JPH11196315A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader capable of photographing an image so as to obtain a more satisfactory overall composite image. SOLUTION: Distance differences D', D" in the depth direction of of an effect part (a part to be used for image composition) of a photographing range T in each of partial areas dividing an area to be photographed are obtained, the number of divided parts is increased until a half of the distance difference is smaller than focal depth to determine the division pattern of the area to be photographed by these partial areas. An image pickup unit having a zoom lens 16 and an image pickup element 18 is inclined so that the center part of the effect part in the photographing range T of each partial area is focused on a photographed surface S and respective partial areas are successively photographed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and more particularly, to an image reading apparatus which divides an object area into a plurality of partial areas and sequentially enlarges the image so that one image of the entire object area can be synthesized later. Related to the device.

[0002]

2. Description of the Related Art Conventionally, a subject area is divided into a plurality of partial areas, and each partial area is enlarged and photographed several times using an image sensor (for example, an area sensor or a line sensor). For example, digital cameras and digital scanners have been proposed as image reading apparatuses that read images. This type of image reading apparatus captures each partial region so that the read images of the respective partial regions are later connected and one image of the entire subject region can be synthesized. Since the image of each partial region is enlarged and photographed by using the entire image sensor as effectively as possible, the resolution is high.
Therefore, this type of image reading apparatus can obtain a high-resolution whole composite image at low cost as compared with a case where the entire subject area is photographed once using the same image sensor.

As a method of photographing each partial region, there is known a method of photographing while fixing the focal position of each partial region (for example, Japanese Patent Application Laid-Open No. Hei 8-26568).

However, in such a method, when a document image is photographed at a short distance, the difference in the photographing distance between the center and the periphery of the screen becomes large due to the movement of the optical axis of the camera. Blurring occurs. Further, when the photographing screen is divided into even numbers such as 4 divisions and 16 divisions, a dividing line is inserted at the center of the photographing screen, so that a positional deviation and a luminance step due to bonding are easily noticeable.

[0005]

SUMMARY OF THE INVENTION Accordingly, a technical problem to be solved by the present invention is to provide a better overall synthesized image in an image reading apparatus which divides the entire subject area into a plurality of partial areas and sequentially enlarges and shoots them. To provide an image reading apparatus for photographing so that images can be combined.

[0006]

In order to solve the above technical problems, the present invention provides an image reading apparatus having the following configuration.

An image reading apparatus according to the present invention is an image reading apparatus that divides the entire subject area into a plurality of partial areas and sequentially takes an image. The image reading apparatus includes an optical system and an image sensor, and faces each of the partial areas. A variable-angle imaging unit capable of capturing an image of each of the partial areas, a scanning drive unit for driving the imaging unit to face each of the partial areas in a predetermined order, the imaging unit, and the scanning drive unit And control means for controlling the operation of (1). The image reading device includes a photographing distance determining unit and a partial area setting unit. The shooting distance setting determines the shooting distance from the camera body to the main subject. The partial area setting means, the effective area of the captured image of each partial area that satisfies the defocus amount within a predetermined range with respect to the imaging surface at the imaging distance, so as to cover the entire imaging area, A division pattern of the object area by each of the partial areas is determined.

In the above configuration, the partial area setting means includes:
An object area division pattern based on the partial area is determined so that the effective area of the captured image of each partial area having a defocus amount within a predetermined range, for example, a range smaller than the depth of focus, can cover the entire object area. That is, the number, size, and arrangement of the partial areas, and the position and size of the effective portion in the imaging range of each partial area are determined. The scanning drive unit directs the imaging unit to a predetermined partial area in a predetermined order. The imaging unit forms an image of the subject in the opposing partial area as large as possible on the effective area of the image sensor via the optical system, and photographs each of the partial areas. At this time,
The focus position of the zoom lens is appropriately adjusted such that a captured image of an effective portion of each partial region is obtained according to the division pattern determined by the partial region setting means. A high-definition overall composition in which the entire subject area is in focus is obtained by bonding the effective parts having a defocus amount within a predetermined range among the captured images of the partial areas thus captured according to the division pattern. Images can be combined.

Therefore, it is possible to take a picture so that a better overall synthesized image can be synthesized.

The image reading apparatus having the above-described configuration appropriately sets, ie, switches, the division pattern according to, for example, the photographing distance and the size of the object area. An image reading apparatus having another configuration to be determined is further provided.

An image reading apparatus according to the present invention is an image reading apparatus which divides the entire subject area into a plurality of partial areas and sequentially takes an image, and has an optical system and an image sensor, and faces each of the partial areas. A variable-angle imaging unit capable of capturing an image of each of the partial areas, a scanning drive unit for driving the imaging unit to face each of the partial areas in a predetermined order, the imaging unit, and the scanning drive unit And control means for controlling the operation of (1). The image reading device arranges the first partial area at least in the center of the object area, and arranges at least one second and third partial area on both sides of the partial area of the first part. I do. When the second and third partial areas are photographed, the focus is set on the photographing range that is within the same plane as the focal plane focused on when photographing the first partial area and that is adjacent to the outside of the subject plane. Match.

According to the above structure, at least three partial regions, that is, the first partial region at the center and both sides thereof (both vertically and both sides in the left and right directions, both sides in the oblique direction) The image is divided into the second and third partial areas. The second and third partial areas are the first
It may overlap with a partial area. Of the captured images of the second and third partial areas, the portion adjacent to the captured image of the central first partial area is in focus on the subject surface position in the same manner as the captured image of the first partial area. A clear image can be obtained.
By bonding this part to the captured image of the first partial area, it is possible to synthesize a high-definition whole composite image in which the entire subject area is in focus. In addition, since the photographed image of the first partial area comes at the center of the whole composite image,
A dividing line can be prevented from entering the center of the screen.

Therefore, it is possible to take an image so that a better overall synthesized image can be synthesized.

The image reading apparatus of each of the above configurations of the present invention may be configured such that the image reading apparatus itself synthesizes the entire composite image of the entire subject area from the captured image of each partial area, or The configuration may be such that data of a captured image of each partial area is output, and an apparatus other than the image reading apparatus synthesizes the entire composite image of the entire object area.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital camera according to an embodiment of the present invention shown in FIGS. 1 to 6 will be described below in detail.

As shown in the perspective view of FIG. 1, the digital camera 10 generally includes an imaging unit 20 and a scanning drive unit imitating an eye, a distance sensor 14, and a shooting start button 12, and includes The subject area can be divided into a plurality of partial areas and magnified in order so that one image can be synthesized later.

The imaging unit 20 includes a zoom lens 16
A zoom motor 17 for driving a zoom lens 16;
An image sensor 18 is provided, and is integrally formed in a substantially spherical shape. The zoom lens 16 changes the photographing magnification of the subject image to form an image on the image sensor 18. Zoom lens 1
In 6, the photographing magnification is changed by driving the zoom motor 17, and the focus position is adjusted by the focus motor 19 (see FIG. 5). The imaging magnification has a magnification range in which an image from the entire screen of the object area to the divided screen of each partial area can be formed on the image sensor 18 according to the number of divisions of the object area. For example, when dividing the subject area into nine partial areas of 3 × 3, a magnification range of 3 times is required. The imaging sensor 18 is a CCD area sensor, and converts an optical signal of a subject image into an electric signal.

As shown in the perspective view of FIG. 2, the scanning drive unit includes a U-shaped guide 23, a rotating shaft 21 extending vertically and rotatably supporting a lower portion of the U-shaped guide 23,
A rotating shaft 25 extending in the horizontal direction and rotatably supported above the U-shaped guide 23 and rotatably supporting the imaging unit 20; a motor and an angle sensor respectively coupled to the rotating shafts 21 and 25 22 and 24, and the imaging direction of the imaging unit 20 can be arbitrarily controlled in the X and Y directions by the rotation of the rotation shafts 21 and 25.

The distance sensor 14 is configured similarly to a known multi-point distance measuring mechanism. Specifically, the distance sensor 14 includes an infrared light emitting unit 14a that irradiates a spot light of an infrared laser light.
(See FIG. 5), a deflecting unit that changes the irradiation angle of the spot light, and a light receiving unit that receives the reflected light from the subject. The light receiving unit is a lens and a position sensor 14b (see FIG. 5).
By detecting the reflection position of the spot light, the distance to the subject is measured using the principle of triangulation. The deflection unit can change the irradiation angle of the spot light, and can measure a two-dimensional distance distribution of the subject.

The shooting start button 12 is used for a shooting start operation.

Further, the digital camera 10 is provided with an image display unit and a mode setting unit (not shown) on the back surface of the main body. The image display section is a liquid crystal monitor 34 (see FIG. 5).
, So that a photographed range, that is, a photographed image of a subject area can be displayed. The mode setting unit is for setting a shooting mode.

The digital camera 10 can divide an object region into a plurality of partial regions by deciding a photographing range and composition while watching the liquid crystal monitor 34 on the back of the main body and pressing a photographing start button 12. .

That is, before photographing, the zoom lens 16
Is in a wide (short focal length, that is, wide angle) state, and the entire subject area is displayed on the liquid crystal monitor 34. When the photographing start button 12 is pressed, the distance to the subject is measured by the distance sensor 14, and the pattern of dividing the subject area by the partial area is determined. Then, the zoom lens 16 is in a telephoto (long focal length, ie, telephoto) state, and sequentially scans and shoots each partial area according to the division pattern.

Next, a method of dividing an object area into a plurality of partial areas will be described with reference to FIGS. Here, a simple example of dividing the subject area only in the horizontal direction will be described.

Assuming that the photographing angle of view of the zoom lens 16 of the image pickup unit is "θ", the distance from the zoom lens 16 to the object plane along the photographing optical axis is L, as shown in FIG.
Then, the horizontal length X of the photographing range T of the single area
Is represented by the following equation 1. (Equation 1) X = 2 · L · tan θ As shown in FIG. 3 (II), when photographing an object area in the range of the angle 4θ, the imaging unit is scanned left and right as in the conventional method, In the case where the image is divided into two, and one image of the entire subject area is combined using all of the two captured images, the photographing optical axis is inclined by ± θ from a right angle with respect to the subject surface S. The distance difference D in the depth direction of the photographing range T on a plane perpendicular to the optical axis is expressed by Expression 2. (Equation 2) D = X · sin θ = 2 · L · tan θ · sin θ Assuming that the focus position is adjusted so as to focus on a position obtained by equally dividing the distance difference D, both ends of the photographing range (FIG. The defocus amount d at the center and both ends of the elongated overall synthesized image shown under II) is expressed by Expression 3. (Equation 3) d = D / 2 = L · tan θ · sin θ

When the depth of focus of the image pickup unit 20 is smaller than the defocus amount d, the image is deteriorated due to defocus at both ends of the photographing range. In such a case, the camera 10 of the present embodiment, as shown in FIG.
Increase the number of partial areas, that is, the number of screen divisions. That is, another screen shot is taken at the center of the subject area,
By pasting a part of the left and right images to this image, the distance difference in the depth direction of the shooting range T is reduced. For example, an image obtained by photographing the object surface S from right to left by tilting the imaging unit 20 and sequentially moving 1 → 2 → 3 is shown in FIG.
I) Paste as shown below. At the time of photographing the center of the object region indicated by reference numeral 2, the focus is adjusted to the object surface S,
A distance difference in the depth direction of the photographing range T is prevented from occurring. At the time of photographing both ends indicated by reference numerals 1 and 2, the outer half of each photographed image is set as an effective portion used for image synthesis, and the object surface S is located at a position that equally divides a distance difference in the depth direction with respect to the effective portion. Adjust the focus position as described above.
By doing so, the defocus amount d 'of the effective portion is as shown in Expression 4. (Equation 4) d ′ = d / 2 = L · tan θ · sin θ / 2 That is, by increasing the number of divisions from two to three, the defocus amount is reduced to half of that in the case of two divisions in FIG. Can be. Therefore, it is possible to obtain a clear overall synthesized image that is more focused.

If the depth of focus is still smaller than the defocus amount d ', as shown in FIG. 4 (IV), the number of divisions is further increased and the outer divisions are made smaller. That is, the image of the entire subject area, as indicated by reference numeral 3,
The entire area of the photographed image is used for the central part of the photographed area, and the two sides are combined using the outer quarters of the respective photographed images as indicated by reference numerals 1, 2, 4, and 5. In general,
Assuming that the number of divisions on both sides excluding the center of the screen is 2n and the outer 1 / n portion of the captured image of each partial region is an effective portion, the minimum defocus amount d ″ is as follows. (Equation 5) d ″ = L · tan θ · sin θ / 2n From this, (Equation 6) n = L · tan θ · sin θ / 2d ″ If the depth of focus is known, the value is substituted for d ″ and the equation is obtained. The number of divisions n can be determined from 6. Since the division number n is an integer, the fractional part is rounded up. The number of divisions of the entire photographing area, that is, the total number of times of photographing of the partial area is 2n
(2n + 1) times obtained by adding one shot at the center of the screen. If the depth of focus is small, the number of divisions 2n increases, and the proportion of the effective portion that can be used for image synthesis in the captured image of the partial area decreases.

The amount of defocus of the image pickup unit 20 is univocal depending on the performance of the zoom lens 16, the angle of view (the focal length of the lens), the size of the aperture at the time of shooting, the resolution, ie, the shooting magnification, and the number of pixels of the image sensor. Is determined based on the specification values of the camera 10 determined by the designer and shooting conditions such as the distance to the subject. Therefore, it is possible to determine the division pattern, that is, the number, size, arrangement, and the like of the partial regions, from the photographing conditions such as the distance to the subject.

As described above, the effective portion of the image pickup unit is reduced to 1/2, (1/2) ² =
Instead of reducing the size to 1/4, (1/2) ³ = 1/8, the size of the effective portion that is within the depth of focus when the imaging unit is tilted to the outermost position is obtained, and conversely, the inner portion is determined from the above. May be determined in order to determine the division pattern. Instead of using the outside of each captured image as an effective part for image synthesis, for example, the center of each captured image may be used as an effective part for image synthesis. In this case, the angle at which the imaging unit 20 is swung becomes large, but a bright image at the center of the lens can be used for image synthesis. Further, instead of changing the shooting direction for each shooting, the focus position may be changed without changing the shooting direction, and shooting may be performed while changing the position of the effective portion in the shot image.

In order to facilitate the image synthesis, it is preferable that each partial area is photographed so as to slightly overlap each other.

Next, referring to the block diagram of FIG.
The configuration of the digital camera 10 will be further described.
The digital camera 10 can be roughly classified into an imaging system and a control system.

The imaging system includes an imaging sensor 18 and an A / A converter for converting an analog signal from the imaging sensor 18 into a digital signal.
A D converter 42, an image memory 43 for storing digital data from the A / D converter 42 and storing image data, and reading image data of each partial area from the image memory 43 to read image data of the entire subject area Image synthesizer 44 that synthesizes
And an image processor 46 for performing a correction process on the combined image data, such as illuminance, gradation characteristics, and image distortion, and an output unit 4 that outputs the corrected image data to a recording medium, a display device, or the like.
8 are connected in series.

The control system is connected to the CPU 3 via a data bus.
0, a photographing control unit 32 for controlling the operation of the image sensor 18
And a motor of the scanning drive unit and the angle sensor 22,
24, a zoom motor 17 and a focus motor 19 of the imaging unit 20, an infrared light emitting unit 14a and a position sensor 14b of the distance sensor 14, and a shooting start button 12
An operation unit 34 such as a camera and a mode setting unit, a liquid crystal monitor 36 of an image display unit, and an image processing control unit 40 for controlling image synthesis are interconnected. The CPU 30 is connected to an internal memory 38 for storing data such as lens performance. The image processing control unit 40 includes the image memory 4 of the imaging system.
3. It is connected to an image synthesizer 44 and an image processor 46. The control system includes: imaging control of the imaging unit 20; magnification control of the zoom lens 16 by the zoom motor 17; control of focus position adjustment of the zoom lens 16 by the focus motor 19; scanning control of the scanning drive unit;
Operation control such as detection control, image data processing / synthesis, and start of photographing is performed by the CPU 30.

Next, the operation of the digital camera 10 will be described with reference to the flowchart of FIG.

In step # 12, the scanning drive unit directs the image pickup unit 20 toward the center of the photographing direction, that is, in front of the camera body. In step # 14, the zoom motor 17 is driven to bring the zoom lens 16 into the wide state. . Next, in step # 16, the imaging unit 20 captures the entire subject area, and in step # 18, displays the captured image on the liquid crystal monitor 36 of the image display unit on the back of the camera body. In step # 20, the process waits until the shooting start button 12 is pressed. That is, steps # 16 and # 18 are repeated until the shooting start button 12 is pressed.

When the photographing start button 12 is depressed, the distance to the subject is measured in step # 22, and in step # 24, the number of divisions of the partial area having a defocus amount within a predetermined range is calculated. The division pattern such as the arrangement of the images is determined.

Next, at step # 26, the zoom motor 17 is driven to bring the zoom lens 16 into the telephoto state.
Set the shooting magnification corresponding to the size of the partial area. Next, in step # 28, the scanning drive unit directs the imaging unit 20 in the direction of the partial area to be imaged next, and in step # 30, the focus motor 19 is driven,
To make the effective part of the captured image of each partial area clear,
Adjust the focus position. Then, in step # 32, the imaging unit 20 performs shooting, and the data of the shot image is A / D converted and stored in the image memory 43. In step # 34, scanning of all partial areas,
Steps # 28 to # 32 are repeated until the photographing is completed.

When the photographing of all the partial areas is completed, in step # 36, the stored image data of each partial area is read out, the photographed images are aligned based on the divided pattern, and in step # 38, the photographed images are By pasting, one image of the entire subject area is synthesized. Finally, in Step # 40, after performing image processing such as correction of illuminance and gradation characteristics on the combined image, Step # 42
Output the data signal to the outside.

The present invention is not limited to the above embodiment, but can be implemented in various other modes.

For example, the present invention can be applied to the case where the object area is divided not only in the horizontal direction but also in the vertical direction, that is, when the object area is divided vertically and horizontally.

[Brief description of the drawings]

FIG. 1 is a perspective view of a digital camera according to an embodiment of the present invention.

FIG. 2 is a perspective view of a scanning drive unit of the digital camera in FIG.

FIG. 3 is an explanatory diagram of a photographing operation of the digital camera in FIG. 1;

FIG. 4 is an explanatory view continued from FIG. 3;

FIG. 5 is a block diagram of the digital camera shown in FIG. 1;

FIG. 6 is a flowchart of the operation of the digital camera in FIG. 1;

[Explanation of symbols]

Reference Signs List 10 digital camera (image reading device) 12 shooting start button 14 distance sensor (shooting distance determining means) 14a infrared light emitting unit 14b position sensor 16 zoom lens (optical system) 17 zoom motor 18 image sensor (imaging element) 19 focus motor 20 imaging Unit 21 Rotation axis 22 Motor and angle sensor 23 U-shaped guide 24 Motor and angle sensor 25 Rotation axis 30 CPU (control means, photographing distance determining means, partial area setting means) 32 Imaging control unit (control means) 34 Operating unit 36 LCD monitor 38 Internal memory 40 Image processing controller 42 A / D converter 43 Image memory 44 Image synthesizer 46 Image processor 48 Output unit L Distance S Subject plane T Shooting range X Length θ Shooting angle of view

Claims (2)

[Claims] 1. An image reading apparatus for dividing an entire subject area into a plurality of partial areas and sequentially photographing the plurality of partial areas, comprising: an optical system and an image sensor; A variable-angle imaging unit capable of photographing each image, a scanning drive unit for driving the imaging unit to face each of the partial areas in a predetermined order, and control for controlling operations of the imaging unit and the scanning drive unit Means for determining a shooting distance from a camera body to a main subject, and a defocus amount within a predetermined range with respect to a subject surface at the shooting distance. In order to cover the entire subject area by the effective part of the captured image of each partial area,
An image reading apparatus, comprising: a partial area setting unit that determines a division pattern of the object area by each of the partial areas. 2. An image reading apparatus for dividing an entire subject area into a plurality of partial areas and sequentially photographing the plurality of partial areas, comprising: an optical system and an image sensor; A variable-angle imaging unit capable of photographing each image, a scanning drive unit for driving the imaging unit to face each of the partial areas in a predetermined order, and control for controlling operations of the imaging unit and the scanning drive unit Means, wherein the first partial area is disposed at least in the center of the object area, and at least one second and third second area are provided on both sides of the partial area of the first part. The partial area is arranged, and when the second and third partial areas are photographed, the first
An image reading apparatus which focuses on an imaging range which is in the same plane as the focused object plane and which is adjacent to the outside of the object plane when the partial area is photographed.