JP2000275357A - Rainfall/snowfall situation detection method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately obtain the amount, strength, direction, or the like of rainfall/snowfall that is calculated from a travel vector obtained from an image by enabling rainfall/snowflake to be handled uniquely in image data where depth information is superposed. SOLUTION: Rainfall/snowflake are illuminated by at least two slit beams being applied by successively switching with a switcher 7 near such image pickup means 1 as a television camera, and the image of the rainfall/snowflake where light is applied is picked up by an image pickup means 1, thus extracting either of the amount, strength, and direction of rainfall/snowfall according to depth information that is not superposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting rainfall and snowfall for automatically detecting rainfall and snowfall by using photographing means such as a television camera.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting the state of rain or snow falling on an automobile road at night, a pillar A is erected on the shoulder of the automobile road as shown in FIG. And a light source B for illuminating rain or snow is mounted with a tilt such that the optical axis of the radiated light is directed toward the road surface. The rain or snow falling on the illuminated part is photographed by the photographing means 1, and the photographed image is extracted by the image processing apparatus shown in FIG. The direction was relatively evaluated.

Next, the image processing apparatus will be described. This image processing apparatus C is disclosed in Japanese Patent Application No. 10-031154 filed by the present applicant company. Hereinafter, an example of the image processing apparatus C will be described with reference to FIGS.

Japanese Patent Application No. 10-031154 discloses three embodiments, namely, a sequential difference method, a dynamic difference processing method, and a Nyquist component extraction method for extracting rainfall and snow components. Here, these three embodiments will be described as one.

The sequential difference method is a method of extracting only a moving object (rain and snow) as a time-series positive / negative component from an image by calculating a difference between two temporally adjacent images. The dynamic difference method is a method of extracting only a moving object from an image by taking a difference between a background image in which only a stationary object is captured and a captured image in which a moving object is captured, and a Nyquist component extraction method. Is obtained by calculating the difference between two temporally adjacent images to determine only one of the Nyquist components of a pair of Nyquist components of a time-series positive / negative polarity by taking only the moving object (rain and snow) from the images. Is extracted by frequency filtering, and only the moving object is extracted by calculating a vector connecting the centers of gravity of the extracted Nyquist components.

Hereinafter, an image processing apparatus C for evaluating rainfall and snow conditions will be described. 1 is a photographing means for outputting image data obtained by photographing a rain / snow detection target area as a digital signal, and 2 is an image for storing a frame image composed of a digital signal and extracting a rain / snow component from a difference between the stored time-series image data. Processing means 3, image analysis means 3 for identifying the individual rainfall snow component to calculate the movement vector, 4 is the amount, intensity, based on the number, length, direction of the calculated movement vector
It is a rain / snow evaluation unit that evaluates one of the directions.

Next, details of each means will be described. The photographing means 1 includes a television camera 101 and the television camera 10.
A low-pass filter (LPF) 102 for removing high-frequency components in the video signal captured in step 1 to prevent noise and prevent aliasing noise at the time of sampling, and an AD converter 103 for converting the video signal into a digital signal. ing.

[0008] The image processing means 2 includes a rain / snow component extraction unit 201 formed by the above-described sequential difference method, dynamic difference method, or Nyquist component extraction method, and an area corresponding to the moving component extracted by the rain / snow component extraction unit 201. An area threshold processing unit 202 that performs threshold processing to exclude a vehicle or pedestrian component having a large area and extracts only a rainfall snow component having a small area.

In the sequential difference method and the Nyquist component extraction method, the image analyzing means 3 includes a moving vector calculating section 301 comprising an absolute value image calculating section, a labeling processing section, and a label area separating processing section. In the case of the dynamic difference method, the moving vector calculation unit 3 includes a labeling processing unit and a label area association processing unit.
01 and a movement vector calculation processing unit 302.

Next, the processing operation of the image processing apparatus C of FIG. 9 will be described with reference to the flowchart of FIG. After the high-frequency component of the video signal of the rain / snow detection area captured by the television camera 101 is cut by the low-pass filter 102, the video signal is converted into a digital signal by the AD converter 103 (step S1). The image data converted into the digital signal is temporarily stored in an image memory (not shown) in the rain / snow component extraction unit 201 (step S2), and the moving object is extracted by the sequential difference method, the dynamic difference method, or the Nyquist component extraction method. (Step S3)

Next, the area threshold value processing unit 202 determines that a moving component (vehicle or the like) having a larger area than a certain value is not a snowflake or a raindrop, and excludes these moving objects from the screen. An image in which only the rainfall snow component remains is extracted (step S4).

Next, the moving vector calculation unit 301 performs a labeling process on the target object by using a propagation method or the like that sequentially propagates information according to a propagation rule determined for adjacent pixels, and performs individual rainfall and snowfall. Labeling is performed to identify the components, and the labeled image is sent to the motion vector calculation processing unit 302, and a vector connecting the centers of gravity of the moving objects is calculated (step S5).
This vector is output as a movement vector for the rainfall snow component. The movement vector of each rain / snow component obtained in this way is sent to the rain / snow evaluation unit 4.

The rain / snow evaluation unit 4 evaluates the amount, intensity, and direction of the rain or snow at that time based on the transmitted movement vector of each of the rain / snow components, and outputs each in an appropriate expression form (step). S6).

[0014]

By the way, in the actual image taken out by the above-mentioned photographing means 1, a rainfall snow component which is deep as seen from the photographing means 1 is also shown as shown in FIGS. That is, in FIG. 11 (a),
FIG. 1 shows a photographing example in which the sizes of rainfall and snow components are equal, and FIG.
2 (a) shows an example of photographing in the case where the sizes of the rainfall snow component are different.

In the rain / snow condition shown in FIG. 11A, the photographed image is as shown in FIG. 11B because of the depth.
That is, with respect to the actual rain snowflakes A, B, and C, the rain snowflakes on the captured image are A, B, and C in FIG.
Even if the actual size and speed of each snowflake are the same, the data is handled two-dimensionally, so that each snowflake in the captured image has a different size and speed.

In the rain / snow condition shown in FIG. 12 (a), the photographed image is as shown in FIG. 12 (b) because of the depth. On the other hand, each rainy snowflake on the captured image is a, b, c in Fig. 11 (b). Even if the actual size and speed of each rainy snowflake are different, the data is handled in two dimensions. It is as if each snowflake in the image had the same size and speed.

Therefore, it is difficult to uniquely treat a rainfall snowflake in image data on which depth information is superimposed, and it is necessary to accurately obtain the amount, intensity, direction, etc. of the rainfall snow calculated from a moving vector obtained from the image. Was difficult.

Therefore, the present applicant has developed a method and an apparatus disclosed in Japanese Patent Application No. 10-368449 in order to reduce the above-mentioned problem of superimposition on depth information. This application discloses at least one light source that emits slit-shaped light in the vicinity of photographing means such as a television camera, and the amount of rainfall snowflakes from an image of a rainfall snowflake illuminated by the slit-like light photographed by the photographing means. , Intensity, or direction.

In this case, if the slit light is white light, it is difficult to separate rainfall snowflakes for each luminance due to the influence of the existing illumination, and as a result, information in the depth direction is superimposed. Happens. Further, in order to avoid the influence of the existing illumination, the above application discloses a device using colored light as slit light, but even in this case, the depth information is superimposed. Was the same, and it was therefore difficult to detect the exact amount, intensity, and direction of rainfall snow.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to switch a plurality of slit lights by a switcher in synchronization with a photographing means or in synchronization with a photographing means. The image of each slit is extracted by the photographing means while the slit light is switched by the switcher, and furthermore, by detecting the continuous color spectrum illumination for each color by the color photographing means, the detection of the rainfall snow component can be detected with higher accuracy. It is an object of the present invention to provide a method and an apparatus for detecting rainfall and snow conditions.

[0021]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for detecting rainfall and snow conditions which achieves the above-mentioned object. The method according to claim 1 is characterized in that a switcher is provided near a photographing means such as a television camera. The rainfall snowflakes are illuminated by at least two or more white or colored slit lights that are switched and radiated in synchronization with the photographing means, and the illuminated rainfall snowflakes are photographed by the photographing means. It is characterized in that any one of the amount, intensity, and direction of rainfall snow is extracted.

[0022] The means of claim 2 is a light source that emits at least two or more white or colored slit lights, a photographing means such as a television camera for photographing an image of rainfall snowflakes illuminated by the slit lights, and the photographing means. A switcher for turning on the light source by switching the light source at regular intervals in synchronization with the means, and extracting any one of the amount, intensity, and direction of rain and snow from an image in which depth information obtained by the photographing means is not superimposed. It is like that.

[0023] The means of claim 3 is characterized in that at least two or more white or colored slit lights, which are switched and illuminated by a switcher operating in synchronization with a video synchronizing signal of the photographing means, near the photographing means such as a television camera. The rainfall snowflakes are illuminated, and the illuminated rainfall snowflakes are photographed by the photographing means, so that any one of the amount, intensity, and direction of the rainfall snow is extracted from an image in which depth information is not superimposed. I do.

The means according to claim 4 is a light source that emits at least two or more white or colored slit lights, a photographing means such as a television camera for photographing an image of rainfall snowflakes illuminated by the slit light, and the light source. And a switcher for turning on and off in synchronization with a video synchronization signal of the photographing means, and extracting any one of the amount, intensity, and direction of rain and snow from an image on which depth information obtained by the photographing means is not superimposed. It is like that.

[0025] The means of claim 5 illuminates rainfall snowflakes by irradiating continuous color spectrum light near the photographing means such as a television camera, and illuminates the illuminated rainfall snowflakes for each color by the photographing means. By classification, any one of the amount, intensity, and direction of rainfall snow is extracted from an image in which depth information is not superimposed.

[0026] The means of claim 6 comprises a continuous color spectrum illuminating light source for irradiating the color spectrum light, and a photographing means such as a television camera for photographing an image of rain snowflakes illuminated by the color spectrum light. The illuminated rain snowflakes are classified for each color by the photographing means, so that any one of the amount, intensity, and direction of the rain snow is extracted from an image in which depth information is not superimposed.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a method and apparatus for detecting a rainfall and snow condition according to the present invention will be described with reference to FIGS.
It will be described together. Reference numeral 1 denotes a photographing unit 1 similar to the conventional example, and a plurality of light sources (three light sources are shown in the drawing, but two or more light sources may be used, and colored light is preferable). Slits 61a on irradiation surfaces 51-53
Slit plates 61 to 63 having 〜63a are disposed.

Numeral 1 denotes photographing means including a television camera similar to that of the conventional example.
An image of the rainfall snowflakes arranged in a direction orthogonal to 1a to 63a and reflected by the slit light emitted from the light sources 51 to 53 is taken. Since the light sources 51 to 53 in the present invention need only illuminate the vicinity of the photographing means 1 including the television camera, a light source of low luminance is arranged near the photographing means 1.

Reference numeral 7 denotes a light source 5 which sequentially switches the blinking of the light sources 51 to 53 at desired times, for example, every 33 m / s, so that slit light is emitted from only one slit.
This is a switcher that controls 1 to 53. The switcher 7 is connected to the photographing means 1 by a control circuit (not shown).
The light sources 51 to 53 are controlled in synchronization with the control. That is, control is performed so that an image captured by the image capturing unit 1 for each slit light can be determined to be which slit light.

In the first embodiment of the present invention configured as described above, the rainfall snowflakes photographed by the photographing means 1 are sequentially illuminated by the slit light from one of the slits 61a to 63a. The photographing means 1 extracts the rainfall snow component on which the depth information is not superimposed.
In addition, as shown in FIGS. 2A, 2B, and 2C, continuous photographing is performed, so that spatial information can be obtained without separating depth information based on luminance.

In the image obtained as described above, since the position of the slit light varies in the optical axis direction in the image for each slit light taken by the photographing means 1, the size of the rainfall snow component is reduced. Although different, each slit light is synchronized with the captured image, so that the size of the rainfall snow component can be corrected and handled for each frame. Therefore, by processing this correction in the image processing apparatus C, the spatial Highly accurate information can be obtained.

Next, a second embodiment will be described with reference to FIGS. In the first embodiment, the lighting timing is switched by the switcher 7 to obtain spatially accurate information. In the present embodiment, the frame synchronization of the photographing means 1 is performed. The switcher 7 is switched in synchronization with a signal.

That is, the light sources 51 to 53 are synchronized with the frame synchronization signal (1 / 30s ≒ 33 ms) of the photographing means 1.
Are sequentially switched, and the slits 61 of the slit plates 61 to 63 are changed.
a to 63a to emit slit light (FIG. 3
reference).

Further, with this configuration, since the photographing means (sampling of the image) and the slit light are synchronized, the photographed image is illuminated with the slit light having only one clear section. Since the rainfall snowflakes are projected, the rainfall snowflakes on which the depth information is not superimposed can be extracted in the image processing apparatus C.

Further, since shooting is performed continuously by the frame synchronization signal (FIGS. 4A and 4B), spatial information can be obtained without separating depth information based on luminance. Further, in the video obtained as described above, since the size of the rainfall snow component captured in each frame is different, by correcting and treating the size of the rainfall snow component for each frame, the first first It is possible to obtain information with higher spatial accuracy than in the embodiment.

Next, a third embodiment will be described with reference to FIG. In the first and second embodiments described above, a plurality of (three in the embodiment) slits 61a are provided.
In this embodiment, continuous color spectrum illumination is used.

Hereinafter, this embodiment will be described. Reference numeral 8 denotes a continuous color spectrum illuminating light source for irradiating continuous color spectrum light, and the optical axis of the photographing means 1 and the color from the illuminating light source 8 as described above. The spectrum light is arranged to be orthogonal.

In this embodiment, since the color of the illumination changes continuously, the photographing means 1 performs, for example, photographing for each frequency component of the color spectrum in the illumination light source 8 as appropriate. Thereby, the depth information is not superimposed, and the information on the depth can be classified for each color in which the information is dense.

In the above-described embodiment, the case where the frame synchronization signal is used has been described, but it goes without saying that the video synchronization signal may be a field synchronization signal. In the above-described embodiment, the light source 51
Although the description has been given of the case where the illumination light source 8 and the illumination light source 8 are arranged below the television camera in the photographing means 1, they may be arranged in either the upper direction or the left or right direction as shown in FIG. As shown in FIG. 7, it may be arranged near the television camera and in the circumferential direction around the television camera.

Further, it is not necessary to use a light source and a slit plate as in the first and second embodiments as a light source for emitting slit-shaped light, and a light source in which LEDs having high directivity are arranged in a line, It is also possible to generate slit-shaped light by using a light source that sweeps a laser beam or the like with a narrowed beam in a fan shape at high speed.

[0041]

As described above, the present invention irradiates a plurality of slit lights, which can be switched at regular intervals, to a rainfall snowflake, and determines which slit light is used as the image of the rainfall snowflake illuminated by the irradiation. In order to extract the amount, intensity, or direction of rain and snow from an image on which the captured depth information is not superimposed, a photograph is taken by a photographing means such as a television camera so that spatial accuracy can be improved. High information can be obtained, and the rainfall snow component can be extracted with high accuracy without being affected by the existing lighting.

Also, a plurality of slit lights are radiated to the rainy snowflake in synchronization with the video synchronizing signal of the photographing means, and the image of the rainfall snowflake illuminated by the irradiation is photographed by the photographing means. And highly accurate information can be obtained, and the rainfall snow component can be extracted with high accuracy without being affected by the existing lighting.

Furthermore, continuous color spectrum light is applied to the rain snowflakes, and the image of the rain snowflakes illuminated by the irradiation is separated and photographed for each color by the photographing means. The present invention has effects such as being able to extract rainfall snow components with high accuracy without being affected by existing lighting.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first embodiment of a method for detecting rainfall and snow conditions and an apparatus therefor according to the present invention.

FIGS. 2 (a) to (c) are explanatory diagrams for each slit light in the above.

FIG. 3 is an explanatory diagram showing a second embodiment.

4A is an explanatory diagram for each slit light in the above, and FIG. 4B is a photographed image.

FIG. 5 is an explanatory diagram showing a third embodiment.

FIG. 6 is an explanatory diagram showing an example of an arrangement position of the light source 5 viewed from an oblique direction.

FIG. 7 is an explanatory diagram showing an example of an arrangement position of the light source 5 as viewed from the front.

FIG. 8 is an explanatory diagram showing a conventional lighting method.

FIG. 9 is a block diagram of an image processing apparatus.

FIG. 10 is a flowchart showing a processing operation.

11A and 11B show rainfall snowflakes photographed by a conventional illumination method, FIG. 11A is a perspective view showing a photographing state, and FIG. 11B is a photographed image.

FIG. 12 shows rainfall snowflakes similarly photographed by a conventional illumination method, (a) is a perspective view showing a photographing state, and (b) is a photographed image.

[Explanation of symbols]

 C image processing device 5 light source 6 slit plate 61 slit 7 switcher 8 continuous color spectrum illumination source

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ritsuo Asai 29-1 Mita-ku, Shinoda, Miwa-cho, Kaifu-gun, Aichi Prefecture Inside the Miwa Plant of Nagoya Electric Industrial Co., Ltd. (72) Yasushi Aihara, Miwa-cho, Kaifu-gun, Aichi 29-1 Mita Plant, Nagoya Electric Industrial Co., Ltd. (72) Inventor Koji Ueda Koji Ueda 29-1 Mita Town, Miwa-cho, Kaifu-gun, Aichi Prefecture Nagoya Electric Industry Co., Ltd.Miwa Plant (72) Inventor Kazuo Ikeya Aichi Nagoya Electric Industrial Co., Ltd. Miwa Plant

Claims (6)

[Claims] 1. A rainfall snowflake is illuminated with at least two or more white or colored slit lights which are switched and radiated by a switcher in synchronization with a photographing means near a photographing means such as a television camera. A method for detecting a rainfall / snow condition, wherein one of the amount, intensity, and direction of rainfall snow is extracted from an image in which depth information is not superimposed by photographing a snowflake by the photographing means. 2. A light source that emits at least two or more white or colored slit lights, a photographing means such as a television camera for photographing an image of rainfall snowflakes illuminated by the slit light, and a synchronizing with the photographing means. A switcher for switching the light source at regular intervals to turn on the light source, and extracting one of the amount, intensity, and direction of rain and snow from an image in which depth information obtained by the photographing unit does not overlap. Characteristic rain / snow detector. 3. A rainfall snowflake is illuminated with at least two or more white or colored slit lights which are switched and illuminated by a switcher operating in synchronization with a video synchronization signal of the imaging means in the vicinity of an imaging means such as a television camera. ,
By photographing the illuminated rainfall snowflakes by the photographing means, the amount of rainfall snowfall can be calculated from an image in which depth information is not superimposed,
A rain / snow condition detection method, wherein one of intensity and direction is extracted. 4. A light source that emits at least two or more white or colored slit lights, a photographing unit such as a television camera that photographs an image of rainfall snowflakes illuminated by the slit light, and A switcher for switching and lighting in synchronization with a video synchronization signal, and extracting any one of the amount, intensity, and direction of rain and snow from an image on which depth information obtained by the photographing unit is not superimposed. Characteristic rain / snow detector. 5. In the vicinity of a photographing means such as a television camera, a continuous color spectrum light is irradiated to illuminate rainfall snowflakes, and the illuminated rainfall snowflakes are separated for each color by the photographing means. A rain / snow condition detection method, wherein any one of the amount, intensity, and direction of rain / snow is extracted from an image on which depth information is not superimposed. 6. A illuminated rain / snowflake comprising: a continuous color spectrum illuminating light source for irradiating a color / spectrum light; and photographing means such as a television camera for photographing an image of the rain / snowflake illuminated by the color spectrum light. The amount of snowfall, intensity, or direction is extracted from an image on which depth information is not superimposed by separating the images for each color by the photographing means.