Cargo compartment monitoring system and cargo compartment monitoring method
The ultrasonic sensor-based cargo compartment monitoring system simplifies and reduces costs for monitoring loading status by processing waveform data to determine cargo volume, enhancing accuracy with multiple sensors.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- JAPAN RADIO CO LTD
- Filing Date
- 2024-11-06
- Publication Date
- 2026-05-19
AI Technical Summary
Existing cargo compartment monitoring systems, such as those using cameras and 3D sensors, are costly due to complex calculations for loading rate estimation, leading to high overall device costs.
A cargo compartment monitoring system utilizing ultrasonic sensors installed in the ceiling of a vehicle to transmit and receive ultrasonic waves, processing waveform data to calculate the loading rate by determining the nearest neighbor peak representing cargo, thereby simplifying the calculation and reducing costs.
The system allows for low-cost monitoring of cargo compartment loading status by using ultrasonic sensors to process waveform data, improving accuracy with multiple sensors, and enabling easy grasp of loading status.
Smart Images
Figure 2026081816000001_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a cargo compartment monitoring system and a cargo compartment monitoring method for grasping the loading status of the cargo compartment of vehicles such as trucks.
Background Art
[0002] In the logistics industry, studies are underway on a system that installs devices such as cameras and 3D sensors in the cargo compartments of trucks used for transporting goods to "visualize" the cargo compartments.
[0003] For example, Patent Document 1 discloses a loading rate estimation device that estimates the loading rate of a cargo compartment using a camera or the like. This device is a device that determines whether there are objects other than the loaded goods in the cargo compartment by using an image captured by a camera installed in the cargo compartment or the like, and then measures the loading rate of the cargo compartment using the detection result of a depth sensor.
Prior Art Documents
Patent Documents
[0004] [[ID=2M
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, in the loading rate estimation device of Patent Document 1, since the loading rate is estimated by analyzing an image captured by a camera and using the detection result of a depth sensor, the process for calculating the loading rate is complicated and the cost of the entire device becomes high.
[0006] Therefore, an object of the present invention is to provide a cargo compartment monitoring system and a cargo compartment monitoring method that can easily grasp the loading status of the cargo compartment of a vehicle while being low-cost.
Means for Solving the Problems
[0007] To solve the above problems, the invention described in claim 1 comprises: an ultrasonic sensor installed in the upper part of the cargo compartment of a vehicle, which transmits ultrasonic waves downward and receives reflected waves from luggage loaded in the cargo compartment and targets other than the luggage; a waveform data acquisition means that acquires waveform data showing the change in signal intensity with respect to distance from the ultrasonic sensor based on the reflected waves; and a loading rate calculation means that calculates the loading rate, which is the ratio of the volume occupied by the luggage to the cargo compartment, using the waveform data, wherein the waveform data acquisition means can detect both the state in which no luggage is loaded in the cargo compartment and the state in which luggage is loaded in the cargo compartment. The cargo compartment monitoring system is characterized by acquiring waveform data for the state in which the cargo is loaded, and the loading rate calculation means creating processed waveform data by deleting peaks included in the waveform data for the state in which the cargo is not loaded from the waveform data for the state in which the cargo is loaded in the cargo compartment, determining the nearest neighbor peak with the minimum distance in the processed waveform data as the peak representing the cargo, estimating the distance component of the nearest neighbor peak as the distance between the ultrasonic sensor and the cargo, and calculating the loading rate based on the estimated distance between the ultrasonic sensor and the cargo.
[0008] The invention described in claim 2 is characterized in that, in the cargo compartment monitoring system described in claim 1, a plurality of ultrasonic sensors are provided according to the size of the cargo compartment, and the loading rate calculation means calculates the loading rate using the waveform data based on the reflected waves received by each ultrasonic sensor.
[0009] The invention described in claim 3 comprises: a transmission and reception step of transmitting ultrasonic waves downward from an ultrasonic sensor installed in the upper part of the cargo compartment of a vehicle and receiving reflected waves from luggage loaded in the cargo compartment and targets other than the luggage; a waveform data acquisition step of acquiring waveform data showing the change in signal intensity with respect to distance from the ultrasonic sensor based on the reflected waves; and a loading rate calculation step of calculating the loading rate, which is the ratio of the volume occupied by the luggage to the cargo compartment, using the waveform data, wherein the waveform data acquisition step includes the state when the luggage is not loaded in the cargo compartment and the state when the luggage is loaded in the cargo compartment. The cargo compartment monitoring method is characterized by: acquiring waveform data for the state in which the cargo is loaded; in the loading rate calculation step, creating processed waveform data by removing peaks included in the waveform data for the state in which the cargo is not loaded from the waveform data for the state in which the cargo is loaded in the cargo compartment; determining the nearest neighbor peak with the minimum distance in the processed waveform data as the peak representing the cargo; estimating the distance component of the nearest neighbor peak as the distance between the ultrasonic sensor and the cargo; and calculating the loading rate based on the estimated distance between the ultrasonic sensor and the cargo. [Effects of the Invention]
[0010] According to the inventions of claims 1 and 3, the loading rate of the cargo compartment can be calculated using only an ultrasonic sensor, making it possible to monitor the loading status of the cargo compartment at low cost. Furthermore, by obtaining waveform data representing the change in signal strength with respect to distance from the ultrasonic sensor based on the reflected wave from the transmitted wave of the ultrasonic sensor, and processing this waveform data to calculate the loading rate of the cargo compartment, it becomes possible to easily grasp and monitor the loading status of the cargo compartment.
[0011] According to the invention of claim 2, since multiple ultrasonic sensors are provided according to the size of the cargo compartment, it is possible to improve the accuracy of monitoring the loading status of the cargo compartment. [Brief explanation of the drawing]
[0012] [Figure 1]This is a functional block diagram showing the schematic configuration of a cargo compartment monitoring system according to an embodiment of the present invention. [Figure 2] This figure shows an example of the cargo area of a vehicle to which the cargo area monitoring system shown in Figure 1 is applied. [Figure 3] This figure shows the detection range of each sonar installed in Figure 2. [Figure 4] This figure shows the waveform data acquired by the waveform data acquisition unit of the cargo compartment monitoring system in Figure 1 when no cargo is loaded in the cargo compartment, and the processed waveform data created by the loading rate calculation unit. [Figure 5] Figure 1 shows the processing procedure in the cargo compartment monitoring system, and is also a flowchart showing the processing procedure of the cargo compartment monitoring method according to this embodiment. [Modes for carrying out the invention]
[0013] The present invention will be described below based on the illustrated embodiments.
[0014] Figure 1 is a block diagram showing the schematic configuration of a cargo compartment monitoring system 1 according to an embodiment of the present invention, and Figure 2 is a diagram showing an example of the cargo compartment 41 of a vehicle 4 to which the cargo compartment monitoring system 1 is applied. This cargo compartment monitoring system 1 is a system for monitoring the cargo compartment 41 of a vehicle 4, and comprises a plurality of sonars (ultrasonic sensors) 2 and a cargo compartment monitoring device (waveform data acquisition means, load rate calculation means) 3, and the plurality of sonars 2 and the cargo compartment monitoring device 3 are connected to each other so as to be able to communicate with each other. This cargo compartment monitoring system is operated, for example, by a transport company that transports goods in a vehicle 4. Note that the ultrasonic sensors are not limited to sonars, but sonars are preferred in terms of cost.
[0015] Here, the vehicle 4 can be any type of vehicle as long as it has a cargo compartment 41, but in this embodiment, as shown in Figure 2, it is a truck 4a. Also, the cargo compartment 41 can be of any shape as long as there is space to install the sonar 2, but in this embodiment, as shown in Figure 2 As shown, it is box-shaped and has a ceiling (upper part) 411. An opening is provided at the rear of the cargo compartment 41 (opposite the driver's seat) (not shown), and luggage 5 can be loaded and unloaded through this opening.
[0016] Sonar 2 is a sensor used to monitor the loading conditions inside the cargo compartment 41, and more specifically, it is a sensor used to measure the distance to luggage 5 and other objects inside the cargo compartment 41. Sonar 2 is installed on the ceiling 411 of the cargo compartment 41 and transmits ultrasonic waves downwards, receiving reflected waves from luggage 5 and other targets (hereinafter, luggage 5 and other targets are collectively referred to as "targets") loaded inside the cargo compartment 41.
[0017] The number of sonar units 2 to be installed should be determined according to their detection range (the range that can be monitored) and the size of the cargo compartment 41. In this embodiment, the range that can be monitored by one sonar unit 2 is limited to a predetermined range centered on the sonar unit 2, as shown in Figure 3. Therefore, multiple sonar units 2a to 2e are installed to monitor the entire cargo compartment 41. As shown in Figures 2 and 3, multiple sonar units 2 may be installed only in the longitudinal direction of the cargo compartment 41, or multiple sonar units may be installed not only in the longitudinal direction but also in the width direction of the cargo compartment 41. By increasing the number of sonar units 2 installed, the accuracy of monitoring the loading status of the cargo compartment 41 can be improved.
[0018] The ultrasonic waves transmitted downward from the sonar 2 installed on the ceiling 411 are reflected by the cargo 5 loaded in the cargo compartment 41 and by other targets (e.g., the walls and floor of the cargo compartment). For example, as shown in Figure 2, the ultrasonic waves transmitted directly downward from sonars 2a to 2c are reflected by cargo 5a to 5c, and the ultrasonic waves transmitted directly downward from sonars 2d and 2e are reflected by targets other than cargo 5, i.e., by the floor of the cargo compartment 41. Note that the direction of transmission of ultrasonic waves from sonar 2 is not limited to directly downward, but for convenience, only ultrasonic waves transmitted directly downward from sonar 2 are shown in Figure 2. When estimating the distance L between sonar 2 and cargo 5, as described later, the reflected waves of ultrasonic waves transmitted directly downward from sonar 2 are used.
[0019] The sonar 2 receives the reflected wave at the target and sends the data of the reflected wave to the cargo hold monitoring device 3 via a cable or the like.
[0020] The cargo hold monitoring device 3 is a computer mounted on the truck 4a that processes the reflected wave received by the sonar 2. In this embodiment, as shown in FIG. 2, it is installed in the cargo hold 41 and connected to the sonar 2 by a cable or the like. As shown in FIG. 1, this cargo hold monitoring device 3 includes a waveform data acquisition unit (waveform data acquisition means) 31, a loading rate calculation unit (loading rate calculation means) 32, a communication unit 34, a storage unit 35, and a central processing unit 33 that controls these.
[0021] The waveform data acquisition unit 31 performs a task of acquiring waveform data indicating the change in signal intensity with respect to the distance from the sonar 2 to the target based on the data of the reflected wave acquired from the sonar 2.
[0022] The waveform data acquired by the waveform data acquisition unit 31 can be illustrated and graphed on a coordinate where the horizontal axis is the distance from the sonar to the target and the vertical axis is the signal intensity, as shown in FIG. 4. On this coordinate axis, the waveform that appears near the sonar 2 is considered to be the reverberation of the transmitted wave and is excluded, and the waveform that appears thereafter is used for distance measurement.
[0023] The waveform data acquisition unit 31 acquires waveform data (hereinafter referred to as first waveform data) based on the reflected wave obtained when ultrasonic waves are transmitted in a state where no cargo 5 is loaded in the cargo hold 41, that is, the reflected wave data at a target other than the cargo 5. A specific example of the first waveform data is shown in FIG. 4(1). In this example, there are targets such as walls, aluminum rails provided on the walls, and the floor mainly in the cargo hold 41 (see the photo in FIG. 4(1)), and in the first waveform data, peaks indicating the aluminum rail, peaks indicating the floor, and peaks indicating the wall appear in order of increasing distance from the sonar 2. appear.
[0024] Furthermore, the waveform data acquisition unit 31 acquires waveform data (hereinafter referred to as "second waveform data") based on the reflected waves obtained when ultrasonic waves are transmitted with the cargo 5 loaded in the cargo compartment 41, that is, the reflected waves from the cargo 5 and targets other than cargo 5. In the case of a cargo compartment as shown in the photograph in Figure 4(2), the second waveform data (not shown) shows peaks indicating aluminum rails, peaks indicating the floor, peaks indicating the walls, and a peak indicating cargo 5. In addition, the second waveform data also shows waveform data indicating multiple reflections from cargo 5, etc.
[0025] The first waveform data and the second waveform data acquired by the waveform data acquisition unit 31 are stored in the storage unit 35 so that they can be used when calculating the load ratio.
[0026] The loading rate calculation unit 32 performs the task of calculating the loading rate of the cargo 5 loaded in the cargo compartment 41. This loading rate represents the ratio of the volume occupied by the cargo 5 to the cargo compartment 41 and is used as an indicator of the loading status of the cargo compartment 41.
[0027] The load factor calculation unit 32 estimates the distance L between the sonar 2 and the cargo 5 using the first waveform data and the second waveform data obtained by the waveform data acquisition unit 31, and calculates the load factor of the cargo 5 in the cargo compartment 41 based on the estimated distance L. Here, the distance L between the sonar 2 and the cargo 5 is the distance measured based on the reflected ultrasonic waves transmitted directly downward from the sonar 2, and is the distance obtained by subtracting the height h of the cargo 5 from the distance H from the sonar 2 to the floor of the cargo compartment 41 (or the height of the cargo compartment 41 if the sonar 2 is installed on the ceiling 411 of the cargo compartment 41).
[0028] The load factor calculation unit 32 estimates the distance L between the sonar 2 and the cargo 5 using the peak of cargo 5 that appears in the waveform data. Here, the second waveform data obtained when ultrasonic waves are transmitted with cargo 5 loaded in the cargo compartment 41 includes not only the peak indicating cargo 5, but also peaks indicating targets other than cargo 5, as described above. Therefore, the load factor calculation unit 32 first creates processed waveform data by deleting the peaks included in the first waveform data, i.e., the peaks indicating targets other than cargo 5, from the second waveform data in order to detect only the peak indicating cargo 5 (see Figure 4(2)).
[0029] The load factor calculation unit 32 determines the peak (nearest neighbor peak) in the processed waveform data, excluding reverberation, to be the peak that minimizes the distance from sonar 2 (value on the horizontal axis of the coordinate system), and estimates the distance component of the nearest neighbor peak to be the distance L between sonar 2 and cargo 5. To explain with specific examples, if sonar 2 is sonar 2a in Figure 2, the distance component of the nearest neighbor peak in Figure 4(2) is La; if sonar 2 is sonar 2b in Figure 2, the distance component of the nearest neighbor peak in Figure 4(2) is Lb; and if sonar 2 is sonar 2c in Figure 2, the distance component of the nearest neighbor peak in Figure 4(2) is Lc. Note that if sonar 2 is sonar 2d or 2e in Figure 2, the ultrasonic waves transmitted directly downward from these sonars are reflected by the floor, so the nearest neighbor peak shown in Figure 4(2) does not appear in the processed waveform data.
[0030] The loading rate calculation unit 32 calculates the loading rate of the cargo compartment 41 based on the distance L between the sonar 2 and the cargo 5, which is the distance component of the nearest peak described above. Specifically, the height h of the cargo 5 is obtained by subtracting the distance L between the sonar 2 and the cargo 5 from the distance H from the floor of the cargo compartment 41 to the sonar 2 (or the height of the cargo compartment 41 if the sonar 2 is installed on the ceiling of the cargo compartment 41), and the loading rate is obtained by dividing the height h of the cargo by the distance H from the floor of the cargo compartment 41 to the sonar 2. If there are multiple sonars 2, the above calculation is performed for each sonar 2a to 2e to obtain the loading rate of the cargo compartment 41 for each detection range of each sonar 2a to 2e, and these loading rates are added together to calculate the overall loading rate of the cargo compartment 41.
[0031] The memory unit 35 is a memory that stores various data, information, and programs, and mainly stores measurement results obtained from the sonar 2, and calculation processing data obtained from the waveform data acquisition unit 31 and the load factor calculation unit 32.
[0032] The communication unit 34 is an interface for communicating with the sonar 2 and an external database server (for example, a database server installed by the transportation company that owns truck 4a). Specifically, it is conceivable that it receives measurement results obtained from the sonar 2 and transmits the calculation data obtained from the waveform data acquisition unit 31 and the load factor calculation unit 32 to the database server.
[0033] Next, the operation of the above embodiment will be explained with reference to the flowchart in Figure 5.
[0034] First, the sonar 2 transmits ultrasonic waves when no cargo 5 is loaded in the cargo compartment 41 and receives the reflected waves (step S1). The cargo compartment monitoring device 3 acquires the measurement results (including reflected wave data) from the sonar 2 in the communication unit 34, acquires first waveform data based on the measurement results in the waveform data acquisition unit 31, and stores it in the storage unit 35 (step S2).
[0035] Steps S1 and S2 are pre-processing steps for calculating the loading rate of the cargo compartment 41, and only need to be performed once for the cargo compartment 41 of each truck 4a.
[0036] Next, the sonar 2 transmits ultrasonic waves with cargo 5 loaded in the cargo compartment 41 and receives the reflected waves (step S3). If steps S1 and S2 have already been performed for the cargo compartment 41 of the target truck 4a, the process will start from step S3. The cargo compartment monitoring device 3 acquires the measurement results (including reflected wave data) from the sonar 2 in the communication unit 34, acquires second waveform data based on the measurement results in the waveform data acquisition unit 31, and stores it in the storage unit 35 (step S4).
[0037] As described above, the second waveform data includes a peak indicating cargo 5 and a peak indicating an object other than cargo 5. Therefore, the loading rate calculation unit 32 creates processed waveform data by deleting the peaks included in the first waveform data (peaks indicating objects other than cargo 5) from the second waveform data stored in the storage unit 35 (step S5).
[0038] Next, the load factor calculation unit 32 detects the nearest neighbor peak in the processed waveform data that is the shortest distance from the sonar 2, determines that the nearest neighbor peak represents the load 5, and estimates its distance component as the distance L between the load 5 and the sonar 2. (Step S6)
[0039] Next, the load factor calculation unit 32 calculates the load factor of the cargo compartment 41 based on the estimated distance L between the cargo 5 and the sonar 2 (step S7). The method for calculating the load factor is as described above.
[0040] As described above, the cargo compartment monitoring system 1 and cargo compartment monitoring method according to this embodiment allow the loading rate of the cargo compartment 41 to be calculated using only the sonar 2, making it possible to monitor the loading status of the cargo compartment 41 at low cost. Furthermore, waveform data representing the change in signal strength with respect to distance from the sonar 2 is acquired based on the reflected wave from the transmitted wave of the sonar 2, and the loading rate of the cargo compartment 41 is calculated by processing this waveform data, making it possible to easily grasp and monitor the loading status of the cargo compartment 41.
[0041] Furthermore, according to the cargo compartment monitoring system 1 and cargo compartment monitoring method of this embodiment, since multiple sonars 2 are provided according to the size of the cargo compartment 41, it is possible to improve the accuracy of monitoring the loading status of the cargo compartment 41.
[0042] Although embodiments of this invention have been described above, the specific configuration is not limited to the embodiments described above, and any design changes, etc., that do not depart from the spirit of this invention are also included. [Explanation of Symbols]
[0043] 1. Cargo area monitoring system 2. Sonar (ultrasonic sensor) 3. Cargo compartment monitoring device 31 Waveform data acquisition unit (waveform data acquisition means) 32 Loading Ratio Calculation Unit (Loading Ratio Calculation Means) 4 vehicles 4a Track 41 Cargo area 411 Ceiling (upper part) 5. Luggage
Claims
1. An ultrasonic sensor is installed in the upper part of the cargo compartment of a vehicle, transmits ultrasonic waves downwards, and receives reflected waves from cargo loaded in the cargo compartment and other targets. A waveform data acquisition means that acquires waveform data showing the change in signal intensity with respect to distance from the ultrasonic sensor based on the reflected wave, The system includes a loading rate calculation means that uses the waveform data to calculate the loading rate, which is the ratio of the volume occupied by the cargo to the volume occupied by the cargo in the cargo compartment, The waveform data acquisition means is The waveform data is acquired for the state in which no cargo is loaded in the cargo compartment and the state in which cargo is loaded in the cargo compartment. The aforementioned load factor calculation means is Processed waveform data is created by removing the peaks included in the waveform data for the state in which the cargo is not loaded into the cargo compartment from the waveform data for the state in which the cargo is loaded into the cargo compartment. In the processing waveform data, the nearest neighbor peak with the minimum distance is determined to be the peak representing the load, and the distance component of the nearest neighbor peak is estimated to be the distance between the ultrasonic sensor and the load. A cargo compartment monitoring system characterized by calculating the load rate based on the estimated distance between the ultrasonic sensor and the cargo.
2. Multiple ultrasonic sensors are provided according to the size of the cargo compartment. The loading rate calculation means calculates the loading rate using the waveform data based on the reflected waves received by each ultrasonic sensor. The cargo compartment monitoring system according to feature 1.
3. A transmitting and receiving step involves transmitting ultrasonic waves downward from an ultrasonic sensor installed in the upper part of the cargo compartment of a vehicle, and receiving reflected waves from cargo loaded in the cargo compartment and targets other than the cargo. A waveform data acquisition step is to acquire waveform data showing the change in signal intensity with respect to distance from the ultrasonic sensor based on the reflected wave, The method includes a loading rate calculation step, which uses the waveform data to calculate the loading rate, which is the ratio of the volume occupied by the cargo to the cargo compartment, In the waveform data acquisition step, The waveform data is acquired for the state in which no cargo is loaded in the cargo compartment and the state in which cargo is loaded in the cargo compartment. In the aforementioned loading rate calculation step, Processed waveform data is created by removing the peaks included in the waveform data for the state in which the cargo is not loaded into the cargo compartment from the waveform data for the state in which the cargo is loaded into the cargo compartment. In the processing waveform data, the nearest neighbor peak with the minimum distance is determined to be the peak representing the load, and the distance component of the nearest neighbor peak is estimated to be the distance between the ultrasonic sensor and the load. A cargo compartment monitoring method characterized by calculating the loading rate based on the estimated distance between the ultrasonic sensor and the cargo.