JP2596573B2 - Pallet with target - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a pallet having a target, and more particularly, to lifting a predetermined load from a pallet using a hang-up tool or loading / unloading a load on the pallet, using the target as a target for positioning the hang-up tool. Suitable for
The present invention relates to a pallet having a target.

[Prior art]

When a load such as a coil is placed at a predetermined position on a pallet in a factory, it is necessary to suspend the load with a crane or the like, position the crane at a predetermined position on the pallet, and drop the load. For this reason, in the method for detecting the center position of a suspended load of a crane disclosed in Japanese Patent Application Laid-Open No. 62-138702, a television camera is provided on the crane, the load is imaged by the camera, and an image signal generated at this time is used. The center of the suspended load is detected.

[Problems to be solved by the invention]

However, in this method, it is difficult to identify the center of the suspended load unless the shape of the suspended load is constant (the distribution specific gravity of the projected area is constant), such as a steel plate, and good positioning accuracy cannot be obtained. In addition, it is effective only for hanging loads,
There is a problem that it cannot be used for unloading.

[Object of the invention]

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to easily form a target having high durability and hard to cause erroneous recognition, and to perform positioning of a hanging tool with high precision. It is an object of the present invention to provide a pallet having a target that can be obtained.

[Means for solving the problems]

The present invention relates to a pallet on which a load is lifted from a pallet using a hanging tool or a load is unloaded on a pallet. A target is provided at a position which has a predetermined relationship with the load, and the target has a contrast with a peripheral portion of the target on the pallet such that a predetermined signal level difference can be obtained in a video signal generated by the imaging means. Thus, the above object has been achieved.

[Action]

In the present invention, a hole-shaped target that is imaged and recognized by the imaging means for positioning the hanging device when lifting the load from the pallet using the hanging device or when unloading the load on the pallet is used. The target is provided on a pallet, the target is provided at a position having a predetermined positional relationship with a load corresponding to the purpose of use of the pallet, and the target is provided on a target peripheral portion of the pallet in a video signal generated by the imaging means. Is formed so as to have a contrast that can obtain the signal level difference of Therefore, the position of the target can be accurately recognized without erroneously recognizing the target pattern as dirt or the like, and the position of the hanger can be positioned at a predetermined position on the pallet. When the pallet is used exclusively for unloading, the target may be provided at a position (for example, below the center of the load) where the target is hidden by the loaded load. On the other hand, when the pallet is used for both lifting and unloading a load, a target is provided at a position which is not hidden when the load is unloaded and is spaced apart from the load by a predetermined distance.

【Example】

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. This embodiment uses a crane 6 as shown in FIG.
Of a load, for example, a hoisting device for lifting a coil, provided on a traversing cart (club) 8 is positioned at a center position of the load on a pallet 14 for mounting the load by using a television camera 12. To this end, a lighting device 13 irradiates a target 16 provided on the pallet 14 with illumination light, images the vicinity of the target, creates a video signal, recognizes the target 16 from the video signal, and suspends 10 positioning is performed. Note that reference numeral 15 in the figure denotes a traveling vehicle (girder). The television camera 12 is mounted on a trolley 8 of a crane, and a video signal generated by the television camera 12 is input to an arithmetic unit 17 for recognizing a target 16. The television camera 12 and the arithmetic unit 17 have the configuration shown in FIG. 2 in detail. In FIG. 2, reference numeral F denotes the field of view of the television camera 12. The arithmetic unit 17 includes a binary conversion unit 18, a buffer memory 2
0, a pattern feature determination unit 22, an address determination unit 24, and an interface (I / F) 26. The video signal input to the arithmetic unit 17 is a binary conversion unit.
Entered in 18. The binary conversion unit 18 converts the input video signal into a binary signal of 1 and 0 (binary processing) (this converted binary signal is referred to as an image signal) and inputs the binary signal to the buffer memory 20. . As described above, the binary conversion unit 18 can perform binary conversion to emphasize and recognize the pattern of the target 16. The buffer memory 20 stores the image signal for one screen after the conversion. The image signal stored in the buffer memory 20 is output to the pattern feature determination section 22. The pattern feature determination unit 22 recognizes a figure having the same pattern as the target 16 from the image signal by comparing and searching the stored image signal and the pattern of the target 16. In order to perform this search, the pattern of the target 16 is previously input and stored as an image signal via the binary conversion unit 18 in the pattern feature determination unit 22. The search result of the pattern feature determination unit 22 is input to the address determination unit 24. The address determination unit 24 determines and measures the position of the target 16 from the input search result. The measurement result of the address determination unit 24 is output to the outside through the interface 26 as a measurement result signal, for example, a position signal of the target 16 and transmitted to the position control device of the crane. An external instruction signal, for example, a measurement start signal is input to the interface 26, and the arithmetic unit 17 is operated. FIG. 3 is a pallet devised for mounting a coil. The target 16 is provided on the ordinary pallet 14 by the number (plurality) of loads to be placed thereon. Further, the target 16 can be provided at a position having a predetermined relationship with the load. That is, if the pallet 14 is used only for loading a load, that is, it is used exclusively for unloading, the position of the target 16 may be recognized in a state where the load is not placed. (Under the center of the target). If the pallet 14 is used for both loading a load and lifting a load therefrom, the target 16 must be recognized in a state where the load is placed. A target 16 is provided on the pallet 14. In this case, the positional relationship between the center of the load and the target 16 is stored in the address determination unit 24 in advance, and the center position of the load is recognized from the recognized position of the target 16 and the stored positional relationship. Position 10 at the center of the load. The target 16 needs to be provided on the pallet 14 so that the target 16 and its surroundings can be provided with a predetermined contrast by giving special consideration to the shape and color arrangement in order to facilitate identification. . Accordingly, in the embodiment, as shown in FIG. 3, a portion other than the target 16 on the valley portion 14B of the pallet 14 is painted with white as a ground color, and a predetermined depth at the bottom portion of the valley portion 14B. Circular holes,
Alternatively, the target 16 is formed on the pallet 14 by providing a through hole. The planar shape of the target 16 is not limited to a circle, but can be any shape. For example, it may be a square or an easily identifiable symbol or mark. The coating color on the valleys 14B other than the target 16 may be any color as long as a contrast with the target 16 can be obtained. Since the target 16 of the hole or the through-hole as described above needs to obtain a contrast with a portion on the valley 14B other than the target 16, the image level of the television camera 12 is a reflected light of illumination light. If portions other than the target 16 to receive the information are bright information, it is desirable that the target 16 be dark information as much as possible. When the load, for example, a coil is placed on the pallet 14, the slope 14A of the pallet 14 with which the load comes into contact is not painted to improve the visibility of the valley 14B. The target thus formed by holes or through holes
In 16, illumination light or natural light from a predetermined lighting device is radiated to the vicinity of the target 16, and the light is irregularly reflected in the hole or the through hole, and an image of the target 16 created by imaging with the television camera 12. To get the desired level in the signal,
The target 16 can be recognized. However, when the target 16 is formed by a hole with a bottom, it is necessary that the TV camera 12 cannot obtain bright information due to the reflected light from the bottom of the hole. That is, in order to make the information of the target 16 dark information as much as possible, it is necessary to form the hole such that the bottom surface is located at a position where the illumination light does not hit the bottom surface of the hole. If the target 16 is formed as a hole or a through hole as described above, even when a load abuts on the valley 14B, unlike the case where the target 16 is formed by painting, the target 16 is scraped off and its pattern is removed. Since there is no change, the labor required for maintenance and inspection of the pallet 16 can be saved, and labor can be saved. Also, no contamination is attached to the target 16, and the recognition accuracy can be improved. The television camera 12 receives reflected light from the pallet 14 generated by irradiating illumination light or natural light from the illumination device, and converts an optical signal based on the reflected light into a photoelectric conversion element (for example, a charge-coupled device “CCD”). Converts an electric signal into a video signal. By the way, when a fixed aperture lens that cannot adjust the amount of light incident on the television camera 12 is used, since the amount of incident light cannot be adjusted, when the irradiation light amount of the camera is large, the imaging sensitivity becomes supersaturated, and The shooting information of the photoelectric conversion element becomes bright information as a whole, and the target
Information from 16 is hidden. When the amount of incident light is small, the imaging sensitivity is insufficient, the imaging information of the photoelectric conversion element is entirely in a dark state, and the information from the target 16 is hidden. Therefore, in order to obtain information from the target 16, it is preferable that the television camera 12 be provided with a light amount adjusting means which can always obtain a light amount capable of capturing an image with a certain optimum sensitivity in a certain light amount range. The distance between the television camera 12 and the pallet 14 is automatically adjusted so that the pallet 14 can be clearly captured. The television camera 12 captures an image such that the white portion of the valley 14B including the target 16 in the field of view F occupies about 1/6 or more of the entire field of view. Thus, even if the illuminance around the target 16 changes, the image signal level can be kept constant, and the video signal level around the target 16 can be raised to increase the contrast between the target 16 and its surroundings. That is, even for a pallet including dirt as shown in FIG. 4 (A), its video signal level is, for example, the video signal level of the line AA in FIG. 4 (A). As shown in (B), a sharp rise can be obtained in the video signal level of the white portion of the valley 14B,
A sharp fall in the video signal level of the target 16 can be obtained. As a result, the reference level SHL can be set to a high level as shown in FIG. 11B, so that noise in the peripheral image can be reliably eliminated (cancelled). Note that the reference level SHL is a threshold for performing a binary conversion by determining black and white from the video signal. Further, as shown in FIG. 3B, the falling edge of the video signal of the target 16 is sharp, so that the shape of the target 16 can be stably identified from the video signal. Therefore, the recognition of the target 16 can be accurately and stably performed. Therefore, in the image signal of the binary conversion value, the pseudo pattern of the surrounding portion is canceled, and a stable contour image of the target 16 can be recognized. Next, the target 16 is formed with a through hole, and the target 16 is formed.
An example of the level of a video signal created by painting the valleys 14B other than 16 into black and white and imaging the pallet 14 and an image signal obtained by binarizing the video signal is shown. FIG. 5 (A) shows a screen based on an image signal in the vicinity of the valley 14B of the pallet 14, and FIG. 5 (B) shows a video signal level including a target of the image signal. As shown in FIG. 7B, since the portion of the valley portion 14B other than the target 16 is painted white in the video signal, the video signal level in that portion is constant and the contrast with the slope portion 14A is reduced. Therefore, it can be seen that the difference from the video signal level from the slope portion 14A becomes clear. Therefore, even if a pseudo pattern as shown by GP in the figure exists in the video signal from the slope portion 14A, after the binarization conversion using the reference level SHL in FIG. The pattern can be erased (canceled), and a stable contour image of the target 16 as shown in FIG. On the other hand, if the periphery of the target 16 is not painted white, an image signal screen as shown in FIG. 6A is obtained. As shown in FIG. 4 (A), the pseudo pattern GP is
In the case of A, since there is no contrast between the slope portion 14A and the valley portion 14B, the video signal level becomes flat with some unevenness as shown in FIG. Therefore,
Since the video signal level of the valley 14B is not strong as shown in FIG. 3B, even if the reference level SHL is provided and the binary conversion is performed, the pseudo pattern such as dirt is not erased and the target is not erased.
It is understood that the recognition is performed together with the target 16 and the recognition accuracy of the target 16 is reduced. From the above, it can be seen that painting the valley portion 14B white is useful for improving recognition accuracy. As described above, the target 16 accurately recognized
Based on this information, a mobile machine such as a crane for lifting or unloading a load in a factory can be automatically operated.

【The invention's effect】

As described above, according to the present invention, the durability is high,
A target that does not easily cause erroneous recognition can be easily formed, and the positioning of the hanger can be performed with high accuracy. Therefore, there are obtained excellent effects such as the ability to shorten the time for lifting and unloading the load and to improve the work efficiency.

[Brief description of the drawings]

FIG. 1 is a front view including a partial perspective view showing a pallet of an embodiment according to the present invention and a crane for loading and unloading the pallet, and FIG. FIG. 3 is a block diagram including a partial perspective view showing the entire configuration of the pallet and the arithmetic unit; FIG. 3 is a perspective view of a main part showing a pallet with a target recognized by the arithmetic unit; Is a plan view showing a dirty palette, FIG. 4 (B) is a diagram showing an example of a video signal level input to the arithmetic unit, and FIG. 5 (A) is a valley around the target. FIG. 5B is a diagram showing the image signal level, and FIG. 6A is a diagram in which the valley is not painted white. FIG. 6 (B) is a plan view showing a screen of an image signal in the case of FIG. It is a diagram showing a. 6 ... Crane, 10 ... Hanging tool, 12 ... TV camera, 14 ... Pallet, 14A ... Pallet slope, 14B ... Pallet valley, 16 ... Target, 22 ... Pattern feature judgment section , 24 ... Address determination unit.

Claims (1)

(57) [Claims] 1. A pallet on which a load is lifted from a pallet by using a hanging tool or a load is unloaded on a pallet. The pallet is picked up by an image pickup means and is recognized for positioning of the hanging tool. A hole-shaped target is provided at a position which has a predetermined relationship with the load, and the target has a predetermined signal level difference in a video signal generated by the imaging means with respect to a target peripheral portion on a pallet. A pallet having a target characterized by having a contrast.