JPH02194312A - Range finder - Google Patents

Abstract

PURPOSE:To perform speedy and smooth focusing operation by an easy method by finding a distance by an arithmetic processing method from the ratio of the varying component and mean component of an image with the photoelectric conversion output signal of a subject image. CONSTITUTION:The light from a subject 1 is imaged on a photoelectric converting means (image sensor) 4 through the stop member 3 of an optical system 2. Then the output of the sensor 4 is detected as the varying component by a varying component detection part 5 and detected as the mean component by a mean component detection part 6. Then a ratio calculation part 7 compares the varying component of the detection part 5 with the mean component of the detection part 6. An arithmetic part 8 controls the stop member 3 and also drives the lens group of an optical system 2 through the lens driving part 9 according to the output of the calculation part 7 and the output of a system processor to calculate a defocusing quantity. Thus, the speedy and smooth focusing operation is easily performed.

Description

[Detailed Description of the Invention] [Mei, Field of Industrial Application] The present invention is an a+ button device, specifically, a method for calculating image reliability from a subject image formed on a light r5 conversion T stage of an image sensor, etc. The present invention relates to a distance measuring device that determines a distance to a subject through processing.

[Conventional technology j Photoelectric conversion means such as image sensors] From the image of the subject formed on the second? Autofocus (hereinafter abbreviated as AF) using a distance measuring device that calculates the subject distance by calculating the subject distance of the captured image f≦ has been provided in various types.This type of AF For example, the device is configured to move the photographing lens in the direction in which the value indicating the degree of focus increases, detect the peak position, and then stop there. is disclosed, for example, in Japanese Patent Publication No. 39-5265.This mountain-climbing method focuses on the fact that the high-frequency components of the video signal increase when the image comes into focus, and uses a band-pass filter (
The high frequency component extracted from the video signal by the shade (hereinafter abbreviated as BPF) is detected as a signal indicating the degree of focus.

58-41487 publication jj (0, deviation, sum of 12 directions or sum of deviations to the nth power (Japanese Patent Application Laid-Open No. 58-5662)
No. 8, JP-A-55-121413 Publication 1 JP-A-55-
1. Reference to each publication of No. 21414 μ((), or one using the sum of the n-th power of the video signal 1; 1 (Special Publication No. 41-162
(Refer to No. 28 f12) There is a hat.

In addition, as a means for detecting the subject image, a method is used in which the number of projection sensors is set by changing the optical path length (Japanese Patent Application Laid-open No.
104245) or one that records the peak value and stops when that value is reached (Japanese Patent Laid-Open No. 62-299)
(Refer to Publication No. 924).

Each of the above-mentioned methods takes advantage of the fact that when the subject image is brought into focus, the high frequency components of the image increase, but at the same time the average light intensity of the entire image also increases, so this is used to maximize the average light intensity. Means of matching the points
No. 5, JP-A-49-22127, JP-A-48-576
26) are also provided.

17 However, with each of the above means, the amount of defocus is unknown until the peak of the value indicating the degree of focus is detected.
It was necessary to constantly move the lens minutely to measure the value that indicates the degree of focus.

Therefore, as means for detecting the defocus amount, Japanese Patent Application Laid-Open No. 62198811 discloses means for detecting the defocus direction and the approximate defocus amount from data on two optical path lengths.

Further, as another means for detecting the amount of defocus, a means for detecting the amount of defocus from the variation rate due to changes in the optical path length of the MTF (modulation transfer function) component of the subject image is disclosed in Japanese Patent Application Laid-Open No. 62-291.610. JP-A-62-284314, JP-A-62-272217, JP-A-62-2722
It is disclosed in various publications such as No. 18.

[Problems to be Solved by the Invention] By the way, in the 111 climbing force type AF, which is one of the conventional examples of focusing detection using the imaging optical system as it is, the defocus direction and defocus amount are determined at one time. Since it is unknown by detection, the in-focus position can only be detected after passing through the in-focus point without having to scan. Therefore, it is necessary to detect the image many times, and near the in-focus point, so-called hunting is unavoidable, in which the camera passes through the in-focus point and then returns to the in-focus point, so it takes time for the focusing operation, and smooth operation is expected. could not.

In addition, in the second conventional means of detecting the defocus direction and the approximate amount of defocus from data on two optical path lengths,
Although the defocus direction and defocus amount can be calculated by detecting the image signal a small number of times, the distance measurement accuracy is insufficient.

Furthermore, in the third conventional method of detecting focus based on the variation rate due to changes in the optical path length of the MTF component of the subject image, in order to perform frequency analysis, the focus is detected based on the frequency component of the image, the direction in which the frequency analysis is performed, and the sampling range. , the ranging accuracy was easily affected.

Furthermore, a circuit such as a BPF and a high-speed, high-precision arithmetic unit are required, and it is also susceptible to the effects of lens aberrations.

Therefore, an object of the present invention is to solve the above-mentioned problems, calculate the defocus direction and defocus amount with a small number of image detections, and provide an all-lens distance for use in an AF device that can perform quick and smooth focusing operations. We are in the process of providing equipment.

[Means and effects for solving the problems 41 of the present invention]
A single distance device includes an optical system that forms an image of a subject, a photoelectric conversion means that photoelectrically converts the subject image formed by this optical system, and a distance that calculates the distance by processing the photoelectric conversion output signal from the photoelectric conversion means. In the distance measuring device, the arithmetic processing means calculates the distance from the photoelectric conversion output signal of the subject image based on the ratio of the fluctuation component and the average component of the image.

[Implementation example] The present invention will be explained below with reference to illustrated embodiments.

First, before explaining the present invention in detail, the dead tree concept of the present invention will be explained using FIGS. 2-3.

FIG. 2 is an optical path diagram showing the relationship between the amount of defocus from the focal plane of the imaging optical system 2 and the point spread distribution of the object. Light from an object (not shown) is transmitted to the imaging optical system 2.
The aperture is controlled by the aperture member 3 and the exit pupil is adjusted.
An image is formed on a focus plane 21a perpendicular to the optical axis 0. Therefore,
If the photoelectric conversion means is placed on the focus plane 21a, f
The point spread distribution of the subject to be LI is a focused point 21, but a defocused surface 22a before and after the focal plane 21a
.

The point spread distribution of the object obtained when the photoelectric conversion means are placed at 23 a and 24 a is as follows: 22° 23 .
As shown in 24, the point spread intensity distribution of the subject image changes depending on the amount of defocus. If the exit pupil of the optical system is made circular in order to find the change in the point spread intensity distribution, the radius of the point spread intensity distribution is determined by the pupil radius. As L, b = -x D.

Assuming that the intensity distribution within the point spread is constant, the point spread intensity distribution h (
x / , y / ) becomes h(r)=01 when -j7s〒z<b, and h(r)-〇 in other cases. Therefore, the OTF (response function) H(S) of the optical system 2 is expressed as follows (see Introduction to Optics in Science and Engineering Basic Course H, "Wave Optics" by Junpei Tsujiuchi, published by Asakura Shoten).

Here, MTFO(s)l of the image with two defocus amounts
and 0(S)2, the MTF of the frequency 81 subject is F(
S), it becomes 2J1 (2πbs), so it is constant regardless of the subject. Here s=
0, therefore, the subject image 1-10 in a certain defocus device
A linear relationship exists between (.) and the diameter of the circle of confusion.

In general, charge conversion 4 is performed so that the average value (s=0) is constant
Since the imaging device as a stage is made up of l+"), if the area of MTFXs of the MTF characteristic of the subject image is kept constant, in other words, the amount of information of the image is kept constant, then the average The fluctuation of the value can be determined by 7Il11.And since the average value has no information, (+'i
The amount of information can be expressed by the variation component of the subject image, that is, the ratio of the amount from low frequency to high frequency, for example, the standard deviation of the subject image.

Therefore, let Σ be the average value or image fluctuation component to be determined. As mentioned above, there is an inversely proportional relationship between 0 (.) and the diameter of the circle of confusion, and in reality, 0 (.) is always a positive value, so they are C1 and C2. However, when C2<01×b, it is generally safe to assume that Σ/merC).

FIG. 3A is a diagram showing the relationship between the diameter of the circle of confusion and Σ/or. In the figure, for a certain subject image, its characteristic is a straight line ρ1
．． Ω1', and in another subject image, its characteristic becomes a straight line ρ2'f12'.

Therefore, it becomes possible to obtain the defocus amount by utilizing this fact. That is, as shown in FIG. 3B, for example, the starting point is a point with a certain amount of defocus, the photographing lens is positioned there, and the inner diameter of confusion at that time is defined as b. Here, if the diameter of the aperture is reduced to half by the aperture member 3, the diameter b' of the circle of confusion becomes b/2. Therefore, if the ratio Σ/7 of the fluctuation component and the average component output from the ratio calculation unit (described later) when the diameter of the circle of confusion is b is yl, and the output when the diameter of the circle of confusion is b/2 is y2, then Twice the difference between y1 and y2 above is Σ when in focus
It is the difference between /¥ and y.

Next, the lens is minutely moved by the lens drive unit to
If we change the diameter of the circle of confusion by the same amount, that is, we can calculate Δb from the amount of minute movement, so ΔΣ/X−
Δy3 can be measured. This makes it possible to detect changes in the diameter of the circle of confusion, the ratio of the fluctuation component to the average component, and the rate of change in Σ/nu.

From the above equation, (size of circle of confusion diameter) - (defocus amount) can be obtained.

By the way, in order to express the above equation in the form of a general equation, the ratio Σ/or of the fluctuation component to the average component when the diameter of the circle of confusion is changed by Δb by slightly moving the pupil diameter by Δp. y3
Then, is iIj.

In other words, the above can be summarized as follows.

The current position of the lens is at point "b", but it is unknown where it is from "0", so this is determined.

■Calculate Σ/ma at the current pupil diameter. Let this be yl.

■Σ/ with a pupil diameter different from the current pupil diameter (for example, 1/2)
Ask for Ma. Let this be y2.

■Change the position of the lens and move the diameter of the circle of confusion by Δb,
Find Δy3.

■Y1 above. Y2. Δy3. Find b from Δb. In this case, the data for calculating Δy3 may be shared with y1y2.

The present invention having such a basic concept will be explained in more detail with reference to examples thereof.

FIG. 1 shows an example in which an AF device using the present invention is applied to a scanning image sensor, and a first embodiment of the present invention will be explained with reference to FIG. In the figure, the first embodiment is not shown, but the distance device 411j includes an optical system 2 that forms an image of light from a subject 1 on an image sensor 4'', and an aperture member 3 that changes the diameter of the exit pupil of the optical system 2. , a fluctuation component detection section 5 that detects a fluctuation component of the output from the image sensor 4, an average component detection section 6 that detects an average component, and a ratio calculation section 7 that compares the fluctuation component with the average component. Based on the output of the calculation unit 7 and the output from the system processor (not shown), the aperture member 3 is controlled to aperture, and the lens drive unit 9
While driving the lens group of the optical system 2 through the
It is composed of a calculation section 8 that calculates the amount of defocus.

The fluctuation component detection section 5. Average component detection section 6. Ratio calculation unit 7. The arithmetic unit 8, whose specific configuration is shown in FIGS. 4 and 6, sends an analog output from the electric circuit shown in FIG. 4 to a CPU 801 shown in FIG.
02,803 is digitally converted and input, and is calculated using the algorithm shown in Figure 8.
Control of the aperture and lens drive is performed according to the flow shown in the figure.

Explaining this using a timing chart, this analog signal output circuit includes a buffer 601 that buffers and amplifies a video signal VIN obtained by photoelectrically converting a subject image, and a switch 602 that extracts a signal within the distance measurement area. A switch 510, which is composed of an adder circuit 111 and an inverter circuit 12, integrates the video signal and operates in the same manner as the integral output switch 602 to extract a signal within the distance measurement area. Addition circuit 16
It consists of an anti-inversion width circuit 17 and the video signal ■lN is input to 222
It is composed of a product output circuit.

The adder circuit 11 constituting the integral output circuit has a resistor 60
3. Integrating capacitor 604. Reset switch 605, which will be described later. The inverting amplifier circuit 12 is formed by an integrator formed by connecting an operational amplifier 606 as shown in the figure, and the inverting amplifier circuit 12 is formed by an integrator formed by connecting resistors 607 and 608 with the same resistance value, and an operational amplifier 609 connected as shown in the figure. It consists of a phase inversion amplifier that inverts only the polarity of input and output signals.

Also, a logarithmic conversion circuit 1 constituting the square integral output circuit
3 is a resistor 501. Diode 502 operational amplifier 503
The amplifier circuit 14 is formed by connecting as shown in the figure, and is composed of a logarithmic conversion circuit that takes the logarithm of an input signal and outputs the logarithm.
is a resistor 504°, a resistor 505. whose resistance value is twice the resistance value of this resistor 504. The inverse logarithmic conversion circuit 15 is formed by connecting an operational amplifier 506 as shown in the figure, and is composed of an amplifier with an amplification factor of 2.
08. It is formed by connecting operational amplifiers 509 as shown in the figure, and is constituted by an anti-logarithmic conversion circuit that converts the index of an input signal, that is, anti-logarithmic and outputs the result.

Further, the adder circuit 16 includes resistors 511 . fa capacitor 512. The inverting amplifier circuit 17 is formed of an integrator formed by connecting a reset switch 513, an operational amplifier 514, and a resistor 515, which will be described later, as shown. This resistance 5
]5 having a resistance value equal to the resistance value of 516. The operational amplifier 517 is connected as shown in the figure to form a phase inverting amplifier with an amplification factor of 1 and inverting only the polarity of input/output signals.

The switches 602 and 510 are as shown in FIG.
The system processor (see FIG. 1) during the distance measurement area on-time tl from the video signal during one vertical scanning period lv.
operates in response to a signal supplied from the
Vertical scanning period] Only the signal within the ranging area is extracted from the video signal within V and integrated. Further, switches 605 and 513 provided in the adder circuit 11 and 16 are for resetting the integral, and operate in synchronization with the start of the vertical scanning period IV, as shown in FIG.
It serves to discharge the charges stored in the 1.16 integrating capacitors 604 and 512, respectively, and reset them to the initial state.

In addition, the timing and CP for controlling each of the above switches
The circuit for controlling the start of the U calculation is omitted because it is common and has no bearing on the essence of the present invention.

Then, the CPU 801 controls the aperture member 3 shown in the A/D converter 1 in accordance with No. 1j from the system processor (see FIG. Be like one.

The operation of this embodiment configured as described above will be explained based on the main flowchart 1 shown in FIG. First, mainly 3 inputs from the system processor (see Figure 1)
11 "Measure the optimum F value" based on the data of the optical system and "set the F value".

Changes in aberrations in the optical system due to changes in pupil diameter are often influenced by the cube or square of Seidel's aberration formula, so if possible, use F as much as possible.
Make the value larger. Next, the ratio ``Σ/X'' between the fluctuation component and the average component is calculated using the set F value. The calculation of the ratio Σ/7 between the fluctuation component and the average component]9 is performed using the CP
It is started by U operation start No. 43.

In Figure 8, "2, Figure 4, and Figure f2J5"
After the switches 605 and 513 are turned on and then turned off, thereby resetting the charges in the capacitors 604 and 512, the video signal VIN passes through the buffer amplifier 601 and the switch 602 selects only the signal in the all+range area. The selected video signal is converted into a current by the resistor 603 of the adder circuit 11, and integrated by the integrator by the operational amplifier 606 and the capacitor 604.However, since the output of this integrator has the opposite polarity, the resistors 607 and 608 The polarity is inverted by an inverting amplifier circuit 12 using an operational amplifier 609, and then logarithmically converted by a logarithmic conversion circuit 13 using a diode 502 and an operational amplifier 503, and a resistor 504.5
05 and an operational amplifier 506.
multiplied by diode 507. Resistance 508. operational amplifier 5
It is inversely transformed by the inverse logarithm transformer 15 according to 09, and is squared as a result.

The squared video signal X is selected by a switch 510 to select the signal in the fl11 distance area, and is then sent to an adder circuit 111 which constitutes the integral output circuit, an adder circuit 161 of the same type as the inverter circuit 12, and an inverter amplifier circuit 17. The square integral output circuit outputs the square integral by the CPU calculation start signal (fifth.
(see Fig. 6), the CPU 801 (see Fig. 6) is A.
/D converters 802 and 803 (see Figure 6) are operated to calculate the integrated output standard deviation and average.

Then, as shown in FIG. 7, after recording the ratio Σ/Y of the fluctuation component and the average component calculated above to yl,
(see Fig. 1), the F value of the lens set above is multiplied by C (C3 is an arbitrary constant). That is, if y2-Σ/or is calculated by setting the diameter of the exit pupil to 1/C3, the ratio Σ/or of the fluctuation component and the average component at the focused point can be predicted. However, since the relationship between the amount of lens movement and the change in Σ/7 is unknown, the change is determined by driving the lens by Δ and finding Y3=Σ/ma.

Therefore, the formula for determining the amount of defocus is Σ at the ri focus.
The difference A1 between /X and Σ/ma, which is initially set at 41, can be calculated by finding how many times the change in Σ/(ya yt) when the lens moves by Δ and multiplying by 6.

In this case, it has already moved by Δ, so find the default and 1
, becomes the first target. This occurs when the distance to the subject is large relative to the amount of movement of the lens, and when the distance between the lens and the subject changes significantly due to movement of the lens, this must also be taken into consideration.

After moving the lens according to the defocus amount d obtained in two series, in order to check whether the distance was measured correctly, 1. Σ/'9: Take the ratio of the values.

In general, in an optical system, the influence of aberrations increases near the focal point, so Σ/or becomes smaller. Considering this, the ratio is 1
-C4 (C4 is the best value determined experimentally). If it is off, it is considered an erroneous distance measurement and the last measured distance Σ/X is used as yl, the F value is changed, and the process is repeated from the point where Σ/X when in focus is predicted. At this time, it is possible to set a tolerance and set the process to end, or to limit the number of times.

In addition, in the above embodiment, y3 was measured using the pupil diameter when yl was measured, but it was also measured using y2 and other pupil diameters, and the corresponding A], lens movement amount Δ, and Σ/X It can also be found in relation to the change in . The diameter of the circle of confusion at that time is (where Δy3 is the amount of change in output when Δb changes) According to the first embodiment described above, the portions that require high-speed operation are constructed using inexpensive and simple analog device circuits. configurable, there is no need for a high-speed CPU or digital device. Moreover, the distance measurement area can be arbitrarily selected, even though expensive large-capacity memory is not required.

FIG. 9 is a block system diagram of the arithmetic processing means in the δI11 distance device, which does not show the second embodiment of the present invention. This second embodiment is an application of the present invention to a type of camera in which video signals are stored in a memory.The main difference from the first embodiment is that the photoelectric conversion means 4 shown in FIG.
In the first embodiment described above, in order to immediately A/D convert the photoelectric conversion signal outputted from the CPU into a digital signal and input this digital signal to the CPU to obtain C, the hardware is required as shown in FIG. In contrast, in the second embodiment, this is done by software.

In the following second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In FIG. 9, the photoelectric conversion signal VIN is transferred to the buffer 60.
1 to an A/D converter 804, which converts it into a digital value and stores it in a memory 806.
is memorized. The data stored in the memory 806 is stored in the CPU 8.
01, and the CPU 801 calculates the ratio Σ/7 between the fluctuation component and the average component.

The above A/D converter 804. Memory 806°CPU8
01 is various synchronization signals transmitted from the controller 805, such as vertical synchronization signal vSYNC and horizontal synchronization signal H3Y.
) is controlled by JC. The overall sequence of the CPU 80 is the same as that of the first embodiment, and operates based on the flowchart shown in FIG. 7 above.

In the second embodiment configured in this way, the optical system 2
．． Aperture member 3. The overall sequence of the photoelectric conversion means 4 and the CPU 801 is the same as that of the first embodiment, so the description thereof will be omitted, and the operation of the arithmetic processing means will be explained based on FIGS. 9, 10, and 11.

As shown in FIG. 9, the photoelectric conversion signal 1N is input to an A/D converter 804 via a buffer amplifier 601. The A/D converter 804 converts the photoelectric conversion signal into a digital value using a pixel corresponding to the memory and stores it in the memory 8.
Supply to 06. The memory 806 is the controller 805
The digital value corresponding to each pixel is stored under the control of the pixel.

After importing 9 minutes of data for all memos, the CPU 80] is the first
Either the algorithm shown in FIG. 0 or FIG. 11 is executed to calculate the ratio Σ/X between the fluctuation component and the average component.

FIG. 10 is a solo chart 1 for calculating the ratio Σ/ma between the fluctuation component and the average component when the fluctuation component is used as in the first embodiment.

In FIG. 10, the CPU 80 waits for a computation start command from the system processor, and when it receives the computation start command, first the CPU 80 waits for a computation start command from the system processor. ．． S2. Clear the memory contents in n. Next, each AIIJ distance area data is read out, and 1 is added to the stored content of area n. Then, the area S1 stores the integrated value of the individual i'1l11 distance data X2, and the area S2 stores the integrated value of the individual distance measurement data x5 squared. This addition operation is performed for each i
Repeat until 'llll distance reach area data is reached. When the addition of the Δ1 distance area data is finished r, calculate the integration stored in the above area S and assign it to the area y, end this subroutine, and return after the main routine where Σ/ma is calculated. do. Since the algorithm shown in FIG. 10 includes many calculations of f and square, the time required for the calculations is longer than that of FIG. 11, which will be described next.

In the 11th step, when the calculation start command is received, areas x, n, and Sl are cleared first, and then each 71! I
Read distance area data. Then, in order to store the number of data in area r], 1 is added each time. Next, area or individual AI distance data X.

] and repeat until there is no more data. When individual data is lost, the data read pointer is reset.
2, divide the value stored in area

Then, the distance measurement area data is read out again, subtracted from the average value stored in the "-" area, and its absolute value is determined and stored in area S1. This is repeated until there is no more data. After adding the difference from the average value of the pigs in the distance measurement area to area S1, the stored contents of area S1 are divided by n-x to obtain the quotient S1. /n-x is calculated, stored in area y, this subroutine is terminated, and the routine returns to the main routine following the routine for calculating Σ/X. Since the algorithm shown in FIG. 11 mainly involves repetition of addition and subtraction, the individual programs are simple, so higher-speed operation is possible than in the flowchart shown in FIG. 10 above. Therefore, these two algorithms may be selectively used depending on the pattern.

As described above, according to the second embodiment, the defocus amount and defocus direction can be detected simply by adding a CPU algorithm without making any major changes to the overall configuration, making it inexpensive and compact. , weight reduction can be achieved, and high-speed, high-performance distance measurement is possible.

In addition, lens minute movement Δ during detection depends on the lens position.
It is also more effective to change the direction of the lens or to correct the detection position using information about lens aberration.

In each of the above embodiments, the distance was measured for the image on the image sensor, but this distance measurement data can be used to control other optical systems or to work as an AF to detect the photosensitive abrasive material on the conjugate surface of the image sensor. If you perform the above focusing, or if it is a relative distance other than focusing, the fluctuation component and (1
Needless to say, it is also possible to obtain it by the ratio Σ/X of the monthly 4J component.

Further, in the embodiment, the amount of change Δb in the diameter of the circle of confusion was obtained by moving the lens, but it goes without saying that two image sensors may be provided in advance in the optical axis direction.

[Effects of the Invention] As described above, according to the present invention, it is possible to calculate the defocus direction and defocus amount with fewer image detections, which enables quick and smooth focusing operation using a simple method. Become. Furthermore, since no processing is required for the optical system or image sensor, if applied to a video camera or a camera 3 with built-in electronic video, it is possible to achieve an Al11 distance just by processing the video signal. In this case, since B, P, F, etc. are not used, not only is there little influence from the subject, but there is no influence from the 111+1 distance window even if an arbitrary distance measurement area is set. Furthermore, it has a simple configuration and has remarkable effects such as being able to detect striped patterns in both vertical and horizontal directions.

[Brief explanation of the drawing]

Fig. 1 is a block system diagram of a distance measuring device showing a first embodiment of the present invention. Fig. 2 shows the relationship between the amount of defocus from the focus plane in the imaging optical system and the point spread distribution of the subject. The optical path diagram, Figures 3A and 3B are diagrams showing changes in the ratio Σ/of the fluctuation component and the average component with respect to the diameter of the circle of confusion, and Figure 4 shows the output from the photoelectric conversion means in Figure 1 above. FIG. 5 is a timing chart showing the operation timing of each switch in FIG. 4, and FIG. Figure 7 is a block diagram of the nrU control system that controls the lens position and pupil diameter of the optical system that forms a subject image from the integral output and square integral output shown in Figure 4 above.
2) Flowchart 3 for explaining the operation of the first embodiment, FIG. 8 is a flowchart 1 for explaining the routine of the Σ/or operation in FIG. Block system diagram of the arithmetic processing means in the 1ill+ distance device showing the second embodiment of 1.0.1
FIG. 1 shows the Σ/ during operation in the second embodiment shown in FIG.
Also, in the flowchart explaining the calculation routine, the 10th
The figure shows a case where the fluctuation component Σ is the standard deviation, and FIG. 11 is a flowchart showing the case where the fluctuation component Σ is taken as the sum of the absolute values of the differences from the average. １・・・・・・・・・・・・・・・Subject 2・・・・・・
......Optical system 4...
・・Photoelectric conversion means 5 ・・・・・・・・・・・ Fluctuation component detection section (arithmetic processing means) 6 ・・・・・・・・・・・
...Average component detection unit (ll) 7...
・・・・・・Ratio calculation part (ll) 8・・・・・・
...... Arithmetic section (ll) Σ/7...
...Ratio of image fluctuation component to average component = 84- QI'Q Ln 0 to l\ Ding Zokuryomon "Ko (spontaneous) <3) From page 10 of the specification, 4th line from the bottom, dimension 1 3rd line “1
Nii) tThis is 8 Self-posting/ko ``When s = C1,'' is changed to ``Here, if S is brought as close to 0 as possible, 1, : 31 display 2, Invention Name 3, Name of the location related to the case of the person making the amendment 4, Address of the agent 1999 Patent Application No. 014654 Distance Measuring Device

Claims (3)

[Claims] (1) An optical system that forms a subject image, a photoelectric conversion means that photoelectrically converts the subject image formed by this optical system, and calculates the distance by processing the photoelectric conversion output signal from this photoelectric conversion means. A distance measuring device comprising: arithmetic processing means; wherein the arithmetic processing means calculates a distance from a photoelectric conversion output signal of the subject image based on a ratio of an image fluctuation component to an average component. (2) The above calculation means b={(y_1-y_2)/[(1-Δp)・(y_3
-y_1)]}・Δb where, b: diameter of the circle of confusion y_1: output of the photoelectric conversion means at the first pupil diameter on the first focusing plane y_2: output at the second pupil diameter on the first focusing plane Output of the photoelectric conversion means y_3: Output of the photoelectric conversion means at the second focus plane Δb: Amount of change in the diameter of the circle of confusion Δp calculated from the amount of movement of the lens to a focus plane different from the first focus plane: Δp of the pupil diameter 2. The distance measuring device according to claim 1, wherein the distance is determined based on the diameter b of the circle of confusion determined from the rate of change. (3) The above calculation means b={(y_1-y_2)/[(1-Δp)・Δy_3
]}・Δb where, b: diameter of the circle of confusion y_1: output of the photoelectric conversion means at the first pupil diameter on the first focus plane y_2: photoelectric conversion means at the second pupil diameter on the first focus plane Output Δy_3: Amount of change in output when Δb changes Δb: 1st
Amount of change Δp in the diameter of the circle of confusion calculated from the amount of movement of the lens to a focal plane different from the focal plane of . 1. The distance measuring device according to 1.