JP2000193879A - Distance measuring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve distance measuring accuracy by detecting a stain on a panel or an abnormality with high accuracy without increasing the cost and the space. SOLUTION: A distance measuring equipment in which a pair of beams from an object are respectively incident on a pair of line sensors through a panel 15 forming a part of accessories, and the distance to the object is obtained based on a pair of output from the line sensors, is provided with a CPU 18 to evaluate the parameter to indicate the relative degree of agreement of a pair of outputs from the line sensors specified times, and display parts 26, 27 to detect and inform an abnormal condition related to distance measuring in response to the result of the evaluation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external light passive distance measuring device, and more particularly, to detecting that a panel which forms a part of the exterior of a camera and functions as a window of the distance measuring device becomes dirty and warns the user. The present invention relates to a distance measuring device having a function of performing

[0002]

2. Description of the Related Art In recent years, in order to meet the needs of users, the cost, size, and weight of the camera, and the magnification of the zoom (lengthening the focal length of the photographing lens) have been rapidly advanced. Under the background of such technological progress, it is indispensable to increase the accuracy of the distance measuring device. However, in pursuit of the high accuracy, the contamination of a panel which forms a part of the exterior of the camera and serves as a window of the distance measuring device. The effect on the distance measurement accuracy cannot be ignored.

In view of such problems, various technical developments have been made conventionally.

[0004] That is, for example, Japanese Patent Application Laid-Open No. Hei 7-146353 discloses a light-emitting device including a light-emitting means for emitting light to a panel, and a light-receiving means for receiving light reflected by the panel. A technique related to a distance measuring device characterized by detecting a change in the diffuse reflectance of the panel due to the contamination of the panel from the received light signal obtained by the method and detecting the contamination of the panel is disclosed.

Further, Japanese Patent Application Laid-Open No. Hei 7-146354 discloses a structure in which a light projecting means and a light receiving means are provided to transmit light inside the panel. There is disclosed a technology relating to a camera, which is characterized in that it is one of the features to detect the dirt on the panel.

[0006]

However, in the above prior art, assuming that the distance measuring device is mounted on a camera, the distance measuring device itself becomes very expensive, and its control and configuration become complicated. The space occupied by the device in the camera was increasing.

That is, although the above-mentioned prior art has been successful in improving the accuracy of a distance measuring apparatus, it solves the above-mentioned problems of recent users, such as low price and small size and light weight. I couldn't do that.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to effectively utilize information obtained for each distance measurement operation without adding a new configuration. For example, by devising information processing on software, it is possible to detect panel dirt and give a predetermined warning without increasing costs and increasing space, and to prevent erroneous ranging due to panel dirt. It is an object of the present invention to provide a distance measuring device which is prevented from occurring and has improved distance measuring accuracy and reliability.

[0009]

In order to achieve the above object, according to a first aspect of the present invention, a pair of objects from a subject is transmitted through a light-transmitting panel and a light-receiving optical system forming a part of an exterior part. A distance measuring device that causes light to be incident on a pair of line sensors and calculates a distance to a subject based on the output of the pair from the line sensor, and indicates a relative coincidence between the pair of outputs from the line sensor. A distance measuring device comprising: an evaluation unit that evaluates a parameter a predetermined number of times; and a unit that detects and notifies an abnormal state related to a distance measurement operation in response to an evaluation result of the evaluation unit. Provided.

According to a second aspect, in the first aspect, the abnormal state related to the distance measuring operation is such that the surface of the light-transmitting panel is dirty and the surface of the light-transmitting panel is an obstacle. A distance measuring device is provided, which includes a state covered with a distance.

Further, in a third aspect, in the first aspect, the notification of the abnormal state relating to the distance measuring operation is made by also using a display means for the distance measuring operation. A ranging device is provided.

According to the above-described first to third aspects, the following operations are provided.

That is, in the first aspect of the present invention, the parameter representing the relative coincidence of the pair output from the line sensor is evaluated a predetermined number of times by the evaluation means, and the notification result of the evaluation means is evaluated by the notification means. , An abnormal state related to the distance measuring operation is detected and notified.

According to a second aspect, in the first aspect, the abnormal condition relating to the distance measuring operation includes a condition in which the surface of the light-transmitting panel is dirty and a surface in which the light-transmitting panel is obstructed. Includes covered state.

[0015] In a third aspect, in the first aspect, the notification of the abnormal state relating to the distance measuring operation is performed by also using the display means for the distance measuring operation.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a camera employing a distance measuring apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, the outputs of a remote control (hereinafter abbreviated as “remote”) light receiving circuit 20 and a photometric (hereinafter abbreviated as “AE”) light receiving circuit 21 are processed by a central processing unit that controls the entire camera. Equipment (CPU; Central
(Processing Unit) 18. The outputs of the CPU 18 are displayed on display units 26 and 27, a distance measuring (hereinafter abbreviated as AF) auxiliary light emitting circuit 22, an AF
The section 23 and the input of the strobe circuit 24 are connected to each other. Further, the CPU 18 is communicably connected to the mechanical drive / control unit 19. In addition, the camera 25 includes a finder optical system 14, an imaging optical system 7, a panel 15
Etc. are provided.

In such a configuration, when the release switch (not shown) is pressed by the photographer, the CPU 18 instructs the AF section 23 to start a distance measuring operation. Then
The CPU 18 monitors the integration operation of the luminance signal of the subject performed by the AF unit 23, outputs an auxiliary light emission request signal to the AF auxiliary light circuit 22 as necessary, turns on the auxiliary light, and At 23, the integration operation is performed.

When the integration operation is completed, the CPU 18
Acquires the luminance signal of the subject from the AF unit 23, performs distance measurement calculation, and obtains the subject distance. At this time, it is a matter of course that the AF unit 23 may execute the processing up to obtaining the subject distance and output the subject distance to the CPU 18.

Subsequently, the CPU 18 controls the AF light receiving circuit 21
Photometry is performed using. When the photometry is completed, an exposure calculation is performed to calculate a shutter speed and an aperture value. Also,
The necessity / unnecessity of the strobe is determined, and in the case of the strobe, the light emission amount is also calculated.

Next, the CPU 18 calculates the driving amount of a focusing lens (not shown) in order to focus on the subject, and drives the focusing lens by the mechanical drive / control unit 19. Furthermore, a shutter (not shown) is driven by the mechanical drive / control unit 19 based on the shutter speed and the aperture value previously calculated by the exposure calculation to perform exposure. At this time, the CPU 18 issues a strobe light emission request signal to the strobe circuit 24 as necessary, and causes the strobe circuit 24 to emit light.

Thus, when a series of exposure operations is completed,
The CPU 18 winds up the film by one frame by the mechanical drive / control unit 19 and prepares for the next photographing operation.

The operation of the camera other than the above is as follows.
If the operation in the remote control mode or the photographing optical system 7 can be converted (zoomable), there is a conversion operation of the photographing optical system 7 and the like, but a detailed description thereof will be omitted.

FIG. 2 is a front view of a camera employing the distance measuring apparatus according to the first embodiment. As shown in the figure, an AF window 1, a finder window 3, and an AF auxiliary light window 2 are arranged side by side at a predetermined position in front of the camera. Like A
An E window 4 and a remote control window 5 are arranged. The pop-up flash window 6 can be stored in the camera body.

FIG. 3 is a view showing a state where the exterior of the camera is seen through from above.

As shown in FIG. 3, the panel 15 is provided with an AF window 1, an auxiliary light window 2, and a finder window 3 as shown. An AF section 23 including an AF optical system 8, an AF housing 9, and an AFIC 10 is provided inside the camera behind the AF window 1. A finder optical system 14 is provided inside the camera behind the finder window 3. Is provided inside the camera behind the auxiliary light window 2.
An auxiliary light optical system 11, a reflector 13, and an auxiliary light source 12 are provided. The AF optical system 8, the AF housing 9, the AFIC
Reference numeral 10 corresponds to the AF unit 23 shown in FIG. 1 described above.

Panels 15 and A, which are part of the exterior of the camera,
The positional relationship of the F unit 23 and the positional relationship between the AF window 1 and the AF unit 23 are as illustrated, and light from the subject is transmitted to the AFIC 10 via the AF window 1, the AF optical system 8, and the AF housing 9. Each member is arranged so as to be guided.

FIG. 4 shows a configuration in which the AF unit 23 is further embodied and will be described.

As shown in FIG. 4, the AF optical system 8
Is composed of a pair of lenses integrally formed, and AF
The housing 9 divides each optical path of the pair of lenses,
It has a structure that prevents unnecessary diffuse reflection inside.

The line sensor 16 and the line sensor 17, which are light receiving means for receiving light from a subject and obtaining a subject luminance signal used for distance measurement, are monolithically formed on the AFIC 10 on one chip. .

The A of the camera according to the first embodiment is described above.
The configuration of the F section 23 and its periphery has been described in detail. Next, the principle of distance measurement will be described in detail.

FIG. 5 shows the relationship between the subject and the AF section 23 and will be described.

In the figure, light from a subject is guided to a line sensor 16 and a line sensor 17 via a panel 15 and an AF optical system 8.

FIG. 6 is a diagram showing luminance information of a subject obtained by the line sensor 17. In the figure, L, C, and R are used to divide the line sensor 17 into a plurality of parts, each of which is used as a distance measurement point, to obtain a plurality of object distances in a direction corresponding to the distance measurement point. This is an example of a possible “multi AF”.

The luminance information (hereinafter referred to as sensor data) of the illustrated subject differs depending on the method of integrating the received light current of each cell of the line sensor 17, and the magnitude of the sensor data is inverted between bright and dark. May be.

In this embodiment, the background is brighter than the subject, and the bright sensor data is smaller. Further, sensor data of a person is formed at a distance measuring point C, and sensor data of a tree is formed at a distance measuring point L.

Here, when calculating the distance to the person at the distance measuring point C, the phase difference (relative shift amount) of the sensor data at the distance measuring point C is calculated. The distance to is obtained. Here, a detailed description of the principle of the triangulation is omitted.

Next, the distance measuring operation of the distance measuring apparatus according to the first embodiment will be described in detail with reference to the flowcharts of FIGS.

The AF unit 23 receives a distance measurement operation start signal from the CPU 18 and receives sensor data (luminance information) of the subject.
The sensor integration is performed in order to obtain (1) (Step S1). Subsequently, the CPU 18 acquires the sensor data shown in FIG. 6 before the AF unit 23 (step S2), and performs a contrast check (step S3).

Generally, the MIN value of sensor data and M
The difference between the AX values is obtained, and when the difference is small, the contrast is low, and it can be estimated that the distance cannot be measured. Depending on the result of such a contrast check, it goes without saying that the process in which the checked distance measurement point remains may be interrupted or stopped.

Next, flare correction of the sensor data is performed (step S4). The flare correction generally corrects a light amount difference or the like of light from an object incident on the line sensor 16 or the line sensor 17 due to a flare. A method of adding only the difference is known.

Subsequently, a correlation operation is performed (step S).
5). This correlation operation is for calculating the integer part of the phase difference, and will be described below with reference to FIGS.

As shown in FIG. 7, an area smaller (narrower) than the distance measuring point is set as a window for the sensor data of one distance measuring point. As shown, the window corresponding to the subject at infinity is located inside the line sensor, and the shift amount at this time is set to zero. The window corresponding to an object at a short distance is outside the window at infinity. In the correlation calculation, the difference data F of the sensor data of the left and right windows is obtained by alternately shifting the left and right windows outward with the window at infinity as the initial position of the window.
(N) (or correlation value) is calculated based on the following equation (1).

[0045]

(Equation 1)

Here, n is the shift amount, m is the number of window sensors, and L (i) and R (i) are i from the left of the window.
This is the second sensor data.

The relationship between the correlation value F (n) and the shift amount n is as shown in FIG.

The correlation value F (n) is the degree of coincidence between the left and right sensor data. Therefore, when F (n) in FIG. 8 is the shift amount at which the minimum value is obtained, the degree of coincidence between the left and right sensor data is the highest, and the shift amount at this time is correlated with the subject distance. Note that the shift amount has a relationship proportional to the reciprocal of the subject distance.

Subsequently, in step S6, an interpolation operation for obtaining the decimal part of the phase difference (the shift amount) is performed. Such an interpolation operation is performed based on equation (2) using F (n) indicating the minimum value in FIG. 8 and F (n-1) and F (n + 1) at both ends.

When F (n−1)> F (n + 1), n + 0.5 × (F (n−1) −f (n + 1) / F (n−1) −F (n)) F (n−1) ) ≦ F (n + 1) n−0.5 × (F (n + 1) −f (n−1) / F (n + 1) −F (n)) (2) Correlation of steps S5 and S6 The calculation and the interpolation calculation are examples and known techniques, and it is a matter of course that other calculation methods can be adopted.

Subsequently, the reliability is determined (step S
7). The reliability determination itself is also a known technique. In the simplest example, the minimum value F of the correlation value shown in FIG.
It is to determine whether (n) is larger or smaller than a predetermined value.

If the value is larger than the predetermined value, the degree of coincidence between the left and right sensor data is low.
The reliability (probability) of the phase difference calculated by the correlation operation and the interpolation operation in S6 is low. On the other hand, when it is small, the reliability is high. In general, when the reliability is low, a process such as calculating the subject distance from another ranging point phase difference without performing the calculation of the subject distance using the phase difference data is performed by CP.
U18 is performed, but since such processing is known,
Detailed description is omitted.

It should be noted that various methods are also known for reliability judgment, and it is possible to employ a reliability judgment according to another method other than the above in the present invention, or to use a plurality of types of reliability judgments. It is. Also, depending on the reliability determination, unlike the above, the relationship between the magnitude of the reliability determination value and the reliability (probability) of the calculated phase difference may be reversed,
The reliability judgment (large / small judgment) is not the one described above.

Next, when a highly reliable calculation result of the phase difference is obtained, 1/1 data (the reciprocal of the object distance) is obtained from the phase difference (step S8). This phase difference and 1 /
The l data is in a proportional relationship (principle of triangulation). CP
U18 converts the 1 / l data into a driving amount of the focusing lens for adjusting the focus.

Subsequently, a subroutine "panel dirt detection" is performed.
Is executed (step S9). This is a feature of the present invention.

When measuring the distance of the subject as shown in FIG. 5, if the panel is not stained, the sensor data as shown in FIG. 6 is obtained. At this time, when the phase difference is obtained at the distance measurement point C, the correlation value F (n) becomes as shown in FIG.

On the other hand, if the panel is dirty,
Thus, sensor data as shown in FIG. The correlation value F (n) at this time is as shown in FIG. When the panel is contaminated and the received light amounts of the left and right line sensors become unbalanced or the like, the degree of coincidence between the left and right sensor data decreases, and the minimum value of the correlation value F (n) increases. In the present invention, when the panel becomes dirty, the correlation value F
The dirt that the minimum value of (n) becomes large and the correlation value F
It is characterized in that the stain on the panel is detected using the relationship of the minimum value of (n).

Next, the sequence of the subroutine "panel dirt detection" executed in step S9 in FIG. 9 will be described in detail with reference to the flowchart in FIG.

The reliability determination value is updated (step S1)
0). Specifically, the data is updated and stored in a non-volatile memory such as an EEPROM (not shown). The CPU 18 uses this EEPRO
Normally, data is called from the M or the like to the RAM and arithmetic processing is performed.

As shown in FIG. 13, the reliability judgment value is updated from the EEPROM in the RAM of the CPU 18 at first with respect to the reliability judgment values related to the past n times of the distance measuring operation. When the ranging operation is performed, the oldest reliability determination value S (n) is discarded, and S (n−1) to S (n−1)
When the storage position of the RAM of (2) is shifted as shown in the figure, the latest reliability determination value related to the current distance measurement operation is further changed to S.
These reliability judgment values are stored in the RAM as (1), and the data is saved in the EEPROM.

Next, an average value of past reliability judgment values is obtained (step S11).

Since this average value is constantly updated with the average value of the past n times, it is generally called a moving average, and is also used as an index indicating, for example, a change in stock price. Subsequently, the warning flag is once cleared (step S12), and the moving average value is compared with a predetermined value (step S13). If the moving average value is larger than the predetermined value, the warning flag is set (step S14). Here, the magnitude comparison between the moving average value and the predetermined value includes various modified examples depending on the reliability determination method as described above, and it is needless to say that the present invention is not limited to the above. Further, it is also possible to compare the moving average value of the plurality of reliability determination values with the plurality of predetermined values and determine the stain on the panel.

Next, a warning method when the dirt on the panel is detected as described above will be described. First, an outline of the warning display will be described. In the present embodiment, AFLE for in-focus display is used.
A warning display is performed using D as well. It goes without saying that a dedicated display member may be provided for this warning. AFLED
Is normally turned on when focused, blinks when out of focus, and turned off when the distance measurement operation is not being performed. The warning display is performed by blinking the AFLED, and the blinking frequency is changed from the display at the time of out-of-focus.
The AFLED blinks when the power of the camera is ON and the distance measurement operation is not being performed in order to actively appeal to the photographer of the stain on the panel. Even if the panel is dirty, the AFLED switches to the in-focus display if it is in focus. Even when out of focus, the AFLED switches to out of focus display. This display method
Various variations are conceivable. For example, when the panel is dirty and out of focus, the warning display of the dirt on the panel may be left as it is.

The operation of the entire camera employing the distance measuring apparatus according to the present embodiment will be described below with reference to the flowcharts of FIGS.

As shown in FIG. 14, when the camera is reset by inserting and removing the battery, first, the CPU 18 performs an initial setting (step S21). This initial configuration includes
An operation of reading a past reliability determination value or the like from a non-volatile memory such as an EEPROM into a RAM, which is a volatile memory of the CPU 18, is also included. Subsequently, the initial setting of the electric type is performed (step S22). That is the initialization of the interface IC.

Next, mechanical initial setting is performed (step S).
23). Here, setting of the state of the switching clutch, detection of the mechanical position, and the like are performed. Subsequently, the switch is detected (step S24), and after step S25, the process branches depending on the result of the SW detection. That is, if there is no SW input, step S
At 26, the CPU 18 enters the halt state. When an interrupt occurs, the process returns to step S24 to form one processing loop.

If the power SW is detected to be ON in step S25, the operation of mechanism setting 1 is executed (step S27). In the mechanical setting 1, for example, the photographing optical system 7 housed in the body of the camera can be photographed (Wi
An operation such as setup in de) is performed.

Subsequently, a subroutine "display setting" is executed (step S28).

Hereinafter, the operation of this subroutine "display setting" will be described in detail with reference to the flowchart of FIG.

First, the mode of the camera is displayed on the LCD (step S40). Next, the number of frames is displayed on the LCD (step S41). Date, time, etc. LC
D is displayed (step S42). Then, the panel dirt warning flag is monitored (step S43), and the flag becomes 0.
If so, the panel is not dirty, and the AFLED is turned off (step S44). If the flag is 1, the panel is dirty, and the AFLED is blinked at 8 Hz to warn the user (step S45). This 8 Hz is only an example of the blinking frequency. After such a series of processing, FIG.
The process returns to step S29.

Returning to the description of FIG.

Subsequently, SW detection 2 is executed (step S29). Based on the result of SW detection 2, step S30
The process branches to steps S31 to S31.

If the power is off in step S31,
After performing mechanical operations such as preparation for power-off and lighting of each display (step S32), the process returns to step S24. When branching to the first release process in step S30, a distance measurement operation is performed (step S33). This distance measuring operation is as described above.

Next, photometry is performed (step S34).
The subroutine "distance measurement / photometry result display" is executed (step S35).

The sequence of the subroutine "distance measurement / photometry result display" will be described below with reference to the flowchart of FIG.

First, it is determined whether or not focus is achieved (step S5).
1) In the case of focusing, the AF LED is turned on (step S)
52), if out of focus, the AFLED blinks at 2 Hz (step S53). However, 2 Hz is an example of the blinking frequency, and if there is a panel dirt warning, the warning may be left as it is, or other variations may be considered. Next, the process branches depending on the necessity / unnecessity of the strobe (step S54), and the STLED is turned on (step S5).
5). Although flashing may be considered when the strobe is not charged, the description is omitted for simplicity.

Then, it waits until the second release is entered (step S56). The AFLED and the STLED are turned off (step S57). The step S56 is the 2nd
When the release is not entered or the first release is released, an infinite loop is formed. However, this is merely an example used for the description of the invention, and the above-described sequence is used for convenience. After the above example sequence, FIG.
Will return to step S36.

Returning to the description of FIG.

Subsequently, the lens is driven (step S3).
6) Exposure (step S37), film winding (step S38), and returning to step S28, one frame has been photographed.

Although the method of canceling the warning display is not shown, it may be canceled by automatically pressing a plurality of SWs, or a dedicated canceling SW may be provided.

In the present embodiment, even if there is no releasing means, if the panel is cleaned, the warning display will eventually disappear. In order to prevent a hunting state in which the warning display is repeatedly turned on and off, once the warning display is made, the predetermined value which is the stain determination value of the panel may be changed by a second predetermined amount.

Next, a second embodiment of the present invention will be described.

In the above-described first embodiment, an example has been described in which the reliability determination value increases as the panel becomes dirty. However, the reliability determination value is used to determine whether or not distance measurement can be performed. And varies depending on the subject. Therefore,
If the moving average is obtained including the reliability determination value of the subject whose distance cannot be measured, the possibility of erroneous panel dirt detection may occur.Therefore, the reliability determination value when distance measurement is not possible is excluded from the panel dirt detection data. This is the second embodiment described in detail below.

FIG. 17 is a diagram showing an example of sensor data of a low-contrast subject. Even if the panel is dirty, the absolute amount of the sensor data is small, so that even if the degree of coincidence between the left and right sensor data is poor, the reliability is low. It can be seen that the sex judgment value becomes smaller.

FIG. 18 is a diagram showing the relationship between the shift amount and the correlation value F (n), and FIG. 19 shows sensor data when the AF window 1 is covered with a finger or the like.

In this case, the relationship between the shift amount and the correlation value F (n) may be as shown in FIG. 11 when the panel is dirty. Furthermore, the same may occur when an extreme flare occurs when an attempt is made to photograph an object near the sun.

As described above, there is a reliability judgment value that is not suitable for use in panel contamination detection. In this embodiment,
Exclude these effects.

Hereinafter, the sequence of panel dirt detection will be described with reference to the flowchart of FIG. First, it is determined whether the distance measurement is possible or impossible by determining whether the contrast is larger than a predetermined value, whether the flare correction amount is larger than the predetermined value, or whether the reliability determination value is larger than the predetermined value (step S1). In S100 to S102), if it is determined that distance measurement is impossible, the process returns. On the other hand, the processing when it is determined that distance measurement is possible (steps S103 to S107) is the same as in the above-described first embodiment (steps S10 to S14 in FIG. 12), and thus redundant description will be omitted. I do.

As described above, according to the present invention, high-precision panel dirt detection and abnormality detection can be realized without increasing the cost and space, and furthermore, the panel dirt and abnormality can be generated. In such a case, a warning is given to that effect, whereby an erroneous distance measurement is prevented beforehand, and a distance measuring device with improved reliability of distance measurement accuracy can be provided.

The above embodiments of the present invention include the following inventions.

(1) Light from a subject is guided to at least a pair of line sensors via a light-transmitting panel and a light-receiving lens which constitute a part of the camera exterior, and based on the output of the line sensors, the light from the subject to the subject is detected. A camera including a distance measuring device for obtaining a distance, wherein the distance measuring device includes: a reliability determining unit that determines reliability of a distance measurement operation result; An abnormality detecting means for detecting an abnormality of the panel, wherein the camera is adapted to warn of an abnormality relating to the distance measuring operation in response to a detection result of the abnormality detecting means.

(2) The abnormality detecting means detects an abnormality of the translucent panel based on a moving average value of reliability judgment values corresponding to a predetermined number of past distance measuring operations. The camera according to (1).

According to the above aspect, the reliability judgment value of the reliability judgment means is accumulated and stored in a predetermined amount, so that the average value of the reliability judgment values corresponding to a plurality of predetermined past distance measurement operations is obtained. (Moving average value). By continuously monitoring the calculation of the moving average value of the reliability determination value, it is possible to detect deterioration in the ranging accuracy or reliability of the ranging device. In other words, it is possible to detect the deterioration of the panel of the camera. Dirt can be detected. When a stain on the panel is detected, a predetermined warning is issued to urge the user to maintain the camera.

[0094]

As described in detail above, according to the present invention,
By effectively utilizing the information obtained for each ranging operation without adding a new configuration, in other words, by devising information processing on software, the cost and space of the panel can be reduced without increasing the cost and space. It is possible to provide a distance measuring device that can detect dirt and give a predetermined warning, prevent erroneous distance measurement due to dirt on the panel, and improve distance measurement accuracy and reliability. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a camera employing a distance measuring device according to a first embodiment of the present invention.

FIG. 2 is a front view of a camera employing the distance measuring device according to the first embodiment.

FIG. 3 is a diagram showing a state in which the exterior of the camera is seen through from above.

FIG. 4 is a diagram showing a configuration in which an AF unit 23 is further embodied.

FIG. 5 is a diagram illustrating a relationship between a subject and an AF unit 23.

6 is a diagram showing luminance information of a subject obtained by a line sensor 17. FIG.

FIG. 7 is a diagram showing changes in shift amounts of line sensors 16 and 17;

FIG. 8 is a diagram illustrating a relationship between a correlation value F (n) and a shift amount n.

FIG. 9 is a flowchart for explaining in detail a distance measuring operation by the distance measuring apparatus according to the first embodiment.

FIG. 10 is a diagram showing a state of sensor data obtained when the panel is dirty.

11 is a diagram showing a correlation value F (n) obtained in the case of FIG.

12 is a flowchart for explaining in detail a sequence of a subroutine “panel dirt detection” executed in step S9 of FIG. 9;

FIG. 13 is a diagram for explaining a process of updating a reliability determination value.

FIG. 14 is a flowchart for explaining the operation of a camera employing the distance measuring device according to the first embodiment.

FIG. 15 is a flowchart illustrating a sequence of a subroutine “display setting” executed in step S28 of FIG. 14;

FIG. 16 is a flowchart for explaining a sequence of a subroutine “distance measurement / photometry result display” executed in step S35 of FIG. 14;

FIG. 17 is a diagram illustrating an example of sensor data of a low-contrast subject;

FIG. 18 is a diagram illustrating a relationship between a shift amount and a correlation value F (n).

FIG. 19 is a diagram showing sensor data when a finger rests on the AF window 1 with the finger or the like hidden.

FIG. 20 is a flowchart illustrating a sequence of panel dirt detection.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 AF window 2 AF auxiliary light window 3 Finder window 4 AE window 5 Remote control window 6 Strobe window 7 Shooting optical system 8 AF optical system 9 AF housing 10 AFIC 11 AF auxiliary light optical system 12 Auxiliary light source 13 Reflector 14 Finder optics System 15 Panel 16 Line sensor 17 Line sensor 18 CPU 19 Mechanical drive / control unit 20 Remote control light receiving circuit 21 AE light receiving circuit 22 AF auxiliary light emitting circuit 23 AF unit 24 Strobe circuit 25 Camera 26 Display unit 27 Display unit

Claims (3)

[Claims] 1. A pair of light from a subject is incident on a pair of line sensors via a translucent panel and a light receiving optical system which form a part of an exterior component, and based on a pair output from the line sensor. A distance measuring device for calculating a distance to a subject, wherein said evaluation means evaluates a parameter representing a relative degree of coincidence of a pair of outputs from said line sensor over a predetermined number of times, and responds to the evaluation result of said evaluation means. And a means for detecting and informing an abnormal state relating to the distance measuring operation. 2. The abnormal state related to the distance measuring operation includes a state in which the surface of the translucent panel is dirty, and a state in which the surface of the translucent panel is covered with an obstacle. Item 7. The distance measuring device according to Item 1. 3. The distance measuring apparatus according to claim 1, wherein the notification of the abnormal state related to the distance measuring operation is made also by a display means for the distance measuring operation.