Use of external stimuli to supplement optical recognition of recyclable items

Abstract

External stimuli and stimuli detectors are provided for a recycling system which identifies recyclable items based on material. The external stimuli may interact with different recyclable items differently, thus giving off different signature responses. Detection of the signature responses may allow for differentiation of the recyclable items. In some embodiments, the stimulus is a thermal stimulus.

Description

Atorney Docket No. E0406.70023WQ00Date of Deposit: December 30, 2025 - 1 - USE OF EXTERNAL STIMULI TO SUPPLEMENT OPTICAL RECOGNITION OF RECYCLABLE ITEMSRELATED APPLICATIONS

[0001] The present application claims the benefit under 35 U.S.C. § 119(e) of U.S.Patent Application Serial No. 63 / 740,662, filed December 31, 2024 under Attorney Docket No. E0406.70023US00 and entitled “USE OF EXTERNAL STIMULI TO SUPPLEMENT OPTICAL RECOGNITION OF RECYCLABLE ITEMS,” which is hereby incorporate by reference herein in its entirety.BACKGROUNDField

[0002] Aspects of the present technology relate to the use of external stimuli to supplement optical recognition of recyclable items.Related Art

[0003] Some recyclable containers have an associated deposit amount. For example, certain beverage bottles and cans have an associated deposit amount, which in some instances is prescribed by law. The amount is sometimes 5 cents or 10 cents per bottle or can. The consumer pays the deposit when purchasing the beverage bottles / cans at the grocery store and can return the bottles / cans after use to be refunded their deposit. Some recycling systems which refund the deposit on the recyclable bottles / cans are account-based systems. A patron establishes an account with the entity which processes the recyclable bottles / cans. After processing the returned bottles / cans to determine which ones are entitled to a refund, the processing entity deposits money into the account-holder’s account based on how many bottles and cans the patron returned.BRIEF SUMMARY

[0004] According to an aspect of the present technology, a system for investigating recyclable items is provided. The system comprises: a stimulus source configured to apply a stimulus to the recyclable items; and a detector configured to detect a response of the recyclable items to the stimulus and provide an output an output indicative of the response.#14708493v2

[0005] In some embodiments, the system further comprises a processor configured to process the output of the detector to identify the recyclable items.

[0006] In some embodiments, the system source is a thermal source.

[0007] In some embodiments, the stimulus source is a light-based stimulus source.

[0008] In some embodiments, the stimulus source is an audio signal source.

[0009] In some embodiments, the recyclable items are in a container.

[0010] In some embodiments, the recyclable items are conveyed through an investigation area in which they are exposed to the stimulus.

[0011] In some embodiments, the processor is configured to combine the output of the detector with an optical recognition output to identify the recyclable items.

[0012] According to an aspect of the present technology, a system for inspecting recyclable items is provided, comprising: a stimulus device configured to apply a stimulus to the recyclable items; a stimulus response detector configured to detect a response of the recyclable items to the stimulus; an optical imaging device configured to capture an image of the recyclable items; and a processing system configured to process in combination the image and an output of the stimulus response detector to identify the recyclable items.

[0013] In some embodiments, the stimulus is a thermal stimulus.

[0014] In some embodiments, the stimulus is an optical stimulus.

[0015] In some embodiments, the stimulus is an acoustic stimulus.

[0016] In some embodiments, the stimulus device is positioned in advance of the optical imaging device.

[0017] In some embodiments, the stimulus device is positioned after the optical imaging device.

[0018] In some embodiments, the processing system is configured to register the image with the output of the stimulus response detector.

[0019] In some embodiments, the system further comprises a conveyor configured to convey the recyclable items from a loading point to the stimulus device and further to the optical imaging device.BRIEF DESCRIPTION OF DRAWINGS

[0020] Various aspects and embodiments of the technology will be described with reference to the following figures. It should be appreciated that the figures are not necessarily#14708493v2drawn to scale. Items appearing in multiple figures are indicated by the same reference number in all the figures in which they appear.

[0021] FIG. 1 illustrates an optical recognition system for recognizing recyclable items, according to a non-limiting embodiment of the present technology.

[0022] FIG. 2 illustrates a supplemented optical recognition system for recognizing recyclable items, having an external stimulus and a stimulus sensor.

[0023] FIG. 3 illustrates a supplemented optical recognition system like that in FIG. 2 in which the external stimulus device is a thermal diffusion stimulus device and the stimulus sensors is a thermal response sensor.

[0024] FIG. 4 illustrates a computing system configured to perform aspects of the present technology.DETAILED DESCRIPTION

[0025] Systems that reimburse patrons for deposits on items returned for recycling / reuse must identify the returned items to credit the patron the appropriate amount and to sort items for downstream processing. Trained operators can perform this task with a high degree of accuracy, relying on a combination of their senses (primarily vision, touch, and hearing) coupled with their training and experience. However, the use of human labor for this purpose is slow and cost prohibitive.

[0026] To automate the identification of recyclable items in a collection of similar items, companies traditionally use specialized equipment, such as a reverse vending machine (RVM) or a singulator to classify and count the recyclable items. These traditional methods may be augmented by the use of optical recognition (machine vision) systems. The accuracy of these methods has been improved by the addition of artificial intelligence (Al) to the identification / counting system.

[0027] Recently, the accuracy of these systems for identifying and counting returned recyclable containers (such as beverage containers) has been challenged by manufacturers producing items that, to enhance the appeal and / or usability of the items, intentionally resemble other items or that mask the material from which the recyclable item is made. For example, manufacturers now produce aluminum beverage cans shaped to resemble traditional beverage bottles as well as glass beverage bottles with wraps that make the containers opaque rather than translucent. These types of items challenge the accuracy of optical recognition systems enhanced by artificial intelligence.#14708493v2

[0028] To address the problem of accurately identifying such containers, additional information beyond size, shape, color, and / or other visual characteristics may be desirable. Aspects of the present technology use a stimulus (or a combination of stimuli) to generate additional data about the recyclable items (e.g., containers such as beverage bottles and cans) that can be collected by sensors and analyzed by Al software applications or other algorithms trained to interpret the data. This approach provides an enriched data set about the containers of the recyclable items for analysis to arrive at more accurate classifications of items. In at least some embodiments, the accuracy of the system for identifying and counting the recyclable items may be significantly improved.

[0029] Aspects of the present technology provide apparatus and methods for using external stimuli to supplement optical recognition of recyclable items such as beverage containers. The external stimuli and corresponding detection equipment may supplement optical recognition equipment at an optical recognition station, with the combination of equipment forming a combined recyclable item detection station. For example, the external stimuli and corresponding detection equipment may be positioned to interact with the recyclable items before the optical recognition equipment does so. Alternatively, the external stimuli and corresponding detection equipment may be positioned to interact with the recyclable items after the optical recognition equipment. The results of the external stimuli may be processed in combination with the optical recognition results to provide a combined detection result identifying the recyclable items. In this manner, identification of recyclable items may be enhanced compared to systems which use optical recognition alone. Processing of the external stimuli results and the optical recognition results may occur at the point of detection, such as in a recycling facility, or remotely.

[0030] The aspects and embodiments described above, as well as additional aspects and embodiments, are described further below. These aspects and / or embodiments may be used individually, all together, or in any combination of two or more, as the disclosure is not limited in this respect.

[0031] As described above, optical recognition systems, including machine vision systems, are subject to challenges in identifying recyclable items and providing desired information on the state of such items. These challenges stem from difficulty in accurately identifying certain features of recyclable items. For example, vision systems that rely on shape and transparency to help identify recyclable containers (e.g., containers such as bottles and cans) may experience difficulty distinguishing items that are designed to look similar to other types of objects. For example, aluminum cans and plastic bottles shaped like traditional glass beverage #14708493v2bottles, as well as wrapped glass containers with surfaces that resemble aluminum or plastic, pose challenges for such systems. Also, machine vision systems have difficulty determining whether an opaque container is empty, which is an important factor in sorting of objects based on material type in a recycling or reuse system since systems often use forced air to blow polyethylene terephthalate (PET) (a type of lightweight, recyclable plastic) containers off a plastic processing line.

[0032] Recycling / reuse systems that categorize and count the containers in a collection of containers associated with a patron’s account (for reimbursement) separate each collection of containers returned by a customer into the necessary categories for reimbursement. For example, the recyclable items may be separated into aluminum cans, glass bottles, plastic bottles, and so forth. Each collection of containers is typically transported using a conveyor belt system to the imaging system which performs the machine vision function, which is in turn connected to a computerized system employing Al.

[0033] FIG. 1 shows an example of an optical recognition (OR) system 100 which may utilize Al to enhance recognition of recyclable items. The OR system 100 includes a loading subsystem 102 to load recyclable items for optical inspection. In the illustrated embodiment, the loading subsystem 102 includes a tray 104 configured to receive a plurality of recyclable items 106 from a container 108. The container 108 may be a bag, although alternative containers may be used. The container 108 may hold any suitable number of recyclable items, including one or more recyclable items. In some embodiments, the container 108 may hold between twenty and one hundred recyclable items. The plurality of recyclable items 106 may include one or more recyclable items.

[0034] The OR system 100 further comprises a transport subsystem 110 configured to transport the recyclable items 106 to an imaging subsystem 120. In this example, the transport system 110 is a conveyor configured to convey trays 104 from the loading subsystem 102 to the imaging subsystem 120. In some embodiments, the transport subsystem 110 may comprise a group of conveyors that transport the recyclable items to the imaging subsystem 120. The recyclable items 106 may be in a tray, as shown, or directly on a conveyor in some embodiments. Other transport technology may be used, as a conveyor is a non-limiting example. For instance, the transport subsystem 110 may include robotic and / or manual transportation of recyclable items 106 to the imaging subsystem 120.

[0035] The imaging subsystem 120 is configured to capture one or more images of the recyclable items 106. For example, the imaging subsystem may include a camera configured to collect digital images of the recyclable items 106 to be used in a recognition process. The #14708493v2captured image(s) may be of all the recyclable items 106 in a tray 104, or of a single recyclable item 106 or a subset of the recyclable items 106 in the tray 104.

[0036] The OR system 100 further comprises computing subsystem 130. The computing subsystem 130 may be separate from the imaging subsystem 120 as shown, or in alternative embodiments may be integrated into the imaging subsystem 120. The computing subsystem 130 may include one or more processors, such as servers or cloud computing devices. The nature of the processor is non-limiting as the various aspects described herein are not limited to using any specific type of processor(s). The computing subsystem 130 may perform image recognition on the collected digital images of the recyclable items 106 to identify them. For example, the computing subsystem 130 may perform image recognition to identify bottles and cans as such. The computing subsystem 130 may categorize the recyclable items 106. In some embodiments, the computing subsystem 130 includes software and is configured to run one or more predictive software programs or algorithms to arrive at a “best guess” categorization of the recyclable item.

[0037] The OR system 100 further comprises a sorting subsystem 140. The sorting subsystem 140 may include equipment configured to sort the recyclable items 106 based on the recognition results from the imaging performed by the imaging subsystem 120. The sorting may include sorting the recyclable items 106 into categories for downstream processing (such as for recycling and / or reuse based on the requirements of the recycling / reuse ecosystem).

[0038] Artificial intelligence (“Al”) may be implemented to improve the ability of optical recognition systems to identify recyclable items that masquerade as other items, but nonetheless optical recognition systems are still imperfect. Al algorithms rely on probability in making such determinations. This ability is hampered in situations where a complete image of the object is not available due to stacked objects, as is often the case on high-speed recycling / reuse processing lines.

[0039] In summary, current systems used for identifying and / or classifying recyclable items either fail to correctly identify such items in many cases or have to rely on human operators to recognize and correctly classify such items. Both incorrect classification and human intervention are costly and affect the efficiency of downstream processes for recycling / reuse.

[0040] As described above, aspects of the present technology add two types of devices to a recycling system to enhance identification of recyclable items and / or the materials or state of such recyclable items. One type of added device may apply a stimulus device and another type of added device may measure the effect of the stimulus applied by the stimulus device and send the resulting data to the computerized Al system for interpretation along with the vision data. The additional use of external stimuli to supplement optical recognition of recyclable items, #14708493v2including optical recognition which utilizes Al to aid in recognition, may provide more accurate identification of recyclable items and their state (e.g., filled v. unfilled). In turn, time and cost may be reduced in recycling operations, and accuracy may be increased.

[0041] Various types of external stimulus and corresponding detection devices may be added. Non-limiting examples include: (a) a thermal device that applies heat or cold to the recyclable items and a thermal imaging device that measures the amount of temperature change that the stimulus produced in each recyclable item; (b) a device that applies a series of lights at specified frequencies to the recyclable items and a sensor device (which might be the imaging camera of the imaging subsystem) that records the reflection and / or refraction of each light source; or (c) an audio device that applies sounds at specified frequencies to the recyclable items and a sensor device that records the reflection and / or refraction of each sound frequency.

[0042] Each of the described stimulus technologies may create an array or map of responses that are returned to the recognition system, which may be an Al-based recognition system. The Al recognition system may be trained to use the information from the external stimuli in addition to the digital images captured by the imaging subsystem 120 to categorize the recyclable item.

[0043] FIG. 2 illustrates an example of a supplemented optical recognition (SOR) system according to an embodiment of the present technology. The SOR system 200 includes many of the same components as the OR system 100 of FIG. 1, such that those components are not described again in detail here. The SOR system 200 additionally includes an external stimulus device and a corresponding detector. The SOR system 200 includes a pre-stimulus sensor subsystem 202, a stimulus application subsystem 204, and a post-stimulus subsystem 206. Also, the SOR system 200 includes an expanded computing subsystem 230.

[0044] The pre-stimulus sensor subsystem 202 includes one or more sensors that collect data regarding selected attributes of the recyclable items 106 prior to application of the stimulus. The pre-stimulus sensor subsystem 202 communicates the data it collects to the computing subsystem.

[0045] The stimulus application subsystem 204 is a subsystem including a stimulus device that applies a stimulus (or various stimuli) to the recyclable items. For example, the stimulus application subsystem 204 may include a device of any of those types described above, such as a thermal stimulus device, an optical stimulus device, or an acoustic stimulus device.

[0046] The post-stimulus sensor subsystem 206 includes one or more sensors that collect data regarding selected attributes of the recyclable items after application of the stimulus by the stimulus application subsystem 204. The post-stimulus sensor subsystem 206 communicates the #14708493v2collected data about the response of the recyclable items to the applied stimulus to the computing subsystem.

[0047] The expanded computing subsystem 230 uses specialized software or algorithms to analyze the effects of the stimulus to the recyclable items and combines this analysis with the analysis of the camera images from the imaging subsystem 120 to arrive at more accurate predictive categorizations of the recyclable items. A feedback loop can be used to train the algorithms employed and to improve the predictive capabilities of the expanded computing system 230.

[0048] It should be appreciated that the stimulus application subsystem 204 may assume various positions relative to the imaging subsystem 120. For example, the stimulus application subsystem 204 and corresponding post-stimulus sensor subsystem 206 may be positioned in advance of the imaging subsystem 120 to apply the stimulus before the recyclable items are imaged by the imaging subsystem 120. Alternatively, the stimulus application subsystem 204 and post-stimulus sensor subsystem 206 may be positioned after the imaging subsystem 120 to apply the stimulus after the images of the recyclable items have been captured. The processing of the resulting data may occur on-site (e.g., at a recycling facility) or remotely (e.g., over the Internet, Cloud, or other remote location).

[0049] While the SOR system 200 of FIG. 2 illustrates a single pre-stimulus sensor subsystem 202, stimulus application subsystem 204, and post-stimulus subsystem 206, it should be appreciated that these subsystems may include a combination of two or more devices operating by different modalities. For instance, a combination of two or more of a thermal stimulus device, optical stimulus device, and acoustic stimulus device may be employed by the subsystems, along with corresponding detectors. In one example, a combination of two or more of the following technologies may be employed: (a) thermal diffusion technology to categorize recyclable items based on their composition (e.g., material type); (b) thermal diffusion technology to determine whether recyclable items (e.g., beverage containers) are empty; (c) ultrasonic energy technology to determine whether recyclable items (e.g., beverage containers) are empty; and (d) light reflection technology / diffusion measurement technology to categorize recyclable items based on their composition (material type).

[0050] FIG. 3 illustrates an example of a SOR system that relies on thermal diffusion technology to categorize recyclable items based on their composition (material type). The illustrated variation of a SOR system uses the following technology for the SOR subsystems: (a) a pre-stimulus subsystem 302; (b) a stimulus applications subsystem 304; (c) a post-stimulus sensor subsystem 306; (d) the expanded computing subsystem 230.#14708493v2

[0051] The pre-stimulus subsystem 302 comprises an ambient temperature sensor which captures the ambient temperature of the operating environment. An infrared camera is positioned to capture the baseline temperature data for the recyclable items (prior to application of the stimulus). The “before stimulus” data is communicated to the expanded computing subsystem 230.

[0052] The stimulus application subsystem 304 comprises a thermal heating device that applies thermal energy (the external stimulus) to the recyclable items 106. The thermal heating device may be in the form of a device that sits over a conveyor system (e.g., transport subsystem 110) if the recyclable items 106 are transported on a conveyor or in the form of a heated cabinet if the recyclable items 106 are transported in trays via robotic means.

[0053] The post-stimulus sensor subsystem 306 comprises a second infrared camera positioned to capture the temperature data for the recyclable items 106 at a designated time after the application of the stimulus by the stimulus application subsystem 304. The “after stimulus” data is communicated to the enhanced computing subsystem 230. This after stimulus data may be a series of images that are used to determine the material of the recyclable items and if the recyclable items are empty.

[0054] In some embodiments, the expanded computing subsystem 230 receives data about the ambient temperature, the baseline infrared data from the pre-stimulus subsystem 302, the post-stimulus infrared data from the post-stimulus sensor subsystem 306 and the date and time are which each data point was captured. The thermal energy application temperature is captured from the stimulus application subsystem 304, along with the date and time when the exposure to heat started and the date and time when the exposure ended. Exposure duration is calculated based on these date and time stamps. The comparison of temperature data collected before and after the exposure to heat, along with the exposure duration, is used to identify a heat signature for each recyclable item (based on the way the object absorbs and dissipates heat). The heat signature for each recyclable item is combined with the camera images of the recyclable item from the imaging subsystem 120 to arrive at more accurate predictive categorizations of the recyclable items. A feedback loop can be used to train the algorithms and improve the predictive capabilities of the system.

[0055] In some embodiments, the data from the post-stimulus subsystems may create a map based on location of the recyclable items within the tray 104 or otherwise positioned on the transport subsystem 110. This map may be registered with the image(s) of the recyclable items 106 from the imaging subsystem 120 to align the data from the image(s) with the data from the post-stimulus subsystem and the pre-stimulus subsystem. Aligning the data in this manner may #14708493v2facilitate correlating the data from the various stages of the SOR system 300 (or, more generally, the SOR system 200) to ensure accurate identification of recyclable items.

[0056] According to aspects of the present technology, the features described herein may be added to a current optical recognition station in a recycling processing facility to improve the accuracy and efficiency of its recycling / reuse operations.

[0057] As should be appreciated from the description above, various aspects of the technology may be implemented on one or more computer systems, such as the exemplary system 400 shown in FIG. 4. For example, one or more of the processors of the stimuli equipment and detectors may have a structure like that in FIG. 4 in some embodiments, or may include components such as those shown in FIG. 4. Computer system 400 includes processor 402, memory 404, nonvolatile storage 406, and a display 408. The processor 402 may be a microcontroller, a central processing unit (CPU), a mobile chipset, or any other suitable type. The processor 402 may perform one or more functions described herein such as the functions of the devices illustrated in FIGS. 1-3. Instructions for the processor 402 may be stored, for example, in non-volatile storage 406, and data may be stored, for example, in memory 404. Alternatively, instructions for the processor may be stored in the memory 404 and data may be stored in the non-volatile storage 406. In still further embodiments, the memory 404 and nonvolatile storage 406 may both store instructions and / or data. The memory 404 and / or nonvolatile storage 406 may be a disk (e.g., an optical disk), a compact disk (cd), a solid-state memory, or any other memory, and in some embodiments may be configured to store processexecutable instructions which, when executed by the processor 402 cause the processor to perform any of the methods described herein. It should be appreciated that the memory 404 and non-volatile storage 406 are non-transitory media in at least some embodiments. Optionally, a display 408 may be provided, for example so that personnel may interact with the processor and view data output by the processor. For example, the display 408 may be a mobile device display or computer display in a data center.

[0058] According to an aspect of the present technology, a computing system comprises a non-transitory computer readable medium configured to store processor executable instructions which, when executed by at least one processor, cause the at least one processor to perform any of the methods described above. For example, in one embodiment, the at least one processor is configured to perform a method comprising receiving an image of recyclable items and receiving data indicative of a response of the recyclable items to an external stimulus, and to process the data in combination to identify the recyclable items. In some embodiments, the at least one processor is configured to control operation of a supplemented optical recognition #14708493v2system by controlling operation of the devices of such system as described above. The at least one processor may control operation of two or more of a pre-stimulus subsystem, stimulus application subsystem, post-stimulus subsystem, imaging subsystem, and transport subsystem to perform the functions described above for such items.

[0059] The aspects described herein have application in both the recycling and reuse industries. Reuse applications include but are not limited to services such as those found at airports that lend items (such as food containers, coffee cups, electronic equipment) to customers at one destination for a fee that is partially or completely reimbursed at another destination.

[0060] Aspects of the present technology provide various benefits, some of which have been described above. Some benefits are listed here. However, it should be appreciated that not all embodiments necessarily provide all embodiments and that benefits other than those listed now may be realized by one or more embodiments. According to some embodiments of the present technology, the use of external stimuli to supplement optical recognition systems provides increased accuracy of identification of recyclable item material and / or the item in general. Identification of materials detrimental to recycling processes may also be improved, such as identification of ceramics or other materials which may degrade recycling processes. As a result, the ability to remove harmful materials from recycling batches may be improved, resulting in more accurate and more efficient recycling of materials. The ability to identify materials and recyclable item state more accurately may facilitate sorting recyclable items into proper locations within a recycling processing line. In some embodiments, operation of a recycling processing line which uses forced air to separate PET from other plastics may be made more accurate by allowing for more identification of recyclable items made of PET.

[0061] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0062] The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified.

[0063] As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily #14708493v2including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified.

[0064] Use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

[0065] The terms “approximately” and “about” may be used to mean within ±20% of a target value in some embodiments, within ±10% of a target value in some embodiments, within ±5% of a target value in some embodiments, and yet within ±2% of a target value in some embodiments. The terms “approximately” and “about” may include the target value.

[0066] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0067] Having described above several aspects of at least one embodiment, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be object of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.#14708493v2

Claims

CLAIMSWhat is claimed is:

1. A system for investigating recyclable items, comprising:a stimulus source configured to apply a stimulus to the recyclable items; anda detector configured to detect a response of the recyclable items to the stimulus and provide an output an output indicative of the response.

2. The system of claim 1, further comprising a processor configured to process the output of the detector to identify the recyclable items.

3. The system of claim 1 or any other preceding claim, wherein the stimulus source is a thermal source.

4. The system of claim 1 or any other preceding claim, wherein the stimulus source is a light-based stimulus source.

5. The system of claim 1 or any other preceding claim, wherein the stimulus source is an audio signal source.

6. The system of claim 1 or any other preceding claim, wherein the recyclable items are in a container.

7. The system of claim 1 or any other preceding claim, wherein the recyclable items are conveyed through an investigation area in which they are exposed to the stimulus.

8. The system of claim 1 or any other preceding claim, wherein the processor is configured to combine the output of the detector with an optical recognition output to identify the recyclable items.

9. A system for inspecting recyclable items, comprising:a stimulus device configured to apply a stimulus to the recyclable items;a stimulus response detector configured to detect a response of the recyclable items to the stimulus;#14708493v2an optical imaging device configured to capture an image of the recyclable items; a processing system configured to process in combination the image and an output of the stimulus response detector to identify the recyclable items.

10. The system of claim 9, wherein the stimulus is a thermal stimulus.

11. The system of claim 9, wherein the stimulus is an optical stimulus.

12. The system of claim 9, wherein the stimulus is an acoustic stimulus.

13. The system of claim 9, wherein the stimulus device is positioned in advance of the optical imaging device.

14. The system of claim 9, wherein the stimulus device is positioned after the optical imaging device.

15. The system of claim 9, wherein the processing system is configured to register the image with the output of the stimulus response detector.

16. The system of claim 9, further comprising a conveyor configured to convey the recyclable items from a loading point to the stimulus device and further to the optical imaging device.#14708493v2

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