JP2018157487A - Image recognition system and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recognition system and a lighting device capable of improving accuracy of image recognition with a simple system configuration.SOLUTION: An image recognition system includes a camera 3, an image processing section 4 for detecting a prescribed detection object 2 from a captured image of the camera 3, and a lighting device 5 for irradiating the imaging region of the camera 3. The lighting device 5 includes an illumination part 51 having more than two light sources 511, and an illumination control part 52 for controlling the number of the light sources 511 to be lighted and the optical intensity. The illumination control part 52 is setting the number of the light sources 511 to be lighted and the optical intensity as lighting condition, for every distance range of the illumination part 51 and the detection object 2, and when the lighting condition in the initial state is the lighting condition corresponding to the distance range farthest from the illumination part 51, the detection object 2 is not detected under current lighting condition, and a high luminance area higher than a prescribed luminance exists in a captured image, switches to lighting condition corresponding to a distance range closer to the illumination part 51 by one stage than current distance range.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image recognition system and an illumination device.

  Conventionally, an image recognition system that recognizes a gesture using a captured image of a camera is known. As such an image recognition system, there is one having an illumination device that irradiates an imaging region of a camera. An illumination device that emits infrared light or visible light is used.

JP2013-97511A JP 2010-66221 A

  By the way, when the illumination distribution (illuminance distribution) is non-uniform in the imaging range, it may be difficult to detect a detection target such as a finger. Also, if the lighting conditions (light intensity and number of lights) of the lighting device are constant, the detection target is detected because the detection target becomes too bright or too dark depending on the distance between the lighting device and the detection target. In some cases, sufficient image recognition accuracy cannot be obtained.

  In Patent Documents 1 and 2, it is proposed that a means for detecting the distance to the detection object is provided, and that the light quantity balance of the light source and the number of light sources to be turned on in the illumination device are changed according to the distance to the detection object. . However, in this case, since a means for detecting the distance to the detection target is indispensable, the system configuration may be complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image recognition system and a lighting device that can improve the accuracy of image recognition with a simple system configuration.

  In order to solve the above-described problems, the present invention provides an imaging device, an image processing unit that detects a predetermined detection object from a captured image of the imaging device, and an illumination device that irradiates an imaging region of the imaging device. The illumination device includes an illumination unit having three or more light sources, an illumination control unit that controls the number of the light sources to be turned on, and the light intensity emitted by the light sources, and the illumination In the control unit, the number of light sources to be turned on and the light intensity are set as illumination conditions for each distance range between the illumination unit and the detection target, and the illumination condition in the initial state is the farthest from the illumination unit. If the detection object is not detected under the current illumination condition and a high-luminance area larger than a predetermined luminance exists in the captured image, one level from the present Distance range close to the lighting unit Switching the lighting condition corresponding to, to provide an image recognition system.

  Further, the present invention is used in an image recognition system including an imaging device and an image processing unit that detects a predetermined detection target object from a captured image of the imaging device for the purpose of solving the above problems. An illumination device that illuminates an imaging region of the imaging device, the illumination unit having three or more light sources, the number of the light sources to be turned on according to the distance between the illumination unit and the detection target, An illumination control unit that controls the light intensity emitted by the light source, and the illumination control unit includes a number of light sources to be turned on and a light intensity for each distance range between the illumination unit and the detection target. It is set as an illumination condition, and the illumination condition in the initial state is an illumination condition corresponding to the farthest distance range from the illumination unit, the detection target is not detected under the current illumination condition, and the captured image is displayed. Greater than predetermined brightness If the luminance area exists, it switches the lighting condition corresponding to the near distance range in one step the illumination unit than the current, to provide an illumination device.

  According to the present invention, it is possible to provide an image recognition system and an illumination device that can improve the accuracy of image recognition with a simple system configuration.

It is a figure which shows the image recognition system which concerns on one embodiment of this invention, (a) is a figure explaining arrangement | positioning of a camera and an illumination part, (b) is a schematic block diagram. In the image recognition system of FIG. 1, it is a figure explaining arrangement | positioning of a light source, and illumination conditions. (A) is a diagram showing the illuminance distribution at the distance Dmin when the third illumination condition is set, (b) is a diagram showing the illuminance distribution at the distance D2 when set at the second illumination condition, and (c) is the first illumination. It is a figure which shows the illumination intensity distribution in the distance D1 when it is set as conditions. It is a flowchart which shows the control flow of the image recognition system of FIG.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(Overall configuration of image recognition system)
1A and 1B are diagrams illustrating an image recognition system according to the present embodiment, in which FIG. 1A is a diagram illustrating the arrangement of a camera and an illumination unit, and FIG. 1B is a schematic configuration diagram.

  As shown in FIGS. 1A and 1B, an image recognition system 1 includes a camera 3 as an imaging device, an image processing unit 4 that detects a predetermined detection object 2 from a captured image of the camera 3, and a camera. And an illuminating device 5 that irradiates the imaging region 7.

  The image recognition system 1 is electrically connected to an electronic device mounted on a vehicle, for example. The image recognition system 1 determines a gesture from a captured image of the camera 3 and outputs a gesture signal corresponding to the determined gesture to an electronic device. In the electronic device, an operation corresponding to the gesture is executed. That is, the image recognition system 1 is used as an input device for operating an electronic device by a gesture, for example.

  The camera 3 is attached to the mounting portion 6 and images in a substantially horizontal direction. The camera 3 includes a semiconductor image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor). A captured image of the camera 3 is output to the image processing unit 4.

  The image processing unit 4 detects a predetermined detection object 2 such as a finger by a known method such as pattern matching on the basis of a captured image of the camera 3 and determines a gesture. The image processing unit 4 outputs a gesture signal corresponding to the determined gesture to the electronic device.

  In the present embodiment, the image processing unit 4 determines whether a high-luminance area larger than a predetermined luminance exists in the captured image of the camera 3. For example, the image processing unit 4 extracts an area larger than a predetermined luminance in the captured image, and determines that a high-luminance area exists when the number of pixels in the area is equal to or larger than a preset threshold value. The image processing unit 4 outputs the presence / absence of detection of the detection target 2 and the presence / absence of a high-luminance area to the illumination control unit 52 (described later) as a detection presence / absence signal.

  The image processing unit 4 is mounted on the control unit 8. The control unit 8 includes, for example, a CPU (Central Processing Unit) that performs operations and processes on acquired data according to a stored program, a RAM (Random Access Memory) that is a semiconductor memory, a ROM (Read Only Memory), and the like. Microcomputer. In this ROM, for example, a program for operating the control unit 8 is stored. The RAM is used as a storage area for storing, for example, a captured image of the camera 3 and a temporary calculation result. Further, the control unit 8 has means for generating a clock signal therein, and executes processing based on this clock signal.

(Description of lighting device 5)
FIG. 2 is a diagram illustrating the arrangement of light sources and illumination conditions in the image recognition system 1. As illustrated in FIGS. 1 and 2, the illumination device 5 includes an illumination control unit that controls the illumination unit 51 including three or more light sources 511, the number of light sources 511 to be turned on, and the light intensity emitted from the light sources 511. 52.

  The illumination unit 51 illuminates the imaging area 7 of the camera 3. Each light source 511 of the illumination unit 51 is attached to the attachment unit 6 together with the camera 3.

  As the light source 511 of the illumination part 51, what irradiates infrared rays and visible light is used. In this embodiment mode, a light emitting diode (LED) is used as the light source 511. In the present embodiment, the case where the illumination unit 51 includes five light sources 511a to 511e will be described.

  The five light sources 511a to 511e are arranged in a line in the horizontal direction, and are arranged at equal intervals. The light sources 511a to 511e emit light in substantially the same direction as the imaging direction of the camera 3 (horizontal direction, depth direction in the captured image). The light irradiation directions of the light sources 511a to 511e are the same. Here, it is assumed that the light sources 511a to 511e are sequentially arranged from the left side to the right side in FIG. Although not shown in FIG. 2, the camera 3 is disposed below the light source 511c disposed at the center. The light sources 511 a to 511 e illuminate light having an intensity corresponding to the drive current supplied from the control unit 8.

  As shown in FIG. 2, in the present embodiment, a predetermined area (area indicated by hatching) in the imaging area 7 is set as a detection area R for detecting the detection target 2. The light sources 511a to 511e are arranged at positions closest to the illumination unit 51 in the detection region R so that irradiation regions within the half-value angle of the light sources 511a to 511e (hereinafter referred to as half-angle irradiation regions) do not overlap. Yes. Hereinafter, the distance from the illumination unit 51 to the position closest to the illumination unit 51 in the detection region R is defined as the shortest distance Dmin. In FIG. 2, the inner and outer boundaries of the half-angle irradiation regions of the light sources 511a to 511e are indicated by bold solid lines. The distance from the illumination unit 51 refers to a distance along the irradiation direction of the light source 511 (the imaging direction of the camera 3 and the depth direction of the captured image).

  In the present embodiment, the lines representing the inner and outer boundaries of the half-value angle irradiation region intersect on the shortest distance Dmin. In other words, in this Embodiment, each light source 511a-511e is arrange | positioned so that the half value angle irradiation area | region of the adjacent light sources 511a-511e may adjoin on the shortest distance Dmin. Hereinafter, the distance from the illumination unit 51 at the position farthest from the illumination unit 51 in the detection region R is referred to as the longest distance Dmax. Further, a distance D2 is a distance from the illuminating unit 51 at a position where the half-angle irradiation regions of the light sources 511a, 511c, and 511e are adjacent when the light sources 511a, 511c, and 511e are turned on. Furthermore, the distance from the illumination part 51 in the position where the irradiation area within the half-value angle of both the light sources 511a and 511e when the light sources 511a and 511e are turned on is defined as a distance D1.

  The illumination control unit 52 is mounted on the control unit 8. The illumination control unit 52 controls whether or not each of the light sources 511a to 511e is turned on and the light intensity at the time of lighting by controlling the drive current to each of the light sources 511a to 511e.

  The illumination control unit 52 includes an illumination condition storage unit 52a in which the number of light sources 511 to be turned on and the light intensity are set and stored as illumination conditions for each distance range between the illumination unit 51 and the detection target 2. Here, in the distance range of distance D1 or more and Dmax or less, it was set as the 1st illumination condition which lights two lamps of the light sources 511a and 511e arrange | positioned at the outermost with predetermined light intensity. In the distance range of distance D2 or more and less than D1, the three light sources 511a and 511e arranged at the outermost position and the light source 511c arranged at the center are turned on with a light intensity lower than the light intensity in the first illumination condition. The second illumination condition was set. Furthermore, in the distance range from the distance Dmin to less than D2, all the light sources 511a to 511e are set to the third illumination condition in which the light intensity is lower than the light intensity in the second illumination condition.

  The number of lighting of the light source 511 is set such that the first illumination condition (2 lights) <the second illumination condition (3 lights) <the third illumination condition (5 lights). The magnitude of the current is set such that the first illumination condition> the second illumination condition> the third illumination condition. In other words, the illumination condition is set such that the distance range closer to the illumination unit 51 increases the number of light sources 511 to be turned on and the light intensity emitted from the light sources 511 decreases.

  FIG. 3A shows the illuminance distribution at the distance Dmin when the third illumination condition is set, and FIG. 3B shows the illuminance distribution at the distance D2 when the second illumination condition is set. The illuminance distribution at the distance D1 is shown in FIG. 3A to 3C, the illuminance by the light from each light source 511 is indicated by a solid line, and the illuminance obtained by combining them is indicated by a broken line.

  As shown in FIGS. 3A to 3C, it is possible to obtain a substantially uniform illuminance distribution in the detection region by appropriately selecting the number of lighting of the light source 511 according to the distance from the illumination unit 51. Become. Furthermore, by appropriately adjusting the light intensity of the light source 511 to be lit, it is possible to adjust the brightness of the detection target object 2 to be substantially constant regardless of the distance from the illumination unit 51.

  The illumination control unit 52 sets the illumination condition in the initial state as the illumination condition corresponding to the farthest distance range from the illumination unit 51 (here, the first illumination condition), and the detection target 2 is not detected under the current illumination condition. When there is a high brightness area larger than the predetermined brightness in the captured image, the illumination condition is switched to the illumination condition corresponding to the distance range closer to the one-step illumination unit 51 than the current one. The presence / absence of detection of the detection object 2 and the presence / absence of a high-luminance area are determined based on a detection presence / absence signal from the image processing unit 4.

  Moreover, the illumination control part 52 is set as the illumination condition corresponding to the distance range farthest from the illumination part 51, when the detection target object 2 is not detected on the present illumination conditions, and a high-intensity area does not exist in a captured image. .

  That is, the illumination control unit 52 sets the first illumination condition in the initial state. When the detection target 2 is detected under the first illumination condition, the first illumination condition is continued. The first illumination condition is continued even when the detection object 2 is not detected under the first illumination condition and there is no high-luminance area. When the detection object 2 is not detected under the first illumination condition and a high-luminance area exists, the second illumination condition is switched.

  When the detection object 2 is detected under the second illumination condition, the second illumination condition is continued. When the detection object 2 is not detected under the second illumination condition and there is no high brightness area, the first illumination condition is switched. When the detection object 2 is not detected under the second illumination condition and a high brightness area exists, the third illumination condition is switched.

  When the detection object 2 is detected under the third illumination condition, the third illumination condition is continued. When the detection object 2 is not detected under the third illumination condition and there is no high-luminance area, the first illumination condition is switched. When the detection object 2 is not detected under the second illumination condition and there is a high-luminance area, the third illumination condition is the illumination condition corresponding to the distance range closest to the illumination unit 51, and thus the third illumination The condition will continue.

  As described above, in the present embodiment, in the standby state in which the detection object 2 is not detected, the first illumination condition is established, and the number of light sources 511 that are turned on is the smallest. When the image recognition system 1 is used as a gesture determination device, it is general that the illumination unit 51 always illuminates. However, in the present embodiment, the number of lighting of the light sources 511 is reduced in the standby state. Therefore, power consumption can be suppressed.

(Description of control flow of illumination control unit 52)
Hereinafter, the control flow of the illumination control unit 52 will be described with reference to FIG. The illumination control unit 52 starts the control flow of FIG. 4 when power supply to the image recognition system 1 is started (for example, when a key is turned on), and while power is supplied to the image recognition system 1 (for example, the key is turned on). 4), the control flow of FIG. 4 is continuously executed.

  First, in step S1, the longest distance Dmax is substituted as an initial value for the assumed distance D, which is the assumed distance from the illumination unit 51 to the detection object 2. In step S2, the illumination condition corresponding to the assumed distance D is extracted from the illumination condition storage unit 52a. Thereafter, in step S3, a predetermined light source 511 corresponding to the extracted illumination condition is turned on with light intensity corresponding to the illumination condition.

  Thereafter, in step S4, based on the detection presence / absence signal from the image processing unit 4, it is determined whether or not the detection object 2 has been detected. When it determines with YES in step S4, step S4 is repeated and the present illumination conditions are maintained. If NO is determined in step S4, it is determined in step S5 whether a high-luminance area exists based on the detection presence / absence signal from the image processing unit 4. If NO is determined in step S5, the process returns to step S1.

  If it is determined NO in step S5, the assumed distance D is reduced by a preset distance α in step S6. Thereafter, in step S7, it is determined whether the assumed distance D is smaller than Dmin. If NO is determined in step S7, the process returns to step S2. When it determines with YES by step S7, the assumed distance D is set to the shortest distance Dmin in step S8, and it returns to step S2.

(Operation and effect of the embodiment)
As described above, in the image recognition system 1 according to the present embodiment, the number of light sources 511 to be turned on and the light intensity are set as illumination conditions for each distance range between the illumination unit 51 and the detection target object. The illumination condition in the initial state is set to the illumination condition corresponding to the distance range farthest from the illumination unit 51, the detection target 2 is not detected under the current illumination condition, and the captured image has a high luminance area that is larger than a predetermined luminance Is switched to the illumination condition corresponding to the distance range closer to the one-stage illumination unit 51 than the present.

  As a result, the illumination distribution (illuminance distribution) can be made uniform particularly at a position close to the illumination unit 51, and the detection object can be detected regardless of the distance between the illumination unit 51 and the detection object. Accuracy can be improved. Further, in the present embodiment, since a means for detecting the distance between the illumination unit 51 and the detection target is unnecessary, it is possible to improve the accuracy of image recognition with a simple system configuration and low cost. it can.

  The embodiment and the modification of the present invention have been described above. However, the embodiment and the modification are merely examples, and do not limit the invention according to the claims. These novel embodiments and modifications can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the scope of the present invention. In addition, not all combinations of features described in these embodiments and modifications are necessarily essential to the means for solving the problems of the invention. Further, these embodiments and modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Image recognition system 2 ... Detection target 3 ... Camera (imaging device)
DESCRIPTION OF SYMBOLS 4 ... Image processing part 5 ... Illuminating device 51 ... Illuminating part 511 ... Light source 52 ... Illumination control part 52a ... Illumination condition storage part 6 ... Mounting part 7 ... Imaging region 8 ... Control part

Claims (5)

An imaging device;
An image processing unit for detecting a predetermined detection object from a captured image of the imaging device;
An illumination device for illuminating the imaging region of the imaging device,
The lighting device includes:
An illumination unit having three or more light sources;
An illumination control unit that controls the number of the light sources to be lit and the light intensity emitted by the light sources;
The illumination control unit
For each distance range between the illumination unit and the detection target, the number of light sources to be turned on and the light intensity are set as illumination conditions,
The illumination condition in the initial state is an illumination condition corresponding to the farthest distance range from the illumination unit,
Illumination corresponding to a distance range closer to the illumination unit by one step than the present when the detection object is not detected under the current illumination conditions and a high-luminance area greater than a predetermined luminance exists in the captured image Switch to condition,
Image recognition system. The illumination conditions are set such that the distance range closer to the illumination unit increases the number of the light sources to be lit, and the light intensity emitted by the light sources decreases.
The image recognition system according to claim 1. The illumination control unit
When the detection object is not detected under the current illumination condition and the high-luminance area does not exist in the captured image, the illumination condition corresponds to the farthest distance range from the illumination unit.
The image recognition system according to claim 1 or 2. The light source is
A light emitting diode,
At the position closest to the illumination unit in the detection area where the detection object can be detected, the irradiation areas within the half-value angle of each light source are arranged so as not to overlap.
The image recognition system according to claim 1. An imaging device;
An illumination device that is used in an image recognition system including an image processing unit that detects a predetermined detection object from a captured image of the imaging device, and irradiates an imaging region of the imaging device,
An illumination unit having three or more light sources;
An illumination control unit that controls the number of the light sources to be turned on and the light intensity emitted by the light sources according to the distance between the illumination unit and the detection target;
The illumination control unit
For each distance range between the illumination unit and the detection target, the number of light sources to be turned on and the light intensity are set as illumination conditions,
The illumination condition in the initial state is an illumination condition corresponding to the farthest distance range from the illumination unit,
Illumination corresponding to a distance range closer to the illumination unit by one step than the present when the detection object is not detected under the current illumination conditions and a high-luminance area greater than a predetermined luminance exists in the captured image Switch to condition,
Lighting device.

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