JP3382321B2 - Optical equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device for determining a focal length to be changed based on a subject image.

[0002]

2. Description of the Related Art Conventionally, a so-called auto-zoom device or a camera for keeping a photographing magnification constant or automatically setting a focal length has to first preset a photographing magnification or information similar thereto which should be kept constant by some means. It was In addition, the focal length is determined so as to obtain the subject distance and obtain the desired photographing magnification accordingly.

[0003]

However, in the above-mentioned conventional example, since the focal length is determined only by the object distance, if the object is not the size of the expected object or the expected object at that time, However, there was a drawback that an appropriate angle of view could not be obtained for the subject.

[0004]

According to the present invention, an image pickup means for converting a subject image into an image signal through a variable focal length optical system, and a subject image signal by using the image signal obtained from the image pickup means. A subject image detecting means for extracting, and a computing means for determining the size of the subject image signal extracted by the detecting means on the screen and computing information on the focal length for the size to occupy a predetermined size. And an optical device for changing the focal length of the variable focal length optical system according to the information on the focal length calculated by the arithmetic means, wherein the focal length is changed according to the information on the focal length calculated by the arithmetic means. After changing the focal length of the optical system, the focal length of the variable focal length optical system according to the extracting operation of the image signal by the subject image detecting means, the arithmetic operation by the arithmetic means and the arithmetic result. The change operation, the current and previous calculation result is to provide an optical device that repeated until convergence to a predetermined range. The present invention can provide a more appropriate auto zoom because the focal length is determined by the size of the subject image on the screen as a factor in the above configuration, and the operation of determining the focal length is repeated until the focal length does not change. , For example, if the focal length is once determined by the above calculation in the wide state and zoomed, even if the focal length cannot be calculated accurately when the screen is wide and the subject is small on the screen, the tele side is calculated again in the above calculation. The focal length is calculated in the zoomed state and the accuracy is improved. In addition, since this operation is repeated until the calculated focal length does not change, even when the accuracy is not obtained even with the focal length obtained by zooming once, the state where the calculation result does not change, that is, the state where the accuracy is sufficient is compensated. It is a worm.

[0005]

[0006]

[0007]

【Example】

[Embodiment 1] FIG. 1 shows a camera automatic zoom device according to Embodiment 1 of the present invention.

In FIG. 1, 1 is a taking lens of a camera,
Reference numeral 2 is a focusing lens which constitutes a part of the taking lens 1, 3 is a variator which constitutes a part of the taking lens 1, 4
Is a compensator forming a part of the taking lens 1, and the variator 3 and the compensator 4 are the zoom motor 1
6 is used as a drive source and is driven in the optical axis direction using a cam means or the like to perform zooming. A relay lens 5 constitutes a part of the taking lens 1. 6 is a quick return mirror of a swinging camera, 7 is a film surface of the camera, 8 is a field lens, 9 is a pair of secondary imaging lenses, 10 is an area sensor having a pair of imaging screens for generating image signals, 1
1 is an AD converter for digitizing an image output signal of the area sensor 10, 12 is a frame memory for storing the digitized image signal, 13 is an area sensor 10, an AD converter 11, a frame memory 12 and a sensor driver 14. A microcomputer for controlling the zoom control to obtain an image signal and performing zoom control based on the image signal.
Is a sensor driver that drives the area sensor 10 according to an instruction from the microcomputer 13, gives a conversion timing signal to the AD converter 11 and gives a data fetch timing to the frame memory 12, and 15 drives a zoom motor 16 according to an instruction from the microcomputer 13. A zoom motor driver for zooming the photographing lens 1, a zoom motor 16 for driving the variator 3 and the compensator 4 in the optical axis direction via a driving means (cam means) (not shown), and a zoom movement 17 And a zoom encoder for detecting the position (focal length).

FIG. 2 is a view showing the optical positional relationship among the taking lens 1, the field lens 8, the secondary imaging lens 9 and the area sensor 10 of the automatic zoom device for the camera shown in FIG. Two imaging screens 10a of 10,
Light fluxes from the different pupil positions of the photographing lens 1 are guided onto 10b, and are re-imaged by the field lens 8 and the secondary imaging lens 9 at the imaging magnification β. At this time, the distance between the two images on the imaging screens 10a and 10b depends on the defocused state of the taking lens 1. Further, in FIG. 2, reference numeral 50 denotes an image forming surface on the image pickup optical path that is optically equivalent to the film surface 7 with respect to the taking lens 1, and the image pickup screens 10a and 10b respectively have a size of the image forming surface. It has β times the size. That is, the imaging screen has the same field of view as the imaging screen.

FIG. 3 shows a layout when the automatic zoom device of the camera shown in FIGS. 1 and 2 is applied to a single-lens reflex camera. 18 is a penta prism, 19 is a split prism, and 20 is a reflection prism. It ’s a mirror, 6, 8, 9,
10 shows the same thing as those of FIG. 1, FIG.

FIG. 4 is a view of the layout of FIG. 3 as seen from above the camera.

FIG. 5 shows an image pickup screen 10 of the area sensor 10.
a and 10b are shown as an array of pixels, and in each of the two shooting screens 10a and 10b, pixels are arrayed in horizontal X pixels and vertical Y pixels. In addition, the horizontal i pixel, vertical j
Arithmetic blocks of M pixels in the horizontal direction and N pixels in the vertical direction are arranged.

With the above structure, the light flux from the subject is incident on the taking lens 1, is turned upward by the quick return mirror 6, and is imaged in the vicinity of a distance optically equivalent to the film surface 7 to form a field. The light passes through the lens 8 and is guided to the penta prism 18. The direction of light is changed by the pentaprism 18, and the light flux emitted rearward is split by the light splitting mirror 19,
A part of the light is reflected in the finder field, and the rest is reflected and output in the lateral direction.
Head to. The pair of secondary imaging lenses 9 includes an area sensor 10
The light beams from different pupil positions of the photographing lens 1 are imaged and applied to the image pickup screens 10a and 10b, respectively, through the above configuration. The interval between the two images changes according to the defocus amount of the taking lens.

Here, the microcomputer 13 shown in FIG.
The operation will be described with reference to FIGS. 6, 7, 8, and 9 as flowcharts.

Step 1: In f _{n -1} which indicates the appropriate focal length of the taking lens 1 previously obtained from the size of the main subject,
As an initial setting, a value corresponding to the widest-angle focal length of the taking lens 1 is given.

Step 2: The zoom motor driver 15 is driven to drive the zoom motor 16 to drive means (cam means).
The variator 3 and the compensator 4 are moved in the direction of the optical axis via the, to set the focal length of the taking lens 1 to the widest angle focal length.

Step 3: Read luminance image. First, the area sensor 10 is driven via the sensor driver 14,
Signal accumulation is performed, and the luminance distribution of the field, that is, the illuminance distribution on the sensor surface is photoelectrically converted and converted into an image signal. After the accumulation is completed, the image signal is read. At the time of reading, the AD converter 11 is operated via the sensor driver 14 in synchronization with the reading timing to digitize the image signal output from the area sensor 10 and give it to the frame memory 12. A read timing signal is given to the frame memory 12 via the sensor driver 14 to read the digitized image signal.

The image of the luminance distribution as described above (hereinafter,
The brightness image) is captured by the area sensor 10 and captured as an image signal in the frame memory 12.

Step 4: Distance image generation. The interval between the images formed on the two image pickup screens 10a and 10b of the area sensor 10 is divided into a plurality of blocks in the image pickup screen and is obtained for each block. The distance between the two images depends on the defocus amount, and a value representing the subject distance can be obtained from the focal length, focus position, etc. of the taking lens 1. As a result, a distribution of distances on the screen, that is, a distance image is obtained. This distance image generation will be further described later with reference to FIG. 7.

Step 5: Main subject discrimination. From the distance image obtained in step 4, an object is extracted and a main subject is selected. This main subject discrimination will be further described later with reference to FIG.

Step 6: Determine focal length. The shape, size, and position of the main subject on the screen are obtained to find out where the top, bottom, left, and right ends of the main subject recognized in step 5 in the image with the current focal length of the taking lens 1 are obtained, and the shooting screen is obtained. The focal length f _n of the taking lens 1 is determined so that the main subject occupies an appropriate size and position.

[0022] Step 7: comparison of the focal length f _n obtained this time with the focal length f _n-1 previously determined, if effectively equal ends, if not effectively equal proceeds to the zoom drive Step 8 .

Step 8: Zoom drive. In _order to change the focal length f _n obtained in step 6, the zoom motor driver 15 is driven to drive the zoom motor 16 in a predetermined direction, and the variator 3 and the compensator 4 are moved in the optical axis direction by the cam means or the like to take the photographing lens. The focal length of 1 is changed.

Step 9: Previously obtained focal length f _n-1
Then, the value of the focal length f _n obtained this time is given to be the next "f _n-1 indicating the previously obtained focal length", and the process is repeated from step 3.

The microcomputer 13 operates as described above, and, for example, an automatic zoom operation is performed as shown in FIG. FIG. 12 is a diagram showing a change in the visual field in the operation of the first embodiment. In the figure, the left shows the visual field itself at each focal length and the division according to each pixel of the distance image, and the right shows. , And a shaded area showing the main subject on the distance image. In FIG. 12, a is an initial wide-angle field of view, b is determined based on the subject detected in the wide-angle field of view a, and imaging magnification changing means (in this case, a photographing magnification including a zoom motor driver 15 and a zoom motor 16) is used. The visual field changed by the changing unit) is determined based on the subject detected in the previous visual field b, and the visual field changed by the imaging magnification changing unit is shown. As shown in FIG.
Initially, a wide field of view is observed at a wide angle to detect the main subject. Next, based on the results, narrow the field of view and
That is, by improving the fineness of the previously detected main subject and the image in the vicinity thereof and detecting the main subject again, the main subject and the size thereof can be obtained with higher accuracy and a more optimal visual field can be obtained.

The distance image generation in step 4 of FIG. 6 will be further described with reference to the flowchart of FIG.

Step 10: As the initial setting of the calculation block position, the block (m, n) = (0, 0) at the upper left end of the image pickup screen shown in FIG. 5 is designated.

Step 11: The correlation between the designated calculation block on the image pickup screen 10a and the corresponding area on the image pickup screen 10b is obtained, and the image intervals having the highest correlation with each other are obtained. The distance between the two images depends on the defocus amount, and a value representing the subject distance can be obtained from the focal length, the focus position, etc. of the taking lens 1. Thus, a value representing the distance to the subject at the position on the screen of the designated calculation block is obtained.

Step 12: If the calculated block is not the lowest stage (m, N-1) in FIG. 5, proceed to step 13, and if so, proceed to step 14.

Step 13: The block to be calculated is set to the adjacent (lower) block (m, n + 1), and the process proceeds to step 11 for calculation.

Step 14: The block to be calculated is set to the uppermost block (m, 0).

Step 15: If the calculated vertical column is not the rightmost column (M-1, n), go to step 16; if it is the rightmost column, the distance image generation is terminated.

Step 16: The block sequence to be calculated is set to the next column on the right (m + 1, n), and the process proceeds to step 11 to perform the calculation.

That is, the calculation is started from the operation block at the upper left corner, and when the calculation is completed, the process moves to the lower stage, and when the calculation is completed up to the lowest stage, that is, when the calculation of the operation block for one vertical column is completed, The calculation proceeds to the upper stage, and vertically from there, and when it reaches the lowermost stage again, the process is repeated again to the rightmost uppermost stage until the calculation of the arithmetic block at the lower right end is completed, and the distance image is obtained.

Here, the calculation of the defocus amount (distance) in step 11 will be described with reference to FIG.

Step 20: The correlation between the designated calculation block of the image pickup screen 10a and the corresponding region of the image pickup screen 10b is calculated by changing the interval in pixel pitch units.

Step 21: The interval having the highest correlation is detected.

Step 22: From the change in the correlation amount near the interval having the highest correlation degree, the interval having the highest correlation degree is calculated by interpolation with accuracy less than the pixel pitch.

Step 23: It is confirmed whether or not the brightness contrast in the calculation block is sufficient to obtain the image shift by the correlation between the two images. If the contrast is low, the calculation is ended, and if it is high, the process proceeds to step 24.

Step 24: The defocus amount, and further the defocus amount, based on the optical characteristic information such as the focal lengths of the taking lens 1, the field lens 8 and the secondary imaging lens 9 and the optical positional relationship from the obtained distance between the two images. The value representing the distance is obtained, and the calculation ends.

Here, the correlation calculation in step 20 will be further described with reference to FIG.

Step 30: Using the image of the image pickup screen 10a as a standard image and the image of the image pickup screen 10b as a reference image, ideally the same image as the reference screen when the photographing lens 1 is in focus with respect to the photographing surface. The position of the image interval at which is obtained is the reference position, and the shift amount from that reference position (pixel pitch unit)
Correlation calculation is performed from the shift amount S that is the maximum shift amount S in which the image shift or the image shift can be detected, that is, the shift position in the upward direction in FIG.

Step 31: Calculate the correlation amount indicating the degree of correlation.

The calculation of the correlation amount at each interval (shift amount) is performed as follows.

[0045]

[Outer 1] However, data (screen, horizontal position of pixel, vertical position of pixel) = luminance value f of the pixel at the position shown in (): function indicating the correlation amount

The function f indicating the correlation amount is expressed by the following equation, for example.

[0047]

[Outside 2] When the correlation amount is obtained by such a function, the position of the point P shown in FIG. 10 is obtained by the interpolation calculation in step 22.

Step 32: When the correlation amount is obtained up to the maximum shift amount S from the reference position, that is, the position shifted downward in FIG. 5, the correlation calculation is terminated, and if not, step 33.
Proceed to.

Step 33: Add 1 to the shift amount shift, that is, shift the position of the reference image downward by one pixel pitch in FIG. 5, and calculate in step 31.

The correlation calculation is performed as described above.

The main subject discrimination in step 5 in FIG. 6 will be further described with reference to FIG.

Step 40: Differentiate the distance image obtained in the previous step.

For example, if the operator is a 3 × 3 pixel operator, ((d (m-1, n-1) + d (m, n-1) + d (m
+1, n-1) -d (m-1, n + 1) -d (m, n +
1) -d (m + 1, n + 1)) ² + (d (m-1, n-
1) + d (m-1n) + d (m-1, n + 1) -d (m
+1, n-1) -d (m + 1, n) -d (m + 1, n +
1)) ² ) ^1/2 or d (m, n) -min (d (m-1, n-1), d
(M, n-1), d (m + 1, n-1), d (m-1,
n), d (m + 1, n), d (m-1, n + 1), d
(M, n + 1), d (m + 1, n + 1)) or d (m, n)-(d (m-1, n-1) + d (m, n-
1) + d (m + 1, n-1) + d (m-1, n) + d
(M + 1, n) + d (m-1, n + 1) + d (m, n +
1) + d (m + 1, n + 1)) / 8 etc. can be used.

Step 41: Detect a point where the absolute value of the differential value is a predetermined value or more.

Step 42: The object is extracted by dividing the image at points where the absolute value of the differential value is equal to or greater than a predetermined value.

Step 43: Recognize an object existing relatively near and relatively near the center of the photographic screen as the main subject. This is the end of the main subject determination in step 5.

In FIG. 11, reference numerals 60-64 represent images processed in each process as an example of the main subject discrimination processing in step 5, where 60 is an original image and 6 is an image.
Reference numeral 1 is a generated distance image, 62 is a portion of the differentiated distance image detected in step 42 having a differential value of a predetermined value or more, and 63 is a step 42, in which the differential value is separated by a point of a predetermined value or more and extracted. The reference numeral 64 indicates an object which is recognized as a main subject in step 43.

[Embodiment 2] FIG. 13 shows an automatic zoom device for a camera according to the present invention.

In FIG. 13, reference numeral 71 is a taking lens of the camera, 72 is a focusing lens forming a part of the taking lens 71, 73 is a variator forming a part of the taking lens 71, and 74 is a part of the taking lens 71. A compensator forming a unit, which is a combination of a variator 73 and a compensator 74, driven by a zoom motor 86 via a zoom cam ring (not shown) to perform zooming. 75
Is a relay lens forming a part of the taking lens 71, and 77 is a film surface of the camera. Reference numeral 79 denotes a pair of image pickup lenses having a variable focal length, which forms an image on the respective image pickup screens 80a and 80b of the area sensor 80 having a pair of image pickup screens via reflecting mirrors 89 and 90. 8
Reference numerals 9 and 90 denote reflection mirrors that guide the image formation light of the pair of image pickup lenses 79 to the image pickup screens 80a and 80b of the area sensor 80.
0 is an area sensor having a pair of image pickup screens 80a and 80b, 81 is an AD converter for digitizing the image output signal of the area sensor 80, 82 is a frame memory for storing the digitized image signal, and 83 is an area Sensor 80, AD converter 81, frame memory 82
Is controlled via the sensor driver 84 to obtain an image signal and zoom control is performed based on the image signal. Reference numeral 84 of the microcomputer 83 drives the area sensor 80 to give a conversion timing signal to the AD converter 81. A sensor driver that gives a timing for capturing data to the frame memory 82, a zoom motor driver 85 that drives a zoom motor 86 according to an instruction from the microcomputer 83 to zoom the photographing lens 71, and a variator 86 through a zoom cam ring (not shown). 73, a zoom motor for driving the compensator 74 for zooming; and 87, a zoom econcoder for detecting the movement and position (focal length) of the zoom. 93
Is a motor driver that drives a motor 94 according to an instruction from the microcomputer 83 to change the focal lengths of the pair of variable focal length imaging lenses 79, and 94 drives the pair of variable focal length imaging lenses 79 to change the focal lengths. A motor 95 is an encoder for detecting the movement and position (focal length) of the focal length of the pair of variable focal length imaging lenses 79.

14 and 15 are a perspective view and a view showing an optical positional relationship between the reflecting mirrors 89 and 90 of the automatic zoom device for the camera shown in FIG. 13, the image pickup lens 79, and the area sensor 80. On the two image pickup screens 80a and 80b of the area sensor 80, light fluxes separated from each other by the base line length B are imaged via the image pickup lens 79 and the reflection mirrors 89 and 90. At this time, the distance between the two images on the image pickup screens 80a and 80b depends on the optical distance f between the image pickup lens 79 and the image pickup screens 80a and 80b, the base line length B, and the subject distance D.

FIG. 16 shows the relationship between the distance between the two images, the optical distance f between the image pickup lens and the image pickup screen, the base line length B, and the object distance D in the automatic zoom device for the camera shown in FIGS. It is the figure which simplified and abbreviate | omitted the reflective mirrors 89 and 90. In FIG. 14, the light beams separated from each other by the base line length B are guided by the reflection mirrors 89 and 90 to the image pickup screens 80a and 80b which are separated by the distance B ′.
As shown in FIG. 6, there are no reflecting mirrors 89, 90 or their equivalents, and are composed of image pickup screens 80a ', 80b' and an image pickup lens 79 which are spaced apart from each other at intervals roughly equal to the base line length B. Can be considered equivalent to The distance between the two images is equal to the baseline length B when the subject is at infinity. The distance between the two images when the subject is at a finite distance is wider by Δ than when it is at infinity.

The relationship between the distance (Δ) between the two images, the optical distance f between the image pickup lens and the image pickup screen, the base line length B, and the subject distance D is expressed by the following equation: D / B = f / Δ You can get the distance from the interval.

FIG. 17 shows the film surface 77 and the taking lens 7.
FIG. 3 is a diagram showing the relationship between the imaging field of view No. 1, imaging screens 80 a ′ and 80 b ′, and the imaging field of view of the imaging lens 79. Figure 1
Similar to FIG. 16, reference numeral 7 shows the relationship between the field of view, the screen and the lens by omitting the reflecting mirrors 89 and 90, and 80 ', 80a' and 80b 'in FIG. The same thing is shown, 71, 77 and 79 are shown in FIG. 14 and FIG.
It has the same configuration as that of No. 5. Both 91 and 92 are photographing lenses 71.
And 91 the filming field of view of the film surface 77. 91 is the longest focal length (telephoto end) of the taking lens 71 due to zooming, and 92 is the shortest focal length (wide-angle end) of the taking lens 71 due to zooming. ) Shows the field of view at each time. Further, the imaging field of view of the imaging lens and the imaging screen is equal to the imaging field of view 92 at the wide-angle end when the focal length on the shortest focal length side in the variable focal length range is set,
The focal length on the longest focal length side of the variable focal length range is substantially equal to the photographing field 91 at the telephoto end.

The image pickup screen 80a of the area sensor 80,
Similar to the area sensor 10 of FIG. 5 of the first embodiment, the two image pickup screens 80a and 80b are arranged such that horizontal X pixels and vertical Y pixels are arranged in the horizontal direction. Arithmetic blocks having a size of i pixels and j pixels in the vertical direction are arranged in M horizontal rows and N vertical rows.

Here, the microcomputer 8 of FIG.
Flowchart of Operation 3 The operation of the automatic zoom device will be described with reference to FIG.

Step 401: f which indicates an appropriate focal length of the taking lens 71 previously obtained from the size of the main subject, etc.
A value corresponding to the widest-angle focal length of the taking lens 71 is given to _n-1 as an initial setting.

Step 402: The motor is driven by the motor driver 93 so that the focal length of the image pickup lens 79 having a variable focal length is changed to the photographing field of view 9 when the photographing lens 71 has the widest focal length.
The focal length on the shortest focal length side is obtained so that an imaging field of view substantially equal to 2 is obtained.

Step 403: Read luminance image. First, the area sensor 80 is driven through the sensor driver 84 to cause signal accumulation, and the luminance distribution of the object field, that is, the illuminance distribution on the sensor surface is photoelectrically converted and converted into an image signal. After the accumulation is completed, the image signal is read. At the time of reading, the AD converter 81 is operated via the sensor driver 84 in synchronization with the timing of reading, and the image signal output from the area sensor 80 is digitized and given to the frame memory 82. In the frame memory 82,
A reading timing signal is given through the sensor driver 84 to read the digitized image signal.

Step 404: Range image generation. The interval between the images formed on the two image pickup screens 80a and 80b of the area sensor 80 is obtained for each block by dividing the image pickup screen into a plurality of blocks. The interval (Δ) between the two images depends on the subject distance D as described above, and the imaging lens 79 and the imaging screen 80
A value representing the subject distance can be obtained from the optical distance f between a and 80b and the base line length B. As a result, a distribution of distances on the screen, that is, a distance image is obtained. This distance image generation will be further described later with reference to FIG.

Step 405: Main subject discrimination. From the distance image obtained in step 404, an object is extracted and a main subject is selected. Regarding this main subject discrimination, FIG.
This is similar to the main subject determination in step 4 of step 1.
As described above.

Step 406: Determine focal length. In the image of the field of view based on the current focal length of the imaging lens 79, the shape, size, and position of the main subject on the screen are obtained, where the top end, bottom end, left end, and right end of the main subject recognized in step 405 are obtained. The focal length f _n of the photographing lens 71 so that the main subject occupies an appropriate size and position in the photographing screen, and the focal length of the photographing lens 79 that obtains an imaging field of view corresponding thereto are obtained.

Step 407: Previously obtained focal length f
_The focal length f _n obtained this time is compared with _n−1. If they are substantially equal, the process ends after executing steps 411 and 412. If they are not substantially equal, the process proceeds to step 408, where the focal length of the imaging lens is changed.

Step 408: Change the focal length of the image pickup lens. In order to change the focal length to obtain the imaging field of view corresponding to the focal length f _n of the photographing lens 71 obtained in step 406, the motor driver 93 drives the motor 94 in a predetermined direction to change the focal length of the imaging lens 79 of the variable focal length. Change the focal length.

Step 409: Zoom drive. Step 4
The zoom motor driver 85 is driven to drive the zoom motor 86 in a predetermined direction so that the focal length f _n obtained in 06 is obtained, and the variator 73 and the compensator 74 are moved in the optical axis direction via a zoom cam ring (not shown) for photographing. The focal length of the lens 71 is changed.

[0075] Step 410: the f _n-1 indicating the focal length previously determined, given a value of the focal length f _n obtained this time, and "f _n-1 indicating the last focal distance obtained" next, step 403 Repeat again.

Step 411: When it is determined that the current focal length of the taking lens 71 and the focal length f _n obtained this time are already substantially equal, step 412 is ended without executing, and they are not substantially equal. If it is determined, then step 412 is executed.

Step 412: Zoom drive similar to step 409. The zoom motor driver 85 is driven to drive the zoom motor 86 so that the focal length f _n obtained in step 406 is obtained, and the variator 73 and the compensator 74 are moved in the optical axis direction via a zoom cam ring (not shown) to take the photographing lens 71. After changing the focal length of, finish.

The microcomputer 83 operates as described above, and as in the first embodiment, the imaging field of view is changed as shown in FIG. 12, and the automatic zoom operation is performed.

Here, in the flow chart of FIG.
The distance image generation in step 404 of 8 will be further described.

Step 110: As the initial setting of the calculation block position, the block (m, n) = (0, 0) at the upper left end of the image pickup screen shown in FIG. 5 is designated.

Step 111: The correlation between the designated calculation block on the image pickup screen 80a and the corresponding area on the image pickup screen 80b is obtained, and the image intervals having the highest correlation with each other are obtained. The distance between the two images depends on the subject distance, and a value representing the subject distance can be obtained from the focal length f of the imaging lens 79 and the base line length B. Thus, a value representing the distance to the subject at the position on the screen of the designated calculation block is obtained.

Step 112: The calculated block is shown in FIG.
If it is not the uppermost stage (m, N-1), step 113
If it is at the bottom, go to step 114.

Step 113: The block to be calculated is set to the adjacent (lower) block (m, n + 1), and Step 11
Go to 1 and calculate.

Step 114: The block to be calculated is set to the uppermost block (m, 0).

Step 115: If the calculated vertical column is not the rightmost column (M-1, n), go to step 116. If it is the rightmost column, the distance image generation is terminated.

Step 116: The block sequence to be calculated is set to the next column on the right (m + 1, n), and the process proceeds to step 111 for calculation.

That is, calculation is started from the arithmetic block at the upper left corner, and when the calculation is completed, go to the lower stage.
In other words, when the calculation of the calculation block for one vertical column is completed, proceed to the uppermost row of the next column on the right next to it, and from there, proceed vertically again, and when it reaches the lowermost row, repeat this to the uppermost row on the right next again, Perform until the calculation of the operation block at the lower right corner is completed,
Get a range image.

Here, the calculation of the distance in step 111 will be described with reference to FIG.

Step 120: The correlation between the designated calculation block of the image pickup screen 80a and the corresponding region of the image pickup screen 30b is calculated by changing the interval in pixel pitch units.

Step 121: The interval with the highest degree of correlation is detected.

Step 122: Interpolation calculation is performed on the interval having the highest correlation degree with an accuracy of less than the pixel pitch based on the change in the correlation amount near the interval having the highest correlation degree.

Step 123: It is confirmed whether or not the brightness contrast in the calculation block is sufficient to obtain the image shift by the correlation between the two images. If the contrast is low, the calculation is terminated, and if it is high, the process proceeds to step 124.

Step 124: From the obtained distance between the two images,
Based on the optical characteristic information such as the focal length f of the imaging lens 79 and the base line length B, a value representing the distance is obtained and the calculation is completed.

Here, the correlation calculation in step 120 will be further described with reference to FIG.

Step 130: When the image pickup screen 80a is used as a reference screen, the image is used as a reference image, and the image of the image pickup screen 80b is used as a reference image, and when the object distance to be the reference is the object distance, that is, ideally with the reference screen. Is the reference position which is the position of the image interval at which the same image is obtained. Then, the correlation calculation is performed from the shift amount (pixel pitch unit) shift from the reference position, which is the maximum shift amount S at which the image shift or the image shift can be detected, that is, the position shifted upward in FIG. .

Step 131: Calculate the correlation amount indicating the degree of correlation.

The correlation amount at each interval (shift amount) is calculated as follows.

[0098]

[Outside 3] However, data (screen, horizontal position of pixel, vertical position of pixel) = luminance value f of the pixel at the position shown in (): function indicating the correlation amount

The function f indicating the correlation amount is expressed by the following equation, for example.

[0100]

[Outside 4] When obtaining the correlation amount by such a function, step 122
In the interpolation calculation of, the position of the point P shown in FIG. 10 is obtained as in step 22 of FIG. 8 of the first embodiment.

Step 132: When the correlation amount is obtained up to the maximum shift amount S from the reference position, that is, the position shifted downward in FIG. 5, the correlation calculation is ended.
Proceed to 33.

Step 133: 1 for shift amount shift
In other words, the position of the reference image is shifted downward by one pixel pitch in FIG. 5, and calculation is performed in step 131.

The above operation is repeated to proceed the correlation calculation.

[Third Embodiment] Similar to the first embodiment, the microcomputer 13 operates according to the flowchart of FIG. 22 with the configuration shown in FIGS.

Flowchart The operation of the automatic zoom device will be described with reference to FIG.

Step 501: f _n-1 indicating the appropriate focal length of the taking lens 1 previously obtained from the size of the main subject and the like.
As a default setting, a value corresponding to the widest-angle focal length of the taking lens 1 is given.

Step 502: Zoom motor driver 1
5, the zoom motor 16 is driven, and the variator 3 and the compensator 4 are moved in the optical axis direction via the cam means or the like to bring the focal length of the taking lens 1 to the widest angle focal length.

Step 503: Read luminance image. First, the area sensor 10 is driven through the sensor driver 14 to cause signal accumulation, and the luminance distribution of the field, that is, the illuminance distribution on the sensor surface is photoelectrically converted and converted into an image signal. After the accumulation is completed, the image signal is read. At the time of reading, the AD converter 11 is operated via the sensor driver 14 in synchronization with the reading timing to digitize the image signal output from the area sensor 10 and give it to the frame memory 12. In the frame memory 12,
A reading timing signal is given through the sensor driver 14 to read the digitized image signal.

As described above, the image of the luminance distribution (hereinafter,
The brightness image) is captured by the area sensor 10 and captured in the frame memory 12 as an image signal.

Step 504: Distance image generation. The interval between the images formed on the two image pickup screens 10a and 10b of the area sensor 10 is divided into a plurality of blocks in the image pickup screen and is obtained for each block. The distance between the two images depends on the defocus amount, and a value representing the subject distance can be obtained from the focal length, focus position, etc. of the taking lens 1. As a result, a distribution of distances on the screen, that is, a distance image is obtained. This distance image generation is the same as step 4 in FIG. 6 of the first embodiment, and the details thereof are as described with reference to FIG. 7.

Step 505: Main subject discrimination. From the distance image obtained in step 504, an object is extracted and a main subject is selected. This main subject determination is the same as step 5 of FIG. 6 of the first embodiment, and the details thereof are as described with reference to FIG.

Step 506: Determine focal length. The shape, size, and position of the main subject on the screen are obtained to find out where the upper end, the lower end, the left end, and the right end of the main subject recognized in step 505 in the image with the current focal length of the taking lens 1 are obtained. The focal length f _n of the taking lens 1 is determined so that the main subject occupies an appropriate size and position.

Step 507: Previously obtained focal length f
_n-1 is compared with the focal length f _n obtained this time, and if substantially equal, the process ends; otherwise, step 5
In step 08, zoom driving is performed.

Step 508: Start zoom drive. The zoom motor driver 15 is started to drive the zoom motor 16 so that the focal length f _n obtained in step 506 is reached from the current zoom position, and the variator 3 and the compensator 4 are moved in the optical axis direction via cam means or the like. To change the focal length of the taking lens 1.

Step 509: If the current zoom position is away from the zoom position corresponding to the focal length f _n by a predetermined value or more, steps 510 to 513 are sequentially executed, and if close, steps 510 to 5
13 is not executed, and the process proceeds to step 514.

Step 510: Read luminance image. First, the area sensor 10 is driven through the sensor driver 14 to cause signal accumulation, and the luminance distribution of the field, that is, the illuminance distribution on the sensor surface is photoelectrically converted and converted into an image signal. After the accumulation is completed, the image signal is read. At the time of reading, the AD converter 11 is operated via the sensor driver 14 in synchronization with the reading timing to digitize the image signal output from the area sensor 10 and give it to the frame memory 12. In the frame memory 12,
A reading timing signal is given through the sensor driver 14 to read the digitized image signal.

At this time, the time at the start and end of the accumulation, the zoom position (or the focal length) is stored and calculated, and the image obtained by the accumulation is compared with the change of the image due to the zooming during the accumulation. Decide what focal length should be treated as an image.

Step 511: Range image generation. Similar to step 504, a range image is generated. However, the focal length used at this time is the focal length during accumulation previously obtained in step 510.

Step 512: Main subject discrimination. Similar to step 505, from the range image obtained in step 511,
The object is extracted and the main subject is selected.

Step 513: Focal length determination. With the focal length of the taking lens 1 being accumulated previously obtained in step 510, where the upper end, the lower end, the left end, and the right end of the main subject recognized in step 512 are in the image, and the shape of the main subject on the screen is displayed. After obtaining the size and the position, the focal length f _n of the photographing lens 1 is determined so that the main subject occupies the proper size and position in the photographing screen.

Step 514: If the current focal length of the taking lens 1 and the focal length f _n are substantially equal, that is, if the zoom position has reached the target focal length, the process proceeds to step 515 to perform zoom drive. Stop and if not equal, repeat from step 509 again.

Step 515: Stop zoom drive. The zoom drive started in step 508 is stopped.

[0123] Step 516: the f _n-1 indicating the focal length previously determined, given a value of the focal length f _n obtained this time, the next time the "f _n-1 indicating the focal length previously determined", the step 503 Repeat again.

As described above, even when the zoom position is far from the zoom position obtained from the image even during zoom driving,
By obtaining the image again and obtaining the focal length again, an appropriate focal length can be obtained more quickly.

[Fourth Embodiment] Similar to the first embodiment, the microcomputer 13 operates according to the flow chart of FIG. 23 in the configuration shown in FIGS.

The operation of the automatic zoom device will be described with reference to the flowchart of FIG.

Step 701: f _n-1 indicating an appropriate focal length of the taking lens 1 previously obtained from the size of the main subject, etc.
Is given as a default value corresponding to the widest focal length of the taking lens 1.

Step 702: Zoom motor driver 1
5, the zoom motor 16 is driven, and the variator 3 and the compensator 4 are moved in the optical axis direction via the cam means or the like to bring the focal length of the taking lens 1 to the widest angle focal length.

Step 703: Read luminance image. First, the area sensor 10 is driven through the sensor driver 14 to cause signal accumulation, and the luminance distribution of the field, that is, the illuminance distribution on the sensor surface is photoelectrically converted and converted into an image signal. After the accumulation is completed, the image signal is read. At the time of reading, the AD converter 11 is operated via the sensor driver 14 in synchronization with the reading timing to digitize the image signal output from the area sensor 10 and give it to the frame memory 12. In the frame memory 12,
A reading timing signal is given through the sensor driver 14 to read the digitized image signal.

As described above, the image of the luminance distribution (hereinafter,
The brightness image) is captured by the area sensor 10 and captured in the frame memory 12 as an image signal.

Step 704: Distance image generation. The interval between the images formed on the two image pickup screens 10a and 10b of the area sensor 10 is divided into a plurality of blocks in the image pickup screen and is obtained for each block. The distance between the two images depends on the defocus amount, and a value representing the subject distance can be obtained from the focal length, focus position, etc. of the taking lens 1. As a result, a distribution of distances on the screen, that is, a distance image is obtained. This distance image generation is the same as step 4 in FIG. 6 of the first embodiment, and the details thereof are as described with reference to FIG. 7.

Step 705: Main subject discrimination. An object is extracted and a main subject is selected from the distance image obtained in step 704. This main subject determination is the same as step 5 in FIG. 6 of the first embodiment.

Step 706: Focal length determination. The shape, size, and position of the main subject on the screen are obtained to find out where the upper end, the lower end, the left end, and the right end of the main subject recognized in step 705 in the image with the current focal length of the taking lens 1 are obtained. The focal length f _n of the taking lens 1 is determined so that the main subject occupies an appropriate size and position.

[0134] Step 707: comparing the focal length value indicating the f _n obtained this time and a value that indicates the focal length of the photographic lens 1 the current focus of the photographing lens 1 of a value indicating the focal length f _n obtained this time current If the distance is more than the predetermined value α, the process proceeds to step 708 to drive the zoom.

Here, the value indicating the focal length does not necessarily have to be the focal length itself or a value proportional to the focal length, and may be, for example, the amount of extension or rotation of a part of the zoom cam ring of the cam means. Further, the distance is not limited to the difference between the predetermined values, and may be a ratio, for example.

Step 708: Zoom drive. Step 7
At the focal length f _n obtained in 06, the zoom motor driver 1
5, the zoom motor 16 is driven, and the variator 3 and the compensator 4 are appropriately moved in the optical axis direction via the cam means or the like to change the focal length of the taking lens 1.

[0137] Step 709: the f _n-1 indicating the focal length previously determined, given a value of the focal length f _n obtained this time, the next time the "f _n-1 indicating the focal length previously determined", the step 603 Repeat again.

Step 710: When it is judged that the current focal length of the taking lens 1 and the focal length f _n obtained this time are already effectively equal, step 711 is ended without executing, and they are not effectively equal. If determined, then step 711 is executed.

Step 711: Zoom drive similar to step 709. At the focal length f _n obtained in step 706,
The zoom motor 16 is driven via the zoom motor driver 15, and the variator 3 and the compensator 4 are appropriately moved in the optical axis direction via the cam means or the like to change the focal length of the taking lens 1, and then the process ends.

As described above, the microcomputer 13 operates and the automatic zoom operation is performed.

In the embodiments, the image of the image pickup means is used as the distance image, but all of the explanations have been made. However, the image for recognizing the subject is not limited to the distance image, and a luminance image or the like can be used. The effect of the present invention is not lost even with the above image.

[0142]

As described above, the subject image is detected from the image signal, the size of the main subject is discriminated using the subject image, and the focal length to be changed based on the size of the main subject ( Since the shooting magnification) was determined, the optimum focal length (shooting magnification) was always obtained based not only on the subject distance information but also on the size of the main subject. Further, when the main subject is discriminated, the field of view of the subject image is changed by operating the variable focal length optical system for the subject image.
I was able to make the main subject more accurate. In addition,
By performing the operation of the focal length optical system for determining the main subject in the tele direction from the wide side, it is possible to accurately determine the main subject from the entire viewable field.

In the embodiment, the object image on the wide side is first detected, and then the object image is detected again with the focal length changed in the tele direction, and this detection is repeated successively to obtain the main image. It is possible to accurately set the shooting focal length based on the size of the subject.

Further, according to the present invention, the image of the subject is used as the distance image, and the changed portion on the distance image is recognized as the boundary between the objects, so that the main subject and the luminance contrast pattern of the background are not confused and the main subject is surely detected. It is now possible to distinguish between the subject and the background.

[Brief description of drawings]

FIG. 1 is a block diagram of an automatic zoom device for a camera according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical positional relationship of the camera automatic zoom device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a layout when the automatic zoom device for a camera according to the first embodiment of the present invention is applied to a single-lens reflex camera.

FIG. 4 is a diagram of the layout of FIG. 3 as viewed from above the camera.

FIG. 5 is a diagram showing an image pickup screen of an area sensor and an array of pixels.

FIG. 6 is a flowchart showing the operation of the microcomputer.

7 is a detailed flowchart of the distance image generation of FIG.

8 is a detailed flowchart of the calculation of the defocus amount in FIG.

9 is a detailed flowchart of the correlation calculation of FIG.

FIG. 10 is a diagram illustrating interpolation calculation.

FIG. 11 is a diagram for explaining the main subject determination of FIG.

FIG. 12 is a diagram illustrating a relationship between an operation and an imaging visual field according to the second embodiment of the present invention.

FIG. 13 is a block diagram of an automatic zoom device for a camera according to a second embodiment of the present invention.

FIG. 14 is a diagram showing an optical positional relationship of an automatic zoom device for a camera according to a second embodiment of the present invention.

FIG. 15 is a diagram showing an optical positional relationship of an automatic zoom device for a camera according to a second embodiment of the present invention.

FIG. 16 is a diagram for explaining the principle of distance measurement according to the second embodiment of the present invention.

FIG. 17 is a diagram for explaining the relationship between the imaging visual field and the imaging visual field according to the second embodiment of the present invention.

FIG. 18 is a flowchart showing the operation of the microcomputer according to the second embodiment of the present invention.

FIG. 19 is a detailed flowchart of the distance image generation of FIG.

20 is a detailed flowchart of the distance calculation of FIG.

21 is a detailed flowchart of the correlation calculation of FIG.

FIG. 22 is a flowchart showing the operation of the microcomputer according to the third embodiment of the present invention.

FIG. 23 is a flowchart showing the operation of the microcomputer according to the fourth embodiment of the present invention.

[Explanation of symbols]

1 Camera lens 3 variator 4 Compensator 7 Film side 9 1-to-2 secondary imaging lens Area sensor having a pair of imaging screens 13 Microcomputer 15 Zoom motor driver 16 zoom motor 17 Zoom encoder 20 reflective mirror 50 Primary image plane on imaging optical path 65 1 pair of secondary imaging lenses 66 Area sensor having a pair of imaging screens 67 Microcomputer 71 Camera lens 73 Variator 74 Compensator 77 Film side 79 1 pair of imaging lenses 80 Area sensor having a pair of imaging screens 83 Microcomputer 85 Zoom Motor Driver 86 Zoom motor 87 Zoom encoder 89, 90 Reflective mirror 91 Field of view at telephoto 92 Wide-angle shooting field of view 93 Imaging lens motor driver 94 Imaging lens motor 95 Imaging lens encoder

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Claims (3)

(57) [Claims] 1. An image pickup means for converting a subject image into an image signal via a variable focal length optical system, and a subject image detection means for extracting a subject image signal using the image signal obtained from the image pickup means. A calculation unit that determines the size of the image of the subject image signal extracted by the detection unit and calculates information about the focal length for the size to occupy a predetermined size; and the calculation unit. In the optical device for changing the focal length of the variable focal length optical system according to the information on the focal length, the focal length of the variable focal length optical system is changed according to the information on the focal length calculated by the calculating means. After that, the extracting operation of the image signal by the subject image detecting means, the arithmetic operation by the arithmetic means, and the focal length changing operation of the focal length variable optical system according to the arithmetic result are performed last time and this time. Optical instrument operation result and performing repeatedly to converge to a predetermined range. 2. The optical apparatus according to claim 1, further comprising a photographing optical system that repeatedly changes the focal length of the photographing optical system every time the calculation unit calculates the information on the focal length. 3. The optical apparatus according to claim 1, further comprising initial setting means for setting a focal length on a wide side as an initial value of the variable focal length optical system.