JPH05284405A - Photographing device - Google Patents

Abstract

PURPOSE:To provide an inexpensive photographing device by extending the degree of freedom of a zoom lens formed to be wide angle and forming inexpensively a wide angled zoom lens. CONSTITUTION:A correction means correcting distortion (especially distortion aberration at a wide angle side) caused by forming a wide angled zoom lens is provided on a device. The correcting means is constituted of an image forming means 1 composed of the wide angled zoom lens used for photographing an object, a storage section 3 storing an object image formed on a sensor by the image forming means 1, a detecting means 5 detecting the zoom position of the wide angled zoom lens, a correction section 6 setting the distortion correction based on the zoom position detected by the detecting means 5 and correcting the distortion of the object image, and a control means 7 reading and controlling the object image whose distortion is corrected by the distortion correction section 6 as a video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographing device for photographing a subject and recording and reproducing the photographed image.

[0002]

2. Description of the Related Art A zoom lens is often used as an image forming means used in a conventional photographing apparatus. In recent years, the zoom lens is being widened as one of the expansions of the photographing function. In widening the angle of view, it is being promoted to make only the wide-angle side wider while keeping the current focal length on the telephoto side. Therefore, in optical design,
As the zoom magnification of the mullens increases, it is very difficult and difficult to correct the distortion (distortion) caused by the wide angle. As disclosed in Japanese Patent Laid-Open No. 63-281113, it is necessary to set design conditions such as defining the focal length of each group in the lens configuration of the zoom lens within a proper range. Therefore, the degree of freedom in optical design is reduced, and it is difficult to achieve with a simple configuration. Further, generally, the lens becomes large in size by widening the angle.

Although a zoom lens can be constructed under the restrictions of the above design conditions, a lens for correcting distortion is required,
As a zoom lens, the number of lenses becomes large. The structure of the zoom lens also becomes complicated. As the number of lenses increases, the number of lens barrel parts that hold the lenses or perform zooming operations increases, and the number of parts for zoom lenses increases. This not only increases the manufacturing cost due to the increase in the number of parts, but also it becomes difficult to secure the lens holding accuracy in consideration of the variation in the part tolerance from the manufacturing viewpoint.
Because it will be difficult to make as a mullens,
It becomes expensive. Therefore, a photographing device equipped with a wide-angle zoom lens also becomes expensive.

[0004]

As described above,
There are the following problems in a photographing device equipped with a wide-angle zoom lens.

The degree of freedom in designing a zoom lens having a wide angle is limited, and since a large number of lenses are required for distortion correction, it is difficult to achieve an optical design with an inexpensive lens structure. Further, since the number of lenses is large, the number of parts for holding the lenses is increased, and thus the zoom lens has a large number of lens barrel parts. In other words, the zoom lens is expensive because it has a complicated structure and a large number of parts. Therefore, a photographing device equipped with this zoom lens also becomes expensive.

An object of the present invention is to solve the above-mentioned problems of the prior art, to widen the degree of freedom in the optical design of a wide-angle zoom lens, and to provide an inexpensive wide-angle zoom lens. By doing so, an inexpensive imaging device is provided.

[0007]

In order to achieve this object, the present invention provides a correction means for correcting the distortion (particularly the distortion aberration on the wide angle side) caused by widening the zoom lens. That is, by providing the correcting means, it is possible to increase the degree of freedom in optical design and provide a wide-angle zoom lens having an inexpensive lens structure as an image forming means to the photographing apparatus. The correction means for this purpose has the following configuration.

[0008] An image forming means composed of a wide-angle zoom lens for photographing a subject, a storage section for storing a subject image formed on the sensor by the image forming means, and a zoom of the wide-angle zoom lens. -A detection means for detecting the zoom position, a correction portion for correcting the distortion of the subject image by setting a distortion correction amount based on the zoom position detected by the detection means, and the distortion correction portion for correcting the distortion. The control unit is configured to read out and control the subject image as a video signal.

[0009]

The operation of each element in the above configuration will be described.

The image forming means is a zoom lens having a wide angle, and has a function of forming an object image on an image reading sensor installed on the image forming surface in a state where the object image is distorted. The storage unit has a function of reading out the image and storing a part or the whole of the image. When storing a part of the image, the range including the distortion portion is stored. The detection means is
The zoom position of the zoom lens is detected. The distortion state of the image stored in the storage unit is corrected by using the design value of the distortion amount generated in the optical design at the zoom position. That is, the amount of distortion is detected by detecting the zoom position. The correction unit has a function of obtaining a correction amount based on the detected distortion amount and performing a process of correcting the image distortion to obtain an image without distortion. The control means acts to correctly read the corrected image as a video signal.

[0011]

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

FIG. 1 is a diagram showing a schematic configuration according to the present invention. Reference numeral 1 is an image forming unit which is formed on a reading sensor 2 for reading an image of a subject, and a zoom lens whose photographing field angle is widened, and 3 is an image formed by reading the image formed on the sensor 2 and reading it. Storage means for storing the image signal thus obtained, 4 is a zoom position detector for detecting the zoom position of the zoom lens, and 5 is detection means for detecting the distortion of the image from the zoom position detector 4. Reference numeral 6 denotes a correction unit that obtains a correction amount for correcting the detected image distortion amount and performs processing so that there is no image distortion. Reference numeral 7 denotes a control unit that outputs the corrected image as a signal to a video signal processing unit of the camera unit. Is.

FIG. 2 is a view showing an example in which an image of a captured straight line is formed on a reading sensor when a straight line is photographed by a wide-angle zoom lens. In FIG. 2, the linear image of the subject is distorted in the vertical direction within the imaging plane frame 8 of the sensor 2. (Distortion in the left-right direction will be described later) 9a and 9b are images on the reading sensor when two upper and lower straight lines are photographed by the photographing means, and indicate straight lines distorted in the horizontal direction. Here is an example. The distortion referred to here is a straight line with respect to line segments 12a and 12b (imaging plane frame) formed by connecting start points 10a and 10b and end points 11a and 11b of a straight line image on the sensor shown in FIG. It is represented by the amount of deviation between the images 9a and 9b. That is, this shift amount A (A / 2 above in FIG. 2 and A / 2 below) is divided by the entire area B in the vertical direction and shown in%. When expressed by a formula, the amount of strain can be expressed by (A / B) × 100. This image is stored in the storage means 4 which can be read from either the horizontal direction or the vertical direction. That is, the storage means 4 is composed of memory element rows finely divided in the vertical direction and the horizontal direction. When reading an image signal in the horizontal direction, the memory element row is read from the memory element rows arranged in the horizontal direction. When reading the image signal,
The data is read from the memory element array arranged in the vertical direction.

First, an example of means for detecting the zoom position (determined by the position of the variator) necessary for detecting the distortion will be described with reference to FIG. Reference numeral 13 is a variator lens group for changing the size of the photographed image, 14 is a holding frame for holding the variator lens group, 15 is a guide rod for guiding the holding frame 14 in the optical axis direction, and 16 is attached to the holding frame. A cam follower, 17 is a cam ring that is a means for moving the cam follower 16 in the optical axis direction, 18 is a fixed cylinder that rotatably holds the cam ring 17, and a cam groove (not shown) is provided in the cam ring 17. The cam follower 16 is fitted in the cam groove. A detection lever 19 of a zoom detector is fitted in the cam follower 16. Next, the operation will be described. When the cam ring 16 rotates, the cam follower 16 moves along the cam groove formed in the cam ring 16. At this time, since the cam follower 16 is attached to the holding frame 14, the holding frame 14 also moves. The movement of the holding frame is restricted by the guide rod 15 and moves in the optical axis direction. Therefore, the variator lens group 13 held by the holding frame 14 also moves in the optical axis direction, and the size of the photographed image changes, and zoom operation is performed. At this time, since the detection lever 19 of the zoom detector is fitted in the cam follower 16, the detection lever 19 also moves as the cam follower 16 moves. The zoom detector 4 is a brush (not shown) provided on the zoom lever according to the movement of the zoom detection lever 19.
However, it slides on the resistor provided in the zoom detector body, and the contact position between the brush and the resistor changes. Therefore, the resistance value taken out from the zoom detector changes in accordance with the change in the contact position. In this way the cam follower
The position of 16 can be taken out as a resistance value. Since the cam follower 16 is attached to the holding frame holding the variator lens group, the position (zoom position) of the variator lens group 13 can be detected by using the extracted resistance value. You can Since the zoom position can be obtained by the zoom detector 4 as described above, the detecting means for detecting the distortion will be described next.

This detection zoom position is used. That is,
The distortion value calculated by the optical design at the zoom position (the distortion value calculated as shown in the above equation) is almost the same as the amount of image distortion of the actually photographed subject. ing. Therefore, in the distortion detection, the optical design value at the detected value is used as the distortion amount by detecting the zoom position described above. When the straight line is vertically distorted as shown in FIG. 2, the image signal is read from the memory element array arranged in the vertical direction. When the distortion is not corrected, it is read as it is, but when correcting the distortion, the distortion correction unit does the following.

The amount of distortion at each position in the horizontal direction (direction from the starting point 10a to the ending point 11a in FIG. 2) calculated by optical design at each zoom position is calculated and obtained. Now, the distortion correction at the central portion P in FIG. 2 will be described. The time for reading an image from the memory element array in the vertical direction of the P portion is t ₁ (entire area B). Distortion section (A / 2 parts) time to read the memory element image than the column in the vertical direction until the t _0/2. FIG. 4 shows the relationship between the read signal from the memory element array in the vertical direction of the P portion and time.

Next, the case where the image is distorted in the direction opposite to the solid line as shown by the dotted line in FIG. 2 will be described. The strain is maximum around the left and right sides, and the strain generation amount is the same as above. The correction of the peripheral R and S parts will be described. Peripheral R ₁ and S ₁ are the reading start part,
R ₄ and S ₄ are end portions. Wherein _{R 1 ~R 2, S 1 ~S} 2 parts upper distortion _{unit, R 3 ~R 4, S 3} ~S 4 is lower distortion section, read out each time is t _0/2. Therefore, in the same manner as described above, the R _{2 to} R ₃ and S _{2 to} S ₃ parts are read out over the entire area, and signal processing is performed so as to reach the time t ₁ , and R _{1 to} R ₂ and S _{1 to} S of the distortion part are processed.
₂ parts of R ₃ to R _4, may be deleted and S ₃ to S ₄ parts.

FIG. 4 shows the relationship between the read signal from the vertical memory element array of the P portion and time. P ₁ is the read start portion, P ₂ is the upper straight portion, P ₃ is the lower straight portion, P
₄ is the end part. Wherein P ₁ to P ₂ parts of P ₃ to P ₄ parts each time that read a t _0/2, P ₁ ~P read up to ₄ time is t _1. Therefore, in order to correct the distortion, the time corresponding to the P _{2 to} P ₃ part (t ₁ −t ₀ ) is read out over the entire area and signal processing is performed so as to become the time t _1, and the P _{1 to} P of the distortion part is processed.
_It suffices to delete part _{2 and} parts P _{3 to} P ₄ . In this way, the distortion is corrected.

FIG. 5 shows an example of the configuration of the distortion correction section. It is composed of a sampling circuit 20, a memory 21, and an arithmetic processing circuit 22. The sampling circuit 20 first uses the output from the distortion detection circuit to delete the portion corresponding to the calculated distortion amount from the optical design value, and creates a gate pulse for extracting the signal. Memory 21 using the gate pulse and the synchronizing signal
The signal part to be corrected of the read signal from is extracted. The t _0/2 excluding portions of the first portion and the end portion of the signal in the example of FIG. 4 gate - withdrawn by Toparusu. The extracted signal is stored in the memory 21. Next, the arithmetic processing circuit takes out the signals input from the memory 21 so as to read out all the signals input to the memory 21 so that the time corresponds to t in FIG. The control unit outputs the processed signal to the camera circuit according to the original synchronization signal. In this way, the distorted portion is corrected.

Next, an example in which the image is distorted in the left-right direction will be described.

FIG. 6 is a diagram showing an example in which an image of a captured straight line is formed on a reading sensor when a straight line in the vertical direction is taken by a wide-angle zoom lens.
Reference numerals 23a and 23b are images on the reading sensor when two straight lines positioned on the left and right are photographed by the photographing means, and are examples showing straight lines distorted in the vertical direction. The distortion referred to here is the starting point 24 of the straight line image on the sensor shown in FIG.
a line image 23 to line segments 26a and 26b (imaging plane frame) formed by connecting a and 24b and end points 25a and 25b.
It is represented by the amount of deviation between a and 23b. That is, this shift amount C (see FIG.
(C / 2 on the left and C / 2 on the right) is divided by the whole area D in the horizontal direction and shown in%. When expressed by a formula, the amount of strain can be expressed by (C / D) × 100. This image is stored in the storage means 4 which can be read from either the horizontal direction or the vertical direction. That is, the storage means 4 is composed of memory element rows finely divided in the vertical direction and the horizontal direction. When reading an image signal in the horizontal direction, it is read from the memory element rows arranged in the horizontal direction, in the vertical direction. When reading the image signal, it is read from the memory element array arranged in the vertical direction.

Here, the signal is read from the memory element array arranged in the horizontal direction to correct the distortion. The distortion correction is performed in the same manner as the vertical distortion correction described above. However, instead of the vertical memory element row, the horizontal memory element row may be replaced. (Detailed description is omitted) FIG. 7 shows a schematic configuration showing an example of another correction method of a horizontally distorted image.

Reference numeral 27 is a signal reading circuit for reading an image connected to the sensor 2, 28 is a correction unit for correcting horizontal distortion, and 29 is a control unit for processing the corrected signal to the camera circuit. is there. Here, the distortion correction unit has the same configuration as that shown in FIG. The distortion correction operation is the same as that described above in the example of FIG. 5, and a horizontal synchronizing signal is used as the synchronizing signal.

Next, a case of correcting an image which is distorted vertically and vertically will be described.

FIG. 8 shows a schematic configuration diagram for distortion correction.

The detector 4, the detection means 5, the signal reading circuit 27, the correction section 28, the control section 29, the storage means 30, the correction section 31, and the control section 32 are included. Next, a distortion correction method will be described. For distortion correction, first correct horizontal distortion, then
Corrects vertical distortion.

In the horizontal distortion correction, the detector 4 and the detecting means 5 detect the zoom position to obtain the distortion amount, the signal reading circuit 27 and the correction unit 28 correct the distortion, and the control unit 29 outputs the signal. It is processed and output as an image signal without horizontal distortion. The distortion correction operation is performed in the same manner as described above. Next, the distortion in the vertical direction is detected by the detector 4, the detection means 5, the storage means 30,
The correction is performed by the correction unit 31 and the control unit 32. The distortion correction operation is performed in the same manner as described above.

[0028]

As described above, by providing the means for correcting the distortion of the subject image by the image forming means capable of photographing a wide angle of view, the degree of freedom of the optical design is increased and the lens forming the zoom lens having a wide angle is provided. The imaging device can be provided as an image forming unit having a lens structure that is inexpensive and has a complicated structure.

That is, the number of parts does not increase because the lens structure is simplified. Further, there is no increase in manufacturing cost due to an increase in the number of parts, and in consideration of dimensional variations due to stacking of component tolerances from the manufacturing side, it becomes easy to ensure lens holding accuracy, and an inexpensive zoom lens is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of distortion of a captured image of a subject.

FIG. 3 is a diagram showing an example of a zoom position detection for detecting a distortion amount according to the present invention.

FIG. 4 is a diagram showing an example of reading out a video signal of a distortion section of the present invention.

FIG. 5 is a diagram showing an example of a configuration of a distortion correction unit of the present invention.

FIG. 6 is a diagram showing another example of distortion of a captured image of a subject.

FIG. 7 is a schematic configuration diagram showing another example of correcting horizontal distortion.

FIG. 8 is a schematic configuration diagram showing an example of correcting horizontal and vertical distortions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Imaging means, 2 ... Sensor, 3,31 ... Storage means, 4 ... Zoom position detector, 5 ... Detection means, 6, 28, 31 ... Correction part, 7, 29, 32 ... Control part, 13 ... Variator lens group, 14 holding frame, 15 ... Guide rod, 16 ... Cam follower, 17 ... Cam ring, 18 ... Fixed cylinder, 20 ... Extraction circuit, 21 ... Memory, 22 ... Arithmetic processing circuit, 27 ... Signal reading circuit.

Claims (5)

[Claims] 1. An image forming means for optically forming an image of light from a subject, and an optical image obtained by the image forming means is converted into electrical information or physical scientific information and output or recorded as a photographed image. In a photographing device including a photographing means,
An image pickup apparatus comprising: a correction unit that corrects a distortion of a captured image of a subject caused by an image forming unit. 2. An image pickup apparatus according to claim 1, wherein said image forming means has a zoom lens capable of shooting a wider angle of view. 3. The correction means for correcting the distortion of the photographed image according to claim 1, further comprising: a storage section for reading and storing the photographed image; a detecting means for detecting a zoom position in the image forming means; A distortion correction unit that sets a distortion correction amount based on the zoom position detected by the detection unit and corrects the distortion of the captured image, and a control unit that reads out and controls the image whose distortion is corrected by the distortion correction unit. An image pickup apparatus having: 4. The correction means for correcting the distortion of the photographed image according to claim 1, comprising a correction means for correcting the image distortion in the horizontal direction and a correction means for correcting the image distortion in the horizontal direction. Shooting device. 5. The photographing apparatus according to claim 1, wherein the correcting means for correcting the distortion of the photographed image is a correcting means for correcting the distortion of the photographed image with a minimum distortion portion as a reference.