JPH08163428A - Image pickup device - Google Patents

Abstract

PURPOSE: To automatically realize swing and tilt correction by means of image processing by calculating a graphic correction amount based on contour information detected by a contour detection means and converting a stored object image into a regular image based on the calculated graphic correction amount. CONSTITUTION: The image pickup device is provided with an image memory 5 storing at least tentatively information of a picked-up object image, an edge detection circuit 6 detecting a contour of the object image stored tentatively, a correction amount calculation means calculating graphic correction amount based on the detected contour information and an image conversion means converting the object image stored in the image memory 5 into a regular image based on the calculated graphic correction amount. Then the edge detection circuit 6 expresses a degree of distortion of each point by a gradient of a straight line and a y-intercept where Y axis is taken in the direction of a vertical line, fixes an x-intercept of the X axis orthogonal to the Y axis and calculates a change in the X coordinate when the y-intercept is set to an infinitive to obtain the graphic correction amount, by which the image is converted. Thus, it is not required for a photographer to make various operations while observing an image of an object and the image pickup with swing and tilt processing is automatically executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly, to an image pickup apparatus in which a function of a conventional lens optical system can be electronically realized by internally providing an image processing function of coordinate conversion. Is.

[0002]

2. Description of the Related Art Conventionally, when performing tilting photography, a lens optical system capable of tilting operation and a tilting (shift) for replacement.
Although the tilting (shifting) effect has been obtained by operating an optical system such as a lens, an imaging apparatus having an image processing function has been proposed with the recent progress of electronic technology.

That is, as shown in FIG. 2, a tall building B
When the camera B is photographed by the camera C, the photographed building B ′ is trapezoidal as shown in FIG. When this distortion is corrected, the outline of the building B ″ becomes a rectangle as shown in FIG.

[0004]

However, in the above-mentioned conventional example, when the optical shift is performed by operating the optical system, a special lens is required, and it is generally large, heavy and expensive, and there is a drawback particularly in operability. .
Image processing (coordinate conversion) to solve these problems
It has been proposed that the function be built in and the tilt (shift) function be performed electronically. However, in the concrete shift operation, it is necessary to manually adjust while looking at an electronic viewfinder (EVF) having a very small screen, and it is difficult to perform accurate adjustment.

It is an object of the present invention to provide an image pickup apparatus capable of automatically performing tilt correction by image processing.

[0006]

According to a first aspect of the present invention, there is provided a storage means for at least temporarily storing information on a photographed subject image, and the storage means. Contour detecting means for detecting the contour of the subject image temporarily stored in the image, correction amount calculating means for calculating the figure correction amount from the contour information detected by the contour detecting means, and figure correction amount calculated by the correction amount calculating means And an image conversion unit that converts the subject image stored in the storage unit into a regular image based on the above.

With this arrangement, the contour detecting means for detecting the distortion of the vertical line in the lens system detects the contour of the subject image.
The degree of distortion at each point is represented by a straight line inclination and a y-connecting piece when the vertical line direction is the y-axis, and x of the x-axis orthogonal to the y-axis.
The image is converted with the figure correction amount obtained by fixing the contact piece and calculating the change amount of the x coordinate when the y contact piece is set to infinity.

Therefore, the photographer does not need to perform various operations while looking at the subject image, and tilt shooting is automatically performed.

In the above arrangement, the image conversion means can select whether or not to photograph a figure by outputting the information that the figure is not corrected when the figure is not corrected.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an electric circuit according to an embodiment of the present invention.
In the figure, reference numeral 1 is an optical system for forming a subject image on the surface of an image pickup element, which will be described later, and reference numeral 2 is an image pickup element for converting the subject image obtained by the optical system 1 from light to electric signal. Reference numeral 3 is a signal processing circuit for processing a time-series signal relating to a subject image obtained from the image pickup element 2, and 4 is an A for converting an electric signal (analog) processed by the signal processing circuit 3 into a digital signal. The / D converter 5 is an image memory for storing image information for one screen. Reference numeral 6 denotes an edge detection circuit for detecting the contour of an image. Such image processing can be easily realized by using a known digital arithmetic circuit, and therefore detailed description thereof will be omitted. Reference numeral 7 denotes an image processing circuit for performing image processing conversion for the function of the tilt (shift) lens.

Reference numeral 8 denotes a D / A converter for returning the digital signal which has been image-processed by the image processing circuit 7 to an analog signal again, and 9 denotes the D / A converted analog signal to a standard video signal 10 such as NTSC. It is an encoder circuit for fixing. Reference numeral 11 is an electronic viewfinder (EVF) for confirming a photographing screen. Reference numeral 12 is a system controller for checking the operating state of an operating member, which will be described later, and controlling each element accordingly, which can be easily realized by using a general-purpose microprocessor. Reference numeral 13 is an operation member for selecting whether to activate (ON) or not (OFF) the tilt (shift) function. 1
Reference numeral 4 denotes an operation member for selecting whether the tilt (shift) function is adopted (ON) or not adopted (OFF).

The above is the configuration of the electric circuit of one embodiment of the present invention shown in FIG. 1, and its operation will be described below.

FIG. 5 is a flow chart for explaining the operation of the embodiment of the present invention in which the electric circuit is shown in FIG. First, when the power switch of the apparatus of this embodiment is turned on, an image is input by the image pickup optical system 1 (step 101). After that, the formed image of the subject is converted from light to electric signal by the image sensor 2 (step 102), and is converted into a time-series signal related to the subject image by the signal processing circuit 3 (step 10).
3).

Here, the system controller 12 is a first switch 13 which is a tilt (shift) preparation function selecting member.
The state of (SW1) is checked to determine whether or not the tilt (shift) preparation function is ON (step 1
04). If the first switch 13 is turned on in step 104, the time-series analog signal relating to the subject image is converted into a digital signal by the A / D converter 4 (step 105), and information for one screen is temporarily stored in the image memory 5. (Step 106). During this time, the edge detection circuit 6 emphasizes and detects the edge portion of the subject image (step 107).

That is, the work of extracting the edge portion of the building from the subject image as shown in FIG. 6 is performed as shown in FIG. Next, the image processing circuit 7 converts the coordinates of all points on the screen. This coordinate conversion operation will be described based on the flowcharts shown in FIGS.

First, the coordinates of the vertical convergence point b _n are calculated from the detected edge portion (trapezoid ABCD in FIG. 8).

Further, the object for tilt (shift) correction is shown in FIG.
If a plurality of diagonal lines are present as shown in FIG. 10, it is possible to find the vertical convergence point b _n as shown in FIG. 10, but in order to find b _n more accurately, Two diagonal lines that are distant from each other or two diagonal lines that are long in the vertical direction are preferentially selected.

Next, a vertical line passing through the vertical convergence point b _n is defined by y
Axis, the bottom horizontal line of the screen is assumed to be the x-axis (step 20)
1). Then, from an expression of a straight line l _n passing through a vertical convergence point b _n (0, b _n ) with respect to an arbitrary point E _n ( _pn , q _n ) on the screen, a point F [b _n · p _n / (b _n -
q _n ), 0] is calculated (step 202). Then x
When the point F which is the intercept is fixed and the vertical convergence point b _n which is the y intercept is moved by the predetermined movement amount α, that is, when b _{n + 1} = b _n + α (step 20)
3), the formula of the straight line l _{n + 1} and the point E _{n + 1} (p _{n + 1} , q _{n + 1} = q _n ) after the coordinate conversion because the coordinate conversion in the y direction is not performed.
To calculate. Here, p _{n + 1} = [(b _{n + 1} −q _n ) / (b
_n -q _n)] · [b _n / b _{n + 1]} is - p _n (step 204). Next, make n one (step 20)
5) It is determined whether or not the value of the vertical convergence point b _n is sufficiently large (step 206). In step 206, when the vertical convergence point b _n is not sufficiently large, the process returns to step 203 and the coordinate transformation is repeated. If it is determined in step 206 that the vertical-direction convergence point b _n is sufficiently large, the straight line l ∞ connecting the point F and the vertical-direction convergence point b _n is regarded as a vertical line with an inclination ∞, and the final conversion coordinate E ∞.
(P∞, q∞ = q _n ). Where p∞ = b _n q _n
/ A (b _n -q _n), to convert all of the image data stored in the image memory 5. Note that in step 108, as mentioned earlier, this image conversion process is an example of the coordinate conversion used in the description, and in reality, step 202.
Since the final conversion coordinates E ∞ (p ∞, q ∞) can be obtained from, it is possible to shorten the calculation time.

As another example of the coordinate transformation, the processing may be such that the tilt (shift) correction is applied only to the tilt (shift) object (building in this case) and the other portions (background, etc.) are not corrected. . In this case, an image overlaps between the corrected portion and the non-corrected portion, but the corrected portion is prioritized for image processing.

Next, the digital signal after coordinate conversion is D /
Converted to analog signal by A converter (step 10
9) and then converted into a standard video signal by the encoder 9 (step 110). Then, the electronic viewfinder (EVF) 11 displays the result of the tilt (shift) correction.
Is displayed (step 111). After that, the system controller 12 checks the state of the second switch (SW2) 14 which is a tilt (shift) adoption selection member, and
It is determined whether or not the switch (SW2) 14 is ON (step 112).

In step 112, the second switch 1
If 4 indicates ON, the standard video signal 10 subjected to the tilt (shift) correction is guided to the recording device.
If the second switch 14 is not ON, the process returns to step 104. In this case, the state of the input signal to the recording device becomes the prohibited state. In order to avoid this, the following operation is performed.

After executing step 103, the first switch 1
Regardless of whether 3 is ON or OFF, the encoder 9 always performs video signal conversion (step 113). First, since the first switch 13 is ON (step 104Y) and the second switch 14 is not ON (step 112N), the information not subjected to the tilt (shift) correction is guided to the recording device.

In step 104, when it is indicated that the first switch 13 is not ON, the subject image for which the tilt (shift) correction is not performed is the electronic viewfinder (EV).
F) 11 (step 114) and the second switch 14 does not indicate ON, the system controller 12
If it is determined (step 112N), the information not to perform the tilt (shift) correction is guided to the recording device.

If it is determined in step 112 that the second switch 14 is ON, the information to the recording device is closed, so that the first switch 13 and the second switch 14 are like a release button of the camera. Switch members having various subordinate relationships are preferable.

[0025]

According to the first aspect of the present invention, the photographer does not need to perform various operations while looking at the subject image, and the tilt shooting is automatically executed.

According to the second aspect of the present invention, when the figure correction is not executed, it is possible to select whether or not the figure correction photographing is performed by outputting the information indicating that the figure correction is not performed.

According to the third aspect of the present invention, the same effect as the optically tilting or shifting effect can be electronically realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an image pickup apparatus showing an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a camera position and a subject showing the concept of tilt shooting.

FIG. 3 is a diagram showing an image having distortion, which is normally captured in FIG. 2;

FIG. 4 is a diagram showing a state in which the distortion of FIG. 3 is corrected.

5 is a flowchart showing the operation of the embodiment of FIG.

FIG. 6 is a diagram showing the concept of the correction processing of FIG.

7 is a diagram showing a state in which edge detection processing is performed on the image having distortion shown in FIG.

FIG. 8 is a diagram showing the conversion processing of FIG.

FIG. 9 is a diagram showing a concept when there are a plurality of correction targets.

FIG. 10 is a diagram showing the edge detection processing of the correction target of FIG. 9;

11 is a flowchart showing the coordinate conversion process of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical system 2 ... Image sensor 3 ... Signal processing circuit 4 ... A / D converter 5 ... Image memory 6 ... Edge detection circuit 7 ... Image processing circuit 8 ... D / A converter 9 ... Encoder 10 ... Standard video signal 11 ... Electronic Viewfinder 12 ... System controller 13, 14 ... Aori switch

Claims (3)

[Claims] 1. A storage unit for at least temporarily storing information on a photographed subject image, a contour detection unit for detecting a contour of the subject image temporarily stored in the storage unit, and a contour detection unit for detecting the contour. And a correction amount calculation unit for calculating a figure correction amount from the contour information, and an image conversion unit for converting the subject image stored in the storage unit into a regular image based on the figure correction amount calculated by the correction amount calculation unit. Image pickup device. 2. The image pickup apparatus according to claim 1, wherein the image conversion means outputs information indicating that the figure correction is not performed when the figure correction is not executed. 3. The image pickup device according to claim 1, wherein the figure correction corresponds to an optical tilt or shift effect.