JP2000047096A - Range-finding device and camera using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurate range-finding even in a bright or dark scene by performing pre-integrating operation before integrating operation for arithmetically calculating a subject distance and controlling the integrating operation for arithmetically calculating the subject distance in accordance with the decided result by a decision means at the time of performing the pre-integrating operation. SOLUTION: A passive AF part 8 is provided with light receiving lenses 1a and 1b and line sensors 2a and 2b behind the lenses 1a and 1b. The outputs of the sensors 2a and 2b are connected to the inputs of a monitor part 9 and an integration circuit 7, and the output of the circuit 7 is connected to the input of an arithmetic calculation control circuit 11 in a CPU 10 through an A/D conversion part 7a. In such constitution, the pre-integrating operation is performed before regular integration, and an integral amount is monitored in timing of required time after starting the pre-integration, then the time for the regular integration is calculated based on the variation and the time difference of the required time. Therefore, whether the regular integration is long or short is predicted at the time of performing the pre-integration, so that a situation that a subject too bright is not brought into focus is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring apparatus used for, for example, a camera or the like, and more particularly, to a so-called passive type autofocus (hereinafter, referred to as AF) for detecting a subject image and focusing on the subject. And a camera using the same.

[0002]

2. Description of the Related Art Conventionally, an image signal from a subject is generally obtained by integrating a photocurrent of a line sensor. However, the integrated value is set to an appropriate value within a limited dynamic range of an electronic circuit. However, it is necessary to finely switch the integration end timing while monitoring the integration amount. Regarding this, for example, Japanese Patent Application Laid-Open No. 54-51556 discloses a technique relating to a distance measuring device that terminates integration when the integration amount reaches a certain value. On the other hand, JP-A-7-984
In Japanese Patent Publication No. 28, there is disclosed a technique relating to a photoelectric conversion device that predicts and determines an integration end timing based on a temporal change in an integration amount.

[0003]

However, according to the technique disclosed in Japanese Patent Application Laid-Open No. 54-55556, when the scene in which the subject exists is dark, the integration end time cannot be predicted. There was a possibility of wasting and missing a photo opportunity.

On the other hand, in the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-98428, when the integration must be terminated rapidly such as in a bright scene or when a strong auxiliary light is projected. In such a case, time is wasted in predicting calculation and the like, and the amount of integration may exceed the dynamic range of the circuit before the control ends.

The present invention has been made in view of the above-described problems, and has as its object to execute appropriate integration control even in a bright scene, a dark scene, or at the time of projecting a strong auxiliary light, to reduce a time lag. To provide a distance measuring device that achieves high-precision distance measurement to a minimum and uses an optical projection type active AF in combination to enable accurate distance measurement in any scene, and a camera using the same. is there.

[0006]

According to a first aspect of the present invention, there is provided a light receiving means for receiving light from a subject, an integrating means for integrating an output of the light receiving means, and A distance measuring device comprising: a determination unit that determines an integration state of the integration unit; and a calculation control unit that controls an integration operation of the integration unit and calculates a subject distance based on an output signal of the integration unit. The control means causes a pre-integration operation to be performed prior to the integration operation for calculating the subject distance, and controls the integration operation for calculating the subject distance in accordance with the determination result of the determination means during the pre-integration operation. A distance measuring device is provided.

In a second aspect, in the first aspect, the arithmetic control means sets an integration operation time for calculating a subject distance based on a determination result of the determination means in the pre-integration operation. A ranging device including an integration time determining means for determining is provided. .

In a third aspect, in the first aspect, the arithmetic control means includes an integration operation for calculating a subject distance in accordance with a determination result of the determination means at two timings during the pre-integration operation. Is provided.

In a fourth aspect, two sensor arrays for detecting two luminance patterns of a subject image incident from two optical paths, integration means for integrating output signals from the sensor arrays, and this integration means Determining means for judging the integration state, auxiliary light means for projecting light toward a subject, and arithmetic control for controlling the integrating operation of the integrating means and calculating the subject distance based on an output signal of the integrating means. Means for comparing the two luminance patterns to calculate a subject distance, and a sensor array for reflecting reflected light from the subject caused by projection light of the auxiliary light means. A distance measuring device configured to be able to switch a second distance measuring mode for receiving a light at a single distance and calculating a subject distance based on an output signal thereof, wherein the arithmetic control means comprises: Prior to the integration operation for computing to perform the pre-integration operation, ranging mode and a second determination result to the first on the basis of the determination means when the pre-integration operation
And a distance measurement mode.

In a fifth aspect, a release switch, light receiving means for receiving light from a subject, integrating means for integrating the output of the light receiving means, determining means for determining the integration state of the integrating means, Calculation control means for controlling the integration operation of the integration means and calculating the subject distance based on the output signal of the integration means; and focusing means for driving the taking lens to a focus position in accordance with the output of the calculation control means Wherein the arithmetic control means causes the pre-integration operation to be performed before the release switch is input and prior to the integration operation for calculating the subject distance, and the determination means during the pre-integration operation is performed. A camera using a distance measuring device, wherein an integration operation for calculating a subject distance is controlled in accordance with a result of the determination.

The first to fifth aspects have the following effects. That is, in the first aspect of the present invention, the light from the subject is received by the light receiving means, the output of the light receiving means is integrated by the integrating means, and the integration state of the integrating means is determined by the determining means. Controls the integration operation of the integration means and calculates the subject distance based on the output signal of the integration means. In particular, the calculation control means performs a pre-integration operation prior to the integration operation for calculating the subject distance. The integration operation for calculating the subject distance is executed according to the determination result of the determination means at the time of the pre-integration operation.

In a second aspect, in the first aspect, the arithmetic control means calculates an object distance by the integration time determining means based on a determination result of the determining means at the time of the pre-integration operation. Is determined.

[0013] In a third aspect, in the first aspect, the arithmetic and control means controls the two-time operation during the pre-integration operation.
An integration operation for calculating the subject distance is controlled according to the determination result of the determination means at one of the two timings.

In the fourth aspect, two luminance patterns of the subject image incident from two optical paths are detected by the two sensor arrays, the output signal from the sensor array is integrated by the integrating means, and the output signal from the sensor array is integrated by the determining means. The integration state of the integration means is determined, light is projected toward the subject by the auxiliary light means, the integration operation of the integration means is controlled by the arithmetic control means, and the subject distance is controlled based on the output signal of the integration means. A first ranging mode in which the object distance is calculated by comparing the two luminance patterns, and a reflected light from the object caused by the projection light of the auxiliary light means is calculated by one of the sensor arrays. And calculates a subject distance based on the output signal.
The pre-integration operation is controlled by the arithmetic control unit prior to the integration operation for calculating the subject distance, and the determination result of the determination unit during the pre-integration operation is set by the arithmetic control unit. Is switched between the first ranging mode and the second ranging mode on the basis of.

In the fifth aspect, light from the subject is received by the light receiving means, the output of the light receiving means is integrated by the integrating means, the integration state of the integrating means is determined by the determining means, and the integration control means determines the integration state. The integration operation of the integration means is controlled, the subject distance is calculated based on the output signal of the integration means, and the focusing lens is driven to the focusing position by the focusing means in accordance with the output of the calculation control means. The arithmetic control means controls the execution of the pre-integration operation before the release switch is input and prior to the integration operation for calculating the subject distance, according to the determination result of the determination means during the pre-integration operation. In this way, the integration operation for calculating the subject distance is controlled.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, an outline of the distance measuring apparatus of the present invention and a camera using the same will be described. A distance measuring apparatus according to the present invention includes a light receiving unit that receives light from a subject, an integrating unit that integrates an output of the light receiving unit, a determining unit that determines an integration state of the integrating unit, and an integrating operation of the integrating unit. And a calculation control means for calculating a subject distance based on an output signal of the integration means, wherein the calculation control means performs an integration operation for calculating a subject distance. A pre-integration operation is performed, and an integration operation for calculating a subject distance is controlled in accordance with a result of the determination by the determination means at the time of the pre-integration operation. The calculation control means includes an integration time determination means for determining a time of an integration operation for calculating a subject distance based on a determination result of the determination means at the time of the pre-integration operation. The calculation control means controls an integration operation for calculating a subject distance in accordance with the determination result of the determination means at two timings during the pre-integration operation.

More specifically, two sensor arrays for detecting two luminance patterns of a subject image incident from two optical paths, integration means for integrating output signals from the sensor arrays, and integration means Determining means for determining the integration state of the means, auxiliary light means for projecting light toward a subject, and an operation for controlling the integrating operation of the integrating means and calculating a subject distance based on an output signal of the integrating means. A first ranging mode (passive AF) for calculating a subject distance by comparing the two luminance patterns, and a reflected light from the subject caused by a projection light of the auxiliary light unit. Measuring device configured to be able to switch a second distance measuring mode (active AF) for receiving light by one of a sensor array and calculating a subject distance based on an output signal thereof The arithmetic control means causes the pre-integration operation to be performed prior to the integration operation for calculating the subject distance, and the first distance measurement mode is performed based on the determination result of the determination means during the pre-integration operation. And the second ranging mode.

On the other hand, a camera using the distance measuring device includes a release switch, light receiving means for receiving light from a subject, integrating means for integrating the output of the light receiving means, and determining the integration state of the integrating means. Determining means for controlling the integrating operation of the integrating means; calculating control means for calculating a subject distance based on the output signal of the integrating means; Wherein the arithmetic and control unit performs a pre-integration operation prior to the input of the release switch and prior to an integration operation for calculating a subject distance. It is characterized in that an integration operation for calculating a subject distance is controlled in accordance with a determination result of the determination means at the time of a pre-integration operation.

Here, in order to better understand the embodiment of the present invention, the principle of a so-called passive AF will be briefly described with reference to FIG. In FIG. 3, reference numeral 3 denotes a subject in the photographic screen 4, and images 6a and 6b of the subject are detected by the light receiving lenses 1a and 1b.
When projected onto 2b, each line sensor 2a, 2b outputs a photocurrent according to its brightness.

The waveform obtained by integrating this for a certain time is shown in FIG.
As shown in (b), since the integration circuit has a dynamic range determined by the power supply voltage and the circuit configuration, it is necessary to store the integrated waveform, that is, the image signal therein.

If the integration is excessive, the outputs of many sensors are saturated, and the information amount of the image signal is reduced as shown in FIG. The image signals 6a and 6b shown in FIG. 3A have a relative position difference of x in the figure due to the parallax B of the lens. The focal length of the light receiving lens 1b is f
Then, the distance L is obtained by the relationship of L = B · f / x (1) according to the principle of triangulation.

Therefore, as shown in FIG. 3D, the accuracy of obtaining the degree of coincidence of the images when the positions of the image signals 6a and 6b are shifted in calculation is an error in focusing. Therefore, when the integration amount is incorrect, that is, in a state as shown in FIG. This is not limited to the triangulation, but is a problem common to the contrast method using an image signal.

Embodiments will be described below based on the principle described above. FIG. 1 is a configuration diagram of a camera employing the distance measuring device according to the first embodiment. As shown in FIG. 1, the configuration is roughly divided into a passive AF unit 8, a CPU 10, and peripheral circuits. In the passive AF section 8,
Light receiving lenses 1a and 1b are provided to receive an image from a subject, and line sensors 2a and 2b corresponding to light receiving means are provided behind the lenses. Outputs of the line sensors 2a and 2b are connected to inputs of a monitor unit 9 and an integration circuit 7 corresponding to integration means, and the output of the integration circuit 7 is subjected to arithmetic control in the CPU 10 via an A / D conversion unit 7a. It is connected to the input of the arithmetic and control circuit 11 corresponding to the means. The output of the monitor 9 is connected to an input of a determination unit 12 corresponding to a determination unit in the CPU 10.

On the other hand, in the CPU 10,
The output of 2 is connected to the inputs of the integration circuit 7 and the arithmetic control circuit 11, and the output of this arithmetic control circuit 11 is connected to the input of the time switching unit 13. The output of the time switching unit 13 is connected to the input of the integration circuit 7. In addition, the output of the CPU 10 is connected to the flash unit 5 via the light emitting circuit 5a, and connected to the focusing lens 15 via the focusing unit 14 via a mechanical mechanism (not shown). The input of the CPU 10 includes
The output of the luminance sensor 16 and the switch 10a are connected.

In such a configuration, the line sensor 2
The outputs of a and 2b are integrated by an integrating circuit 7, and the integration results or the outputs of the line sensors 2a and 2b are monitored in real time by a monitor unit 9. The A / D converter 7a
The result of the integration is converted into a digital value, and the arithmetic control circuit 1
Output to 1. Note that, depending on the configuration of the camera, the A / D converter 7a may be built in the CPU 10.

The CPU 10 controls the sequence of the entire camera, and determines the timing of starting distance measurement and the timing of starting photographing from the input state of the switch 10a operated by the user. That is, the arithmetic control unit 11 controls the A / D conversion unit 7
The shift amount between the two image signals (6a and 6b in FIG. 3) converted into digital values by a is calculated, and the focus position is obtained according to the above equation (1). The determination unit 1 determines the integration state based on the monitor output. The time switching unit 13 generates a predetermined timing signal using a counter or the like.

In this manner, the focusing lens 1 is obtained by the focusing signal obtained by the CPU 10.
5 is driven and controlled by a focusing unit 14 including a driver, a position encoder, and the like. In addition, the luminance sensor 16, the flash unit 5, and the like function to determine the exposure and supplement the exposure amount.

Before describing the operation of the first embodiment in detail, the disadvantages of the conventional integral control will be described in order to clarify the difference from the prior art. That is, FIG.
As shown in the flow chart of the prior art, in the prior art, after the integration is started (step S1), it is determined that the integration is at an appropriate level while repeating the monitoring operation (steps S2 and S3), and the appropriate level is determined. When the operation is performed, the operation is stopped (step S4). In such a system, the relationship shown in FIG. 2A is obtained in consideration of the time (TM) for A / D conversion of the image signal and monitoring, and the time (TH) required for completion determination.

That is, in the case of a "high-brightness" scene in which the level exceeds the appropriate level earlier than the time of TM + TH or when a strong auxiliary light is projected, the integration cannot be kept within the appropriate level. At "medium brightness", the above function works normally, but at "low brightness", it is difficult to know the timing to reach the appropriate level. I was

The first embodiment of the present invention solves these problems. Hereinafter, with reference to the flowchart of FIG. 4 and the time chart of FIG. 5, a characteristic operation of the first embodiment will be described in comparison with the above-described conventional technology.

In the first embodiment, as shown in FIG. 5A, the pre-integration operation is performed before the main integration, and after the start of the pre-integration, the integration amount (A) is obtained at timings t1 and t2. / D1, A / D2) and monitor the change (A /
D2−A / D1) and a method of calculating a time tINT of the main integration based on a time difference Δt between t1 and t2 (steps S11 to S18). According to this, whether the main integration becomes longer or shorter can be predicted at the time of the pre-integration, and there is no case where a shutter chance is missed or a subject that is too bright is not focused as in the related art.

Here, since the times t1 and t2 can be generated by a hard timer or the like without being monitored or determined, extremely high-level control is possible. Now, assuming that the appropriate integration level is VS, from the relationship tINT: VS = .DELTA.t: (A / D2-A / D1), tINT = .DELTA.t.VS / (A / D2-A / D1) (2) The time for the main integration is determined.

If it is determined in step S17 that the A / D2 is too large with high luminance,
As shown in the time chart of (b), the integration is completed in a time shorter than the time t1 (in this example, t1 / 2), and the integration amount is prevented from being saturated (step S19, step S19). S20).

Further, the time t calculated by the above equation (2)
If it is determined that INT is too long (step S21), a setting is made to end the integration at an appropriate time tINT1 so as not to miss a photo opportunity (steps S22 and S22).
23).

In addition to the above, it goes without saying that the sensitivity may be switched by switching the capacity of the integral C or the like at the same time as the integration time is changed. Thus, the set time tIN
The main integration is executed at T1 (steps S24 to S27), and all operations are completed.

As described above, according to the first embodiment, it is possible to provide a distance measuring apparatus capable of performing accurate focusing without missing a photo opportunity at high luminance or low luminance. In addition, since sensitivity switching is also used,
The integration time can be optimized according to the circuit response capability.

Next, a second embodiment will be described. The configuration for realizing the second embodiment is the same as that shown in FIG.
Therefore, the detailed description is omitted here. Hereinafter, the operation of the second embodiment will be described in detail with reference to the flowchart of FIG. 6 and the time chart of FIG.

When the operation is started, first, integration is performed for a fixed time t1, and after setting the variable n to 2, the integration operation is stopped and the integration amount A / D1 is monitored (steps S31 to S34). Next, after resetting once, the integration time is set to tn (here, n = 2), which is Δt longer than the above-mentioned t1 (steps S35 and S36), the integration is performed again only for the time t2, and the integration operation is stopped. Then, the obtained integration amount A / D2 is monitored (steps S37 to S39).

As described above, in the second embodiment, the pre-integration is not performed by one operation, but the monitoring of the timings of t1 and t2 is performed while resetting each time. As a result, the time difference Δt between the times t1 and t2 can be reduced, and as is clear from the above equation (2), the time tIN
T can be further subdivided and controlled.

However, in the case of the second embodiment, if the time difference Δt is too short, the integration amount ΔVINT becomes too small, and the denominator of the above equation (2) may become small and the accuracy may deteriorate. . Therefore, in the second embodiment, as shown in FIG. 7B, when the difference VINT1 between the integration amounts is small, the pre-integration is further repeated to obtain a sufficient maximum VINT.
Is controlled so as to extend the integration time until the time is generated between the first integration amount A / D1 (steps S37 to S41).

In this way, the difference between the integration amount and the integration time is increased to reduce the error margin, thereby improving the calculation accuracy of the integration time control of the main integration (steps S42 to S45). ). It should be noted that the digital operation involves a quantization error, but if the operation is not performed by increasing the data, the effect of the error cannot be ignored.

As described above, according to the second embodiment, the difference between the pre-integration times t1 and t2 can be reduced, and the calculation accuracy is increased by taking measures against the difference. In addition, finely integrated control can be performed.

Next, a third embodiment will be described. This embodiment is to further speed up the second embodiment. Since the configuration for realizing the third embodiment is the same as that shown in FIG. 1 described above, a detailed description is omitted here.

The operation of the third embodiment will be described below with reference to FIG. The feature of this embodiment is that pre-integration is completed before inputting the release button, and the time lag after pressing the release button is reduced as much as possible.

That is, when the operation is started, various variables and the like are reset (initial setting), integration is performed for a fixed time t1, and
When the integration is stopped, the integration amount A / D1 is monitored (steps S51 to S54). Then, resetting is performed again, integration for a fixed time t2 (= t1 + tH) is executed, and when the integration is stopped, the integration amount A / D2 is monitored, and the main integration time tIN is calculated from the integration amounts A / D1 and A / D2.
T is calculated (steps S55 to S59). And
If tINT is longer than the predetermined time, the setting for projecting the auxiliary light during the pre-integration is made (step S61), and the series of operations of steps S51 to S60 is repeated.

As described above, in the third embodiment, when the main switch for the power supply of the camera is operated, the pre-integration is performed by the operations of steps S51 to S62. Not only the time but also whether or not to project the auxiliary light is determined. The auxiliary light supplements light or an image to the subject by projecting an LED, a lamp, or strobe light when the subject is dark or has no contrast, and in the present embodiment, the calculated main integration is used. When the time tINT is too long, auxiliary light is projected.

The conventional technique has a problem in that, when strobe light is used as auxiliary light, the amount of light that is instantaneously emitted and supplemented is too strong, and the amount of integration is instantaneously saturated. On the other hand, according to the technique of the third embodiment, the times t1 and t2 are shortened to irradiate the auxiliary light each time the pre-integration is performed. Can be performed.

In the prior art method (as described above with reference to FIG. 2), the saturation occurs during the monitoring time tM determination time tH. However, according to the third embodiment, the time t1,
Since the timing such as t2 is made by a hard timer or the like, the timing can be made shorter and more accurate. Also, the time tINT is controlled by the open loop control based on the value calculated by the processing of step S59 in the sequence, so that the integration can be completed at high speed and with high accuracy.

When the release button is depressed in this way, after the reset, the main integration is performed (steps S62 to S65), and the obtained image signal is used to perform triangular ranging by comparing the two images described earlier with reference to FIG. The focus distance can be calculated, and focus control is performed (S6).
6, S67). Thereafter, photographing is performed, but the integration control technique for forming an image signal is not limited to triangulation, but is also applicable to TTL focus position detection or contrast AF (step S68).

As described above, according to the third embodiment, by performing the pre-integration before the input of the release button, the time lag after the release button is pressed can be reduced.

Next, a fourth embodiment will be described. FIG. 9 is a diagram showing a configuration of a distance measuring apparatus according to the fourth embodiment. As shown in FIG. 9, the distance measuring apparatus according to the fourth embodiment has a light source 31 controlled to emit light via a driver 30 and a condensing lens 32 in a light emitting system. Even if 3 has no contrast, the distance can be measured by the signal light projected from the light source 31. That is, not only the passive method of measuring the distance using only the image signal but also the active method of obtaining the subject distance L from the incident position x of the signal light projected from the camera side is used.

The technique in which the two ranging methods compensate for each other's weaknesses makes it possible to cope with any subject, but conventionally there is a weakness such that the time lag becomes longer due to the use of these two ranging methods. Was. On the other hand, in the distance measuring apparatus according to the fourth embodiment, the pre-integration is performed before the main integration, whereby the state of the subject can be monitored in advance. Since it is possible to determine whether or not to perform the operation, the two methods, the active method and the passive method, are selected at a high speed, and the focusing can be performed without a time lag and without a weak subject.

The operation of the fourth embodiment will be described below with reference to the flowchart of FIG. When the operation is started, first, integration is performed at a fixed time t1, and the integration amount A / D1
Is obtained (step S71). Similarly, integration is performed at a fixed time t2 to obtain an integration amount A / D2 (step S72).
It is determined whether the subject is bright according to the results A / D1 and A / D2 of the two pre-integrations (step S7).
3).

If the subject is a bright scene, t1,
When the integration is performed while changing the time to t2, the difference becomes large, and such a scene is a specialty of the passive system. On the other hand, when there is no difference in the amount of integration even when the integration time is changed, the scene is a dark scene, so the active method is preferable. This is because in this dark scene, the integration time for the main integration takes time, and the image signal also has low contrast.

If it is determined in step S73 that the subject is bright, the triangulation by the passive method described in the above embodiment is executed (steps S74 to S77). A detailed description of this will be omitted.

On the other hand, if it is determined in step S73 that the subject is dark, distance measurement by the active method is performed. That is, the CPU 10 transmits the IR
The ED31 infrared light emitting diode emits light. This signal light is condensed and projected on the subject 3 by the lens 32 and then reflected and enters the sensor array 2b via the light receiving lens 1b.
In the present embodiment, in the active mode, light that constantly enters the sensor array is canceled as a DC component, and only the signal light of the IRED changes in a pulsed manner. I have.

The stationary light removing circuit 33 is a circuit for preventing a signal due to DC light from entering the integrating circuit, and this circuit operates when active. In this way, only the signal light enters the integration circuit. From this integration result, it can be determined which sensor has the most signal light, and the incident position x is obtained (step S78).

Now, assuming that the distance between the light emitting and receiving lenses is S and the focal length of the light receiving lens is f, the subject distance is obtained from this x as L = S · f / x (3) according to the principle of triangulation.

Therefore, based on the obtained integration result, the CPU 1
When 0 finds x, the focusing distance is found (step S79). As described above, according to the fourth embodiment, the scenes that the active system and the passive system are good at can be shared by the respective systems and the sharing can be discriminated and switched at a high speed. It is possible to provide a distance measuring device that realizes high-speed AF corresponding to a wider range of subjects.

The above embodiment of the present invention includes the following inventions. (1) Light receiving means for receiving light from a subject, integrating means for integrating the output of the light receiving means, determining means for determining the integration state of the integrating means, and controlling the integrating operation of the integrating means, A distance measuring device having a calculation control means for calculating a subject distance based on an output signal of the integration means, wherein the calculation control means performs a pre-integration operation prior to the integration operation for calculating the subject distance, A distance measuring apparatus for controlling an integration operation for calculating a subject distance in accordance with a result of the determination by the determination means during the pre-integration operation. (2) The distance measurement according to (1), wherein the arithmetic control unit includes a sensitivity switching unit that switches a sensitivity of an integration operation for calculating a subject distance based on a determination result of the determination unit during the pre-integration operation. apparatus. (3) There is an auxiliary light means for projecting light toward the subject at the time of the integration operation, and the arithmetic control means calculates an object distance based on a determination result of the determination means at the time of the pre-integration operation. The distance measuring apparatus according to (1), further comprising an auxiliary light operation determining means for determining whether or not to operate the auxiliary light means at the time of the integration operation. (4) The arithmetic control unit controls the integration operation for calculating the subject distance according to the determination result of the determination unit at each pre-integration operation, by performing the pre-integration operations having different integration operation times a plurality of times. The distance measuring device according to the above (1). (5) The distance measuring apparatus according to (4), wherein when the difference between the determination results at the time of each pre-integration operation is smaller than a predetermined value, the integration operation time is extended to perform the pre-integration operation again. (6) An auxiliary light means for projecting light toward the subject at the time of the integration operation, wherein the arithmetic control means determines that the subject is dark based on the result of the determination at the pre-integration operation. The distance measuring apparatus according to (1) or (3), wherein the auxiliary light means is operated to perform the pre-integration operation again. (7) Two sensor arrays for detecting two luminance patterns of a subject image incident from two optical paths, integrating means for integrating output signals from the sensor arrays, and determining an integration state in the integrating means. Determining means, auxiliary light means for projecting light toward a subject, and a first ranging mode for controlling an integration operation of the integration means and calculating a subject distance based on an output signal of the integration means; A second ranging mode in which reflected light from the subject caused by the projection light of the auxiliary light means is received by any one of the sensor arrays and a subject distance is calculated based on an output signal thereof can be switched. A distance measuring device configured to measure the distance in the first distance measuring mode during a normal operation, wherein the arithmetic control unit performs a pre-integration operation prior to the integration operation for calculating the subject distance. The done was, the distance measuring apparatus and wherein the switching between said first distance measurement mode and the second distance measurement mode based on the determination result of the determination means when the pre-integration operation. (8) In a camera that focuses on a subject in accordance with an image signal of the subject, a sensor array that receives and integrates light from the subject, a determination unit that determines an integrated output of the sensor array, and the determination at a predetermined timing Integral control means for controlling the integration operation for forming the image signal in accordance with the output result of the means, and integral time determining means for determining the time of the integral control after determining the integral time in accordance with the output of the determining means. An autofocus camera characterized by the following. (9) The predetermined timings are two timings during the predictive integration preceding the integration period for forming the image signal.
The autofocus camera according to (8), wherein said integration time determination means determines the integration end time according to two corresponding outputs of said determination means at said two timings. (10) The predetermined timing is a timing during a plurality of integrations with different integration times performed prior to the integration period for forming the image signal. The autofocus camera according to the above (8), wherein the integration end time is determined according to two corresponding outputs of the determination means. (11) a release switch is provided, and the predetermined timing is performed before the integration period for forming the image signal,
The timing before the release switch is input, the integration time determination means determines the integration end time in accordance with the two corresponding outputs of the determination means at the two timings, and determines the integration time of the image signal. Is the timing after the input of the release switch. (12) The autofocus camera according to (8), further including an active AF device, wherein the active AF device is operated when the determined integration time is not appropriate.

[0061]

As described in detail above, according to the present invention,
Performs appropriate integration control to minimize time lag, achieve high-precision distance measurement, and use light projection type active AF even in bright or dark scenes or when projecting strong auxiliary light. In addition, it is possible to provide a distance measuring device that enables accurate distance measurement in any scene and a camera using the same.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a camera to which a distance measuring device according to a first embodiment is applied.

FIG. 2A is a time chart in a case where integral control for distance measurement is performed by the distance measurement device of the first embodiment, and FIG. 2B is a time chart of the distance measurement device of the first embodiment. 5 is a flowchart in a case where integral control for distance measurement is executed by using the following equation.

FIG. 3 is a diagram illustrating the principle of passive AF and a problem with a conventional control method.

FIG. 4 is a flowchart showing an operation according to the first embodiment.

FIG. 5 is a time chart showing an operation according to the first embodiment.

FIG. 6 is a flowchart showing an operation according to the second embodiment.

FIG. 7 is a time chart showing an operation according to the second embodiment.

FIG. 8 is a flowchart showing an operation according to the third embodiment.

FIG. 9 is a block diagram illustrating a configuration of a distance measuring apparatus according to a fourth embodiment.

FIG. 10 is a flowchart showing an operation according to the fourth embodiment.

[Explanation of symbols]

 Reference Signs List 1 light receiving lens 2 line sensor 3 subject 4 photographic screen 5 strobe unit 5a light emitting circuit 6 image signal 7a A / D conversion unit 7 integration circuit 8 passive AF unit 9 monitor unit 10 CPU 10a switch 11 arithmetic control circuit 12 determination unit 13 time switching Unit 14 Focusing unit 15 Focusing lens 16 Brightness sensor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H011 AA01 BA05 BA14 BB04 BB05 DA01 DA08 2H051 BA15 BA20 CB24 CC03 CE01 CE06 DA22 EA25 EB01

Claims (5)

[Claims] A light receiving means for receiving light from a subject;
Integrating means for integrating the output of the light receiving means, determining means for determining the integration state of the integrating means, controlling the integrating operation of the integrating means, and calculating the subject distance based on the output signal of the integrating means A distance measuring device having arithmetic control means, wherein the arithmetic control means causes a pre-integration operation to be performed prior to an integration operation for calculating a subject distance, and the pre-integration operation is performed in accordance with a determination result of the determination means during the pre-integration operation. A distance measuring device for controlling an integral operation for calculating a subject distance by using the distance measuring device. 2. The arithmetic control unit includes an integration time determination unit that determines an integration operation time for calculating a subject distance based on a determination result of the determination unit at the time of the pre-integration operation. 3. The distance measuring device according to 1. 3. The distance measurement according to claim 1, wherein the arithmetic control unit controls an integration operation for calculating a subject distance in accordance with a determination result of the determination unit at two timings during the pre-integration operation. apparatus. 4. Two sensor arrays for detecting two luminance patterns of a subject image incident from two optical paths, integration means for integrating an output signal from the sensor array, and an integration state in the integration means. Determination means, auxiliary light means for projecting light toward the subject, and arithmetic control means for controlling the integration operation of the integration means and calculating a subject distance based on an output signal of the integration means. A first distance measurement mode for calculating the subject distance by comparing the two luminance patterns, and a reflected light from the subject caused by the projection light of the auxiliary light means, using one of the sensor arrays. A distance measuring device configured to switch a second distance measuring mode for receiving light and calculating a subject distance based on an output signal thereof, wherein the arithmetic control means calculates the subject distance; A pre-integration operation is performed prior to the integration operation of the above, and the first distance measurement mode and the second distance measurement mode are switched based on the result of the judgment by the judgment means at the time of the pre-integration operation. Distance measuring device. 5. A release switch, light receiving means for receiving light from a subject, integrating means for integrating the output of the light receiving means, determining means for determining the integration state of the integrating means, and integration of the integrating means. A camera having operation control means for calculating an object distance based on an output signal of the integration means, and a focusing means for driving a photographic lens to a focus position in accordance with an output of the operation control means. In the above, the arithmetic control means causes a pre-integration operation to be performed prior to the input of the release switch and prior to an integration operation for calculating a subject distance, and the determination result of the determination means at the time of the pre-integration operation is determined. A camera using a distance measuring device, wherein an integral operation for calculating a subject distance is controlled in accordance therewith.