JP2009150843A - Lens abnormality self-diagnosis method, imaging device, lens abnormality self-diagnosis system, and vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens abnormality self-diagnosis system performing a self-diagnosis of lens abnormality using an MTF value concerning a plurality of incident angles and vehicles equipped with the lens abnormality self-diagnosis system. <P>SOLUTION: In an obstacle detection system comprising: an infrared radiation imaging device 1 having a group of infrared radiation lenses 11 and an infrared radiation imaging section 13; and an image processing device, the infrared radiation imaging device 1 includes a shielding member 14b having a part of light transmitting portion, a light source 14a irradiating the shielding member 14b with light, a collimator lens 14c making the light passing through the shielding member 14b into approximately parallel light to enter the group of infrared radiation lenses 11, and a piezo-electric element 20 changing the incidence angle of the light approximately parallel to the optical axis L of the group of infrared radiation lenses 11; the image processing device includes a means calculating the MTF value of the group of infrared radiation lenses 11 based on a pick-up image obtained by the imaging of the infrared radiation imaging section 13 and a means diagnosing existence or nonexistence of abnormality of the group of infrared radiation lenses 11. In addition, a vehicle is equipped with the obstacle detection system. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens abnormality self-diagnosis method for self-diagnosis of the presence or absence of a lens abnormality based on an MTF (MTF: Modulation Transfer Function) value of the lens, an imaging apparatus and a lens abnormality self-diagnosis system for performing the lens abnormality self-diagnosis method, The present invention also relates to a vehicle including the imaging apparatus and the lens abnormality self-diagnosis system.

An automobile safety system including an imaging device and an image processing device mounted on an automobile, such as a night vision system and a pre-crash safety system, has been put into practical use. An image pickup apparatus used for an automobile safety system is required to have high reliability. For this reason, various reliability tests of the image pickup apparatus are performed before shipment to ensure high reliability.
For example, MTF is used as one index indicating the optical characteristics of an infrared lens. The MTF is obtained by imaging a chart having a periodic structure such as a sine wave pattern with an infrared lens as a subject, and expressing the change in contrast of the chart image obtained by imaging as a function of spatial frequency. The presence or absence of abnormality of the infrared lens can be diagnosed by referring to the MTF.
In addition, an infrared detector that can perform self-diagnosis of an infrared imaging element abnormality at the time of component manufacture has been proposed (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2005-98872

  However, the lens and infrared image sensor of the imaging device mounted on the vehicle are exposed to harsh environments such as heat, vibration, moisture, and scattered matter. There is a possibility that a malfunction or failure may occur during use of the system. In particular, the self-diagnosis of the lens abnormality cannot be performed by the infrared detector according to Patent Document 1.

  The present invention has been made in view of such circumstances, and it is possible to self-diagnose the presence / absence of lens abnormality due to dirt, cracks, scratches, peeling of a coating, and the like using MTF values related to a plurality of incident angles. An object of the present invention is to provide a lens abnormality self-diagnosis method, an imaging device and a lens abnormality self-diagnosis system that implement the lens abnormality self-diagnosis method, and a vehicle including the imaging device and the lens abnormality self-diagnosis system.

  A lens abnormality self-diagnosis method according to a first aspect of the present invention is a lens abnormality self-diagnosis method for an imaging apparatus having an imaging unit that captures an image obtained by condensing a lens and the lens, and a plurality of incident angles on the lens The MTF value of the lens is calculated for each incident angle based on the gradation value of each of the plurality of pixels constituting the captured image obtained by causing the image capturing unit to capture substantially parallel light separately from each other, and the calculated MTF The presence or absence of abnormality of the lens is diagnosed based on the value.

  An image pickup apparatus according to a second aspect of the present invention is an image pickup apparatus including a lens and an image pickup unit that picks up an image obtained by condensing with the lens, and an irradiating unit that makes substantially parallel light incident on the lens, and the image pickup unit Calculating means for calculating the MTF value of the lens based on the gradation value of each of the plurality of pixels constituting the captured image obtained by imaging, and whether there is an abnormality in the lens based on the MTF value calculated by the calculating means And an incident angle changing means for changing an incident angle of the substantially parallel light with respect to the lens.

  A lens abnormality self-diagnosis system according to a third aspect of the present invention includes a lens and an imaging device that has an imaging unit that captures an image obtained by condensing with the lens, and a plurality of images that are captured by the imaging unit. A lens abnormality self-diagnosis system comprising a diagnostic device that obtains a gradation value of each pixel and diagnoses the presence or absence of abnormality of the lens based on the gradation value, wherein the imaging device is substantially parallel to the lens Irradiation means for making light incident and incident angle changing means for changing an incident angle of the substantially parallel light to the lens, and the diagnostic device calculates the MTF value of the lens based on the acquired gradation value It is characterized by comprising a calculating means and a diagnosing means for diagnosing the presence or absence of abnormality of the lens based on the MTF value calculated by the calculating means.

  In a lens abnormality self-diagnosis system according to a fourth aspect of the invention, the imaging device includes an openable / closable shutter that blocks external light other than substantially parallel light from the irradiation unit, and the irradiation unit has the shutter closed. In this case, substantially parallel light is irradiated.

  The lens abnormality self-diagnosis system according to a fifth aspect of the invention is characterized in that the imaging device includes a reflecting mirror that reflects substantially parallel light from the irradiating means and enters the lens.

  The lens abnormality self-diagnosis system according to a sixth aspect of the invention is characterized in that the incident angle changing means includes means for changing the posture of the reflecting mirror with respect to the lens.

  In a lens abnormality self-diagnosis system according to a seventh aspect of the invention, the shutter has a plate-like shape facing the lens, and the imaging device reflects a substantially parallel light from the irradiating means and makes it enter the lens. A rotating shaft that rotatably supports the reflecting mirror on the lens-side surface of the shutter, and the incident angle changing means is a piezoelectric element interposed between the shutter and the reflecting mirror. And the posture of the reflecting mirror is changed by applying different voltages to the piezoelectric element.

  The lens abnormality self-diagnosis system according to an eighth aspect of the invention is characterized in that the incident angle changing means includes means for changing a posture of the irradiation means with respect to the lens.

  In the lens abnormality self-diagnosis system according to a ninth aspect of the present invention, there are a plurality of irradiation means, and the plurality of irradiation means are arranged such that incident angles of substantially parallel lights from the irradiation means to the lens are different from each other. The incident angle changing means selectively turns on the plurality of irradiation means.

  In a lens abnormality self-diagnosis system according to a tenth aspect of the invention, the diagnostic apparatus includes a storage unit that stores a threshold value, and the diagnostic unit diagnoses that the lens has an abnormality when the MTF value is smaller than the threshold value. It is characterized by being.

  In the lens abnormality self-diagnosis system according to an eleventh aspect of the invention, the calculation means is configured such that the substantially parallel light is incident on the lens at one incident angle, and the irradiating means emits the substantially parallel light. The gradation value of each of the plurality of pixels constituting the captured image obtained by the imaging unit, and the captured image obtained by the imaging unit when the irradiating unit does not irradiate substantially parallel light are configured. Difference calculating means for calculating a difference between gradation values of each of the plurality of pixels is provided, and the MTF value of the lens is calculated based on the difference calculated by the difference calculating means.

  The lens abnormality self-diagnosis system according to a twelfth aspect of the invention is characterized in that the diagnostic device includes means for issuing a warning when diagnosing that the lens is abnormal.

  A vehicle according to a thirteenth aspect includes the imaging device according to the second aspect or the lens abnormality self-diagnosis system according to any one of the third to twelfth aspects.

In the first, second, third, and thirteenth inventions, a plurality of images constituting a captured image obtained by causing the imaging unit to capture images by causing substantially parallel light to enter the lens of the imaging device from a plurality of incident angles. The MTF value of the lens is calculated based on the gradation value of each pixel, and the presence / absence of abnormality of the lens is diagnosed based on the MTF value. Specifically, the irradiating unit causes substantially parallel light to enter the lens of the imaging apparatus, and the imaging unit captures an image obtained by condensing with the lens. Then, the calculating means calculates the MTF value of the lens based on the gradation value of each of the plurality of pixels constituting the captured image obtained by the imaging unit, and the diagnosing means calculates the MTF value calculated by the calculating means. Based on this, the presence or absence of lens abnormality is diagnosed. In addition, the incident angle changing means can change the incident angle of the substantially parallel light to the lens, and the imaging unit captures images obtained before and after the incident angle of the substantially parallel light is changed, that is, different. By using the MTF value obtained from each of the captured images of the irradiation means obtained by imaging from a plurality of directions, a lens abnormality cause, for example, when there are a plurality of lenses, one lens having an abnormality in optical characteristics is obtained. Can be identified. In particular, in the third invention, the imaging device and the diagnostic device are configured separately, and the diagnostic device can perform self-diagnosis based on MTF values related to a plurality of incident angles. In the thirteenth invention, the diagnosis means can self-diagnose the presence or absence of abnormality of the lens of the imaging device mounted on the vehicle based on the MTF values related to a plurality of incident angles.
Note that substantially parallel light means parallel light or substantially parallel light, that is, light that is so parallel that an image capable of calculating the MTF value can be obtained.

In the fourth and thirteenth inventions, an openable / closable shutter blocks external light incident on the lens. The irradiating means causes the substantially parallel light to enter the lens in a state where the shutter is closed and the external light is blocked, and the imaging unit performs imaging. Since the influence of external light can be blocked by closing the shutter, it is possible to more accurately calculate the MTF value of the lens and diagnose the presence or absence of the lens.
Further, when the irradiating means irradiates substantially parallel light with the shutter opened, the intensity of the light condensed on the imaging unit may be saturated. However, according to the fourth aspect of the invention, since the irradiating means is configured to allow the substantially parallel light to enter the lens with the shutter closed, the lens MTF value is calculated regardless of the intensity of the external light, and the abnormality of the lens. The presence or absence of can be diagnosed.

  In the fifth and thirteenth inventions, the substantially parallel light from the irradiation means is reflected by the reflecting mirror and enters the lens. Therefore, the degree of freedom of arrangement of the irradiation means is high and the imaging apparatus can be downsized as compared with the case where the irradiation means is arranged on the front side without using a reflecting mirror.

In the sixth and thirteenth inventions, the incident angle changing means changes the incident angle of the substantially parallel light with respect to the lens by changing the posture of the reflecting mirror that reflects the substantially parallel light from the irradiation means.
Further, when the posture of the reflecting mirror fluctuates, the position where the substantially parallel light enters the lens also changes. Therefore, the imaging unit can calculate MTF values at a plurality of locations of the lens and diagnose the presence or absence of lens abnormality.

  In the seventh and thirteenth inventions, the reflecting mirror is supported on the lens-side surface of the plate-shaped shutter so as to be rotatable about the rotating shaft, and the piezoelectric element is interposed between the shutter and the reflecting mirror. Has been. The incident angle changing means can change the incident angle of the substantially parallel light that has passed through the shielding member to the lens by changing the relative position of the reflecting mirror with respect to the shutter by applying different voltages to the piezoelectric element.

In the eighth and thirteenth inventions, the incident angle changing means changes the incident angle of the substantially parallel light with respect to the lens by changing the posture of the irradiating means.
Further, when the posture of the irradiation unit is changed, the position where the substantially parallel light is incident on the lens also changes. Therefore, the imaging unit can calculate MTF values at a plurality of locations of the lens and self-diagnose the lens abnormality.

In the ninth and thirteenth inventions, a plurality of irradiation means are arranged so that substantially parallel light enters the lens at a plurality of incident angles. The incident angle changing means changes the incident angle of the substantially parallel light with respect to the lens by selectively lighting a plurality of irradiation means.
In addition, when different irradiation means are turned on, the position where the substantially parallel light is incident on the lens also changes. Therefore, the imaging unit can calculate MTF values at a plurality of locations of the lens and self-diagnose the lens abnormality.

  In the tenth and thirteenth inventions, the storage means of the diagnostic device stores a threshold value for diagnosing the presence or absence of lens abnormality, and the diagnosis means includes the MTF value calculated by the calculation means and the storage means The presence or absence of lens abnormality is diagnosed by comparing the stored threshold value. Specifically, when the MTF value is smaller than a predetermined threshold, it is diagnosed that the lens is abnormal. Therefore, it is possible to diagnose the presence or absence of lens abnormality by a simple comparison process.

  In the eleventh and thirteenth inventions, the difference calculating means calculates the gradation value of each of the plurality of pixels constituting the picked-up image obtained by the image pickup section when the irradiating means emits substantially parallel light. Then, when the irradiating means does not irradiate substantially parallel light, the difference between the gradation of each of the plurality of pixels constituting the captured image obtained by the imaging unit is calculated. The difference calculated by the difference calculation means is obtained by removing the influence of external light. Accordingly, the calculation means can calculate a more accurate MTF value of the lens based on the difference, and the diagnosis means can diagnose an abnormality of the lens based on the MTF value.

  In the twelfth and thirteenth inventions, the diagnostic device issues a warning when diagnosing that there is an abnormality in the lens. Therefore, it is possible to notify the user of the imaging apparatus that there is an abnormality in the lens.

  According to the present invention, substantially parallel light is incident on the lens of the imaging apparatus from a plurality of incident angles, and the MTF value of the lens is calculated for each incident angle based on the gradation value of each of the plurality of pixels constituting the captured image. Then, by diagnosing the presence or absence of the lens abnormality based on the calculated MTF value, the presence or absence of the lens abnormality due to dirt, cracks, scratches, coating peeling, etc. on the lens is determined based on the MTF values for a plurality of incident angles. Can self-diagnose.

(Embodiment 1)
Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a schematic diagram showing an infrared imaging device 1 constituting an obstacle detection system as a lens abnormality self-diagnosis system according to Embodiment 1 of the present invention.
In the figure, reference numeral 11 denotes an infrared lens group composed of a plurality of infrared lenses, and the infrared lens group 11 is fixedly fitted inside a lens barrel 12 made of aluminum. An infrared imaging unit 13 is disposed on the back side of the infrared lens group 11. For convenience of drawing and explanation, the infrared lens group 11 is shown as a single lens having optical performance equivalent to that of the condensing optical system composed of the plurality of infrared lenses.

  The infrared lens group 11 is a sintered body obtained by sintering, for example, zinc sulfide raw material powder by a hot press method, and has transparency to infrared rays of 8 to 12 μm band. In order to improve the environmental resistance of the infrared lens group 11, the front surface of the infrared lens group 11 may be covered with a DLC (diamond like carbon) film. The DLC film is an amorphous carbon thin film having characteristics similar to diamond.

  The infrared imaging unit 13 captures the front of the vehicle with infrared rays having a wavelength of 7 to 14 μm, that is, an element that photoelectrically converts an image formed by the infrared lens group 11 into a luminance signal, such as a thermopile, pyroelectric element, bolometer, SOI A substantially rectangular infrared imaging element 13a is provided which includes diodes arranged in a matrix. In the infrared imaging element 13a, the optical axis L of the infrared lens group 11 passes through the center thereof, and the distance between the principal point of the infrared lens group 11 and the infrared imaging unit 13 in the direction of the optical axis L is the infrared ray in order to focus at infinity. They are arranged so as to be substantially equal to the focal length of the lens group 11. Since the depth of field becomes deeper as the focus is adjusted farther, the subject in the distance range of about 50 m to infinity is taken from the infrared imaging apparatus 1 without adjusting the focus by adjusting the focus to infinity. Will be able to. The aspect ratio of the infrared imaging element 13a is 4/3. The infrared imaging unit 13 performs imaging processing continuously or intermittently, generates, for example, 30 pieces of captured image data per second, and outputs them to the signal processing unit 18. In addition, each pixel which comprises a captured image is arranged in two dimensions, and captured image data contains the data which show the brightness | luminance of each pixel shown as a position of each pixel, and a gradation value.

  The signal processing unit 18 is controlled by a control unit 17 formed of a microcomputer, and AD-converts analog captured image data into digital captured image data. More specifically, each pixel constituting the image is converted into digital captured image data represented by a gradation value such as 256 gradations (1 Byte). Then, the signal processing unit 18 performs various correction processes on the AD-converted captured image data, and outputs the captured image data to an external device via the output unit 19.

  In addition, the infrared imaging device 1 includes a light source 14a, a shielding member 14b, and a collimator lens 14c for diagnosing whether the infrared lens group 11 is abnormal. The light source 14a, the shielding member 14b, and the collimator lens 14c constitute an irradiation unit according to the present invention.

  The light source 14 a has a filament that generates heat by, for example, energization and emits infrared rays of a predetermined intensity, and the light source 14 a is controlled to be turned on and off by the control unit 17.

  The shielding member 14b includes a black painted aluminum plate-like member having a pinhole (light passage portion) having a diameter of 0.5 mm to 1 mm, and is disposed on the front side of the light source 14a. In addition, in order to improve the corrosion resistance of the shielding member 14b, the surface of the shielding member 14b may be anodized. The material of the shielding member 14b is not limited to aluminum, and may be an aluminum alloy or stainless steel. Moreover, the shape of the light passage part of the shielding member 14b is not limited to a circle, and may be a slit, for example.

  The collimator lens 14c is arranged on the front side of the shielding member 14b so that the focal point is located in the pinhole of the shielding member 14b.

  The lens barrel 12 is integrally formed on a cylindrical main body 12a that holds the infrared lens group 11, and an outer peripheral surface of the main body 12a, and a holding portion 12b that holds the light source 14a, the shielding member 14b, and the collimator lens 14c. It has. The holding portion 12b has a posture such that the collimator lens 14c faces the front and obliquely inside. Specifically, the optical axis of the collimator lens 14c and the optical axis L of the infrared lens group 11 are in the same plane, and each light The collimator lens 14c is held in such a posture that the angle θ formed by the axis L is equal to or less than the half angle of view α.

Further, the infrared imaging device 1 includes a shutter 15 and a shutter driving unit 15a.
The shutter 15 has a plate shape that can be opened and closed, and is provided on the front side of the infrared lens group 11. Opening and closing of the shutter 15 is controlled by the control unit 17. The control unit 17 gives a shutter drive signal to the shutter drive unit 15a, and the shutter drive unit 15a opens and closes the shutter 15 when receiving the shutter drive signal. When the shutter 15 is opened, external light is incident on the infrared lens group 11, and when the shutter 15 is closed, the external light incident on the infrared lens group 11 is blocked.
Although a mechanical plain shutter is taken as an example, a shutter having another configuration may be used as long as external light can be blocked.

  The shutter 15 is provided to block outside light that hinders the lens abnormality diagnosis, but infrared rays are also emitted from the shutter 15 itself, and the infrared rays may hinder the lens abnormality diagnosis. Therefore, it is preferable to perform a self-diagnosis of lens abnormality while keeping the intensity of infrared rays emitted from the shutter 15 constant. When the intensity of infrared rays emitted from the shutter 15 is constant and known, the presence or absence of lens abnormality can be diagnosed in consideration of the influence of the infrared rays. In order to keep the infrared intensity constant, for example, the shutter 15 is formed of a metal having high thermal conductivity so that the surface temperature of the shutter 15 is uniform, and is constant by a thermocouple temperature detector and a Peltier element (not shown). Control to temperature.

  Furthermore, since the shutter 15 that blocks external light is necessary not only for lens abnormality diagnosis but also for periodically offset correcting sensitivity variations of the infrared imaging device 13a, the shutter 15 is used for lens abnormality diagnosis. You may comprise so that it may be shared by the object for offset correction.

  A plane reflecting mirror 16 is disposed on the surface of the shutter 15 on the infrared lens group 11 side where the substantially parallel light from the collimator lens 14c is irradiated. One side portion of the plane reflecting mirror 16, for example, one side portion located on the radially outer side of the infrared lens group 11, is rotatably supported by a rotation shaft 16 a substantially perpendicular to the optical axis L. A piezoelectric element 20 is interposed between the plane reflecting mirror 16 and the shutter 15. The piezoelectric element 20 is formed by stacking a plurality of piezoelectric ceramics, for example, and constitutes a piezoelectric actuator. The voltage applied to the piezoelectric element 20 is controlled by the control unit 17, and the control unit 17 gives a drive signal indicating the voltage to be applied to the piezoelectric element 20 to the piezoelectric element driving unit 20a. The piezoelectric element driving unit 20a When the drive signal is received, a voltage indicated by the drive signal is applied to the piezoelectric element 20. The rotation range of the plane reflecting mirror 16 is such that the incident angle of substantially parallel light reflected by the plane reflecting mirror 16 and incident on the infrared lens group 11 changes between 0 and θ (<half angle of view α). Is set to In addition, the incident angle with respect to the infrared lens group 11 is an angle with respect to the optical axis L direction. The control unit 17 changes the incident angle in five steps, for example, by raising and lowering the applied voltage in five steps.

FIG. 2 is an optical path diagram showing changes in the optical path when the planar reflecting mirror 16 is rotated. FIG. 2A shows a state where no voltage is applied to the piezoelectric element 20. When no voltage is applied to the piezoelectric element 20, the reflecting surface of the planar reflecting mirror 16 is substantially perpendicular to the optical axis L. Accordingly, the substantially parallel light from the collimator lens 14c enters the plane reflecting mirror 16 at an incident angle θ, is reflected at the reflecting angle θ, and the substantially parallel light reflected by the planar reflecting mirror 16 is incident on the infrared lens group 11 at the incident angle θ. Is incident on.
FIG. 2B shows a state in which a predetermined voltage is applied to the piezoelectric element 20. When a predetermined voltage is applied to the piezoelectric element 20, the dimension in the optical axis L direction of the piezoelectric element 20 increases, and the plane reflecting mirror 16 rotates toward the infrared lens group 11, so that the infrared lens group 11 and the collimator lens 14c The posture of the plane reflecting mirror 16 with respect to the surface changes. Specifically, the plane reflecting mirror 16 has an inclination angle of θ / 8 with respect to the shutter 15, and the reflection surface has an inclination of 7θ / 8 with respect to the optical axis L. Accordingly, the substantially parallel light from the collimator lens 14c is incident on the planar reflecting mirror 16 at an incident angle of 7θ / 8 and reflected at a reflecting angle of 7θ / 8. As a result, the substantially parallel light reflected by the planar reflecting mirror 16 is incident on the incident angle. The light enters the infrared lens group 11 at 6θ / 8.
Similarly, FIGS. 2C, 2D, and 2E show cases where the voltage applied to the piezoelectric element 20 is increased in order, and in FIG. 2C, the incident angle is 4θ / 8, The incident light is incident on the infrared lens group 11 at an incident angle 2θ / 8 in FIG. 2D and at an incident angle 0 in FIG.

  FIG. 3 is a schematic diagram illustrating the configuration of an obstacle detection system including the infrared imaging device 1 and a vehicle. An obstacle detection system (lens abnormality self-diagnosis system) that implements the lens abnormality self-diagnosis method according to Embodiment 1 of the present invention includes two infrared imaging devices 1 that constitute a stereo vision infrared imaging device, and a front of the vehicle. The image processing apparatus (diagnosis apparatus) 3 having an obstacle detection function for detecting an obstacle and issuing a warning and a lens abnormality self-diagnosis function for diagnosing the presence or absence of abnormality of the infrared lens group 11 is provided. The system is mounted on the vehicle.

  The infrared imaging device 1 is juxtaposed inside the front grill. One infrared imaging device 1 is arranged on the right side in the vehicle width direction when viewed from the driver's seat side. The other infrared imaging device 1 is arranged on the left side in the vehicle width direction and at a position where the height from the road surface is equal to the one infrared imaging device 1. Moreover, each infrared imaging device 1 is fixed in a posture such that the optical axis L direction is substantially parallel. By capturing a common imaging target with the two infrared imaging devices 1, the parallax of the imaging target in both images can be calculated, and the distance to the imaging target can be obtained based on the principle of triangulation.

  FIG. 4 is a block diagram illustrating a configuration of the image processing apparatus 3. The image processing apparatus 3 includes a control unit 31, an image memory 32, a RAM 33, an input unit 34, a video output unit 35, a communication interface unit 36, and a storage unit 37.

  The input unit 34 is connected to the output unit 19 of the infrared imaging device 1 via the cable 7 and inputs captured image data output from the infrared imaging device 1. The captured image data input to the input unit 34 is sequentially stored in the image memory 32 in units of one frame.

  The video output unit 35 is connected to the display device 4 via the cable 8, for example, an in-meter display, a navigation display, a head-up display, and the like. The video output unit 35 appropriately transmits the input captured image data to the display device 4 and causes the display device 4 to display the captured image obtained by the infrared imaging device 1.

  An alarm device 5 is connected to the communication interface unit 36 via an in-vehicle LAN cable 6 compliant with CAN (Controller Area Network), and an alarm signal according to the control of the control unit 31 is transmitted via the communication interface unit 36. The alarm device 5 is configured to be transmitted.

The alarm device 5 includes a buzzer, a speaker, and the like, and when a pedestrian that may contact or collide is detected in the obstacle detection process, the alarm device 5 outputs that effect by voice, warning sound, etc. , “Danger” is displayed.
In addition, when the alarm device 5 is diagnosed as having an abnormality in the infrared lens group 11 in the lens abnormality self-diagnosis process described later, the alarm device 5 outputs a message to that effect by a voice, a warning sound, or the like. "Or the like is displayed.

  The image memory 32 is SRAM, flash memory, SDRAM or the like, and temporarily stores captured image data input from the infrared imaging device 1 via the input unit 34.

The storage unit 37 stores in advance a threshold value for determining whether the infrared lens group 11 has a normal MTF value. The threshold value is set based on the MTF value of the infrared lens group 11 obtained by measuring in advance at the time of manufacturing the infrared imaging device 1, that is, the MTF value of the normal infrared lens group 11 before the start of use, which is free from dirt and scratches. .
Specifically, the light source 14a is turned on with the shutter 15 closed, and a captured image of the shielding member 14b output from the infrared imaging element 13a is acquired. Next, a light intensity distribution is detected based on the acquired captured image data of the shielding member 14b, and an MTF value at a predetermined frequency, for example, a Nyquist frequency, is calculated from the light intensity distribution. Then, in consideration of a decrease in the MTF value due to the use of the infrared imaging device 1, a predetermined value, for example, a value lower by about 0.1 than the MTF value is set as a threshold value.
Moreover, you may set the MTF value requested | required of an obstruction detection system as a threshold value. For example, 0.2 may be set as the MTF value of the spatial frequency 20 (cycles / mm). When the infrared imaging element 13a having a pixel pitch of 25 μm is employed, it is empirically known that the contrast of the image is remarkably lowered when the MTF value at a spatial frequency of 20 (cycles / mm) is less than 0.2.
Since the MTF value varies depending on the incident angle of the substantially parallel light that has passed through the shielding member 14b, a different threshold may be stored in the storage unit 37 for each incident angle. The threshold values at other incident angles may be set in the same procedure as described above by changing the voltage applied to the piezoelectric element 20.

  Preferably, the threshold value is set by calculating the MTF value while maintaining the surface temperature of the shutter 15 at a predetermined temperature at the time of lens abnormality diagnosis. This is because the influence of infrared rays emitted from the shutter 15 on the lens abnormality diagnosis is eliminated by setting the surface temperature of the shutter 15 to be the same at the time of setting the threshold and at the time of lens abnormality diagnosis.

  The control unit 31 reads captured image data stored in the image memory 32 in units of frames, and executes an obstacle detection process for detecting an obstacle ahead of the vehicle based on the read captured image data. The control unit 31 also performs a lens abnormality self-diagnosis process described later at a predetermined timing.

Next, the operation of the infrared imaging device 1 and the image processing device 3 according to the present invention when performing lens abnormality self-diagnosis processing will be described.
FIG. 5 is a flowchart showing a processing procedure of the control unit 17 on the infrared imaging device 1 side related to the self-diagnosis of the infrared lens group 11.

  The control unit 17 of the infrared imaging device 1 provides the shutter drive signal to the shutter drive unit 15a, thereby closing the shutter 15 (step S11) and turning on the light source 14a (step S12). When the shutter 15 is closed, the surface temperature of the shutter 15 is preferably heated or cooled to a predetermined temperature when the threshold is set. This is because the influence of infrared rays emitted from the shutter 15 on the diagnosis of lens abnormality is excluded.

  Next, the control unit 17 captures the image condensed by the infrared lens group 11 with the infrared imaging element 13a (step S13), and outputs captured image data obtained by imaging to the image processing device 3 (step S14). ).

  Next, the control unit 17 determines whether captured image data at all incident angles has been output (step S15). For example, as shown in FIGS. 2A to 2E, it is determined whether or not the captured image data of the shielding member 14b obtained by imaging in five directions is output. When it determines with there being unoutput imaged image data (step S15: NO), the control part 17 changes the voltage applied to the piezoelectric element 20 (step S16), and returns a process to step S13.

  When it is determined that the captured image data at all incident angles has been output (step S15: YES), the control unit 17 turns off the light source 14a (step S17), and gives a shutter drive signal to the shutter drive unit 15a, thereby releasing the shutter. 15 is opened (step S18), and the process ends.

FIG. 6 is a flowchart showing a processing procedure of the control unit 31 on the image processing apparatus 3 side relating to the self-diagnosis of the infrared lens group 11, and FIG. 7 is an explanatory diagram conceptually showing the processing contents of the control unit 31.
The control unit 31 of the image processing device 3 acquires captured image data at all incident angles output from the infrared imaging device 1 (step S31). Next, the control unit 31 detects the light intensity distribution in the predetermined range A of the captured image, as shown in FIGS. 7A and 7B, based on the acquired one captured image data (step S32).

  FIG. 7A is an explanatory diagram conceptually illustrating an example of a captured image. The rectangular portion in FIG. 7A is a captured image, the X axis indicates the horizontal line of the captured image, and the Y axis indicates the vertical line of the captured image. A circle portion in the captured image is an image P of the pinhole portion of the shielding member 14b. The predetermined range A includes a pixel of the image P of the pinhole portion and a plurality of pixels on both sides in the horizontal direction of the pixel. In step S32, the control unit 31 determines the gradation value of each pixel constituting the predetermined range A. It is specified as the light intensity distribution.

  FIG. 7B is a graph showing an example of the light intensity distribution detected in step S32. The horizontal axis represents the horizontal line, and the vertical axis represents the gradation value of each pixel constituting the predetermined range. When the shielding member 14b having a pinhole is used, a normally distributed light intensity distribution as shown in FIG. 7B is obtained.

  Next, the control unit 31 obtains an MTF function by Fourier transforming the light intensity distribution detected in step S32, and calculates the MTF value of the infrared lens group 11 at a predetermined frequency, for example, the Nyquist frequency (step S33).

  FIG. 7C is a graph showing an MTF curve. The horizontal axis indicates the spatial frequency (cycles / mm). The spatial frequency is a numerical value corresponding to the number of shading stripes per millimeter, for example. The vertical axis shows the contrast normalized to 1 with a spatial frequency of 0. The contrast is defined as (maximum luminance−minimum luminance) / (maximum luminance + minimum luminance) based on the maximum luminance and the minimum luminance of the gray stripes.

  When the process of step S33 is completed, the control unit 31 reads the threshold value from the storage unit 37 (step S34), and determines whether or not the MTF value calculated in step S33 is less than the threshold value (step S35). That is, it is determined whether or not the MTF value of the infrared lens group 11 is in the normal range.

FIG. 8 is a graph showing the MTF curve of the normal infrared lens group 11 and the MTF curve of the abnormal infrared lens group 11. FIG. 8A shows an example of the MTF curve when there is no abnormality in the infrared lens group 11. In this case, the MTF value of a predetermined spatial frequency, for example, 20 (cycles / mm) is about 0.3, which is a value larger than the threshold value 0.2. When the MTF value is larger than the threshold value, a captured image having a certain contrast can be obtained, and an obstacle can be detected from the captured image.
FIG. 8B shows an example of the MTF curve when the infrared lens group 11 is abnormal. In this case, the MTF value of a predetermined spatial frequency, for example, 20 (cycles / mm) is about 0.1, which is a value smaller than the threshold value of 0.2. When the MTF value is smaller than the threshold value, a captured image having a constant contrast cannot be obtained, and obstacle detection may be hindered.

  When it is determined that the MTF value is less than the threshold value (step S35: YES), the control unit 31 issues a warning that the infrared lens group 11 is abnormal (step S36), and ends the process. When it determines with an MTF value being more than a threshold value (step S35: NO), the control part 31 determines whether the MTF value of all the incident angles was calculated (step S37). For example, it is determined whether or not MTF values relating to five incident angles as shown in FIGS. If it is determined that there is an uncalculated MTF value (step S37: NO), the control unit 31 returns the process to step S32. When it determines with having calculated the MTF value of all the incident angles (step S37: YES), the control part 31 complete | finishes a process noting that there is no abnormality in the infrared lens group 11. FIG.

  In the lens abnormality self-diagnosis method, the obstacle abnormality detection system as the lens abnormality self-diagnosis system, and the vehicle according to the first embodiment, the MTF value of the infrared lens group 11 is calculated and calculated for a plurality of incident angles. Based on the MTF value, the presence or absence of abnormality of the infrared lens group 11 can be self-diagnosed. When the abnormality of the infrared lens group 11 is diagnosed using the MTF value, the abnormality of the infrared lens group 11 can be diagnosed from the viewpoint of the quality of contrast. Moreover, since the presence or absence of abnormality of the infrared lens group 11 is diagnosed using the MTF values at a plurality of incident angles, the presence or absence of abnormality of the infrared lens group 11 can be diagnosed more accurately. For example, it is possible to specify one lens having an abnormality in optical characteristics from the infrared lens group 11.

  Moreover, since the incident position of the substantially parallel light that has passed through the shielding member 14b can be changed by rotating the plane reflecting mirror 16, MTF values at a plurality of locations in the infrared lens group 11 are calculated, and the infrared lens group The presence or absence of 11 abnormalities can be diagnosed.

  Further, since the light source 14a is turned on with the shutter 15 closed and an image of the shielding member 14b is taken, a more accurate MTF value of the infrared lens group 11 is measured, and the infrared lens group 11 The presence or absence of abnormality can be diagnosed.

  Furthermore, since the light source 14a is turned on with the shutter 15 closed and the shielding member 14b is imaged, the light intensity that can be imaged by the image sensor 13a is not saturated regardless of the intensity of external light, and the infrared lens. By calculating the MTF value of the group 11, it is possible to self-diagnose whether there is a lens abnormality.

  Furthermore, based on the MTF value of the infrared lens group 11, the presence or absence of an abnormality in the infrared lens group 11 is diagnosed, and if the infrared lens group 11 is abnormal, a warning can be issued.

  Furthermore, since the infrared ray that has passed through the shielding member 14 b is reflected by the plane reflecting mirror 16 and is incident on the infrared lens group 11, the light source 14 a is compared with the case where the light source 14 a is disposed on the front side of the infrared lens group 11. Thus, the infrared imaging device 1 can be reduced in size.

  In the first embodiment, as an example, an infrared imaging device that captures an image of a subject using infrared light is illustrated. However, the present invention is applied to an imaging device that captures an image of a subject using visible light or light of other wavelengths. You may do it.

  Further, although the image processing apparatus performs lens abnormality self-diagnosis processing, the infrared imaging apparatus may be configured to perform lens abnormality diagnosis. Specifically, the control unit of the infrared imaging device may be configured to sequentially execute steps S11, 12, 13, 15 to 18 shown in FIG. 5 and steps S32 to 37 shown in FIG.

(Embodiment 2)
The obstacle detection system according to the second embodiment is mounted on a vehicle as in the first embodiment, and includes an infrared imaging device 201, an image processing device 3, a display device 4, an alarm device 5, and the like.
9 and 10 are schematic diagrams showing an infrared imaging device 201 constituting an obstacle detection system as a lens abnormality self-diagnosis system according to Embodiment 2 of the present invention. The infrared imaging device 201 according to the second embodiment includes an infrared lens group 11, a lens barrel 212, an infrared imaging unit 13, a light source 14a, a shielding member 14b, a collimator lens 14c, and the like, similar to the infrared imaging device 1 according to the first embodiment. A shutter 15, a shutter drive unit 15a, a wedge-shaped reflecting mirror 216, a control unit 17, a signal processing unit 18, and an output unit 19 are provided. By changing the attitude of the collimator lens 14c, a plurality of incident angles can be obtained. It differs from the infrared imaging device 1 according to the first embodiment in that the MTF value is calculated and the infrared lens group 11 is diagnosed for abnormality.

  The infrared imaging apparatus 201 according to Embodiment 2 includes a cylindrical light source support 14d that supports the light source 14a, the shielding member 14b, and the collimator lens 14c. The configuration and positional relationship of the light source 14a, the shielding member 14b, and the collimator lens 14c are the same as those in the first embodiment. The light source support 14d is rotatably supported by the holding part 212b of the lens barrel 212 by a support rotating shaft 21b substantially perpendicular to the optical axis L. As shown in FIGS. The light source support 14d is configured to rotate around the support rotating shaft 21b by the stepping motor 21. The rotation of the stepping motor 21 is controlled by the control unit 17, and the control unit 17 gives a motor drive signal to the motor drive unit 21a. When the motor drive unit 21a receives the motor drive signal, the stepping motor 21 is controlled. Rotate. The rotation range of the light source support 14d is such that the incident angle of substantially parallel light reflected by the reflecting mirror 216 and incident on the infrared lens group 11 changes between 0 to θ (<half angle of view α), and the infrared lens. It is set so that scanning can be performed across both ends of the group 11 in the radial direction.

  When the light source support 14d rotates, the attitude of the collimator lens 14c with respect to the reflecting mirror 216 and the infrared lens group 11 changes, and the incident angle of the substantially parallel light that has passed through the shielding member 14b changes with respect to the infrared lens group 11.

  FIG. 11 is a flowchart illustrating a processing procedure of the control unit 17 on the infrared imaging apparatus 201 side in the second embodiment.

  The control unit 17 of the infrared imaging device 201 closes the shutter 15, turns on the light source 14 a, takes an image, and outputs the captured image data of the shielding member 14 b obtained by imaging, similarly to steps S 11 to 15 shown in FIG. 5. Steps S51 to S55 are executed. In step S55, the control unit 17 determines whether or not the captured image data of all incident angles has been output, and if it is determined that there is unoutput captured image data (step S55: NO), the control unit 17 The stepping motor 21 is rotated by a predetermined angle (step S56), and the process returns to step S53.

  When it is determined that the captured image data of all incident angles has been output (step S55: YES), the control unit 17 turns off the light source 14a (step S57) and gives a shutter drive signal to the shutter drive unit 15a, thereby releasing the shutter. 15 is opened (step S58), and the process ends.

  Even in the lens abnormality self-diagnosis method, the obstacle detection system, and the vehicle according to the second embodiment, as in the first embodiment, the MTF value of the infrared lens group 11 is calculated for a plurality of incident angles, and the MTF value is calculated. Can be used to self-diagnose whether there is an abnormality in the infrared lens group 11.

  In the second embodiment, the substantially parallel light that has passed through the shielding member 14b is configured to enter a part of the infrared lens group 11. However, the substantially parallel light is centered on the infrared lens group 11. You may comprise so that it may inject into part or all including a part.

  The lens abnormality self-diagnosis method, obstacle detection system, and other configurations, operations, and effects according to the second embodiment are the same as the lens abnormality self-diagnosis method, infrared imaging device 1, obstacle detection system, and vehicle according to the first embodiment. Since it is the same as that of a structure, an effect | action, and an effect of a vehicle, the same code | symbol is attached | subjected to a corresponding location and the detailed description is abbreviate | omitted.

(Embodiment 3)
As in the first embodiment, the obstacle detection system according to the third embodiment includes an infrared imaging device 301, an image processing device 3, a display device 4, an alarm device 5, and the like.
FIG. 12 is a schematic diagram showing an infrared imaging device 301 according to Embodiment 3 of the present invention. The infrared imaging device 301 according to the third embodiment includes an infrared lens group 11, a lens barrel 312, an infrared imaging unit 13, a plurality of light sources 14 a, 14 a, 14 a, and a shielding member similar to the infrared imaging device 1 according to the first embodiment. 14b, 14b, 14b, collimator lenses 14c, 14c, 14c, shutter 15, side-section wedge-shaped reflecting mirror 316, control unit 17, signal processing unit 18, output unit 19, and a plurality of light sources 14a, 14a, The infrared ray according to the first embodiment is configured so that the shielding members 14b, 14b, and 14b are imaged from a plurality of directions by selectively turning on the light 14a and the presence or absence of abnormality of the infrared lens group 11 is diagnosed. Different from the imaging device 1.

  The infrared imaging device 301 according to Embodiment 3 includes a plurality of sets, for example, three sets of the light source 14a, the shielding member 14b, and the collimator lens 14c. The configurations of the light source 14a, the shielding member 14b, and the collimator lens 14c that constitute each set are the same as those in the first embodiment, and the light source 14a, 14a, 14a is turned on and off by the control unit 17. The holding portion 312b of the lens barrel 312 supports the collimator lenses 14c, 14c, and 14c so that the optical axes thereof are directed in different directions. Since the directions of the optical axes of the collimator lenses 14c, 14c, and 14c are different, substantially parallel light from the collimator lenses 14c, 14c, and 14c is incident on the infrared lens group 11 at different incident angles. Therefore, when each of the light sources 14a, 14a, and 14a is selectively turned on, the incident angle of the substantially parallel light incident on the infrared lens group 11 changes.

  FIG. 13 is a flowchart illustrating a processing procedure of the control unit 17 on the infrared imaging device 301 side in the third embodiment.

  The control unit 17 of the infrared imaging device 301 closes the shutter 15, turns on the one light source 14 a, picks up an image, and picks up the imaged image data of the shielding member 14 b obtained by taking the image, as in steps S 11 to 15 shown in FIG. 5. Are executed in steps S71 to S75. In step S75, the control unit 17 determines whether or not the captured image data is output at all incident angles, and when it is determined that there is unoutput captured image data (step S75: NO), the control unit 17 The light source 14a to be turned on is changed (step S76), and the process returns to step S73.

  If it is determined that the captured image data of all incident angles has been output (step S75: YES), the control unit 17 turns off the light source 14a (step S77), and gives a shutter drive signal to the shutter drive unit 15a, thereby releasing the shutter. 15 is opened (step S78), and the process ends.

Even in the lens abnormality self-diagnosis method, the obstacle detection system, and the vehicle according to the third embodiment, as in the first embodiment, the MTF value of the infrared lens group 11 is calculated for a plurality of incident angles, and the MTF value is calculated. Can be used to self-diagnose whether there is an abnormality in the infrared lens group 11.
Furthermore, by selectively turning on the plurality of light sources 14a, 14a, and 14a, the incident angle of substantially parallel light from the collimator lens 14c with respect to the infrared lens group 11 can be changed, so that the configuration is simple and the cost is low. The same effect as in the first embodiment can be obtained.
In the third embodiment, the case where three light sources are selectively turned on has been described. However, the number of collimator lenses, shielding members, and light sources is not limited to three, and may be two or four or more. May be.

  The lens abnormality self-diagnosis method, the obstacle detection system, and other configurations, operations, and effects according to the third embodiment are the same as the lens abnormality self-diagnosis method, the infrared imaging device 1, the obstacle detection system, and the vehicle according to the first embodiment. Since it is the same as that of a structure, an effect | action, and an effect of a vehicle, the same code | symbol is attached | subjected to a corresponding location and the detailed description is abbreviate | omitted.

(Embodiment 4)
The obstacle detection system according to the fourth embodiment is mounted on a vehicle as in the first embodiment, and includes an infrared imaging device 401, an image processing device 3, a display device 4, an alarm device 5, and the like.
FIG. 14 is a schematic diagram showing an infrared imaging device 401 according to Embodiment 4 of the present invention. The infrared imaging device 401 according to the fourth embodiment includes an infrared lens group 11, a lens barrel 12, an infrared imaging unit 13, a light source 14 a, a shielding member 14 b, a collimator lens 14 c, similar to the infrared imaging device 1 according to the first embodiment. A control unit 17, a signal processing unit 18, and an output unit 19 are provided.
However, in the infrared imaging device 401 according to Embodiment 4, a shutter 415 used for offset correction of the infrared imaging element 13a is arranged between the infrared lens group 11 and the infrared imaging element 13a. In this case, since the infrared rays from the light source 14a are also blocked by closing the shutter 415, it is impossible to diagnose the presence or absence of lens abnormality after blocking outside light using the shutter 415 as described in the first embodiment. .
The infrared imaging apparatus 401 according to the fourth embodiment enables self-diagnosis of a lens abnormality without closing the shutter 415. The configuration of the plane reflecting mirror 416 and the processing procedure of the control unit 31 are the same. Different from the infrared imaging apparatus according to the first embodiment. Below, the said difference is mainly demonstrated.

  A flat plate-like reflecting mirror support 416 c that supports the flat reflecting mirror 416 is extended to the front side in the optical axis L direction at the front end portion of the lens barrel 12. The flat reflecting mirror 416 is rotatably supported at the tip of the reflecting mirror support 416c by a rotating shaft 416a, and the flat reflecting mirror 416 is folded toward the reflecting mirror support 416c as shown by a two-dot chain line. The closed state and the open state in which the planar reflecting mirror 416 faces the infrared lens group 11 can be taken as shown by the solid line. Moreover, the opening degree of the planar reflecting mirror 416 can be adjusted between the open state and the closed state.

  The flat reflecting mirror 416 is driven to rotate by the reflecting mirror driving unit 416b. The reflecting mirror driving unit 416b includes, for example, a stepping motor that rotates the planar reflecting mirror 416, a motor driving unit that drives the stepping motor, and the like. The operation of the reflecting mirror driving unit 416b is controlled by the control unit 17. Yes.

  FIG. 15 is a flowchart illustrating a processing procedure of the control unit 17 on the infrared imaging device 401 side in the fourth embodiment.

  The control unit 17 of the infrared imaging device 401 opens the planar reflecting mirror 416 by supplying a reflecting mirror driving signal to the reflecting mirror driving unit 416b (step S91), and turns on the light source 14a (step S92). Next, the control unit 17 captures an image collected by the infrared lens group 11 with the infrared imaging element 13a in a state where the light source 14a is turned on (step S93), and outputs captured image data obtained by the imaging. (Step S94).

Then, the control unit 17 turns off the light source 14a (step S95), and picks up an image collected by the infrared lens group 11 with the infrared imaging element 13a in a state where the light source 14a is turned off (step S96). The captured image data obtained by imaging is output (step S97).
Note that the captured image data when the light source 14a is turned on and off in steps S93 and S96 is preferably data when the captured image is stable, for example, when the vehicle is stopped. This is because it takes time to turn on and off the light source 14a and the imaging process, and therefore accurate difference data cannot be obtained when the captured image is not stable. Therefore, for example, a receiving unit that receives a vehicle speed sensor signal indicating whether or not the vehicle is stopped, and a vehicle stop determination that determines whether or not the vehicle is stopped based on the vehicle speed sensor signal received by the receiving unit. And when the vehicle stop determination means determines that the vehicle is stopped, it may be configured to determine whether or not there is an abnormality in the lens based on a captured image obtained by the imaging device. With this configuration, it is possible to more accurately determine whether there is a lens abnormality.

  Next, the control unit 17 determines whether or not captured image data of all incident angles has been output (step S98). When it is determined that there is unoutput captured image data (step S98: NO), the control unit 17 changes the opening of the plane reflecting mirror 416 by rotating the stepping motor (step S99), and the process is stepped. Return to S93.

  When it is determined that the captured image data of all incident angles has been output (step S98: YES), the control unit 17 closes the planar reflecting mirror 416 by giving the reflecting mirror driving signal to the reflecting mirror driving unit 416b (step S100). ) Finish the process.

FIG. 16 is a flowchart illustrating a processing procedure of the control unit 31 on the image processing apparatus 3 side according to the fourth embodiment.
The control unit 31 of the image processing device 3 acquires captured image data of all incident angles output from the infrared imaging device 401 when the light source 14a is turned on (step S111). Next, the control unit 31 acquires captured image data of all incident angles output from the infrared imaging device 401 when the light source 14a is extinguished (step S112).

  Then, based on the acquired captured image data, the control unit 31 determines the gradation value of the captured image when the light source 14a is turned on at one incident angle and the gradation value of the captured image when the light source 14a is turned off at the one incident angle. The difference from the value is calculated for each pixel (step S113).

  FIG. 17 is a schematic diagram illustrating a captured image acquired from the infrared imaging device 401 and a captured image after difference calculation. 17A shows a captured image when the light source 14a is turned off, FIG. 17B shows a captured image when the light source 14a is turned on, and FIG. 17C shows each pixel constituting the captured image when the light source 14a is turned on. This is a captured image obtained by subtracting the gradation value of each pixel constituting the captured image when the light source 14a is turned off from the gradation value. As shown in FIG. 17C, the image of the subject is removed by subtracting the gradation value of the captured image when the light source 14a is turned off from the gradation value of the captured image when the light source 14a is turned on, and only the shielding member is obtained. Images can be obtained.

  When the process of step S113 is completed, the control unit 31 detects the light intensity distribution in the predetermined range of the captured image from the difference between the calculated gradation values (step S114). The predetermined range is the same as that in the first embodiment. Then, the control unit 31 obtains an MTF function by performing Fourier transform on the light intensity distribution, and calculates the MTF value of the lens at a predetermined frequency (step S115). Next, the control unit 31 reads the threshold value (step S116), and determines whether or not the MTF value calculated in step S115 is less than the threshold value (step S117). That is, it is determined whether or not the MTF value of the infrared lens group 11 is in the normal range.

  If it is determined that the MTF value is less than the threshold (step S117: YES), the control unit 31 issues a warning that the infrared lens group 11 has an abnormality (step S118), and ends the process. When it determines with an MTF value being more than a threshold value (step S117: NO), the control part 31 determines whether the MTF value of all the incident angles was calculated (step S119). If it is determined that there is an MTF value that has not been calculated (step S119: NO), the control unit 31 returns the process to step S113. When it determines with having calculated the MTF value of all the incident angles (step S119: YES), the control part 31 complete | finishes a process noting that there is no abnormality in the infrared lens group 11. FIG.

  In the lens abnormality self-diagnosis method, the obstacle detection system, and the vehicle according to the fourth embodiment, even when the shutter 415 is disposed between the infrared lens groups 11, the infrared lens is related to a plurality of incident angles. The MTF value of the group 11 is calculated, and the presence or absence of abnormality of the infrared lens group 11 can be self-diagnosed using the MTF value.

  In the fourth embodiment, the case where the image of the shielding member cannot be obtained with the shutter closed is explained. However, as in the first embodiment, the abnormality of the infrared lens group when the shutter is closed. The above-described processing procedure may be applied to an obstacle detection system capable of diagnosing the presence or absence. That is, in the first embodiment, the configuration is such that the outside light is blocked by closing the shutter and the MTF value is calculated, but in this case as well, the difference between the gradation values is calculated as shown in the fourth embodiment. It is good to comprise so that it may calculate. When the above-described processing procedure is applied to the first embodiment, even if the amount of infrared rays emitted from the shutter may vary depending on the surrounding environment of the infrared imaging device 1, the influence of infrared rays emitted from the shutter may also be affected. Since it can be removed, the MTF value of the infrared lens group can be calculated more accurately and the presence or absence of abnormality of the infrared lens group can be diagnosed. Moreover, based on the captured image of the shielding member imaged in a plurality of directions, MTF values at a plurality of incident angles can be calculated, and the presence or absence of abnormality of the infrared lens group can be self-diagnosed using the MTF values.

  Further, the infrared imaging device and the obstacle detection system according to Embodiment 4 are configured to capture an image of the shielding member without blocking external light with the shutter. Therefore, when the light source is turned on, the intensity of light condensed on the image sensor may be saturated. In this case, the difference between the light intensity distributions when the light source is turned off and when the light source is turned on cannot be accurately calculated, and it is difficult to calculate the MTF value. Therefore, when the gradation value of the pixels constituting the acquired captured image reaches the maximum value, the control unit of the image processing apparatus reduces the gradation value as a whole before calculating the difference, and corresponds to the maximum value. It is preferable to configure so as to correct the portion that is present from the tendency of change in the gradation values of the surrounding pixels. Alternatively, the infrared imaging device may be configured to adjust the gain of the imaging element so that the light intensity is saturated and the gradation value does not reach the maximum value.

  The lens abnormality self-diagnosis method, the obstacle detection system, and other configurations, operations, and effects according to the fourth embodiment are the same as the lens abnormality self-diagnosis method, the infrared imaging device 1, the obstacle detection system, and the vehicle according to the first embodiment. Since it is the same as that of a structure, an effect | action, and effect of a vehicle, the same code | symbol is attached | subjected to a corresponding location and the detailed description is abbreviate | omitted.

  It should be understood that the embodiment disclosed this time is illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

It is a schematic diagram which shows the infrared imaging device which comprises the obstruction detection system as a lens abnormality self-diagnosis system which concerns on Embodiment 1 of this invention. It is an optical path diagram which shows the change of the optical path when a plane reflective mirror is rotated. It is a mimetic diagram showing composition of an obstacle detection system provided with an infrared imaging device, and vehicles. It is a block diagram which shows the structure of an image processing apparatus. It is a flowchart which shows the process sequence of the control part by the side of the infrared imaging device which concerns on the self-diagnosis of an infrared lens group. It is a flowchart which shows the process sequence of the control part by the side of the image processing apparatus which concerns on the self-diagnosis of an infrared lens group. It is explanatory drawing which shows the processing content of a control part notionally. It is a graph which shows the MTF curve of a normal infrared lens group, and the MTF curve of an abnormal infrared lens group. It is a schematic diagram which shows the infrared imaging device which comprises the obstruction detection system as a lens abnormality self-diagnosis system which concerns on Embodiment 2 of this invention. It is a schematic diagram which shows the infrared imaging device which comprises the obstruction detection system as a lens abnormality self-diagnosis system which concerns on Embodiment 2 of this invention. 10 is a flowchart illustrating a processing procedure of a control unit on the infrared imaging device side in the second embodiment. It is a schematic diagram which shows the infrared imaging device which concerns on Embodiment 3 of this invention. 10 is a flowchart illustrating a processing procedure of a control unit on the infrared imaging device side in the third embodiment. It is a schematic diagram which shows the infrared imaging device which concerns on Embodiment 4 of this invention. 14 is a flowchart illustrating a processing procedure of a control unit on the infrared imaging device side in the fourth embodiment. 15 is a flowchart illustrating a processing procedure of a control unit on the image processing apparatus side in the fourth embodiment. It is a schematic diagram which shows the captured image acquired from the infrared imaging device, and the captured image after difference calculation.

Explanation of symbols

1, 201, 301, 401 Infrared imaging device 3 Image processing device (diagnostic device)
DESCRIPTION OF SYMBOLS 11 Infrared lens group 13a Infrared imaging device 14a Light source 14b Shielding member 14c Collimator lens 14d Light source support body 15 Shutter 16, 416 Planar reflecting mirror 16a, 416a Rotating shaft 17 Control part (incident angle change means)
20 Piezoelectric element (incident angle changing means)
21 Stepping motor (incident angle changing means)
21b Support body rotation axis 31 control unit (acquisition means, calculation means, diagnosis means, difference calculation means)
37 Memory 216 Reflector L Optical axis

Claims (13)

A lens abnormality self-diagnosis method of an imaging apparatus having an imaging unit that captures an image obtained by condensing a lens and the lens,
Substantially parallel light is incident on each of the lenses from a plurality of incident angles,
The MTF value of the lens is calculated for each incident angle based on the gradation value of each of the plurality of pixels constituting the captured image obtained by the imaging unit.
A lens abnormality self-diagnosis method comprising diagnosing the presence or absence of abnormality of the lens based on the calculated MTF value. An imaging apparatus including a lens and an imaging unit that captures an image obtained by condensing with the lens,
An irradiating means for causing substantially parallel light to enter the lens;
Calculating means for calculating an MTF value of the lens based on gradation values of a plurality of pixels constituting a captured image obtained by the imaging unit;
Diagnosing means for diagnosing the presence or absence of abnormality of the lens based on the MTF value calculated by the calculating means;
An imaging apparatus comprising: an incident angle changing unit that changes an incident angle of the substantially parallel light with respect to the lens. An image pickup apparatus having an image pickup unit that picks up an image obtained by condensing the lens and the lens, and a gradation value of each of a plurality of pixels constituting the picked-up image obtained by the image pickup unit A lens abnormality self-diagnosis system comprising a diagnostic device for diagnosing the presence or absence of an abnormality of the lens based on a tone value,
The imaging device
An irradiating means for causing substantially parallel light to enter the lens;
An incident angle changing means for changing an incident angle of the substantially parallel light with respect to the lens,
The diagnostic device comprises:
Calculating means for calculating the MTF value of the lens based on the acquired gradation value;
A lens abnormality self-diagnosis system comprising: a diagnosis unit that diagnoses the presence or absence of abnormality of the lens based on the MTF value calculated by the calculation unit. The imaging device
An openable / closable shutter that blocks external light other than substantially parallel light from the irradiation means;
The irradiation means includes
4. The lens abnormality self-diagnosis system according to claim 3, wherein when the shutter is closed, substantially parallel light is irradiated. The imaging device
5. The lens abnormality self-diagnosis system according to claim 3, further comprising a reflecting mirror that reflects substantially parallel light from the irradiating unit and enters the lens. The incident angle changing means includes
The lens abnormality self-diagnosis system according to claim 5, further comprising means for changing the posture of the reflecting mirror with respect to the lens. The shutter has a plate shape facing the lens,
The imaging device
A reflecting mirror that reflects substantially parallel light from the irradiating means and enters the lens;
A rotating shaft that rotatably supports the reflecting mirror on the lens side surface of the shutter;
The incident angle changing means includes
The piezoelectric element interposed between the shutter and the reflecting mirror is provided, and the posture of the reflecting mirror is changed by applying different voltages to the piezoelectric element. The lens abnormality self-diagnosis system described. The incident angle changing means includes
The lens abnormality self-diagnosis system according to any one of claims 3 to 5, further comprising a unit that varies a posture of the irradiation unit with respect to the lens. The irradiation means is plural,
The plurality of irradiating means are arranged such that incident angles of substantially parallel light from the irradiating means to the lens are different from each other,
The incident angle changing means includes
The lens abnormality self-diagnosis system according to any one of claims 3 to 5, wherein a plurality of the irradiation units are selectively turned on. The diagnostic device comprises:
Storage means for storing the threshold value;
The diagnostic means includes
The lens abnormality self-diagnosis system according to any one of claims 3 to 9, wherein when the MTF value is smaller than the threshold value, the lens is diagnosed as having an abnormality. The calculating means includes
When the substantially parallel light is incident on the lens at one incident angle and the illuminating means irradiates the substantially parallel light, each of a plurality of pixels constituting the captured image captured by the imaging unit is captured. A difference calculating unit that calculates a difference between a gradation value and a gradation value of each of a plurality of pixels constituting an image captured by the imaging unit when the irradiating unit does not irradiate substantially parallel light; The lens abnormality self-diagnosis system according to any one of claims 3 to 10, wherein the MTF value of the lens is calculated based on the difference calculated by the difference calculation means. . The diagnostic device comprises:
The lens abnormality self-diagnosis system according to any one of claims 3 to 11, further comprising a unit that issues a warning when the lens is diagnosed as having an abnormality. A vehicle comprising the imaging device according to claim 2 or the lens abnormality self-diagnosis system according to any one of claims 3 to 12.

Images