JP2020162005A - Image acquisition device and image acquisition method - Google Patents

Abstract

To take clear pictures of subjects with various shapes without causing saturation.SOLUTION: The image acquisition device includes: a photographing unit 1 for acquiring an image of a subject W moving in a predetermined direction (arrow M direction); an illumination unit 2 for irradiating the subject W with light rays from a direction different from an optical axis 1A of the photographing unit 1; and a shape measuring unit 3 for measuring the shape of the subject W. In the illumination unit 2, each point where the optical axis 1A of light sources 2A, 2B, 2C... for irradiating the subject W with light ray K and the optical axis 1A of the photographing unit 1 intersects is set at a different position along a direction (arrow 1a direction) of the optical axis 1A of the photographing unit 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image acquisition device and an image acquisition method capable of acquiring a high-quality image having a high SN ratio (Signal-Noise Ratio) by performing illumination lighting control according to an object shape.

In a photographing device that acquires an image of an object moving at high speed (for example, 1 m / sec to 4 m / sec), it is necessary to shorten the shutter speed of the camera in order to suppress image blurring due to the movement of the object.
Under such shooting conditions with a short shutter speed, it is inevitable that the exposure time of the image sensor of the above-mentioned shooting device will be short, and a moving object may be illuminated with high brightness in order to obtain an image having a high SN ratio. is there.

For example, in the scanning apparatus shown in Patent Document 1, a translucent table on which a subject can be placed, first and second lighting means for projecting light from below the translucent table toward the subject on the table, and the like. A scanning reading means for scanning and reading the concave shape of a subject illuminated by these lighting means is provided.
Further, in this scanning device, when photographing a concave-shaped portion of a subject, scanning reading is performed by the scanning head of the scanning reading means while turning on or off the first lighting means and turning on the second lighting means. Do.
Further, in this scanning device, when photographing a normal flat object, the second lighting means is turned off, the first lighting means is turned on, and scanning reading is performed by the scanning head of the scanning reading means.

Japanese Unexamined Patent Publication No. 2004-177698

In the scanning apparatus shown in Patent Document 1, the lighting / extinguishing of the first and second lighting means is switched according to the situation of the subject.
However, in the scanning device of Patent Document 1, since the first and second lighting means are installed at positions that are substantially equidistant to the subject in the optical axis direction, if the subject is inclined, it is excessive. There is a problem that the specular reflection component returns and causes saturation in the case of lighting.

The present invention has been made in view of the above circumstances, and provides an image acquisition device and an image acquisition method capable of taking a clear image of a subject having various shapes without causing saturation.

In order to solve the above problems, the present invention proposes the following means.
In the image acquisition device shown in the first aspect of the present invention, an imaging unit that acquires an image of a subject moving in a predetermined direction and an illumination unit that irradiates the subject with light from a direction different from the optical axis of the imaging unit. The illumination unit has a plurality of light sources that irradiate light rays toward the subject, and each point where the optical axis of each of these light sources intersects with the optical axis of the photographing unit is the photographing unit. It is characterized in that it is set at different positions along the direction of the optical axis of.

In the image acquisition method shown in the second aspect of the present invention, an irradiation step of irradiating a subject moving in a predetermined direction with a light beam and a shooting step of irradiating the subject irradiated with the light beam with a photographing unit are performed. In the irradiation stage, the points where the optical axes of the plurality of light sources that irradiate the subject with light rays intersect with the optical axes of the photographing unit are set at different positions in the direction of the optical axes of the photographing unit. It is characterized by doing.

According to the present invention, when shooting a subject moving at high speed, it is possible to shoot with good image quality while suppressing saturation.

It is a schematic block diagram of the image acquisition apparatus which concerns on this invention. It is a schematic block diagram of the image acquisition apparatus which concerns on embodiment of this invention, (A) is a front view, (B) is a plan view. 2 is a schematic configuration diagram including an optical control unit of the image acquisition device shown in FIG. 2, where FIG. 2A is a front view and FIG. 2B is a plan view. It is a flowchart which shows the control content of an image acquisition apparatus. It is explanatory drawing which shows the lighting control of the light source which explains the control content in FIG. It is a schematic block diagram of the image acquisition apparatus which concerns on modification 1 of embodiment, (A) is a front view, (B) is a plan view. It is a schematic block diagram of the image acquisition apparatus which concerns on modification 2 of embodiment, (A) is a front view, (B) is a plan view.

The image acquisition device 100 according to the present invention will be described with reference to FIG.
The image acquisition device 100 has a photographing unit 1 and an illumination unit 2.
The photographing unit 1 continuously photographs an image of the subject W moving in a predetermined direction (direction of arrow M) at a constant speed.
The illumination unit 2 irradiates the subject W with light rays from a direction different from that of the optical axis 1A of the photographing unit 1.

Further, the irradiation position of the illumination unit 2 is set so that the distance (d1 to d3) from the subject W along the optical axis direction (arrow 1a direction) of the photographing unit 1 is different, and the light beam K is directed toward the subject W. It has a plurality of light sources 2A, 2B, 2C ... For irradiating (K1 to K6).
Specifically, in the illumination unit 2, each point where the optical axes of the light sources 2A, 2B, 2C ... That irradiate the subject W with the light beam K intersect with the optical axis 1A of the photographing unit 1 is the photographing unit. It is set at different positions along the direction of the optical axis 1A of 1 (direction of arrow 1a).
In the lighting unit 2, for example, the lighting of these light sources 2A, 2B, 2C ... Can be manually operated based on the shape of the subject W measured by the shape measuring unit 3 located upstream of the photographing unit 1, and separately. The built-in light control unit 4 can automatically control the irradiation contents such as ON / OFF and the amount of light of these light sources 2A, 2B, 2C ... Based on the shape of the subject W measured by the shape measurement unit 3.

According to the image acquisition device 100 configured as described above, the irradiation positions are set so that the distances (d1 to d3) to the subject W along the optical axis direction (arrow 1a direction) of the photographing unit 1 are different. The light sources 2A, 2B, 2C ... Can be controlled based on the shape of the subject W measured by the shape measuring unit 3.
For example, in the illumination unit 2, a plurality of light sources 2A, 2B, 2C ... Can be partially turned off and the amount of light can be adjusted based on the shape of the subject W measured by the shape measurement unit 3. It is possible to take a clear image of the subject W having a shape without causing saturation.

(Embodiment)
The image acquisition device 101 according to the embodiment of the present invention will be described with reference to FIGS. 2 to 5.

As shown in FIG. 2, the image acquisition device 101 includes a photographing unit 11, an illumination unit 12, and a shape measuring unit 13 (described later) as main components.
The photographing unit 11 continuously photographs an image of the subject W moving in a predetermined direction (direction of arrow M1) at a constant speed by the conveying device 10.
In the photographing unit 11, a line sensor or the like that scans along a plane direction (arrow M2 direction) orthogonal to the arrow M1 direction, which is the transport direction of the subject W, is used.
Then, with this line sensor, as the subject W moves, identification information such as characters and barcodes attached to the upper surface of the subject W can be read as an image.
Further, the photographing unit 11 is installed so that the photographing lens 14 is directed downward and the optical axis 11A of the photographing lens 14 is vertical to the transport path of the transport device 10.

The illumination unit 12 irradiates the subject W with light from a plurality of directions different from the optical axis 11A of the photographing unit 11.
Specifically, the illumination unit 12 has a distance (d4, d5) from the subject W along the optical axis direction (arrow a11 direction) of the photographing unit 11 as shown in FIGS. 2 (A) and 3 (A). It has light sources 20R / 20L and 21R / 21L whose irradiation positions are set so as to be different from each other, and an optical control unit 15 for controlling these light sources 20R / 20L and 21R / 21L.
With such a configuration, the optical axis 11A of the photographing unit 11, that is, the axis imaged by the line sensor and the points where the optical axes K11 to 14 of the respective illuminations of the illumination unit 12 intersect (that is, the irradiation position). However, the positions are different in the direction of the optical axis 11A of the photographing unit 11.

In these light sources, the light source 20R / 20L is located at the same height (indicated by reference numeral d4) in the lower stage near the subject W, and the light source 21R / 21L is located in the upper stage above the light source 20R / 20L and away from the subject W. Are located at the same height (indicated by reference numeral d5).
The light sources 20R and 21R are located on the right side of the figure, which is downstream of the optical axis 11A of the photographing unit 11, and the light sources 20L and 21L are located on the left side of the figure, which is upstream of the optical axis 11A of the photographing unit 11. However, they are located so as to be symmetrical with respect to the optical axis 11A.

As shown in FIG. 3A, the shape measuring unit 13 is a sensor for measuring the shape of the subject W on the upstream side of the photographing unit 11 and the lighting unit 12 along the transport path of the transport device 10. The shape data such as whether the subject W has a flat shape, has a constant height, and the upper surface is inclined in which direction is acquired. The shape data of the subject W measured by the shape measuring unit 13 is supplied to the light control unit 15 of the lighting unit 12.
The shape measuring unit 13 is provided on both sides of the transport path of the transport device 10, and the shape of the subject W is grasped by blocking the light at a specific location by the subject W in addition to the image sensor. Sensors etc. are used.

Then, the light control unit 15 of the illumination unit 12 turns on / off the light sources 20R / 20L and 21R / 21L based on the shape data of the subject W output from the shape measurement unit 13 as shown in FIG. 3 (B). , Control the irradiation content such as adjusting the amount of light.
For example, in the optical control unit 15, as shown in FIG. 3A, more light rays (indicated by reference numeral P) than necessary for the subject W having a thickness and inclination equal to or greater than a predetermined value enter the photographing unit 11. In order to prevent the resulting saturation, control such as selectively turning off the specific light sources 20R / 20L and 21R / 21L or adjusting the amount of light is performed.
In this example, in the optical control unit 15, as shown in FIG. 3A, the reflected light from the subject W becomes a specular reflection component that coincides with the optical axis 11A of the photographing unit 11, and more light rays P than necessary are generated. In order to prevent saturation caused by entering the photographing unit 11, the lower light source 20R / 20L and the upper left light source 21L can be turned off, and only the upper right light source 21R can be turned on.

Next, the control content of the entire image acquisition device 101 including the control content of the light control unit 15 of the lighting unit 12 will be specifically described with reference to FIGS. 4 and 5.
The trigger input (1) shown in the flowchart below is a signal indicating that the subject W has entered the measurement area of the shape measuring unit 13, and the trigger input (2) is the trigger input (2) in which the subject W has entered the measurement area of the shape measuring unit 13. It is a signal indicating that it came out from. Further, the trigger input (3) is a signal indicating that the subject W has entered the shooting area of the shooting unit 11, and the trigger input (4) is a signal indicating that the subject W has exited the shooting area of the shooting unit 11. is there.

[Step S1]
First, as shown in FIGS. 2 and 3, when the transport of the subject W to the shape measuring unit 13 is started, the process proceeds to step S2 below.

[Step S2]
When the trigger input (1) indicating that the subject W has entered the measurement area of the shape measuring unit 13 is received, the shape measuring unit 13 is made to start the shape measurement of the subject W.

[Step S3]
When the trigger input (2) indicating that the subject W has exited the measurement area of the shape measuring unit 13 is received, the shape measuring unit 13 ends the shape measurement of the subject W.

[Step S4] to [Step S5]
The shape data of the subject W measured by the shape measuring unit 13 is taken in (step S4), and the shape data is analyzed (step S5).

[Step S6]
It is determined whether or not the height of the subject W is equal to or higher than a predetermined value, and if NO, the process proceeds to step S7, and if YES, the process proceeds to step S11.

[Step S7]
For a thin subject W that does not have a height higher than the default value, it is determined whether or not the inclination of the upper surface is equal to or higher than a predetermined default value (+ A degree, -A degree), and "plane + A degree or higher". If it is, the process proceeds to step S8, if it is “less than the plane ± A degree”, it proceeds to the step S9, and if it is “the plane −A degree or more”, it proceeds to the step S10.
As shown in FIG. 5, the angle here indicates how many times the upper surface of the subject W viewed from the front is tilted with respect to the plane, and the tilt of the upper surface of the subject W in the clockwise direction is "+ A". The degree is defined as "degree", and the inclination of the upper surface of the subject W in the counterclockwise direction is defined as "-A degree".

[Step S8]
As shown in S8 of FIG. 5, an optical control signal for turning off the upper light source 21R / 21L and the lower right light source 20R and turning on only the lower left light source 20L is output to the illumination unit 12.
[Step S9]
As shown in S9 of FIG. 5, an optical control signal for turning off the upper light source 21R / 21L and turning on the lower light source 20R / 20L by 50% is output to the illumination unit 12. Note that 50% lighting is an example, and the setting can be changed as appropriate.
[Step S10]
As shown in S10 of FIG. 5, an optical control signal for turning off the upper light source 21R / 21L and the lower left light source 20L and turning on only the lower right light source 20R is output to the illumination unit 12.

[Step S11]
For the subject W having a height equal to or higher than the default value, it is determined whether or not the inclination of the upper surface is equal to or higher than a predetermined default value (+ A degree, −A degree), and when it is “plane + A degree or higher”. The process proceeds to step S12, and when the value is "less than the plane ± A degree", the process proceeds to step S13, and when the value is "more than the plane −A degree", the process proceeds to step S14.

[Step S12]
As shown in S12 of FIG. 5, an optical control signal for turning off the lower light source 20R / 20L and the upper right light source 21R and turning on only the upper left light source 21L is output to the illumination unit 12.
[Step S13]
As shown in S13 of FIG. 5, an optical control signal for turning off the lower light source 20R / 20L and turning on the upper light source 21R / 21L by 50% is output to the illumination unit 12. Note that 50% lighting is an example, and the setting can be changed as appropriate.
[Step S14]
As shown in S14 of FIG. 5, an optical control signal for turning off the lower light source 20R / 20L and the upper left light source 21L and turning on only the upper right light source 21R is output to the illumination unit 12.

[Step S15]
When the trigger input (3) indicating that the subject W has entered the shooting area of the shooting unit 11 is received, the lighting unit 12 uses the light source based on the irradiation contents determined in steps 8 to 10 and 12 to 14. Lighting control of 20R / 20L and 21R / 21L is performed.

[Step S16]
Have the photographing unit 11 photograph the subject W.
[Step S17]
When the trigger input (4) indicating that the subject W has come out from the shooting area of the shooting unit 11 is received, the shooting of the subject W by the shooting unit 11 ends.
[Step S18]
This flowchart ends after all the light sources 20R / 20L and 21R / 21L in the lighting unit 12 are turned off as the shooting is completed.

According to the image acquisition device 101 configured as described above, the plurality of light sources 20R provided so as to have different distances (d4, d5) from the subject W along the optical axis direction (arrow a11 direction) of the photographing unit 11. The / 20L and 21R / 21L are controlled based on the shape of the subject W measured by the shape measuring unit 13.
For example, the light control unit 15 of the illumination unit 12 selectively turns ON / OFF and adjusts the amount of light of a plurality of light sources 20R / 20L and 21R / 21L based on the shape of the subject W measured by the shape measurement unit 13. This makes it possible to take a clear image of a subject W having various shapes without causing saturation.

(Modification example 1)
In the image acquisition device 101 of the above embodiment, each pair of light sources 20R / 20L and light sources 21R / 21L are positioned at the same height (d4, d5) from the subject W.
However, the present invention is not limited to this, and in the image acquisition device 102 of the first modification, as shown in FIG. 6, each of these light sources 20R, 20L, 21R and 21L is asymmetric with respect to the optical axis 11A of the photographing unit 11. Moreover, the height may be changed step by step so that the subject W may be irradiated with light to have variations.

(Modification 2)
In the image acquisition device 101 of the above embodiment, two pairs of light sources 20R / 20L and light sources 21R / 21L are provided.
However, the present invention is not limited to this, and in the image acquisition device 103 of the second modification, the left and right lighting and the amount of light may be controlled for the light sources 20R / 20L provided as only one pair as shown in FIG. Left and right ON / OFF control and light intensity control may be performed for a large number of pairs of light sources provided in pairs or more.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within a range not deviating from the gist of the present invention are also included.

The present invention relates to an image acquisition device and an image acquisition method capable of acquiring a high-quality image having a high SN ratio by performing illumination lighting control according to an object shape.

1 Imaging unit 1A Optical axis 2 Illumination unit 2A Light source 2B Light source 2C Light source 3 Shape measurement unit 4 Optical control unit 10 Conveyor device 11 Imaging unit 11A Optical axis 12 Lighting unit 13 Shape measurement unit 14 Photographic lens 15 Light control unit 20R Light source 20L Light source 21R light source 21L light source 100 image acquisition device 101 image acquisition device 102 image acquisition device 103 image acquisition device

Claims (7)

A shooting unit that acquires an image of a subject moving in a predetermined direction,
It has an illumination unit that illuminates the subject from a direction different from the optical axis of the photographing unit.
The illumination unit has a plurality of light sources that irradiate light rays toward the subject, and each point where the optical axis of each of these light sources intersects with the optical axis of the imaging unit is the direction of the optical axis of the imaging unit. An image acquisition device characterized in that it is set at different positions along the optical axis. The plurality of light sources constituting the illumination unit irradiate light rays from both sides of the optical axis of the imaging unit toward the subject on the transport path.
The first aspect of claim 1, wherein each point where the optical axis of the photographing unit and the optical axis of each light source intersect is set at different positions stepwise along the direction of the optical axis of the photographing unit. Image acquisition device. A shape measuring unit for measuring the shape of the subject is provided on the upstream side of the photographing unit.
The image acquisition device according to any one of claims 1 or 2, wherein the illumination unit has an optical control unit that controls the light source based on the shape of the subject measured by the shape measurement unit. The third aspect of the present invention is characterized in that the light control unit controls the amount of light of a plurality of light sources constituting the lighting unit and the irradiation content such as ON / OFF based on the object shape measured by the shape measurement unit. The image acquisition device described. The light control unit is characterized in that when the height of the surface of the subject measured by the photographing unit is larger than a predetermined value, the light source located on the lower side is controlled to be turned off. The image acquisition device according to 4. The light control unit turns off the light source on either side of the optical axis of the photographing unit when the inclination of the surface of the subject measured by the photographing unit is larger than the predetermined value. The image acquisition device according to any one of claims 4 or 5, characterized in that the image acquisition device is controlled. The irradiation stage of irradiating a subject moving in a predetermined direction with light rays,
It has a shooting stage in which a subject irradiated with the light beam is shot by a shooting unit.
In the irradiation step, the points where the optical axes of the plurality of light sources that irradiate the subject with light rays intersect with the optical axes of the photographing unit are set at different positions in the direction of the optical axes of the photographing unit. An image acquisition method characterized by.

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