Patent Publication Number: US-2022225828-A1

Title: Infrared toaster

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/448,359, filed on Jun. 21, 2019, which claims priority of U.S. Provisional Patent Application No. 62/688,127, filed on Jun. 21, 2018, the content of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Many restaurants serve toasted breads and toasted English muffins as regular menu items. Many of those menu items include sandwiches that are comprised of toasted English muffins or toasted bread. 
     Toasted food products have a distinctly different flavor than to the same products prior to toasting. Toasting a food product also changes the bread product&#39;s color and its texture. In addition to changing flavor, color and texture, the toasting process often gives off a pleasing aroma. 
     Toasting food products like sliced bread, English muffins, bagels, pizza and other bread products is usually accomplished using infrared energy emitted from one or more electrically-heated wires in a toaster or broiler. The process of toasting, is the result of a chemical reaction known as the Maillard reaction. The Maillard reaction is considered to be the reaction between carbohydrates and proteins that occurs upon heating and which produces toasting. 
     It is believed that when the Maillard reaction goes too far or too long, carbohydrates in a bread product will oxidize completely and form carbon. Carbon absorbs light. The surface of a burned bread product therefore appears black. The term “burn” is therefore considered to be the thermally-induced oxidation of carbohydrates to a point where the carbon content of the bread product surface is high enough to absorb visible light that impinges on the bread product surface and therefore makes the surface of the bread product appear to an ordinary observer to be black in color. 
     A well-known problem with prior art toasters of all kinds is that they often cannot consistently achieve a uniform toasting across bread products in the same amount of time. Because of their mass, surface irregularities and temperatures, bread products like English muffins are especially difficult to uniformly and consistently toast in a short amount of time period because the peaks and valleys of each English muffin&#39;s surface are at different distances from the IR source that effectuates the toasting process. Since many restaurant operators need and prefer to be able to toast bread products like English muffins as quickly as possible, attempts to shorten toasting time by simply increasing the input thermal energy usually results in more bread products being burned rather than toasted. A toaster and a method of toasting food products like bread and English muffins and which can consistently provide uniform browning in a relatively short period of time would be an improvement over the prior art. 
     BRIEF DISCLOSURE 
     In an example of a toaster, a support is configured to hold a bread product. An infrared source is arranged relative to the support and operates to direct IR energy to the bread product on the support. A light source is arranged relative to the support and operates to illuminate the bread product on the support while the IR source operates to direct the IR energy. A camera operates to capture images of the bread product on the support. A processor receives the images from the camera. The processor analyzes successive images received from the camera. Based upon the analysis, the processor operates the IR source to achieve a predetermined toasting level of the bread product. 
     In examples of the toaster, the processor operates the IR source to terminate operation directing IR energy when the predetermined toasting level is reached. The comparison performed by the processor calculating a difference image using a current acquired image of the images from the camera and evaluating the difference image based upon the predetermined toasting level. The processor isolates pixels associated with the bread product in each of the images received from the camera. The processor evaluates the isolated pixels of the difference image based upon the predetermined toasting level. The processor calculates an average pixel value from the isolated pixels of the difference images and compares the average pixel value to the predetermined toasting level. The isolated pixels of the difference image may each have a pixel difference value and the average pixel value may be an average of the difference values. The isolated pixels of the difference image may each have a normalized difference value and the average pixel value may be an average of the normalized pixel values. The normalized difference values are normalized to an expected toasting range based upon an identification of a type of the bread product. The processor may apply edge detection to the captured images from the camera to isolate pixels in each of the images associated with the bread product. 
     In further examples of the toaster, the processor receives an input indicative of the predetermined toasting level. The input may be an identification of a bread product type and a doneness. The processor may be communicatively connected to a kitchen management system which receives a customer order, identifies a toasted bread product for the received customer order and electronically communicates the bread product type and the doneness of the toasted bread product for the received customer order to the processor. The supplemental light source may be a white light source. The supplemental light source may provide light energy limited to wavelengths between 380 nm and 570 nm. The images of the bread product may be grayscale. The IR source may be configured as an annulus and the camera is positioned centrally to the IR source. The camera may include a wide-angle lens. A forced gas source and a duct open about the camera between the camera and the IR source to produce a flow of forced gas about the camera. The support may be a tray configured to hold the bread product relative to the IR source and the processor operates the tray to release the bread product when the predetermined toasting level is reached. The support may be a conveyor operable to receive the bread product and move the bread product into a position relative to the IR source, the processor operates the conveyor to move the bread product away from the IR source when the predetermined toasting level is reached. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a system diagram of an exemplary embodiment of a toaster. 
         FIG. 2  is a graph of change in bread product surface color over time while toasting. 
         FIG. 3  is a flow chart of an exemplary embodiment of a method of toasting. 
         FIGS. 4A-4C  depict examples of a bagel toasting. 
         FIG. 5  depicts an exemplary embodiment of a camera. 
         FIGS. 6A-6C  depict an exemplary embodiment of a toaster. 
         FIG. 7  depicts a further exemplary embodiment of a toaster. 
         FIG. 8  is a cross-sectional view taken along line  8 - 8  of  FIG. 7 . 
         FIGS. 9A-9B  depict another exemplary embodiment of a toaster. 
         FIG. 10  is a system diagram of an exemplary embodiment of a kitchen system including a toaster. 
     
    
    
     DETAILED DISCLOSURE 
       FIG. 1  depicts an exemplary embodiment of a toaster  10 . The toaster  10  uses at least one infrared (IR) source  12 , and, as depicted in  FIG. 1 , exemplarily two IR sources  12 . The IR sources may take the form of one or more IR emitting LEDs, for example, an array arrangement of IR emitting LEDs. It will be recognized that there are other sources of IR energy which may be used in other embodiments, including, but not limited to electrified wire coils, which when energized with electrical current, are known to heat and emit IR energy. In one example, the IR source  12  may be a 1,200 watt electrically resistive heating coil. The IR sources  12  are arranged to direct IR energization  14  at a food product  16 . The food product  16  is exemplarily a bread product that is desired to be toasted, although thermal treatments, exemplarily cooking, searing, broiling, or baking may be achieved in other embodiments. The bread products may include, but are not limited to sliced bread, English muffins, bagels, pizza, and flat bread, rolls, or buns. 
     As previously noted, the challenge to toasting equipment is to quickly provide the amount of energy to the food product  16  to achieve a desired level or amount of toasting of the exterior of the food product, without overtoasting or undertoasting the food product within a narrow quality range.  FIG. 2  is a graph that exemplarily represents the general change in color of a bread product as it is toasted. From the S curve shape of the graph of  FIG. 2 , it can be seen that the desirable range of toasting occurs at the steepest portion of the curve and thus the difference between an acceptable and unacceptable level of toasting may be a short difference in duration of IR exposure. As will be described in embodiments, such difference may be a second or less. 
     Referring back to  FIG. 1 , the toaster  10  includes features that will be described in further detail herein whereby the toasting process of the food product  16  can be closely monitored and the operation of components of the toaster  10  controlled to quickly toast the food product to a predetermined toasting level and ending the toasting process so as to not exceed the predetermined toasting level. 
     The toaster  10  includes a camera  20  that is oriented relative to the food product  16 . While the camera  20  is shown in  FIG. 1  in generalized form, more specific exemplary embodiments of such a camera will be disclosed in further detail herein and it will be recognized that embodiments of the toaster  10  may include other features within the camera  20  than those provided in the examples herein. The camera  20  exemplarily acquires digital image captures of the surface of the food product that is being toasted and provides these digital image captures to a processor  22  for analysis and resulting control of the IR sources  12 . As depicted, in an embodiment designed to toast two surfaces of the food product  16 , a cameras  20  may be directed at each of the surfaces to be toasted. 
       FIG. 1  depicts the camera  20  in a position arranged centrally to the IR sources  12 . It will be recognized that in other embodiments, the IR sources may be located in other positions relative to the IR sources  12 , for example, arranged at another position intermediate of the IR source or at a position or positions to the sides of the IR sources  12 . While a single camera  20  is provided with each IR source and/or each surface to be toasted, it will be recognized that in embodiments, more than one camera per IR source  12  or surface to be toasted may be used. 
     In embodiments as described in further detail herein, in addition to the IR wavelength light supplied from the IR sources  12 , embodiments of the toaster  10  may also direct supplemental light at the surfaces of the food product from one or more light sources  24 . The light sources  24  may operate to emit visible spectrum light, IR spectrum light, UV spectrum light, or specific wavelengths or combinations of wavelengths within this range depending upon the specific embodiments as described herein. In exemplary embodiments, the supplemental light may be provided at a range between 380 nm and 570 nm. Such a range may include some or all of 380 nm-450 nm (e.g. violet), 450 nm-495 nm (e.g blue), and 495 nm-570 nm (e.g. green) spectrum light. 
     The food product  16  is supported between the IR sources  12  by a support  18 . Embodiments of the support  18  may take a number of forms as will be described in further detail herein. These forms of supports may include grates, trays, conveyors, or platforms and may be operable in such forms and as described herein to facilitate loading and ejection of the food product  16  relative to the toaster  10 . 
     The processor  22  is communicatively connected to a computer readable medium (CRM)  26  which is non-transient and upon which is stored computer readable code in the form of computer programs or software configured for execution by the processor  22 . It will be recognized that the processor  22  is exemplarily incorporated into any of a variety of known controller circuits, integrated circuits, microcontrollers, or associated circuitry. The processor  22  may be part of a central processing unit (CPU) which includes integrated memory, although in embodiments the CRM  26  may be a separate component or communicatively connected to the processor  22 . The processor that accesses software or firmware in the form of computer readable code stored on the CRM  26  as either integrated memory or external memory. The processor  22  executes the computer readable code as an instruction set to carry out the functions as described herein, including the receipt of input, calculations, and outputs as will be described. 
     The processor  22  receives the digital image captures from the camera  20  and uses image processing techniques as described in further detail herein to monitor the toasting process and provide operational commands to the components of the toaster  10  in a manner so as to achieve a predetermined level of toasting of the food product  16 . 
       FIG. 3  is a flow chart that depicts an exemplary embodiment of method  100  which will be described in further detail herein, for example with reference to the toaster  10  of  FIG. 1 , although it will be recognized that other embodiments of toasters may be operated to carry out the method  100  as described herein. The method  100  assumes that a food product has been loaded into the toaster. This may be done in manual, automated, or semi-automated manners, for example with the loading of a food product in a tray, slot, and/or conveyor which orients the food product relative to the IR sources  12 . 
     At  102 , an initial image of the food product is acquired. In exemplary embodiments, an initial image of each surface to be toasted is acquired, for example, the top and bottom of a food product as depicted in  FIG. 1 . In embodiments with multiple IR sources, such IR sources may be individually operated relative to the toasting of a particular surface or area. In exemplary embodiments, the digital images acquired in the system and method may be RGB images, although in other embodiments, the images may instead be captured as a grayscale image or converted to a grayscale image. In some embodiments, it has been found that acquisition of grayscale images or conversion of RGB images to grayscale images may improve processing times, while not adversely affecting the analysis, outcomes, and controls as described herein. In other embodiments, particular light spectrum wavelengths may be used. The acquisition of the digital images may be limited to particular light spectrum wavelengths or the acquired color digital image may be processed and or otherwise filtered or limited to the selected wavelengths for analysis. 
     Optionally, at  104  one or more toasting inputs are received. In an exemplary embodiment, the toaster  10  includes a user interface  28  through which user inputs are received, for example, to identify a food product to be toasted and a desired level of toasting. It will be recognized that while such inputs may be received on a case by case basis, in other embodiments, the toaster  10 , and more specifically, the processor  22  of the toaster  10  may be communicatively connected to a kitchen management system (KMS) from which inventory and customer order instructions may be provided, thus providing the toaster with information regarding the food product to be toasted and the desired level of toasting. In still further exemplary embodiments, the toaster  10  may be operated as a dedicated toasting device for a particular bread product (e.g. English muffin, bagel) with pre-established settings for that product and toasting level which are used as a default absent any further input or instruction. 
     In a still further exemplarily embodiment, the processor  22  may perform image processing whereby image processing techniques and algorithms are applied to the initial image acquired at  102  in order to automatedly identify the food product type that has been loaded into the toaster. Such identification may include, but is not limited to, comparison by the processor of the acquired initial digital images to stored models or standardized images representative of different types of food, and particularly of bread products. A toasting level may be associated with each possible food type and once the food type is identified, the associated toasting level selected for the subsequent toasting operation. While a toasting level may be predefined for each bread product, customer orders or preferences may include a doneness level or adjustment to the predefined toasting level. Such a doneness level may include an indication of lightly toasted which would result in less thermal treatment than the predefined toasting level or darkly toasted which would result in more thermal treatment than the predefined toasting level. 
     At  106  one or more IR sources of the toaster are operated to apply IR energization to the food product. In an exemplary embodiment, the IR source may be a 1,200 watt heating coil and multiple such IR sources may be arranged to simultaneously toast both sides of the bread product. 
     While operating the IR source, sequential new images of the bread product are acquired at  108  by the camera  20  arranged in the toaster  10 . In an embodiment with multiple cameras  20  including cameras oriented at different sides of the bread product, this acquisition includes images from each camera. In an exemplary embodiment, the new images are acquired at a refresh rate. In an exemplary embodiment, the new images are acquired at a 10 Hz refresh rate, although it will be recognized that in other embodiments more or fewer images may be acquired per second. For each acquired image, at  110  the newly acquired image is compared to a previous image. In a first example, the comparison at  110  is a comparison between the initial image acquired at  102  and the most recent newly acquired at  108 . The comparison is exemplarily a difference function whereby the newly acquired image is subtracted from the previously acquired initial image to produce a difference image. For the sake of simplicity in an example, this function in a grayscale analysis will produce a “black” image whereby all of the pixels are value zero with the first image acquisition as the color of the bread product will not have changed during the first 1/10 of a second operation of the IR source. As the product toasts, the surface of the product will become darker and thus have a lower grayscale value, that when subtracted from the initial image, will produce a higher value in the pixels of the difference image. It will be recognized that similar analysis can be done with a full color spectrum of acquired digital images, or may be done within specific wavelengths of acquired images. 
     In an exemplary embodiment, a mean or average pixel value may be calculated for the difference image and such mean value used to define and determine toasting level. This mean pixel value models the desired toasting outcome to which the difference image is compared at  112 . In an exemplary embodiment, the input of the toasting level corresponds to an average pixel value of the difference image at  112 , other examples of the toasting level model are described herein, but may include and are not limited to a rate of change model, a percentage change model, or a representative image of a toasted bread product. When evaluating the acquired images against the toasting model, the images may be limited to those portions of the image identified to be the bread product. This may similarly apply to the difference images and the resulting average pixel values of the difference images. In calculating the difference image, in general, the area surrounding the bread product will not change or experience minimal change across the acquired images. Therefore, the boundary of the bread product in the images may be identified and analysis focused on that portion of the images representative of the bread product. 
     After analysis of the acquired images based upon the toasting model, then at  114 , the processor may determine whether to continue toasting or to take an action. At  116 , an action to end the toasting function is taken based upon this determination. This action may be to terminate the operation of the IR source. This action may be to mechanically eject the bread product from the toaster. In still further examples, the action at  116  may be to do both. In an example, the action at  116  may be taken when the average pixel value of the difference image matches the average pixel value corresponding to the desired toasting level of the toasting model. 
     In another example, the desired toasting level may be defined as an average pixel value less than the actual desired toasting level, knowing that if the bread product is not ejected immediately, the heat within the toaster, even after the IR source is turned off, may cause continued toasting of the bread product. In further embodiments, the actions at  116  may include producing an indicating alert, or message that the toasting is complete or near complete. This may provide notice to a next device in an automated system or to a food service worker that the toasted bread product is about to be ejected from the toaster. 
     Returning to  114 , if the bread product still requires toasting, then at  118  a determination is made whether the toaster should maintain the current settings or adjust an operation of the toaster. If an adjustment is to be made, then at  120  such operational adjustment is determined by and commanded by the processor. The toaster continues to operate the IR source, returning to  106  and monitoring the progress of the toasting of the bread product with subsequent images. 
     In an exemplary embodiment, the toaster  10  may further include blowers which are not depicted in  FIG. 1 , but are exemplarily described in further detail U.S. Patent Application Publication No. 2010/0239724 entitled “Toaster with Cooling Air Stream”, which is herein incorporated by reference in its entirety. It will be recognized that the operation of blowers in coordination with an IR source may serve to slow toasting in a localized area that is impinged with air by the blower. Therefore, in an exemplary embodiment, if it is determined at  118  by the analysis of the images described above that a portion of the bread product is toasting faster than the rest of the product, then operation of a blower or blowers at  120  can limit toasting in an area of blower impingement such that the entire bread product achieve an even level of toasting at the desired level of toasting. In one non-limiting embodiment, such adjustment may be made if one side of the bread product is toasting faster than another side. In a still further exemplary embodiment, blowers may be used if there is a desired instruction to toast the two sides of the bread product to different levels of toasting. In still further exemplary embodiments, the operation adjustment at  120  may be to increase or decrease the electrical energization provided to the IR source or a duty cycle of the energy provided which may serve to increase or decrease the IR energy applied to the bread product. Relatedly, in toasters with multiple IR sources, for example to toast different portions of a bread product or to toast opposite sides of a bread product, the operation adjustment  120  may be applied to a subset of the IR sources, for example to slow the toasting of one side (e.g. a bagel exterior) by blowers or reduced energization while continuing toasting of the opposite side (e.g. a crumb side). 
     The analysis between images captured may be on a zoned basis in that specific portions of the bread product (e.g. halves, quadrants, concentric circles/rings, etc.) may be comparatively analyzed. In such an example, the bread product in the image is isolated from the background and then a portion or portions of the bread product analyzed for change in color level. This may provide improved resolution of monitoring of toasting progression and refined control of the toasting process. For example, toasting may be terminated if one monitored portion reaches a predetermined toasting level threshold. This may serve to ensure that no portion of the bread product becomes over-toasted. In other embodiments, zoned control of the IR source(s) and/or localized blowers can be used to increase or decrease localized toasting within a portion to promote even toasting of the bread product. 
     The method returns to  106  where the IR source is operated according to the same operational settings or to the operational adjustments made at  120 . The new image is acquired again at  108  and the analysis is continued to be performed, for example at a 10 Hz refresh rate of newly acquired and analyzed images until the toasting is deemed complete. 
     While one example of the comparison and analysis as may be used by the toaster has been described herein, it will be recognized that there are other comparison functions that may be used in other embodiments as well. In another example, the difference image may be represented as a decimal percentage either above a minimum pixel value (e.g. zero) or below a maximum pixel value (e.g. 255). In such embodiments, the toasting levels may be defined as either percentages of darkness or percentages of lightness. Related to this embodiment, the initial image may be analyzed to evaluate the image/imaged bread product to determine a baseline initial darkness of the imaged bread product. A numerical pixel value difference between the initial value and “black” may define a relative “toasting range”. As an example, a piece of white bread may have a significantly larger “toasting range” than a piece of dark rye by this evaluation. The white bread may have an initial pixel value of  220 , while a piece of dark rye bread has an initial pixel value of  100 . The toasting level may then be defined as a percentage of the toasting range. If the desired toasting level is 50% then a piece of white bread may experience greater absolute change, e.g.  110  for the white bread versus  50  for the dark rye, but both the white bread and dark rye may exhibit a similar relative change. 
     In an additional example, a rate of change between subsequent images may be calculated. In the comparison at  110 , the previous image may be deemed a previously acquired image rather than the initial image and therefore, the difference image may be representative of only the instantaneous change between image acquisitions. Other similar techniques may be used to calculate the current rate of change in the darkness of the monitored surface. At  112 , the toasting model used may instead reflect the associated rate of change with each toasting level or to identify a time for the toaster to take action to achieve the desired toasting level. 
     In a still further example, the new image acquired at  108  may be compared to the previous or initial image at  110  to assist in edge detection or isolation of the bread product in the image. After this processing to place the analysis focus on the bread product in the image, the bread product image is compared to a toasting model representative of an appearance of the bread product at the desired toasting level. 
       FIGS. 4A-4C  exemplarily depict varying levels of toasting of a raisin bagel. A raisin bagel provides an example of some of the challenges that have been overcome by the present disclosure. The raisin bagel progresses from untoasted in  FIG. 4A  to lightly toasted in  FIG. 4B  to darkly toasted at  FIG. 4C . This exemplarily corresponds to points A, B, and C as found in the graph of  FIG. 2 . The raisin bagel of  FIGS. 4A-4C  provides a first challenge having both circular shape and having a hole in the center which therefore results in large portions of the digital image containing irrelevant information to the determination of the toasting level of the bagel. Therefore, in embodiments, image processing may be performed as part of the image acquisition or the comparison to previous images for the purpose of edge detection. Edge detection analysis identifies sharp transitions in the pixel values of the digital image and may be applied to the digital images to identify only those portions that which are related to the bread product being monitored. In the case of the bagel depicted in  FIGS. 4A-4C , this includes identifying and removing portions of the image associated with the central hole of the bagel. Further analysis may proceed with only those portions of the digital image determined to be associated with the bread product. In embodiments, because the average pixel value across the analyzed portion of the digital image may be used, the analysis may err on the side of removing part of the digital image that is associated with the bread product to ensure that only portions of the digital image associated with the bread product are analyzed. The use of edge detection and focusing the analysis on only relevant portions of the digital image associated with the bread product can further simplify the digital image making it less computationally intensive to further analyze the digital images. As noted above, in some embodiments only a portion of the bread product in the digital image may be analyzed. 
     As a still further example, the raisin bagel includes discontinuities in the darkness values of pixels within the digital image as a result of the raisins. These localized dark areas undesirably increase the overall average pixel darkness across the entire digital image but also do not exhibit the same change in darkness as the bagel is toasted. Therefore, in embodiments due to the comparison between a current image and a previous image, the resulting difference image provides a more accurate reflection of the change in surface color of the bagel as compared to a determination based solely upon the currently acquired image. 
     However, the localized darkened areas associated with the raisins also do not exhibit the same change in color as the rest of the bread product, therefore, in a further example the two described techniques may be combined whereby edge detection is further used to identify the localized darkened portions of the raisins and remove those portions of the digital images from consideration in assessing the toasting level of the bread product. 
     Supplemental light sources  24  ( FIG. 1 ) are used to illuminate the surface of the bread product that is being monitored. It will be recognized that the IR sources, which as noted above are exemplarily 1,200 watt heating coils, also give off visible spectrum light in addition to IR spectrum light. In order to maintain a consistent acquired image and representation of monitored surface darkness, supplemental light is added to the surface at an intensity that washes out any light that may be produced by the IR source. In exemplary embodiments, the supplemental light sources may produce white visible light, IR spectrum light, UV spectrum light, or any of the above, also including, but not limited to specific ranges of light wavelengths, for example, to provide specific colors of supplemental light. In examples, but not limiting on the wavelengths of light that may be used, the supplemental light may include the provision of green (495 nm-570 nm), blue (495 nm-570 nm), and/or purple (380 nm-450 nm) light in an effort to wash out the orange or red-orange hue that is common with resistive wire IR energy sources. In still further exemplary embodiments, the intensity of this supplemental light may be counteracted in the camera by operating the camera with a fast shutter speed so as to not overexpose the acquired image. In still further exemplary embodiments, the provision of the supplemental light may be coordinated with the acquisition of each image and therefore, the supplemental light need not be continuously applied within the toaster during times in which the camera is not acquiring images. 
       FIG. 5  depicts an exemplary embodiment of a camera  20 . The camera  20  may be arranged centrally to the IR source  12 . Exemplarily, the camera  20  uses a two-megapixel CMOS optical sensor  32  and the optical sensor  32  is fitted with a wide-angle lens  34 . In embodiments, a wide angle lens  34  helps to enable the optical sensor  32  and associated camera electronics to be positioned in close proximity to the surface of the bread product being monitored while still being able to capture an image, either of the entire monitored surface, or a significant enough portion so as to accurately monitor the toasting progress. As mentioned earlier, in embodiments, multiple of these optical sensors  32  may be arranged to capture different views or portions of the bread product. 
     The camera further faces challenges of keeping the lens clean while the optical sensor  32  and wide-angle lens  34  are in close proximity to food products. Additionally, the optical sensor  32  is located in close proximity to the IR source  12  and therefore, the thermal exposure to the optical sensor  32  must also be limited. To address these challenges, the toaster may include a source of forced gas  35 , for example, a compressor, blower, or supply of compressed gas that is provided through ducting  36  to form a curtain or flow of gas  37  about the optical sensor  32  and the lens  34 . The flow of gas  37 , which may be air or an inert gas such as nitrogen, may further be directed through an orifice  38  so as to increase the velocity of the flow of air. This flow of air does not obstruct the digital images acquired by the optical sensor but does prevent debris from the food being toasted from contacting the lens or the optical sensor. Additionally, the flow of air helps to cool the optical sensor  32 , maintaining it at a temperature suitable for operation despite the proximity of the optical sensor to the IR source. In another example, the lens  34  may extend proud of the orifice in an arrangement that maintains a similar protective flow of gas  37  about the lens  34 . 
     In a still further exemplary embodiment, the processor of the toaster may further calculate and apply a latent heat adjustment factor when determinations are made regarding whether the toasting process should be terminated. It has been observed that when the toaster operates through a toasting cycle, latent heat from the IR source is retained within the toaster. This latent heat dissipates over time, but if a subsequent toasting cycle is initiated prior to the dissipation of this latent heat, then the additional latent heat within the toasting system accelerates the toasting process in a subsequent toasting cycle. Therefore, the processor can monitor a time between the toasting cycles. The processor can also operate to make a determination of latent heat within the toaster, for example based upon one or more temperature sensors within the toaster, or based upon the known thermal output of the IR sources combined with modelled thermal dynamics of the toaster and the toasted bread product to arrive at an estimation of latent heat within the toaster when a new toasting cycle is initiated. Therefore, in embodiments wherein the processor has determined that latent heat remains within the toaster at the start of a toasting cycle, the processor may adjust the toasting model used to shorten the expected times between various toasting levels. 
       FIGS. 6A-6C  depict an example of a toaster  50 . It will be understood that in the description of  FIGS. 6A-6C  provided herein will focus on the mechanical systems for loading and unloading the toaster, while the electrical components and IR source operation may exemplarily be similar to that as described above with respect to  FIG. 1 . The toaster  50  includes a tray  52  that translates in the direction of arrow  53  through an opening  55  into and out of the interior of the toaster  50 . The bread product is loaded on the tray  52  and the user operates a handle  54  to slide the tray  52  containing the bread product through the opening  55  into the toaster  50 . The toaster  50  further includes a door  64  across the opening  55  that is operable to limit access into the toaster  50 . When the tray  52  is inserted into the toaster  50  with a bread product to be toasted, the door  64  closes behind the tray  52 . The door  64  may translate or pivot relative to the opening  55 . In an exemplary embodiment, wherein the door  64  pivots, the door  64  may be spaced such that the tray  52  can pass below the door  64  and the door  64  pivots inwardly into the interior of the toaster  50 . The door  64  exemplarily provides multiple functions as described herein. As a first function, the door  64  closes to block a user from access into the interior of the toaster when the IR sources are operating to toast the bread product. 
       FIG. 6B  exemplarily shows the toaster  50  in a loading position, ready to receive a bread product on the tray  52 . The toaster  50  exemplarily includes a bottom heater  56  connected to a pivot  58 . As the tray  52  is translated into the toaster  50  in the direction of arrow  53 , the tray  52  engages a lever  60  as the tray  52  is slid into position in the toaster  50 . Engagement of the tray  52  with the lever  60  forces the connected bottom heater  56  to rotate into position relative to the tray  52  with the bread product positioned on the tray above the bottom heater  56 . The toaster  50  operates as described in the present disclosure until the processor determines that the toasting process should be terminated. 
     Upon a determination to terminate the toasting process, the tray  52  is slid out of the toaster  50 . This is exemplarily depicted in  FIG. 6C  and may be performed manually with the operation of the handle  54 , for example, wherein the IR source is automatedly turned off. The tray  52  may also be moved out of the toaster as part of an electromechanical process of the toaster actuated by the processor determining to terminate the toasting process as described above. By operating the tray to exit the toaster  50 , the tray  52  disengages from the lever  60  and the lower IR source  56  is separated from the tray  52 , for example in position against a ramp  62 . The door  64  may remain in place while allowing the tray  52  to pass through the opening  55  below the door  64 . The door  64  blocks the bread product within the toaster  50  separating the bread product from the tray  52  and the bread product drops onto the lower heater  56  and/or the ramp  62  for ejection from the toaster  50 . 
       FIGS. 7 and 8  depict another example of a toaster  50 .  FIG. 8  is a cross-sectional view of the toaster  50  as taken along line  8 - 8  of  FIG. 7 . As with the toaster  50  described above with respect to  FIGS. 6A-C ,  FIGS. 7 and 8  exemplarily depict mechanical features of the toaster  50 , primarily a driven conveyor  66  which operates to move a bread product into the toaster  50  and to extract the bread product from the toaster  50  when the desired toasting level has been reached. In an exemplary embodiment, bread products to be toasted are positioned on the conveyor  66  exterior of the toaster  50  and the conveyor  66  operated, for example with a motor drive (not depicted), to circulate the bread product into the toaster and into a position relative to a heat source  57  or sources within the toaster. While  FIG. 7  depicts a single conveyor  66  associated with two IR sources  57 , exemplarily creating two toasting paths for parallel toasting of bread products, it will be recognized that each toasting path may include its own independently operated conveyor. In an example, the two toasting paths may be used to simultaneously toast crown and heel portions of a bread product. Additionally, while the toaster  50  of  FIG. 7  includes a single IR source  57  for each toasting path, it will be recognized that an additional IR source (not depicted) may be positioned intermediate the conveyor  66  to toast the other side of the bread product. The toaster  50  operates in the manner as described herein until the processor determines to terminate the toasting process whereby the processor may turn off the one or more IR sources and operate the conveyor  66  to eject the bread product. 
     As described above, in a configuration of a toaster  50  as depicted in  FIGS. 7 and 8 , the toasted bread product may still be exposed to heat, for example, the latent heat of the toaster  50 , while the conveyor  66  is operated to remove the toasted bread product from the toaster  50 . Therefore, the toasted bread product may continue to toast and/or receive thermal treatment after the IR source  57  is turned off. This additional exposure may be modeled into the definition of the desired toasting level and the determination to turn off the IR source  57  and operate the conveyor  66  to eject the toasted bread product. The toaster  50  includes a compartment  68  internal the toaster  50  from the conveyor  66 . The toasted bread product extends into the compartment  68  as the bread product is rotated off of the conveyor  66 . A cantilevered lever  70  catches the toasted bread product in the compartment  68  and flexes in the direction of arrow  72  to receive and redirect a lagging end of the toasted bread product and to direct the bread product down ramp  74  to exit the toaster  50 . The compartment  68  and the cantilevered lever  70  function to maintain the toasted bread product in the same orientation as it was positioned on the conveyor  66  originally and has toasted such that the toasted bread product is ejected in a consistent orientation for collection by a kitchen worker or automated device for a next step of an order assembly. 
       FIGS. 9A and 9B  depict another example a toaster  50 . Similar to the descriptions above with respect to  FIGS. 6-8 ,  FIG. 9  exemplarily depicts the mechanical features of the toaster  50 , other features as depicted and described above, for example with respect to  FIGS. 1 and 2  will be recognized to be exemplarily used within the toaster  50 . The mechanical features shown in  FIGS. 9A and 9B  relate to the loading and unloading of the bread product to be toasted and exemplarily depict a process of loading and unloading a bread product  16  for toasting by the toaster  50 . The bread product  16  is exemplarily placed on a loading tray  52  that extends outwardly from the toaster  50 . In an embodiment, the loading tray  52  may be stationary or may be operable for movement relative to the toaster  50 . The bread product  16  enters the toaster  50 , for example by a gravity feed and is held in position between a stationary top IR source  57  and a movable lower IR source  56 . In an embodiment, the bread product  16  is held in position relative to the top IR source  12  and the movable lower IR source  56  by a stationary backstop  90 . In another embodiment, a retaining feature on the top IR source  57  or the movable lower IR source  56  engages the bread product  16  to hold it in position. Another type of retaining feature may be located within the toaster  50  for this purpose as well. A door  64  may be movable across the opening  55  to further limit access to the interior of the toaster  50  during operation. 
     The top IR source  57  and the movable lower IR source  56  operate as described to toast the bread product  16 , although it will be recognized that in other embodiments, only the top IR source  57  may be used, for example in configurations to toast bagels, roll crowns or heels, English muffins, or the like. Upon completion of the toasting process, as also described, a movable support, which may include, or have included the lower IR source  56  in a two IR source embodiment, slides or otherwise moves in the direction of arrow  92  within the toaster  50 . If the toasted bread product is not already in engagement with the backstop  90 , this movement causes the toasted bread product to contact the backstop  90 . As the movable lower IR source  56  is further slid from beneath the toasted bread product  16 , the bread product  16  rotates downward in the direction of arrow  59  to an exit ramp  62  which directs the toasted bread product  16  out of the toaster  50 . After the toasted bread product  16  is dispensed from the toaster  50 , the movable lower IR source  56  returns to its original position. The door  64  may open to accept a new bread product  16  into the toaster  50  to be toasted. It will be recognized that rather than the IR source  56  or movable support moving relative to the backstop  90 , the backstop  90  may be the movable support, supporting the bread product  16  at a position relative to the top IR source  57  and then moving, either by pivoting or retracting to direct the toasted bread product  16  out of the toaster, for example as shown in  FIG. 8 . 
       FIG. 10  depicts an exemplary embodiment of a kitchen system  76 . It will be recognized that the kitchen system  76  depicted in  FIG. 10  is for exemplary purposes and other devices or systems as will be recognized by a person of ordinary skill in the art that may exist within a kitchen system  76  as described herein may also be used due to the present disclosure. The kitchen system  76  includes a toaster  10  as has herein been described. The toaster  10  is communicatively connected to a kitchen management system (KMS)  78 . It will be recognized that in exemplary embodiments, the KMS  78  exemplarily coordinates communication between other devices within the kitchen and/or other information systems within the kitchen, some of which may be located locally to the kitchen or may be located remotely as through a cloud computing configuration and arrangement. The KMS  78  exemplarily coordinates with a point-of-sale (POS) system  80  which operates to receive customer orders and monitor customer order completion and delivery. The KMS  78  also coordinates with an inventory management system  82 . The inventory management system  82  may operate to track the inventory and use of foods and supplies within the kitchen. While the KMS  78 , POS  80 , and inventory management system  82  have been depicted as separate components, it will be recognized that in some embodiments these components may be configured individually or may operate as a single computer/software system. 
     In addition to the toaster  10 , the kitchen system  76  may also include other devices that include, but are not limited to bread holding  84 , condiment dispensing  86 , and protein holding  88 . These other devices may be communicatively connected to one another either directly or through the KMS  78  as depicted in  FIG. 10 . The bread holding  84  may exemplarily store the bread products prior to use and/or toasting for use. The condiment dispenser  86  may operate to automatedly dispense condiments to a toasted bread product to facilitate completion of a customer order. Protein holding  88  may operate to hold cooked proteins in an environmental condition such as prolong flavor, texture, and safety for use in assembling customer orders, for example with toasted bread products. In exemplary embodiments, the KMS coordinates with the toaster  10  to provide the toaster  10  with order information exemplarily obtained from the POS  80  and to give the toaster  10  input instructions regarding the type of bread product being toasted and the desired level of toasting for the bread product to complete the customer&#39;s order. In exemplary embodiments, the toaster  10  returns information to the KMS  78  for example to provide a predicted time of completion of the bread product to be toasted and/or a notification that the ordered bread product has been toasted. This notification can be used to update and manage the inventory system  82 , but also the completion prediction and/or indication of completed toasting may be used coordinate the operation of other devices within the kitchen system  76 . For example, a notification may be made a protein holding station  88  that the bread product has been toasted and is ready to receive the held protein. Similarly, the condiment dispenser  86  may be operated to receive the toasted bread product and to dispense condiments thereon according to a customer&#39;s order from the POS  80 . In exemplarily and non-limiting embodiments, the toaster  10  may be connected to the condiment dispenser  86 , for example by a conveyor or by physical arrangement of the condiment dispenser  86  proximate to the toaster  10  such that the toasted bread product is ejected from the toaster  10  into the condiment dispenser for the automated dispense of condiment thereon. Additionally, the bread holding device  84  may be operated in connection with a received toasting completion prediction and/or indication of toasting completion to coordinate the dispense of a next bread product to be toasted from the bread holding device  84  either directly into the toaster  10  for toasting or for notification to a kitchen worker of the next bread product to be toasted by the toaster  10 . 
     As noted in the embodiments described herein, the processor may operate using the determined current level of toasting of the bread product in coordination with a model of the expected toasting process to provide an estimate of when the toasting process will be complete or to determine that the toasting process is complete and the bread product is to be ejected. Thus, with these determinations, the processor of the toaster  10  can help to coordinate termination of a toasting process and dispense of the toasted bread product while subsequently facilitating loading of the next bread product to be toasted into the toaster  10 . Also noted above, within a toasting process, the processor may determine that adjustments to the toasting process should be made, for example to at a flow of air into the toaster, adjust a duty cycle of the IR source or sources, to inject microwaves into the toaster, or to operate the toaster to provide zoned control of the toasting process. In still further exemplary embodiments, the toaster may either integrated with components for the addition of foods and/or condiments to the toasting bread product or directly connected to components for adding additional foods or condiments, for example as described above with respect to the condiment dispenser  86 . In a still further exemplary embodiment, the processor may use the determination of the toasting completion prediction or determined remaining toasting time to add a food or condiment directly to the bread product during the toasting process. This may exemplarily include the addition of a protein within the toaster, the addition of butter, or cheese. 
     In still further exemplary embodiments, each of the difference images and/or mean brightness of the difference images may be stored to produce a data set or graph of the change in brightness of the difference image during the toasting process. As depicted in  FIG. 2 , the toasting process generally occurs over an S-shaped curve. Thus, the toasting process can be characterized in three phases: an initial pre-toasting phase (I), an active toasting phase (II), and an over-toasting phase (III). In the pre-toasting phase (I) the humidity within the bread product is released, drying out the bread product. Once a sufficient amount of humidity from the bread product has been released, then the carbohydrates and proteins on the surface of the bread product can begin to oxidize, darkening in color representative of the active toasting phase (II). However, once the carbohydrates on the surface of the bread product have oxidized completely, this characterizes the over-toasting phase (III) or burning of the bread product. It has been recognized that the humidity of a bread product is related to that product&#39;s freshness and quality. Therefore, the length of time that a particular bread product spends in the pre-toasting phase is related to the freshness and/or quality of that bread product, relative to other bread products of the same type. Therefore, embodiments of the toaster can additionally monitor the quality of the input bread product and use this further determination to coordinate with the kitchen management system  78  and/or the inventory management system  82 . In an exemplary embodiment, this can provide an indication to the inventory management system  82  that the bread is within or outside of a defined quality specification (e.g. bread humidity). In another embodiment, the toaster may determine that the bread input into the toaster is of an insufficient quality and operates to terminate the toasting process and provide an indication that the bread product should not be used as it is deemed to be of insufficient quality. Such information may also be communicated to the bread holding machine  84  and/or the POS  80  for coordination between those devices and systems for product management. 
     In still further exemplary embodiments, additional sensors, monitors, or manual or automated inputs may be provided into the toaster  10  and such inputs may be used to further refine the toasting model as used or otherwise adjust the operation of the toaster. In embodiments, the toaster may identify an initial temperature of the input bread product, a humidity of the bread product, a density, a mass, a surface roughness, a height, or a volume of the input bread product. Some or all of these may be used in identifying a bread product type and/or used to select an initial setting for the operation of the toaster to toast the input bread product. In still further exemplary embodiments, the toaster may measure or receive input values of ambient temperature, ambient humidity, or ambient altitude as these may also affect the toasting process. In still further exemplary embodiments, the toaster may exemplarily self-monitor the operation or thermodynamics of the toaster itself, including, but not limited to the received voltage, the power used, the heating element resistance, the heating system mass, the control system response time, and/or the bread product load or eject position. Monitoring one or more of these operational values may help to refine operation over time and to adjust for system wear, wear on the heating element. In still further exemplary embodiments, the system may receive inputs as to the air flow within the toaster regarding temperature, speed, or humidity of the air flow within the toaster and, as described above, the latent heat within the toaster between toasting cycles may be monitored. 
     Citations to a number of references are made herein. The cited references are incorporated by reference herein in their entireties. In the event that there is an inconsistency between a definition of a term in the specification as compared to a definition of the term in a cited reference, the term should be interpreted based on the definition in the specification. 
     In the above description, certain terms have been used for brevity, clarity, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different systems and method steps described herein may be used alone or in combination with other systems and methods. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims. 
     The functional block diagrams, operational sequences, and flow diagrams provided in the Figures are representative of exemplary architectures, environments, and methodologies for performing novel aspects of the disclosure. While, for purposes of simplicity of explanation, the methodologies included herein may be in the form of a functional diagram, operational sequence, or flow diagram, and may be described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance therewith, occur in a different order and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology can alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all acts illustrated in a methodology may be required for a novel implementation. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.