Intelligent sample storage system

Abstract

The utility model relates to the technical field of sample storage systems, in particular to an intelligent sample storage system, which is characterized in that a plurality of storage units are arranged in each intelligent container, each storage unit is matched with a corresponding first electronic tag, and a second electronic tag is arranged on a storage sample. Therefore, when the automatic transfer robot identifies the sample information on the first electronic tag and the sample information on the second electronic tag through the mobile card reader on the manipulator, as long as the sample information on the first electronic tag and the sample information on the second electronic tag are consistent, the storage position of the storage sample stored on the storage unit is accurate; at the moment, the multi-joint manipulator can take, place and store the sample; and a fixed card reader is arranged on the intelligent material table, and the second electronic tag is read by utilizing the fixed card reader, so that whether the stored sample is the stored sample needing to be stored by the system background or not can be further ensured, and the correctness of the storage position of the stored sample is ensured.

Description

Technical Field

[0001] This utility model relates to the field of storage system technology, specifically to an intelligent sample storage system. Background Technology

[0002] Mandatory standards have been established for the storage of materials such as soil surveys, plant and animal seeds, and specimens to ensure compatibility with subsequent analysis and testing. Currently, automated storage facilities are gradually being adapted to automated storage systems, utilizing sample cabinets in sample libraries to classify and store samples according to specific methods for temporary storage and retrieval during later testing.

[0003] For example, Chinese document CN 104267655 A discloses a method and system for intelligent storage of coal samples, which is used to store induction bottles containing coal samples. The induction bottles are equipped with contactless IC cards that have stored card numbers and coal sample information. Then, a robotic arm drives a card reader to read the card number and coal sample information of the IC card. The system automatically stores the position information of the empty tray in the sample cabinet in the background. The position information of the empty tray is sent to the PLC, and the PLC controls the robotic arm to place the induction bottle on the empty tray. However, simply reading the IC card number and coal sample information one-to-one with a card reader and matching them individually, if the sensor bottle is stored in the correct location, the robotic arm can easily find the correct IC card number and coal sample information. However, in addition to automatic sensor bottle retrieval, manual retrieval is usually also available during the retrieval process. This coexistence of two retrieval methods leads to the problem of incorrect sensor bottle placement. Even with automated retrieval of reaction vessels, sensor bottle placement errors are still inevitable due to system instability and data processing. This means that even if the system records the sensor bottle's location, the robotic arm may still struggle to find the correct one. Therefore, there is an urgent need for a method that can effectively ensure accurate sample retrieval and reduce the risk of errors to solve these problems. Utility Model Content

[0004] In order to overcome one of the shortcomings of the existing technology, the purpose of this utility model is to provide an intelligent sample storage system. This intelligent sample storage system can effectively reduce errors in sample storage and retrieval and has a high degree of automation.

[0005] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0006] An intelligent sample storage system, including

[0007] Several smart vending machines are arranged in sequence. Each smart vending machine is equipped with several storage units. Each storage unit is equipped with a first electronic tag for storing sample information, and the stored sample is equipped with a second electronic tag.

[0008] An automated handling robot is equipped with a multi-jointed manipulator, which can open and close each storage unit and pick up and place stored samples; the automated handling robot is equipped with a mobile card reader for identifying a first electronic tag and a second electronic tag;

[0009] The intelligent material platform is equipped with a material picking area and a material storage area, and both the material picking area and the material storage area are equipped with fixed card readers for identifying the second electronic tag;

[0010] The central control unit is used to query and store the sample information stored in each of the storage units, and to communicate with the automated handling robot and the intelligent material platform via a wireless network, and to control the automated handling robot to move between the intelligent material platform and the intelligent container to pick up and put in the stored samples.

[0011] Furthermore, the central control unit includes a server and a switch, which are communicatively connected. The switch is communicatively connected to the smart vending machine, and the switch is communicatively connected to the automated handling robot and the smart material platform via a wireless network.

[0012] Furthermore, the switch is connected to a client PC.

[0013] Furthermore, a terminal PC is installed on the intelligent material platform, and the terminal PC is communicatively connected to the central control terminal.

[0014] Furthermore, it also includes an alarm. When the information of the second electronic tag identified by the fixed card reader is inconsistent with the information of the first or second electronic tag identified by the mobile card reader, the central control terminal controls the alarm to sound an alarm and controls the automatic handling robot to move to the material pick-up and drop-off position of the intelligent material platform.

[0015] Furthermore, each of the smart vending machines includes a cabinet body and several drawer compartments disposed within the cabinet body, and each of the drawer compartments is provided with several storage units.

[0016] Furthermore, the automated guided vehicle (AGV) includes an AGV cart, an environmental recognition module, and a position sensor. The environmental recognition module and the position sensor are both mounted on the AGV cart. The multi-joint manipulator is mounted on the AGV cart. A control module is mounted on the AGV cart. The control module, the environmental recognition module, and the position sensor are all connected to the central control terminal via a wireless network. The central control terminal can plan a walking route based on the detection data from the environmental recognition module and the position sensor, and send the data containing the walking route to the control module. The control module can control the AGV cart to move.

[0017] Furthermore, the multi-joint manipulator includes a robotic arm and a gripping claw, a positioning camera, a door opening hook, and a door closing telescopic buffer disposed on the moving end of the robotic arm. The robotic arm is mounted on the lifting arm of the AGV trolley. A positioning photoelectric switch is disposed on the moving end of the robotic arm. The positioning photoelectric switch, the positioning camera, the gripping claw, the door opening hook, and the door closing telescopic buffer are connected to the manipulator controller. The manipulator controller communicates with the central control terminal via a wireless network.

[0018] Furthermore, it also includes a smart charging pile, which is connected to the central control terminal via a wireless network. The central control terminal can control the automated handling robot to adapt to the smart charging pile for charging based on the remaining power in the automated handling robot.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] This invention discloses an intelligent sample storage system. Each intelligent cabinet contains several storage units, each equipped with a corresponding first electronic tag. A second electronic tag is also attached to the stored sample. When an automated handling robot uses a mobile card reader on its robotic arm to identify the sample information on the first and second electronic tags, a match between the two tags indicates that the sample is correctly positioned within the storage unit. Only then can the multi-joint robotic arm retrieve or place the sample. A fixed card reader on the intelligent platform further ensures that the retrieved sample matches the one required by the system, guaranteeing the correctness of the sample's storage location.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0022] Figure 1 This is a structural layout diagram of an embodiment of the present utility model;

[0023] Figure 2 This is a network layout diagram of an embodiment of the present invention;

[0024] Figure 3 This is a partial structural schematic diagram of the smart vending machine in an embodiment of this utility model;

[0025] Figure 4 This is a control principle diagram of the automatic handling robot in an embodiment of this utility model;

[0026] Figure 5 This is a schematic diagram of the structure of the automatic handling robot in an embodiment of this utility model;

[0027] Figure 6 This is a partial structural schematic diagram of the automatic handling robot in an embodiment of this utility model.

[0028] Explanation of icon numbers:

[0029] 10. Smart Vending Machine; 11. Storage Unit; 12. First Electronic Tag; 13. Second Electronic Tag; 14. Cabinet Body; 15. Drawer Compartment; 20. Automated Handling Robot; 21. Mobile Card Reader; 22. AGV Cart; 23. Environmental Recognition Module; 24. Position Sensor; 25. Control Module; 26. Robotic Arm; 27. Gripping Gripper; 28. Positioning Camera; 29. ​​Door Opening Hook; 2a. Door Closing Telescopic Buffer; 2b. Positioning Photoelectric Switch; 30. Smart Material Platform; 31. Material Picking Area; 32. Material Storage Area; 33. Fixed Card Reader; 34. Terminal PC; 40. Central Control Terminal; 41. Server; 42. Switch; 43. Customer PC; 50. Alarm; 60. Smart Charging Pile Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this utility model and are not intended to limit this utility model.

[0031] Reference Figures 1 to 6The intelligent sample storage system shown includes several intelligent cabinets 10 arranged in sequence, an automated handling robot 20, an intelligent material platform 30, and a central control terminal 40. Each intelligent cabinet 10 is equipped with several storage units 11, and each storage unit 11 is equipped with a first electronic tag 12 for storing sample information. The stored samples are equipped with a second electronic tag 13. The automated handling robot 20 is equipped with a multi-jointed manipulator, which can open and close each storage unit 11 and pick up and place stored samples. The automated handling robot 20 is equipped with... A mobile card reader 21 is provided for identifying the first electronic tag 12 and the second electronic tag 13; the intelligent material platform 30 is provided with a material picking area 31 and a material storage area 32, and each of the material picking area 31 and the material storage area 32 is provided with a fixed card reader 33 for identifying the second electronic tag 13; the central control terminal 40 is used to query and store the sample information stored in each of the storage units 11 and to communicate with the automatic handling robot 20 and the intelligent material platform 30 through a wireless network, and to control the automatic handling robot 20 to move between the intelligent material platform 30 and the intelligent cabinet 10 to pick up and put in the stored samples.

[0032] Specifically, in actual use, an electronic fence will be used to enclose a storage area, and all the smart vending machines 10 will be arranged sequentially within this area. The electronic fence will also limit the movement range of the automated handling robot 20 and prevent unauthorized access. The electronic fence is equipped with electronic gates for easy opening and closing and entry / exit. In practice, the electronic fence can be a room, simply installed on its walls. The smart vending machines 10 can be traditional trackless high-density storage cabinets, which can increase the storage density of the entire storage area. In addition, the automated handling robot 20 is equipped with a robotic arm or other opening mechanism specifically for driving the opening and closing of the trackless high-density storage cabinets, facilitating the rotation of the grippers and the hand-cranked wheel mechanism on the trackless high-density storage cabinets.

[0033] Furthermore, the intelligent material station 30 in this application is also equipped with a main switch for the entire storage area and individual switches for each electrical device, as well as a personal PC for easy monitoring of the usage status of each device within the storage area. In an improved embodiment, the intelligent material station 30 is equipped with a terminal PC 34, which is communicatively connected to the central control terminal 40. The purpose of the terminal PC 34 is to facilitate staff monitoring of the entire storage system. The central control terminal 40 is essentially a back-end control system, which can be a conventional terminal server.

[0034] This intelligent sample storage system has several storage units 11 set up in each intelligent cabinet 10, and each storage unit 11 is equipped with a corresponding first electronic tag 12. At the same time, a second electronic tag 13 is set on the stored sample. When the automatic handling robot 20 identifies the sample information on the first electronic tag 12 and the second electronic tag 13 respectively through the mobile card reader 21 on the robotic arm, if the sample information on the first electronic tag 12 and the second electronic tag 13 are consistent, it means that the storage sample stored in the storage unit 11 is in the correct storage position. At this time, the multi-joint robotic arm can pick up and put down the stored sample. A fixed card reader 33 is set on the intelligent material platform 30. The fixed card reader 33 reads the second electronic tag 13, which can further ensure that the stored sample is the same as the storage sample required by the system backend, and ensure the correctness of the storage position of the stored sample.

[0035] See Figures 1 to 2 In one embodiment of this application, the central control terminal 40 includes a server 41 and a switch 42. The server 41 and the switch 42 are communicatively connected. The switch 42 is communicatively connected to the intelligent vending machine 10 and to the automated handling robot 20 and the intelligent material platform 30 via a wireless network. The server 41 is used to query and store sample information stored in each storage unit 11 and to control the actions of the automated handling robot 20 and the intelligent material platform 30 via the wireless network. In this application, the server 41 can be a conventional server host. However, in some embodiments, the server 41 can be replaced with a workstation. In this application, the processor inside the server 41 can process the data transported by the automated handling robot 20 and the intelligent material platform 30 at high speed, ensuring to a certain extent that the automated handling robot 20 can accurately access and store samples. Simultaneously, the server 41 ensures the stability of network communication between various devices, while the switch 42 facilitates communication between the server 41 and various devices.

[0036] In one embodiment of this application, the switch 42 is communicatively connected to a client PC 43, which can actually be multiple client PCs 43, thus facilitating the simultaneous access of multiple client PCs 43 to the storage system.

[0037] In one embodiment of this application, the storage device further includes an alarm 50. When the information of the second electronic tag 13 identified by the fixed card reader 33 is inconsistent with the information of the first electronic tag 12 or the second electronic tag 13 identified by the mobile card reader 21, the central control terminal 40 controls the alarm 50 to sound an alarm and controls the automated handling robot 20 to move to the material handling position of the intelligent material platform 30. The material handling position is actually a preset position, which is the position of the automated handling robot 20 when handling materials on the intelligent material platform 30. The alarm 50 can be set anywhere within the entire storage area, and can be set externally, facilitating timely handling of storage errors by staff, and allowing modification of the storage location information of the corresponding stored sample in the server 41 via the client PC 43 or terminal PC 34, i.e., modifying the information of the stored sample recorded in the first electronic tag 12, thus achieving overall error correction.

[0038] See Figure 1 and Figure 2 In this application, the storage system also includes a smart charging pile 60, which is connected to the central control terminal 40 via a wireless network. The central control terminal 40 can control the automated handling robot 20 to adapt to the smart charging pile 60 for charging based on the remaining power in the automated handling robot 20. Of course, in some embodiments, when the automated handling robot 20 has no retrieval or placement task, it can automatically find the smart charging pile 60 and charge. When the server 41 issues a retrieval or placement task, the automated handling robot 20 leaves the smart charging pile 60 and enters the route planned inside the server 41 to retrieve and place the stored samples.

[0039] See Figure 1 In one embodiment of the application, for ease of storage, each smart vending machine 10 includes a cabinet body 14 and several drawers 15 disposed within the cabinet body 14, each drawer 15 having several storage units 11. An electronic tag is also disposed on one side of the cabinet body 14, recording broad category information. Before the automated handling robot 20 reaches the corresponding cabinet body 10, it needs to scan and read the electronic tag to achieve category matching. Alternatively, it can skip the electronic tag and directly retrieve the corresponding storage unit 11 based on the location information of the samples stored in the server 41. In this case, a multi-joint robotic arm needs to open the drawer 15 and then retrieve or place samples from the corresponding storage unit 11.

[0040] See Figure 3 and Figure 4In one embodiment of this application, the automated guided vehicle (AGV) 20 includes an AGV trolley 22, an environmental recognition module 23, and a position sensor 24. The environmental recognition module 23 and the position sensor 24 are both mounted on the AGV trolley 22. A multi-joint manipulator is mounted on the AGV trolley 22. A control module 25 is mounted on the AGV trolley 22. The control module 25, the environmental recognition module 23, and the position sensor 24 are all connected to the central control terminal 40 via a wireless network. The central control terminal 40 can plan a walking route based on the detection data from the environmental recognition module 23 and the position sensor 24, and send the data containing the walking route to the control module 25. The control module 25 can control the AGV trolley 22 to move. The control module 25 can be a conventional AGV core controller, and the environmental recognition module 23 can be a combination of a conventional camera and a corresponding image processing module. This design can be implemented using existing technologies, such as the technical solution in CN117082334A - A Vehicle-mounted Camera Image Recognition Processing Device and Method, which will not be detailed here.

[0041] In the above embodiments, in order to facilitate the handling and storage of samples, since the samples are basically placed in sample bottles, in one embodiment of this application, the multi-joint manipulator includes a manipulator 26 and a gripper 27, a positioning camera 28, a door opening hook 29, and a door closing telescopic buffer 2a disposed on the moving end of the manipulator 26. The manipulator 26 is mounted on the lifting arm of the AGV trolley 22. A positioning photoelectric switch 2b is provided on the moving end of the manipulator 26. The positioning photoelectric switch 2b, the positioning camera 28, the gripper 27, the door opening hook 29, and the door closing telescopic buffer 2a are connected to the control module 25. The clamping gripper 27 is used to hold the sample bottle, the opening hook 29 is used to pull out the drawer compartment 15, and the closing telescopic buffer 2a pushes the drawer compartment 15 back to its closed position. The positioning camera 28 is mainly used to facilitate spatial position calibration and assist the clamping gripper 27, the opening hook 29, and the closing telescopic buffer 2a in spatial positioning. The positioning photoelectric switch 2b is used to accurately position the clamping gripper 27, the opening hook 29, and the closing telescopic buffer 2a during their respective operations. In fact, to facilitate control and reduce the difficulty of data processing for the control module 25, in an improved embodiment, the positioning photoelectric switch 2b, the positioning camera 28, the clamping gripper 27, the opening hook 29, and the closing telescopic buffer 2a are connected to the robot controller, which communicates with the central control terminal 40 via a wireless network.

[0042] See Figures 1 to 6The specific working principle in this application is as follows: When the staff sends a sampling request to the server 41 through the client PC 43 or the terminal PC 34, if the sampling is a pre-set or previously configured storage sample, the server 41 sends a sampling instruction to the control module 25. The control module 25 plans the sampling route according to the sampling instruction. If sampling is being performed, the control module 25 controls the AGV trolley 22 to travel to the preset position according to the planned route, and then controls the robotic arm 26 to move, so that the door hook 29 is adjusted to the preset position. The door hook 29 is used to pull out the corresponding drawer compartment 15. The positioning camera 28 positions and adjusts the storage unit 11 in the opened drawer compartment 15. At this time, the robotic arm 26 adjusts its position again, and the mobile card reader 21 reads the first electronic tag 12 and the second electronic tag 13 at the preset storage unit 11 position respectively. If the first electronic tag 12 and the second electronic tag 13 are... If the stored information on the first electronic tag 12 and the second electronic tag 13 is consistent, the control module 25 controls the robotic arm 26 to sample the sample stored in the corresponding storage unit 11, that is, to use the gripper 27 to grip and sample, and the photoelectric switch 2b assists in gripping. If the sample information stored on the first electronic tag 12 and the second electronic tag 13 is inconsistent, the control module 25 sends an error message to the server 41, and the server 41 controls the alarm 50 to sound an alarm. At this time, the AGV trolley 22 uses the door closing telescopic buffer 2a to push the drawer compartment 15 back to its original position and return to the waiting area, waiting for the staff to handle it or for the staff to deactivate the alarm. After successful clamping, the robotic arm 26 adjusts its position and then uses the door-closing telescopic buffer 2a to push the drawer compartment 15 back to its original position. Finally, the control module 25 travels along a preset route to the corresponding pick-up and drop-off area of ​​the intelligent material station 30 and stops. It then controls the robotic arm 26 and the gripper 27 to place the clamped storage sample onto the pick-up area 31. At this time, the fixed card reader 33 on the pick-up area 31 will read the second electronic tag 13 on the storage sample again and send the read information to the server 41. The server 41 compares the read information with the sample information in the sampling request issued by the task. If the comparison results are consistent, the alarm 50 will not sound, and the staff can pick up the sample normally in the pick-up area 31. If the comparison results are inconsistent, it means that the server 41 controls the alarm 50 to sound an alarm. At this time, the staff needs to check the sample information stored in the server 41, the sample information stored on the first electronic tag 12 and the second electronic tag 13, until the staff manually resolves the above problem or actively puts the error aside, and the automatic handling robot 20 proceeds to the next storage sample sampling operation.

[0043] Similarly, during sample storage, the fixed card reader 33 in the storage area 32 pre-reads the sample information stored on the second electronic tag 13 on the stored sample and sends the read information to the server 41. The server 41 compares the read information with the sample information in the sampling request issued by the task. If the comparison results are consistent, the processor on the server 41 controls the automatic handling robot 20 to move to the picking and placing area; and uses the gripper 27 to pick up the stored sample in the storage area 32. At the same time, the control module 25 also reads the sample information stored on the second electronic tag 13 on the stored sample through the moving card reader 21. Then, the control module 25 on the automatic handling robot 20 plans the forward route according to the storage location provided by the server 41. The automated handling robot 20 moves to the corresponding smart vending machine 10 according to the planned route. Then, the control module 25 controls the door opening hook 29 on the robotic arm 26 to adjust to the preset position according to the sample information stored on the second electronic tag 13. The door opening hook 29 is used to pull out the corresponding drawer compartment 15. The positioning camera 28 positions the storage unit 11 in the opened drawer compartment 15 and adjusts the posture of the robotic arm 26. At this time, the mobile card reader 21 reads the first electronic tag 12 on the corresponding storage unit 11. The control module 25 compares the sample information stored on the second electronic tag 13 and the first electronic tag 12. If the comparison results are inconsistent, the control module 25 controls the robotic arm 26 to stop working and pushes the drawer compartment 15 back to its original position and closes it through the door closing extension buffer 2a. Then, an error alarm is sent to the server 41. The server 41 controls the alarm 50 to sound an alarm and controls the AGV trolley 22 to move to the waiting position and wait for the staff to handle it. If they match, the gripper 27 on the robotic arm 26 will assist in the storage with the positioning camera 28 and the positioning photoelectric switch. After the gripper 27 correctly places the stored sample in the corresponding storage unit 11, the control module 25 controls the robotic arm 26 to adjust its posture and pushes the drawer compartment 15 back to its original position through the door closing telescopic buffer 2a. At the same time, it controls the AGV trolley 22 to move to the waiting position to wait for the next task or to directly execute the next task.

[0044] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. An intelligent sample storage system, characterized in that, include Several smart vending machines are arranged in sequence. Each smart vending machine is equipped with several storage units. Each storage unit is equipped with a first electronic tag for storing sample information, and the stored sample is equipped with a second electronic tag. An automated handling robot is equipped with a multi-jointed manipulator, which can open and close each storage unit and pick up and place stored samples; the automated handling robot is equipped with a mobile card reader for identifying a first electronic tag and a second electronic tag; The intelligent material platform is equipped with a material picking area and a material storage area, and both the material picking area and the material storage area are equipped with fixed card readers for identifying the second electronic tag; The central control unit is used to query and store the sample information stored in each of the storage units, and to communicate with the automated handling robot and the intelligent material platform via a wireless network, and to control the automated handling robot to move between the intelligent material platform and the intelligent container to pick up and put in the stored samples.

2. The intelligent sample storage system according to claim 1, characterized in that: The central control unit includes a server and a switch, which are communicatively connected. The switch is communicatively connected to the smart vending machine and communicates with the automated handling robot and the smart material platform via a wireless network.

3. The intelligent sample storage system according to claim 2, characterized in that: The switch has a communication connection to a client PC.

4. The intelligent sample storage system according to claim 1, characterized in that: The intelligent material platform is equipped with a terminal PC, which is communicatively connected to the central control terminal.

5. The intelligent sample storage system according to claim 1, characterized in that: It also includes an alarm. When the information of the second electronic tag identified by the fixed card reader is inconsistent with the information of the first or second electronic tag identified by the mobile card reader, the central control terminal controls the alarm to sound an alarm and controls the automatic handling robot to move to the material picking and placing position of the intelligent material platform.

6. The intelligent sample storage system according to claim 1, characterized in that: Each of the smart vending machines includes a cabinet body and several drawer compartments disposed within the cabinet body, and each of the drawer compartments is provided with several storage units.

7. An intelligent sample storage system according to any one of claims 2-6, characterized in that: The automated guided vehicle (AGV) includes an AGV cart, an environmental recognition module, and position sensors. The environmental recognition module and position sensors are both mounted on the AGV cart. A multi-joint manipulator is mounted on the AGV cart. A control module is installed on the AGV cart. The control module, environmental recognition module, and position sensors are all connected to a central control unit via a wireless network. The central control unit can plan a walking route based on the detection data from the environmental recognition module and position sensors, and send the data containing the walking route to the control module. The control module can control the AGV cart to move.

8. The intelligent sample storage system according to claim 7, characterized in that: The multi-joint manipulator includes a robotic arm and a gripper, a positioning camera, a door opening hook, and a door closing telescopic buffer mounted on the robotic arm's moving end. The robotic arm is mounted on the lifting arm of the AGV trolley. A positioning photoelectric switch is provided on the robotic arm's moving end. The positioning photoelectric switch, positioning camera, gripper, door opening hook, and door closing telescopic buffer are connected to the manipulator controller. The manipulator controller communicates with the central control terminal via a wireless network.

9. An intelligent sample storage system according to any one of claims 1-6, characterized in that: It also includes a smart charging station, which is connected to the central control terminal via a wireless network. The central control terminal can control the automated handling robot to adapt to the smart charging station for charging based on the remaining power in the automated handling robot.

Images