TURBIDITY DETECTOR DEVICE

Abstract

Turbidity detector device (10, 25), comprising: - several cameras (11A, 11B) for recording environmental information of a vehicle from inside the vehicle through a glass pane (13); - a turbidity operation section (14) for controlling the occurrence of turbidity on a part of the glass pane (13) in front of one of the cameras (11A, 11B); - a turbidity feature calculation unit (16) configured to calculate a turbidity feature value from images acquired by each of the cameras (11A, 11B); and - a turbidity determination unit (17) configured to determine a turbidity state of each part of the glass pane (13) in front of the corresponding of the multiple cameras (11A, 11B) according to a difference in the turbidity feature size calculated by the turbidity feature calculation unit (16).

Description

Background of the invention; Field of the invention

[0001] The present invention relates to a turbidity detector device for detecting a turbidity state of a glass pane in front of several cameras that record environmental information of a vehicle from an inside of the vehicle through the glass pane. Description of the state of the art

[0002] Patent specification 1 (JP 2009- 29 350 A) discloses a method for detecting a three-dimensional location of an imaged object by processing signals acquired from multiple image sensors, by comparing information recorded in each case with reference location information, and by determining condensation based on the comparison result.

[0003] However, according to the method described in patent specification 1, a camera image taken in the past and a camera image taken just now are compared to determine the condensation; however, the same landscape is not photographed when determining the turbidity, which may cause a false detection of turbidity. Disclosure of the invention

[0004] The present invention was made in view of the above circumstances and it is an objective of the invention to provide a turbidity detector device that accurately detects the turbidity state of the glass pane in front of the camera, without influence from the environment.

[0005] A turbidity detector device according to one aspect of the present invention comprises multiple cameras, a turbidity operation section, a turbidity feature calculation unit, and a turbidity determination unit. The multiple cameras capture environmental information from inside the vehicle through a glass pane. The turbidity operation section controls the appearance of turbidity on a portion of the glass pane in front of one of the multiple cameras. The turbidity feature calculation unit is configured to calculate a turbidity feature value from images captured by each of the multiple cameras. The turbidity determination unit is configured to determine the turbidity state of each portion of the glass pane in front of each of the multiple cameras based on a difference in the turbidity feature value calculated by the turbidity feature calculation unit.

[0006] According to the invention, different opacity states appear on parts of the glass pane in front of the respective cameras. These states are recorded by the cameras in order to calculate the opacity characteristic value from the recorded images. Subsequently, the opacity state in each part of the glass pane in front of the corresponding camera (of several cameras) is determined according to a difference in the opacity characteristic value. Therefore, even if only slight fog exists, the fog state of the glass pane in front of the camera can be precisely detected.

[0007] Furthermore, since images acquired by multiple cameras are used, the images captured by these cameras can depict the same landscape (this is environmental information) simultaneously from the same direction. Therefore, it is less likely that there will be a negative influence from changes in the environment, such as the landscape in front of the camera, and changes in lighting, thus reducing the possibility of misdiagnosing turbidity. Brief description of the drawings Fig. Figure 1 is a block diagram illustrating an example of the first embodiment of a turbidity detector device according to the invention. Fig. 2 is a perspective view showing a state in which the in Fig. The camera shown is attached to the windshield of the vehicle. Fig. 3 is a perspective view showing a support for attaching the in Fig. 2 cameras are illustrated. Fig. 4A is an explanatory image without turbidity, taken by the in Fig. 1 camera shown. Fig. 4B is a low-turbidity explanatory image taken by the in Fig. 1 camera shown. Fig. 4C is an explanatory image with strong turbidity, taken from the in Fig. 1 camera shown. Fig. Figure 5A is an explanatory diagram showing the frequency distribution of brightness, where brightness is an example of a turbidity characteristic variable that is determined by the in Fig. The turbidity characteristic calculation unit shown in 1 is calculated. Fig. 5B is an explanatory graphical representation showing the brightness ratio in relation to Fig. 5A illustrates. Fig. Figure 6A is a clear representation of the frequency distribution of spatial frequencies, where the spatial frequency is another example of the turbidity characteristic parameter that is determined by the in Fig. The turbidity characteristic calculation unit shown in 1 is calculated. Fig. Figure 6B is an illustrative representation of the spatial frequency ratio with reference to Fig. 6A. Fig. 7 is a flowchart of an example of the operation of the in Fig. Turbidity detector device shown in 1. Fig. Figure 8 is a block diagram of an example of the second embodiment of the turbidity detector device according to the invention. Fig. 9 is a flowchart which is an example of the operational process of the in Fig. Figure 8 shows the turbidity detector device. Fig. 10 is a perspective view of a camera unit, which is another example of the in Fig. 1 and Fig. The turbidity operation section shown in section 8 is shown. Detailed description

[0008] An embodiment of the present invention will be explained in more detail below with reference to the drawings. [A] First embodiment (Figures 1 to 7)

[0009] Fig. Figure 1 is a block diagram illustrating an example of the first embodiment of a turbidity detector device according to the invention. Fig. 2 is a perspective view and illustrates a state in which the in Fig. The camera shown is attached to the windshield of the vehicle. The haze detector device 10 according to the Fig. 1 and Fig. 2 detects the opacity (such as fog, frost, or dew) that appears on the window glass pane (for example, the windshield of the vehicle) in front of the first camera 11A and the second camera 11B. The opacity detector device 11 contains several cameras (the first camera 11A and the second camera 11B), the opacity operation unit 14, and the image processing unit 15, and the image processing unit 15 contains the opacity feature calculation unit 16 and the opacity determination unit 17.

[0010] As in the Fig. 2 and Fig. As shown in Figure 3, the first camera 11A and the second camera 11B are attached to and held by the support 18 on the upper part of the window glass 13, arranged side by side in a horizontal direction. The support 18 has a block shape and is attached to the front circumferential region of the support 18 by means of a mounting surface 19 for attachment to the glass pane 13. Several, for example two, concave sections 20 are provided inside the mounting surface 19. The lenses 12 of the first camera 11A and the second camera 11B are located at the innermost points of the concave sections 20 of the support 18, and the support 18 holds the first camera 11A and the second camera 11B.

[0011] When the mounting surface 19 of the support 18 is attached to the window glass 13, the respective lenses 12 of the first camera 11A and the second camera 11B, as well as the respective parts of the window glass 13 in front of these lenses 12 (i.e., the first glass surface section 13A in front of the lens 12 of the first camera 11A and the second glass surface section 13B in front of the lens 12 of the second camera 11B), are covered by the support 18. As a result, the first camera frontal area 21A in front of the first camera 11A is formed by the surrounding concave section 20 of the support 18, the lens 12 of the first camera 11A, and the first glass surface section 13A. A second camera front chamber 21B is also formed in front of the second camera 11B by being surrounded by the other concave section 20 of the carrier 18, the lens 12 of the second camera 11B and the second glass surface section 13B.The first camera front chamber 21A and the second camera front chamber 21B are configured independently of each other without communication. The first camera 11A and the second camera 11B, which are held by the support 18 described above and attached to the window glass 13, simultaneously capture the same environmental information (landscape) of the vehicle from inside the vehicle through the window glass 13 and from the same direction. The first camera 11A and the second camera 11B can, in particular, be a stereo camera, a unit consisting of a wide-angle camera and a telephoto camera, a unit consisting of a high-resolution monochrome camera and a color camera, a unit consisting of a single camera and an omnidirectional monitor camera, and the like.

[0012] The turbidity operation section 14 after Fig. 1 processes / controls the occurrence of opacity on the part of the window glass 13 that is located in front of one of the cameras 11A and 11B, for example, in front of the first glass surface section 13A in front of the first camera 11A. In particular, the opacity operation section 14 is the gap 22 according to Fig. 3. That is, within the carrier 18, the first camera front chamber 21A is formed on the front of the first camera 11A, and the second camera front chamber 21B is formed on the front of the second camera 11B, and a portion of the mounting surface 19 corresponding to one of the camera front chambers, for example, the first camera front chamber 21A, is cut out, forming the gap 22 at the first glass surface section 13A. In this example, the gap 22 connects the first camera front chamber 21A and the vehicle interior to allow air from within the vehicle interior to flow into and out of the first camera front chamber 21A.

[0013] The difference in the amount of air flowing into and out of the first camera front chamber 21A and the second camera front chamber 21B is determined by changing the size of the gap 22 of the support 18, which causes the difference in the degree (the level, the state) of turbidity appearing on the first glass surface section 13A and the second glass surface section 13B. When the air in the vehicle interior, whose water content increases due to the passengers, flows into the first camera front chamber 21A through the gap 22, as is the case in Fig. 2, as indicated by the hatched area, the first glass surface section 13A, which forms the first camera front room 21A, is more easily clouded than the second glass surface section 13B.

[0014] The following describes an image taken by the first camera 11A through the first glass surface section 13A, as well as an image taken by the second camera 11B through the second glass surface section 13B. The images taken by the first camera 11A and the second camera 11B are described according to Fig. 4A is clear if the first glass surface section 13A and the second glass surface section 13B are not cloudy. If the first glass surface section 13A and the second glass surface section 13B are slightly cloudy (fogged or covered with frost), the image will be clear according to... Fig. 4B slightly unclear. If the first glass surface section 13A and the second glass surface section 13B are heavily clouded, the image will be as follows: Fig. 4C unclear.

[0015] The in Fig. The depicted turbidity feature calculation unit 16 extracts the overlap area from the images taken by each of the multiple cameras (for example, images taken by the first camera 11A and the second camera 11B) and calculates the turbidity feature magnitude in the image overlap area. The turbidity feature magnitude includes luminance and spatial frequency. If the glass surface sections 13A and 13B are turbid, the first glass surface section 13A and the second glass surface section 13B will appear white due to irregular reflection, so that consequently the brightness distribution of the images taken by the first camera 11A and the second camera 11B will be shifted towards the side of high brightness.If the first glass surface section 13A and the second glass surface section 13B remain opaque, the high-frequency component of the spatial frequency is cut off due to the opacity, consequently the spatial frequency of the images taken by the first camera 11A and the second camera 11B has a distribution in which the high-frequency zone is attenuated.

[0016] If, for example, the first glass surface section 13A is opaque and the second glass surface section 13B is not opaque, the resulting frequency distribution of brightness is calculated by the opacity characteristic calculation unit 16, as shown in Fig. 5A is shown, where a frequency distribution of the spatial frequency is shown in Fig. The course shown in 6A is also shown. Furthermore, the turbidity characteristic calculation unit 16 calculates the brightness ratio (see Fig. 5B) by comparing the frequency distributions of the brightness of the image in the case of clouding and the image in the case without clouding, and calculates the spatial frequency ratio (see Fig. 6B) by comparing the similarity of the frequency distributions of the spatial frequency.

[0017] The brightness ratio is the ratio of the image brightness when opacity is present to the image brightness when no opacity is present. The spatial frequency ratio is the ratio of the image's spatial frequency when opacity is present to the image's spatial frequency when no opacity is present. If opacity occurs in the first glass surface section 13A and the second glass surface section 13B, the brightness distribution shifts towards the side of higher brightness, as determined by the brightness ratio. Fig. 5B is illustrated, and the high-frequency component of the space frequency is attenuated, as shown by the space frequency ratio according to Fig. 6B illustrates this.

[0018] The turbidity determination unit 17 according to Fig. 1 determines the relative turbidity state in each part of the window glass 13 in front of each of the several cameras, for example, in the first glass surface section 13A and the second glass surface section 13B in front of the first camera 11A and the second camera 11B respectively, according to the difference in the turbidity characteristic size, as calculated by the turbidity characteristic calculation unit 16. That is, as in the Fig. 5A, Fig. 5B, Fig. 6A and Fig. As shown in Figure 6B, the turbidity determination unit 17 determines whether there is a significant difference (a difference equal to or greater than a predetermined value) in the differences α, β, γ, and δ. The difference α represents the difference in the frequency distribution of brightness between the image captured by the first camera 11A and the image captured by the second camera 11B (see Figure 6B). Fig. 5A). The difference β represents the difference in the frequency distribution of the spatial frequencies (see Fig. 6A). The difference γ is the difference with respect to the numerical value “1.0” of the luminance ratio (see Fig. 5B), and the difference δ is the difference with respect to the numerical value “1.0” of the spatial frequency ratio (see Fig. 6B). If there is a significant difference (a difference equal to or greater than the predetermined value) in at least one of these differences α, β, γ and δ, the turbidity determination unit 17 determines the relative turbidity state between the first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B. For example, it is determined that the first glass surface section 13A is turbid with respect to the second glass surface section 13B.

[0019] If there is no significant difference in the differences α, β, γ and δ, the turbidity determination unit 17 determines that the first glass surface section 13A and the second glass surface section 13B are not turbid.

[0020] The following will be based on the Fig. 1 and Fig. 7 The operation of the turbidity detector device 10 with the above-explained setup is described.

[0021] Due to the opacity operation section 14 (gap 22) on the support 18, which holds the first camera 11A and the second camera 11B, the air inside the vehicle is more likely to flow into and out of the first camera front chamber 21A than into and out of the second camera front chamber 21B. Therefore, the first glass surface section 13A in front of the first camera 11A has a higher probability of becoming opaque than the second glass surface section 13B in front of the second camera 11B. In this situation, the first camera 11A and the second camera 11B simultaneously record the same landscape (environmental information) from the same direction in the same lighting environment (S1).

[0022] The turbidity feature calculation unit 16 of the image processing unit 15 acquires the images acquired by the first camera 11A and the second camera 11B and extracts their overlapping areas (S2). Furthermore, the turbidity feature calculation unit 16 calculates the turbidity feature quantity, for example, the frequency distribution of the brightness and the spatial frequency for the overlapping area of ​​each image acquired by the first camera 11A and the second camera 11B (S3). The turbidity feature calculation unit 16 also calculates the brightness ratio by comparing the brightness to the turbidity feature quantity obtained from the overlapping area of ​​each image of the first camera 11A and the second camera 11B, and it calculates the spatial frequency ratio by comparing the spatial frequency to the turbidity feature quantity (S4).

[0023] The turbidity determination unit 17 of the image processing unit 15 determines whether there is a difference in the turbidity characteristic quantity calculated by the turbidity characteristic calculation unit 16 (S5). For example, the turbidity determination unit 17 determines whether there is a significant difference in at least one of the differences α in the frequency distribution of brightness between the images of the first camera 11A and the second camera 11B, the difference β in the frequency distribution of the spatial frequency between the images of the first camera 11A and the second camera 11B, the difference γ with respect to the brightness ratio value “1.0”, and the difference δ with respect to the spatial frequency ratio “1.0”.

[0024] If there is a significant difference in at least one of the differences α, β, γ, and δ, the turbidity determination unit 17 determines that the glass surface section 13A in front of the first camera 11A is turbid, compared with the second glass surface section 13B in front of the second camera 11B (S6). If there is no significant difference in the differences α, β, γ, and δ, the turbidity determination unit 17 determines that the first glass surface section 13A and the second glass surface section 13B are not turbid (S7).

[0025] According to the first embodiment, the following modes of action (1) to (3) can be achieved.

[0026] The turbidity operation section 14 (the gap 22) on the support 18, which holds the first camera 11A and the second camera 11B and is attached to the window glass 13, causes the turbidity state to differ between the first glass surface section 13A on the one hand and the second glass surface section 13B on the other, which are located in front of the first camera 11A and the second camera 11B, respectively. The turbidity feature calculation unit 16 calculates the brightness and the spatial frequency, which are the turbidity feature quantities, from the respective images of the first camera 11A and the second camera 11B, which were taken in this state, and it further calculates the brightness ratio and the spatial frequency ratio.

[0027] Subsequently, the turbidity determination unit 17 determines the relative turbidity of the first glass surface section 13A in front of the first camera 11A and of the second glass surface section 13B in front of the second camera 11B according to the brightness difference α and the spatial frequency difference β, calculated from the respective images of the first camera 11A and the second camera 11B, as well as the brightness ratio difference γ and the spatial frequency ratio difference δ. As a result, the turbidity in the first glass surface section 13A can be accurately detected even if the turbidity in the first glass surface section 13A, in which the turbidity is particularly promoted by the turbidity operation section 14 (the gap 22), is significantly higher.

[0028] (2) The images taken by the first camera 11A and the second camera 11B, which are mounted on the carrier 18, are images of the same landscape (environmental information) taken simultaneously from the same direction under the same lighting conditions. Therefore, the images are less likely to be affected by changes in the environment, such as the landscape in front of the camera and the lighting conditions, and it is possible to reduce the risk of misdiagnosis in turbidity detection.

[0029] (3) The opacity control section 14, which differentiates the opacity state of the first glass surface section 13A in front of the first camera and the second glass surface section 13B in front of the second camera, is a gap 22 located in the support 18, which holds the first camera 11A and the second camera 11B and attaches them to the window glass 13. Air inside the vehicle is able to flow into and out of the first camera front chamber 21A on the front of the first camera 11A through the gap 22. Therefore, the design of the opacity control section 14, which creates a difference in opacity state between the first glass surface section 13A and the second glass surface section 13B, can be implemented at low cost. [B] Second embodiment (Figures 8 and 9)

[0030] Fig. Figure 8 is a block diagram of an example of the second embodiment of the turbidity detector device according to the invention. In the second embodiment, identical components as in the first embodiment are provided with the same reference numerals as in the first embodiment to simplify the description.

[0031] The turbidity detector device 25 of the second embodiment differs from the turbidity detector device of the first embodiment in that it additionally includes the turbidity detector 26 with a single camera (hereinafter referred to as "turbidity detector 26 with single camera"), the defroster control 27, the turbidity change test unit 28, and the determination unit 29. The turbidity detector device 25 is particularly effective when turbidity occurs in both the first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B, and thus the turbidity determination unit 17 of the turbidity detector device 10 of the first embodiment would detect: "not turbid".

[0032] That is, if both the first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B are opaque, the opacity determination unit 17 of the first embodiment may determine that the first glass surface section 13A and the second glass surface section 13B are “not opaque”, due to the false determination that there is no significant difference in the difference α of the frequency distribution of the brightness, the difference β of the frequency distribution of the spatial frequency, the difference γ of the brightness ratio and the difference δ of the spatial frequency ratio.

[0033] In this case, the turbidity detector 26 with single camera captures an image taken by the first camera 11A or the second camera 11B (for example, the first camera 11A), and from the captured image it determines whether the first glass surface section 13A or the second glass surface section 13B (for example, the first glass surface section 13A) is turbid. This turbidity detection is likely to be adversely affected by the environment outside the vehicle, and it is highly probable that a false "turbid" detection will occur in an environment with few features, such as bad weather like fog or a snowstorm, or in an environment with few features, such as a plain or rocky landscape.

[0034] When the defroster control 27 receives a signal from the opacity detector 26 with single camera, which means that the opacity of the first glass surface section 13A or the second glass surface section 13B has been detected (opacity is detected), the defroster control 27 activates the defroster with which the vehicle is equipped, and the defroster blows dry air against the window glass 13 to eliminate the opacity formed on the window glass 13. The air blown by the defroster flows primarily into the first camera front chamber 21A through the haze operation section 14 (the gap 22) of the support 18, which holds the first camera 11A and the second camera 11B, and thus there is a difference in the amount of air flowing into and out of the first camera front chamber 21A and the second camera front chamber 21B on the front of the second camera 11B.Consequently, the turbidity occurring in the first glass surface section 13A is eliminated more quickly than in the second glass surface section 13B.

[0035] The turbidity feature calculation unit 16 of the image processing unit 15 also operated at predetermined time intervals before the defroster was activated. After the defroster was activated, the turbidity feature calculation unit 16 calculates the brightness and the spatial frequency as turbidity feature parameters from the images taken by the first camera 11A and the second camera 11B. It calculates the brightness ratio by comparing the brightness obtained from the image of the first camera 11A with the brightness obtained from the image of the second camera 11B. It further calculates the spatial frequency ratio by comparing the spatial frequency obtained from the first image of the first camera 11A with the spatial frequency obtained from the image of the second camera 11B, all at predetermined times.The turbidity characteristic calculation unit 16 sequentially transmits the brightness, the spatial frequency, the brightness ratio and the spatial frequency ratio, which were calculated in predetermined time intervals before the activation of the defroster, to the turbidity state change check unit 28.Upon receiving any data such as the brightness received by the turbidity feature calculation unit 16 of the image processing unit 15, the turbidity state change detection unit 28 determines whether the differences α, β, γ and δ have undergone temporal changes, where the difference α is the difference in the frequency distribution of the brightness obtained from the recorded images of the first camera 11A and the second camera 11B, the difference β is the difference in the frequency distribution of the spatial frequency obtained from the recorded images of the first camera 11A and the second camera 11B, the difference γ is the difference with respect to the numerical value “1.0” of the brightness ratio, and the difference δ is the difference with respect to the numerical value “1.0” of the spatial frequency ratio.

[0036] The turbidity state change detection unit 28 checks whether a change over time occurs from a state in which there is no significant difference in the differences α, β, γ, and δ to a state in which there is a significant difference in at least one of the differences α, β, γ, and δ. As an example of such a change over time, consider a change from a state in which the first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B are not turbid, to a state in which the defroster blows away the turbidity of the first glass surface section 13A.

[0037] The determination unit 29 determines that the turbidity detection performed by the turbidity detector 26 with single camera is correct if the turbidity state change test unit 28 confirms that the difference α in the brightness frequency distribution, the difference β in the spatial frequency distribution, the difference γ in the brightness ratio, and the difference δ in the spatial frequency ratio have undergone a temporal change due to the activation of the defroster. If the defroster operates for a predetermined time and the turbidity state change test unit 28 confirms that the differences α, β, γ, and δ have not changed over time, the determination unit 29 determines that the turbidity detection by the turbidity detector 26 with single camera was caused by factors other than turbidity and determines that the turbidity detection performed by the turbidity detector 26 with single camera is a false positive.The detection unit 29 sends a signal to stop the defroster to the defroster control unit 27, together with the detection of a false positive.

[0038] The following will be based on the Fig. 9 The operation of the turbidity detector device 25 with the above-described setup will be explained with reference to the flowchart.

[0039] If turbidity occurs both on the first glass surface section 13A in front of the first camera 11A and in front of the second glass surface section 13B in front of the second camera 11B, and if the turbidity determination unit 17 of the first embodiment delivers the result "not turbid" in the first glass surface section 13A and the second glass surface section 13B, the turbidity detector 26 with single camera of the second embodiment detects the image detected by the first camera 11A or the image detected by the second camera 11B (for example, the image detected by the first camera 11A) and performs a turbidity detection (S11).

[0040] When the turbidity of the first glass surface section 13A or the second glass surface section 13B (for example, of the first glass surface section 13A) has been detected by the turbidity detector 26 with a single camera (turbidity has been detected), the defroster control 27 activates the defroster (S12, S13). Before and after activation of the defroster, the turbidity feature calculation unit 16 of the image processing unit 15 calculates the brightness and the spatial frequency from the respective images taken by the first camera 11A and the second camera 11B at predetermined time intervals. It also calculates the brightness ratio, that is, the ratio of the brightness from the image taken by the first camera 11A to the brightness from the image taken by the second camera 11B, and the spatial frequency ratio, as the ratio of the spatial frequency from the image taken by the first camera 11A to the spatial frequency from the image taken by the second camera 11B (S14).

[0041] The turbidity change test unit 28 confirms whether there is a temporal change in the respective differences α, β, γ, and δ of brightness, spatial frequency, brightness ratio, and spatial frequency ratio, which are calculated by the turbidity characteristic calculation unit 16 at predetermined time intervals (S15). If the turbidity change test unit 28 confirms that the differences α, β, γ, and δ have undergone a temporal change, the determination unit 29 determines that the turbidity detected by the turbidity detector 26 with single camera in step S11 is correct (S16).

[0042] If the turbidity change test unit 28 confirms in step S15 that the differences α, β, γ and δ have not changed over time, the determination unit 29 determines whether the defroster has operated for a certain time (S17), and if the predetermined time has not elapsed, steps S14 and S15 are performed again.

[0043] If, in step S17, it is determined that the defroster has operated for a predetermined period of time, and if, in step S15, the turbidity change test unit 28 has confirmed that the differences α, β, γ, and δ have not changed over time, the determination unit 29 determines that the turbidity detection performed by the single-camera turbidity detector 26 in step S15 was caused partly by turbidity due to other factors, and it determines that this is a false detection (S18), and simultaneously instructs the defroster fault 27 to stop the operation of the defroster (S19).

[0044] In the second embodiment, in addition to the modes of operation (1) to (3) of the first embodiment, the following modes of operation (4) and (5) can be achieved.

[0045] (4) The vehicle is equipped with a defroster to blow air to remove haze from the window glass 13, and the support 18 holding the first camera 11A and the second camera 11B is equipped with the haze operation section 14 (the gap 22) that connects the first camera front chamber 21A on the front of the first camera 11A and the interior of the vehicle. With these features, the dry air (the airflow) from the defroster can more easily flow into and out of the first camera front chamber 21A through the haze operation section 14 (the gap 22) than into and out of the second camera front chamber 21B on the front of the second camera 11B, thus easily removing the haze that appears on the first glass surface section 13A in front of one camera 11A.

[0046] Even if turbidity occurs on both the first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B, and the turbidity determination unit 17 of the first embodiment determines that the first glass surface section 13A and the second glass surface section 13B are "not turbid" by determining that there is no significant difference in the difference α of the frequency distribution of the brightness, nor in the difference β of the difference distribution of the spatial frequency, nor in the difference γ of the brightness ratio, nor in the difference δ of the spatial frequency ratio, the defroster control 27 can activate the defroster after the turbidity detector 26 with single camera has detected turbidity from the image recorded by the first camera 11A or the second camera 11B (for example, the first camera 11A).

[0047] This makes it possible to determine whether there is a difference in the degree of turbidity between the first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B. This is confirmed by the turbidity change test unit 28 by verifying whether there is a temporal change in the differences α, β, γ, and δ, based on the brightness, spatial frequency, brightness ratio, and spatial frequency ratio, which are calculated from the images taken by the first camera 11A and the second camera 11B before and after activation of the defroster. Therefore, the accuracy of the turbidity detected by the single-camera turbidity detector 26 can be precisely determined.

[0048] (5) Even after the predetermined time has elapsed following activation of the defroster by the defroster control 27, if the differences α, β, y, and δ do not change over time, where the differences α, β, y, and δ represent the brightness, spatial frequency, brightness ratio, and spatial ratio, respectively, which are calculated based on the images taken by the first camera 11A and the second camera 11B, the defroster is stopped by the defroster control 27 because the turbidity detector 26 with a single camera was operating before the defroster was activated. A false positive is detected due to a factor other than the turbidity. As a result, the operating time of the defroster can be reduced to the necessary minimum, and unnecessary operation of the defroster can be prevented.

[0049] The embodiments described above are presented merely as examples and are not intended to limit the scope of protection of the inventions. The embodiments described here can be implemented in various ways. Furthermore, omissions, substitutions, and modifications of the present embodiments are possible without departing from the scope of protection of the invention. The appended claims and their equivalents are intended to cover such modifications within the scope of protection of the invention.

[0050] For example, for the first and second embodiments, the following example was described in which the opacity operation section 14 is realized as a gap 22 in the support 18, which holds the first camera 11A and the second camera 11B in the manner described; however, the opacity operation section 14 can be realized as a structure that creates a difference in the ease with which opacity occurs in the first glass surface section 13A in front of the first camera 11A on the one hand and the second glass surface section 13B in front of the second camera 11B on the other, by causing a temperature difference in front of each of the first camera 11A and the second camera 11B.

[0051] In particular, according to Fig.11 in a camera unit 30, in which the first camera 11A and the second camera 11B are arranged at a predetermined interval, a heat generation section 31, in which heat-generating components such as ICs (integrated circuit packages) are integrated, is arranged offset to one side of the first camera 11A and the second camera 11B (for example, to the side of the first camera 11A), whereby the temperature of the first camera front chamber 21A on the side of the first camera 11A becomes higher than in the second camera front chamber 21B on the side of the second camera 11B, in order to suppress the occurrence of turbidity in the first glass surface section 13A in front of the first camera 11A. The first glass surface section 13A in front of the first camera 11A and the second glass surface section 13B in front of the second camera 11B can thus be made different with respect to the turbidity state.

Claims

[1] Turbidity detector device (10, 25), comprising: - several cameras (11A, 11B) for recording environmental information of a vehicle from inside the vehicle through a glass pane (13); - a turbidity operation section (14) for controlling the occurrence of turbidity on a part of the glass pane (13) in front of one of the cameras (11A, 11B); - a turbidity feature calculation unit (16) configured to calculate a turbidity feature value from images acquired by each of the cameras (11A, 11B); and - a turbidity determination unit (17) configured to determine a turbidity state of each part of the glass pane (13) in front of the corresponding of the multiple cameras (11A, 11B) according to a difference in the turbidity feature size calculated by the turbidity feature calculation unit (16). [2] Turbidity detector device (10, 25) according to claim 1, wherein the turbidity operation section (14) has a structure that creates a difference in the amount of air flowing into each space in front of each of the multiple cameras (11A, 11B). [3] Turbidity detector device (10, 25) according to claim 2, wherein: a support (18) for holding the multiple cameras (11A, 11B) covers each lens (12) of each of the cameras (11A, 11B) and each part of the glass (13) in front of the respective lens (11) in order to form the respective space (21A, 21B) in front of the respective lens (12) independently of each other; and the difference in the amount of air flowing into the respective space (21A, 21B) in front of each of the several cameras (11A, 11B) is formed by changing the size of a gap (22) between the glass (13) and the support (18) according to one of the spaces (21A, 21B). [4] Turbidity detector device (25) according to claim 2 or 3, wherein: the vehicle has a defroster that blows on the glass to remove the haze; and the difference in the amount of air flowing into each room in front of each of the multiple cameras is created by activating the defroster. [5] Turbidity detector device (25) according to claim 4, wherein if the difference in the turbidity characteristic size calculated from the images taken by the multiple cameras does not change after the defroster has been activated for a predetermined time, the defroster is stopped. [6] Turbidity detector device according to claim 1, wherein the turbidity operation section has a structure that creates a temperature difference in front of each of the multiple cameras. [7] Turbidity detector device according to claim 6, wherein the turbidity operation section (14) is configured to form the temperature difference in front of each of the multiple cameras by means of a heat generation section (31) located inside a camera unit (30) which includes the multiple cameras (11A, 11B).

Images