasonable accumulation time is determined in consideration of various conditions, and the determined integration time is used to perform accumulation on the image sensor.

[0009]

[Problem to be Solved by the Invention] In the conventional line of sight detection device, the integration time of the image sensor when the image sensor receives a luminous flux is set in advance by considering various conditions as described above, and the fixed time set at this time is set. Light was received using integration time.

[0010] For this reason, various problems may occur depending on, for example, the illuminance of the anterior segment of the eyeball. For example, when the illuminance is low, the difference in brightness between the pupil and the iris (difference in output signal value)
is small, making it difficult to detect the pupillary limbus. Conversely, when the illuminance is very high, the image sensor becomes saturated,
There is a problem in that the difference between the Purkinje first image, which originally has a difference in brightness, and the output signal of the iris portion disappears, making it impossible or difficult to detect the Purkinje first image.

The present invention detects the first Purkinje image within the dynamic range of the image sensor by appropriately controlling the integration time of the image sensor and the amount of light emitted from the light projecting means when the image sensor receives the light beam. It is an object of the present invention to provide a line-of-sight detecting device that can obtain a signal with sufficient contrast for detecting the pupil and detecting the line-of-sight with high accuracy.

0012

[Means for Solving the Problems] A line of sight detection device having an integral time control means of the present invention makes a light beam from a light projection means enter an eyeball, and determines the position coordinates of a Purkinje image based on the light reflected from the eyeball. When the positional coordinates of the pupil are detected by a detection means having an image sensor, and the line of sight of the eyeball is determined using these positional coordinates detected by the detection means, a photometric sensor that measures the brightness near the anterior segment of the eyeball is used. The present invention is characterized in that the integration time control means changes the integration time of the image sensor based on the output signal of the image sensor, and the light emission control means changes the amount of light emitted from the light projecting means.

As described above, in the present invention, the integration time of the image sensor is determined according to the output from the photometric sensor, and the amount of light emitted from the light projecting means for forming the first Purkinje image is changed accordingly. In other words, the amount of emitted light is increased when the brightness of outside light is high, which shortens the integration time, and conversely, the amount of emitted light is decreased when the brightness of outside light is low, where the integration time becomes long. This enables highly accurate line-of-sight detection by obtaining images of the anterior segment of the eyeball without any problems.

[0014]

[Embodiment] Fig. 1 is a block diagram of main parts of Embodiment 1 of the present invention.
FIG. 2(A) is a schematic diagram of the main part when the line of sight detection means according to the present invention is applied to a single-lens reflex camera, and FIG.
) is a perspective view of a part of the main part.

In FIG. 1, reference numeral 1 denotes a microprocessing unit (M.P.U.), which performs various calculation processes such as line of sight calculations using Purkinje's first image and pupil position information. 2 is a memory, and 3 is an interface circuit, which has an A/D conversion function. Reference numeral 7 denotes a light projecting means, which causes infrared light emitted from an infrared light emitting diode 7a, which is insensitive to the viewer, to enter the eyeball of the viewer via a light projecting lens 7b. 5 is a light emission control circuit (light emission control means);
The amount of light emitted from the infrared light emitting diode 7a is controlled according to an output signal from a photometric sensor 8, which will be described later. 6 is a position sensor, which detects the vertical and horizontal directions of the camera when the line of sight detection device is applied to the camera.

4 is a detection means, and an image sensor 4
a, a drive circuit 4b, a light-receiving lens 4c, etc., and a Purkinje first image based on reflected light from the eyeball and the pupil are formed on the surface of the image sensor 4a via the light-receiving lens 4c.

A photometric sensor 8 measures the illuminance of the anterior segment of the eyeball. Reference numeral 9 denotes an integral time control circuit (integral time control means), which controls the integral time (accumulation) of the image sensor 4a when the image sensor 4a receives the light flux based on the first Purkinje image and the pupil based on the signal from the photometric sensor 8. time).

Next, the configuration when the present invention is applied to a single-lens reflex camera will be explained using FIGS. 2(A) and 2(B).

Reference numeral 21 in the figure is an eyepiece lens, and inside thereof is a dichroic mirror 21 that transmits visible light and reflects infrared light.
A is provided obliquely and also serves as an optical path splitter. 4a is an image sensor, 4c is a light receiving lens, 7a1, 7a2
is a light source which is one element of the light projecting means 7 and is made of, for example, a light emitting diode.

The image sensor 4a is composed of a two-dimensional array of photoelectric elements, and is located at a predetermined position with respect to the light receiving lens 4c and the eyepiece 21 (the general eye point position of a photographer who does not use glasses). It is placed so that it is conjugate with the vicinity of the pupil of the eye. 8 is a photometric sensor, which is arranged near the eyepiece lens 21.

Reference numeral 29 denotes a processing device, in addition to the functions of line-of-sight correction calculation, line-of-sight correction data storage, and line-of-sight calculation functions, M.29 in FIG. P. U1
, integral time control circuit 9, light emission control circuit 5, memory 2,
It has an interface circuit 3 and the like.

201 is a photographing lens, 202 is a quick return (QR) mirror, 203 is a display element, 204 is a focusing plate, 205 is a condenser lens, 206 is a penta roof prism, 207 is a sub-mirror, and 208 is a multi-point focus detection device. , focus detection is performed by selecting a plurality of areas within the photographic screen using a known method. A camera control device 209 has functions such as driving a display element in the finder, performing focus detection calculations, and driving a lens.

In this embodiment, a part of the object light transmitted through the photographing lens 201 is reflected by the QR mirror 202 to form an object image near the focusing plate 204. Focus board 20
The subject light diffused by the diffusion surface of 4 is transferred to the condenser lens 2.
05, the light is guided to the eye point E via the pentagonal roof prism 206 and the eyepiece lens 21.

The display element 203 is, for example, a two-layer guest-host type liquid crystal element that does not use a polarizing plate, and displays the distance measurement area (focus detection position) within the field of view of the finder.

[0025] Also, a part of the subject light that has passed through the photographic lens 201 passes through the QR mirror 202, and then passes through the sub-mirror 20.
7 and is guided to the aforementioned multi-point focus detection device 208 placed at the bottom of the camera body. Furthermore, based on the focus detection information of the position on the subject surface selected by the multi-point focus detection device 208, the photographic lens 201 is extended (or retracted) by a photographic lens driving device (not shown) to adjust the focus.

The principle of the line of sight detection method is described in the above-mentioned Japanese Patent Application Laid-Open No. 2-2.
This method is the same as the method proposed in JP-A No. 09125 and JP-A-2-264632.

In this embodiment, the infrared light emitting diode 7
Infrared light emitted from a1 and 7a2 enters the eyepiece lens 21 from above in the figure, is reflected by the dichroic mirror 21a, and illuminates the eyeball 211 of the observer located near the eye point E. Further, the infrared light reflected by the eyeball 211 is reflected by the dichroic mirror 21a and is converged by the light receiving lens 4c to form an image on the image sensor 4a.

In this embodiment, the line of sight of the eyeball is determined from the first Purkinje image formed on the image sensor 4a at this time and the position of the center of the pupil. That is, the image sensor 4a
M.I. P. U1 is read through the interface circuit 3, and the coordinates of the pupil center calculated from the coordinates of the first Purkinje image and the coordinates of a plurality of pupillary rings are determined from the image signal. From these two quantities, the rotation angle of the photographer's eyeball and the amount of relative shift with respect to the camera are used to determine the position of the line of sight on the finder system.

At this time, in this embodiment, the amount of light emitted from the infrared light emitting diode 7a is appropriately set by the light emission control circuit 5, and the integration time of the image sensor 4a is appropriately set by the integral time control circuit 9. I am getting a suitable signal.

In this embodiment, the integration time of the image sensor is changed according to the output from the photometric sensor, and the amount of light emitted from the infrared light emitting diode for forming the first Purkinje image is increased or decreased accordingly. By doing so, a signal output suitable for calculation is obtained from the image sensor in any case, and the line of sight of the eyeball is detected with high precision.

For example, when the brightness of external light is high, the integration time of the image sensor is shortened, and the amount of light emitted from the infrared light emitting diode is correspondingly increased. When the anterior segment of the eyeball is sufficiently illuminated by this external light, the contrast between the boundary between the pupil and the iris is relatively high, and a good image for detecting the pupil can be obtained.

However, since the signal strength of the iris is strong,
When the first Purkinje image is formed on the iris, the difference in signal intensity is small, making it difficult to detect the first Purkinje image. Normally, when the brightness of external light is high, the pupil diameter is small, so there is a high possibility that a Purkinje first image will be formed on the iris.

Therefore, in this embodiment, in such a case, the integration time of the image sensor is shortened, the overall signal intensity is lowered, and the amount of light emitted from the infrared light emitting diode is increased to increase the signal intensity of the first Purkinje image. There is.

Conversely, when the brightness of outside light is low, the integration time of the image sensor is lengthened, and the amount of light emitted from the infrared light emitting diode is correspondingly reduced. When the anterior segment of the eyeball is not sufficiently illuminated by this external light, the contrast between the boundary between the pupil and the iris is low, making it difficult to detect the pupil.

On the other hand, since the intensity of the first Purkinje image is almost constant regardless of external light, its detection is easy. Therefore, in this embodiment, in such a case, the integration time of the image sensor is lengthened, the overall signal is increased, the contrast between the pupil and the iris is increased, and the amount of light emitted from the infrared light emitting diode is reduced, so that the first Purkinje image is The intensity is lowered to prevent the image sensor from becoming saturated.

Furthermore, when the integration time of the image sensor becomes long, the amount of light emitted from the infrared light emitting diode is reduced to reduce the energy of the infrared light emitting diode irradiated to the eyeball, thereby protecting the eyeball.

FIG. 3 shows a flowchart of the operation of this embodiment. In the figure, when a line-of-sight detection request is generated by pressing the line-of-sight mode switch (not shown), the M. P. Control of U enters a line of sight detection routine. When entering the line of sight detection routine, M. P. U emits light from the infrared light emitting diode and starts an integration operation based on the amount of light emitted from the infrared light emitting diode and the integration time of the image sensor, which are set by a method described later.

After the integration operation is completed, the output of the image sensor is read, the first Purkinje image and the pupil are determined, and the line of sight position of the photographer is determined, and the values are stored in the memory as necessary. Then, if a release request is made, the routine shifts to a release routine.

FIG. 4 is a circuit explanatory diagram of the integral time control circuit 9 of FIG. 1, and FIG. 5 is a timing chart of the integral time control circuit 9 of FIG.

In the figure, 100 is an OR circuit, 101,
103 is a counter, 102 and 104 are AND circuits, 1
05 is an N-ary counter with a preset function, 106
is an inverter, 107 is a resistor for stabilizing the input to the counter 105, 108 is an A/D converter, 109
is a voltage dividing resistor for providing the minimum voltage for A/D conversion.

When the main switch of the camera is turned on and the reference clock is applied, one end of the input of the OR circuit 100 is "Low", so the reference clock is input to the counter 101 from the output of the OR circuit 100. When (2a + 2b) reference clocks are input, the AND circuit 102
The output, that is, the integral signal becomes "High". At the same time, one end of the input of the OR circuit 100 also becomes "High", and O
The output of the R circuit 100 is fixed at "High", the supply of the reference clock is stopped, and the integral signal maintains "High" until a reset voltage is applied to the reset terminal of the counter 101.

The reference clock is also given to the counter 103, and when this number reaches (2c + 2d), the AN
The output of the D circuit 104 becomes "High", a reset voltage is applied to the reset terminal of the counter 103, and the AND
The output of the circuit 104 also becomes "Low".

Since the reference clock is always supplied to the counter 103, a short width pulse is outputted to the output terminal of the AND circuit 104 every time, for example, (2c + 2d) pulses are supplied to the counter 103. Become. And this short width pulse has a preset function.
input to the digit counter 105.

When (N-M+1) short width pulses are input to the N-ary counter 105, the output to the CARRY terminal is inverted from "High" to "Low". However, M is the value set in the preset terminals (J1 to J4 in FIG. 5). When the output of the CARRY terminal is inverted, a reset voltage is applied to the reset terminal of the counter 101 via the inverter 106, and the AND circuit 102
The output, that is, the integral signal becomes "Low". At the same time O
Since one end of the input of the R circuit 100 also becomes "Low", the reference clock is supplied to the counter 101 again. After that, the above operation is repeated.

As explained above, the integral signal becomes "High" when (2a+2b) reference clocks are input, and becomes "Low" when (2c +2d)×(N-M+1) are input. That is, the integration time T is T={(2c +2d)(N-M+1)-(2a
+2b)}/fCK (3)
fCK: This is the frequency of the reference clock.

In this example, a, b, c, d, N, M, f
Integration time is made variable by arbitrarily combining CKs.

Next, a description will be given of changing the integration time in accordance with the output of the photometric sensor 8 (ie, the brightness near the anterior segment of the eyeball).

The output from the photometric sensor 8 is sent to the amplifier 110.
The signal is applied to the A/D converter 108 via the A/D converter 108. Each A/D converted output terminal is connected to a preset terminal of the N-ary counter 105. Therefore, the greater the output from the photometric sensor 8, that is, the brighter the area near the anterior segment of the eyeball, the greater the digital output of the A/D converter 108, and the greater the preset value M of the N-ary counter 105. The integration time shown by equation (3) also becomes shorter.

On the other hand, the zero level VL and the maximum level VH of A/D conversion are determined by the voltage dividing resistor 109 and the constant voltage VH, respectively.
is given by. When the input voltage of the A/D converter 108 becomes less than the voltage VL given by the voltage dividing resistor 109, all the preset terminals of the N-ary counter 105 are set to "Low" (ie, M=0).

As is clear from equation (3), the maximum value of the integration time is given when M=0, so a shown in equation (3)
, b, c, d, N, and fCK to determine the maximum value of the integration time, give a zero level voltage VL, and determine the corresponding photometric sensor output. As described above, the longest integration time is set when the brightness near the anterior segment of the eyeball is below a certain brightness, and then as the brightness increases, the integration time becomes shorter.

In the above explanation, a two-input AND circuit is shown, and a hexadecimal (4-bit) N-ary counter with a preset function is shown in FIG. 5, but in actual circuits, this is not the case. isn't it. For example, AN
If the D circuit 102 has l1 input and l2 input, respectively.

Next, a method for setting the amount of light emitted from the infrared light emitting diode 8 by the light emission control circuit 5 in this embodiment will be explained.

FIG. 6 is a circuit explanatory diagram of the light emission control circuit 5. In the figure, 120 is an amplifier, 121 is an A/D converter, 12
2, 123, 124, 125 are resistors for regulating the current flowing to the infrared light emitting diode, 126, 127,
128 and 129 are transistors each serving as a switching element, and 130 is a resistor for providing a minimum level voltage for A/D conversion.

The output from the photometric sensor 8 is sent to the amplifier 120.
A/D converter 1 amplifies it to a level suitable for A/D conversion.
I sent it to 21. Therefore, the A/D converted digital signal is sent to transistors 126, 127, 128, and 129, and as a result, the transistors are turned on and off according to the value of each bit of the digital signal. That is, the transistor corresponding to the bit whose value is "1" is turned on, and the other transistors are turned off.

On the other hand, the resistors 122, 123, 124, 12
The resistance values R1, R2, R3, and R4 of 5 are, for example, R
It is set so that 1:R2:R3:R4=8:4:2:1. Therefore, the current flowing through the infrared light emitting diode 7a is proportional to the digital output of the A/D converter 121 (corresponding to the output from the photometric sensor 8).

Since the amount of light emitted from the infrared light emitting diode 7a is generally proportional to the current flowing therein, the amount of light emitted from the infrared light emitting diode 7a is obtained in a manner substantially proportional to the output from the photometric sensor 8.

In the circuit of FIG. 6, the minimum value of the digital output of the A/D converter 121 is set to 1. Therefore, in this embodiment, the resistor 130 is used to determine the lowest level of A/D conversion. Note that the amplifier 120 may be a linear amplifier or a nonlinear amplifier. Also A/D
Although a 4-bit converter 121 is used in this embodiment, the converter 121 is not limited to this. Furthermore, it is also possible to use a photometric sensor for controlling exposure of a camera as the photometric sensor 8. In this case, there will be a slight difference in the output due to the difference between the location of the photographer and the location of the subject, but this difference is generally within an allowable range and poses no problem.

FIG. 7 is a flowchart of a second embodiment of the present invention, and FIG. 8 is a block diagram of main parts of the second embodiment of the present invention.

The feature of this embodiment is that M. P. Based on the output from the photometric sensor 8, U1 calculates the integration time T of the image sensor 4a and the amount of light emitted from the infrared light emitting diode 7a I (actually calculated by M.P.U1 is a constant D proportional to the amount of light emitted I). ) is calculated and set.

In this example, M. P. U1 reads the output of the photometric sensor 8 via the interface circuit 3. Using this value, first, the integration time T of the image sensor 4a is set. This is done by setting a numerical value M corresponding to the integration time T in an N-ary counter 105 having a preset function as shown in FIG. However, M
is expressed as M=(V-VL)/(VH-VL)*N, but if M becomes negative, M=0,
Also, the maximum value of M is set to N. Here, V is the output voltage from the photometric sensor 8, and VH and VL are arbitrary constants determined for setting the integration time and correspond to the maximum and minimum values of the expected output from the photometric sensor 8. When M is set in the N-ary counter 105 in this way, the integration time T is determined as follows.

From this, M is determined so that the desired integration time T can be obtained. After M is calculated, M. P. U1
sets this value M to the preset terminals (J1 to J4) of the N-ary counter 105 via the interface circuit 3.

Next, M. P. U1 determines a constant D in order to set the light emission amount I and the light emission amount I of the infrared light emitting diode 7a. The amount of emitted light I is calculated in advance from the energy E that can be irradiated to the eyeball (this is obtained by referring to laser safety standards, etc., and currently we use a value of 1/10 of the laser irradiation tolerance). From the integration time T, I=E
/T.

[0063] In this way, by keeping the integration time constant regardless of the length, the safety of the line of sight detection device is ensured. Here, the procedure for calculating the constant D will be described.

The luminous efficiency of the infrared light emitting diode 7a is η,
The power supply voltage of the circuit is VCC, and the apparent resistance value of the circuit is R.
Then, it is expressed as I=η·VCC/R. By setting the constant D, the transistor is turned on and off according to the value of D, and the resistance value R is determined. In the example of the circuit shown in FIG. However, R1 is the minimum resistance value among the resistors 122 to 125, and there is a relationship of 8R1 = 4R2 = 2R3 = R4 between the resistance values R1, R2, R3, and R4.

Therefore, in this embodiment, a constant D is determined so as to obtain the desired amount of emitted light I, and this value is set via the interface circuit 3 and the buffer 131.

In this way, in this embodiment, the integration time T,
After setting the amount of emitted light I, if there is a request for line-of-sight detection from the camera, a line-of-sight detection routine is entered. When entering the line of sight detection routine, M. P. U1 causes the infrared light emitting diode to emit light according to the amount of emitted light and the integration time set as described above, and starts the integration operation. After the integral operation is completed, the output of the image sensor is read, the first Purkinje image and the pupil are detected, and the position of the photographer's line of sight is determined from these two values, and the value is stored in memory as necessary. Then, if a release request is made, the routine shifts to a release routine.

In this example, as in Example 1, AN
You may use something other than 2 inputs as the D circuit, or you can use N
An arbitrary counter 105 may also be used.

Furthermore, the number of transistors used to set the amount of emitted light is not limited to four, but may be any number. The photometric sensor 8 may also be used for camera exposure control.
Alternatively, the output signal from the image sensor 4a may be regarded as the output of the photometric sensor and used.

[0069]

According to the present invention, as described above, the dynamic range of the image sensor can be improved by appropriately controlling the integration time of the image sensor and the amount of light emitted from the light projecting means when the image sensor receives the light flux. It is possible to obtain a signal with sufficient contrast for both the detection of the first Purkinje image and the detection of the pupil, thereby achieving a line-of-sight detection device that enables highly accurate line-of-sight detection.

In particular, in the present invention, a photometric sensor is provided, and the integration time of the image sensor is determined according to its output, and at the same time, the amount of light emitted by the infrared light emitting diode for forming the first Purkinje image is changed accordingly. In other words, the amount of emitted light is increased when the brightness of outside light is high, which shortens the integration time, and conversely, the amount of emitted light is reduced when the brightness of outside light is low, where the integration time is lengthened. It is possible to obtain a good image of the anterior segment of the eyeball and perform highly accurate line-of-sight detection without causing any damage, and to ensure the safety of the eyeball by keeping the energy irradiated to the eyeball (product of the amount of light emitted and the time of light emitted) constant. It has the following characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts of Embodiment 1 of the present invention.

2(A) is a schematic view of the main parts when the present invention is applied to a single-lens reflex camera, and (B) is a perspective view of the main parts of a part of FIG. 2(A).

FIG. 3 is a flowchart of Embodiment 1 of the present invention.

FIG. 4 is an explanatory diagram of the integration time control circuit according to the first embodiment of the present invention.

5 is a timing chart of the integral time control circuit of FIG. 4. FIG.

FIG. 6 is a schematic diagram of main parts of a light emission control circuit according to Example 1 of the present invention.

FIG. 7 is a flowchart of Embodiment 2 of the present invention.

FIG. 8 is a block diagram of main parts of Embodiment 2 of the present invention.

FIG. 9 is a schematic diagram of the main parts of a conventional line of sight detection device.

[Explanation of symbols]

1 Microprocessing unit (M.P.U)
2 Memory - 3 Interface circuit 4 Detection means 4a Image sensor 4b Drive circuit 4c Light receiving lens 5 Light emission control circuit 7 Light projection means 7a Infrared light emitting diode 7b Light projection lens 8 Photometric sensor 9 Integral time control circuit 29 Processing circuit 211 Eyeball

Claims (3)

[Claims] 1. A light beam from a light projection means is made incident on an eyeball, and a detection means having an image sensor detects the position coordinates of a Purkinje image and the position coordinates of a pupil based on light reflected from the eyeball, the detection means When determining the line of sight of the eyeball using these position coordinates detected by , the integration time of the image sensor is controlled by the integration time control means based on the output signal from the photometric sensor that measures the brightness near the anterior segment of the eyeball. A line of sight detecting device characterized in that the amount of light emitted from the light projecting means is changed by a light emitting control means. 2. The line of sight detection device according to claim 1, wherein the photometric sensor also serves as an image sensor of the detection means. 3. The line of sight detection device according to claim 1, wherein the light projecting means includes an infrared light emitting diode, and the light emission control means controls the amount of light emitted from the infrared light emitting diode. .