Imaging system for imaging an egg comprising egg presence & colour shade detection

Abstract

Imaging system for imaging an egg, the system comprising: - a seat for holding the egg, an imaging irradiator arranged on an imaging irradiation side of the seat, wherein the imaging irradiator is configured to irradiate the egg present in the seat, - an imaging device arranged on an imaging side of the seat, wherein the imaging side of the seat is preferably substantially opposite to the imaging irradiation side with respect to the seat, wherein the imaging device is configured for imaging the egg present in the seat, - a determination system for determining a presence and a colour shade of an egg in a seat, an exposure controller configured to control the imaging irradiator and / or the imaging device based on a determination of a presence and colour shade of an egg in a seat performed by the determination system.

Description

[0001] Title: Imaging system for imaging an egg comprising egg presence & colour shade detection

[0002] Field of the invention

[0003] The present invention relates to imaging systems for eggs, in particular to imaging systems using an irradiator to irradiate the egg and an imaging device to image the egg.

[0004] Background of the invention

[0005] In egg processing, eggs are often inspected to assess presence of any cracks or other damage to the shell. This is commonly done by transmitting radiation such as electromagnetic radiation (e.g. red light) through the egg and assessing the radiation that passed through the egg, e.g. by making an image of the egg. For example, brighter parts in an image of the egg indicate a fractured, partially absent or otherwise damaged shell, seeing that the eggshell normally blocks at least part of the radiation from passing through the egg. A region such as a crack therefore passes more radiation, leading to a bright spot in the image.

[0006] In view of the large numbers of eggs that are processed, egg inspection is often performed at high speed, on automated production lines. The sources of (electromagnetic) radiation and the imaging devices are controlled automatically.

[0007] A known problem is that, in the absence of an egg, irradiating the position where the machine expects the egg to be can lead to overexposure of the imaging device. Usually, images made by the imaging device contain multiple eggs such that one image is used for inspecting multiple eggs. In the event that a position where the machine expects an egg in fact does not hold an egg, irradiating that position results in overexposure of the imaging device, such that the image is unusable. As a result, the image cannot be used to inspect eggs in other positions that are also in the image, because the image is unusable due to overexposure. Such overexposure can even damage the imaging device.

[0008] Another known problem is that eggs of different properties transmit light or other (electromagnetic) radiation at different rates. For example, a darker egg transmits less light than a lighter egg, because a darker egg absorbs more light than a lighter egg. Thus, with a certain combination of irradiation and imaging, an image of a dark egg may be too dark (underexposed) and / or an image of a light egg may be overexposed. In such a case, cracks in one or both eggs cannot be detected.

[0009] Object of the invention

[0010] It is thus an object of the invention to provide a device in which at least one of the above problems is addressed. It is a further object of the invention to provide a method in which at least one of the above problems is addressed. Summary of the invention

[0011] In order to achieve at least one of the above mentioned objects, the invention provides, in a first aspect, an imaging system comprising:

[0012] - a seat for holding the egg,

[0013] - an imaging irradiator arranged on an imaging irradiation side of the seat, wherein the imaging irradiator is configured to irradiate the egg present in the seat,

[0014] - an imaging device arranged on an imaging side of the seat, wherein the imaging side of the seat is preferably substantially opposite to the imaging irradiation side with respect to the seat, wherein the imaging device is configured for imaging the egg present in the seat,

[0015] - a determination system for determining a presence and a colour shade of an egg in a seat, an exposure controller configured to control the imaging irradiator and / or the imaging device based on a determination of a presence and colour shade of an egg in a seat performed by the determination system.

[0016] The determination system included in the imaging system allows determining whether or not an egg is present in the seat and determining the colour shade of the egg if there is indeed an egg present in the seat. This information can then be used by the exposure controller to prevent overexposing the imaging device.

[0017] For example, if no egg is present in the seat, the imaging irradiator is not activated and / or the imaging device is not activated. This prevents overexposing the imaging device. This is particularly useful in practical devices where multiple seats are present, each configured to hold an egg, in combination with e.g. a camera or other imaging device that has multiple seats in its field of view. If, within the field of view of the imaging device, a single seat has no egg in it and it is irradiated by the imaging irradiator in spite of this, the imaging device may be overexposed. This may result in problems in imaging the eggs in other seats which are in the field of view at the same time, for example lack of contrast such that cracks or other shell defects cannot be properly detected.

[0018] The determination of the colour shade of the egg by the determination device can be used to optimise detection performance of shell deficiencies such as cracks, by controlling the imaging irradiator and / or the imaging device based on the determined colour shade of the egg. Darker eggs absorb more light and transmit less light than lighter eggs. Thus, a darker egg requires a longer exposure time of the imaging device and / or a higher irradiation intensity or a longer irradiation duration by the imaging irradiator than a lighter egg, because otherwise the image of the egg made by the imaging device would be too dark and / or not have enough contrast to discern defects in the shell. Besides optimising image quality per egg, can also prevent overexposing the imaging device, which could occur if a light egg is irradiated with too much irradiation energy.

[0019] Alternatively to configuring the determination system to determine both the presence of the egg in the seat and the colour shade of the egg (if it is present), the determination system may also be configured to determine one of the presence of the egg in the seat and the colour shade of the egg. This may for example be desirable if it is already determined whether or not an egg is present in the seat in another part of a machine which comprises the imaging system. In that case, it may not be necessary to determine presence of the egg. Similarly, it may not be necessary to determine the colour shade of the egg if the colour shade is already known, e.g. if all processed eggs are of similar colour shade.

[0020] In an embodiment of the imaging system according to the invention, the exposure controller is configured to control an irradiation energy amount of the imaging irradiator and / or an exposure time of the imaging system based on the determination of a presence and a colour shade of an egg in a seat performed by the determination system, wherein the exposure controller is preferably configured to control the irradiation energy amount by controlling an irradiation time of the imaging irradiator.

[0021] The irradiation energy amount can for example be controlled by controlling an intensity of a radiation source of the imaging irradiator, or by controlling an irradiation time, i.e. the time during which the egg is exposed to radiation. It is noted that the terms ‘irradiation energy’ and ‘irradiation energy amount’ do not refer to energy of individual photons, but to the total energy with which the egg is irradiated. The irradiation energy amount may thus be modified by modifying the individual energy of the individual photons and / or by modifying the amount of photons used in irradiating the egg.

[0022] The intensity of a radiation source can be for example be controlled by controlling the current and / or voltage of a light source such as a lamp. The irradiation time can be controlled by controlling an activation time of the radiation source of the imaging irradiator, or by a shutter or similar device included in the imaging irradiator, arranged between the egg and the radiation source, for example.

[0023] In an embodiment of the imaging system according to the invention, the imaging irradiator comprises an imaging source of electromagnetic radiation, wherein the imaging irradiator is configured to expose the egg in the seat to electromagnetic radiation from the imaging source, wherein the imaging device is preferably configured to image electromagnetic radiation which is scattered by the egg and / or electromagnetic radiation which is passed through the egg.

[0024] By imaging electromagnetic radiation which is scattered by the egg and / or electromagnetic radiation which is passed through the egg, the imaged radiation has interacted with the egg, such that information regarding defects in the eggshell is included in the imaged radiation. When imaging electromagnetic radiation which is passed through the egg, cracks and holes in the shell generally show up as bright areas in the image, as in those areas more radiation passes through the egg because there is no shell there to reduce transmission of radiation.

[0025] In an embodiment of the imaging system according to the invention, the determination system comprises: a determination source of electromagnetic radiation arranged on a determination side of the seat, wherein the determination source is configured to irradiate the seat and the egg present in the seat with electromagnetic radiation, - a determination sensor sensitive to electromagnetic radiation, wherein the determination sensor is configured to receive electromagnetic radiation reflected and / or scattered from an egg shell of the egg present in the seat, wherein the determination sensor is configured to provide a determination sensor output signal representative of an intensity of received radiation, wherein the determination sensor is preferably arranged on the determination side of the seat, wherein the determination side of the seat is preferably the same as the imaging irradiation side of the seat, wherein the exposure controller is configured to receive the sensor output signal and determine the presence and the colour shade of the egg shell of the egg present in the seat based on the determination sensor output signal.

[0026] By measuring electromagnetic radiation reflected and / or scattered from an egg shell of the egg present in the seat, information regarding the colour shade of the egg can be obtained, seeing that a lighter egg reflects and / or scatters more electromagnetic radiation such as light than a darker egg.

[0027] In an embodiment of the imaging system according to the invention, the determination source of electromagnetic radiation is arranged below the seat and / or the determination sensor is arranged below the seat.

[0028] By arranging the determination source of electromagnetic radiation and / or the determination sensor below the seat, space above the seat is kept free for other machine parts and devices. Other elements of the imaging system arranged below the seat may include the imaging irradiator, in which case the imaging device is preferably arranged above the seat.

[0029] In an embodiment of the imaging system according to the invention, the exposure controller is configured to determine a determination signal amplitude of the determination sensor output signal, wherein the exposure controller is configured to determine the presence of an egg in the seat based on the determination signal amplitude with respect to a first threshold value, wherein the exposure controller is configured to determine that an egg is present in the seat if the determination signal amplitude exceeds the first threshold value and wherein the exposure controller is configured to determine that an egg is not present in the seat if the determination signal amplitude does not exceed the first threshold value.

[0030] The determination signal amplitude is representative of the amount of electromagnetic radiation received by the determination sensor. If little or no electromagnetic radiation is received by the determination sensor, there is no egg in the seat, as otherwise that egg would have reflected and / or scattered electromagnetic radiation from the determination source of electromagnetic radiation to the determination sensor. The first threshold value is not necessarily zero, since there may be some stray electromagnetic radiation which reaches the determination sensor even if no egg is present, for example due to reflection or scattering from other parts of the imaging system, or from ambient background radiation. In an embodiment of the imaging system according to the invention, the exposure controller is configured to determine a determination signal amplitude of the determination sensor output signal, wherein the exposure controller is configured to determine the colour shade of an egg present in the seat based on the determination signal amplitude, wherein a lower determination signal amplitude is indicative of a darker colour shade of the egg and wherein a higher determination signal amplitude is indicative of a lighter colour shade of the egg.

[0031] The determination signal amplitude is representative of the amount of electromagnetic radiation received by the determination sensor. A darker egg reflects and / or scatters less electromagnetic radiation than a lighter egg. Therefore, in the case of a lighter egg, the determination sensor will receive more electromagnetic radiation reflected and / or scattered from the egg than in the case of a darker egg. This results in a higher determination signal amplitude in the case of a lighter egg than in the case of a darker egg. Thus, a lower determination signal amplitude indicates a darker egg, whereas a higher determination signal amplitude indicates a lighter egg.

[0032] In an embodiment of the imaging system according to the invention, the exposure controller comprises a memory in which one or more calibration signal amplitude values are stored, wherein the stored calibration amplitude values are associated with reference colour shades of eggs, wherein the exposure controller is configured to determine the colour shade of the egg by comparing the determination signal amplitude of the determination sensor output signal to the calibration signal amplitude values, wherein optionally the exposure controller is configured to associate a determination signal amplitude below a calibration signal amplitude associated with a darkest possible colour shade of an egg with absence of an egg in the seat.

[0033] The exposure controller can then compare the determination signal amplitude with values stored in the memory.

[0034] The determination signal amplitude may be compared to calibration signal amplitude values stored in memory. If one of the stored calibration signal amplitude values matches the determination signal amplitude, the determination system determines that the egg has the same colour shade as the reference colour shade associated with that calibration signal amplitude.

[0035] If none of the stored calibration signal amplitude values matches the determination signal amplitude, the closest calibration signal amplitude may be used to determine the colour shade of the egg as the reference colour shade associated with said closest calibration signal amplitude. Alternatively, a (weighted) average of the two closest calibration signal amplitude values may be used to determine the colour shade of the egg as an intermediate colour shade of the two reference colour shades associated with said two closest calibration signal amplitude values.

[0036] It is envisaged that a fitting function may be used to generate a calibration curve based on the calibration signal amplitude values. Then, the parameters of the fitting function may be stored in the memory instead of the calibration signal amplitude values. Furthermore, the fitting function may be used to determine the colour shade of the egg based on the determination signal amplitude.

[0037] In an embodiment of the imaging system according to the invention, the determination source of electromagnetic radiation comprises a visible light source such as red light, blue light, green light, or white light, the visible light source preferably comprising an LED light source.

[0038] In an embodiment of the imaging system according to the invention, the determination sensor comprises a photosensitive element such as a photo resistive sensor.

[0039] In an embodiment of the imaging system according to the invention, the imaging system comprises a radiation shield arranged between the determination source of electromagnetic radiation and the determination sensor, wherein the radiation shield is configured to prevent radiation travelling in a straight path from the determination source of electromagnetic radiation from reaching the determination sensor directly, without scattering or reflecting prior to reaching the determination sensor.

[0040] The radiation shield prevents radiation travelling in a straight path from the determination source of electromagnetic radiation from reaching the determination sensor directly, such that the determination signal amplitude is not or at least less determined by radiation that did not scatter or reflect from the egg. This increases accuracy of the measurement of egg colour shade and / or presence.

[0041] In an embodiment of the imaging system according to the invention, the imaging system comprises a transport device configured to move the seat in a transport direction along a transport trajectory, wherein the transport trajectory passes the determination sensor and / or the determination source of electromagnetic radiation, wherein the determination sensor is preferably stationary with respect to an environment, wherein the determination source of electromagnetic radiation is preferably stationary with respect to the determination sensor, wherein the transport direction is preferably substantially horizontal, wherein the transport device optionally comprises multiple seats, each configured to hold an egg.

[0042] The transport device allows moving multiple eggs past the determination sensor, the determination source and the imaging irradiator and the imaging device. This enhances productivity, as a large number of eggs can be processed in an efficient manner. A single determination sensor and a single determination source may be used, wherein the transport device is configured to move multiple seats past the single determination sensor and the single determination source. Alternatively, multiple parallel determination sensors and determination sources may be used, wherein the transport device is configured to move multiple seats past the multiple parallel determination sensors and determination sources. This can increase the number of eggs that can be processed per unit per unit time, as the multiple parallel determination sensors and determination sources can work in parallel. As a further alternative, each seat may have a respective associated determination sensor and / or determination source.

[0043] In order to achieve at least one of the above mentioned objects, the invention provides, in a second aspect, a determination system comprising:

[0044] - a seat for holding an egg,

[0045] - a determination source of electromagnetic radiation arranged on a determination side of the seat, configured to irradiate the seat and the egg present in the seat with electromagnetic radiation,

[0046] - a determination sensor sensitive to electromagnetic radiation configured to receive electromagnetic radiation reflected and / or scattered from an egg shell of the egg present in the seat, wherein the determination sensor is configured to provide a determination sensor output signal representative of an intensity of received radiation, wherein the determination sensor is preferably arranged on the determination side of the seat, wherein the determination side of the seat is preferable the same as the imaging irradiation side of the seat.

[0047] The determination system can be used to advantage in the imaging system according to the first aspect of the invention. Furthermore, the determination system may also be of benefit in other applications than imaging eggs to determine shell defects such as cracks, for example in determining egg colour shade for sorting eggs in different colour shade brackets. This is especially useful for markets where certain egg colour shades are preferred over other egg colour shades, for example light or white coloured eggs are preferable over dark coloured eggs in some markets. In other markets, brown coloured eggs may be preferred. By measuring electromagnetic radiation reflected and / or scattered from an egg shell of the egg present in the seat, information regarding the colour shade of the egg can be obtained, seeing that a lighter egg reflects and / or scatters more electromagnetic radiation such as light than a darker egg.

[0048] In an embodiment of the determination system, the determination system comprises a determination controller configured to receive the sensor output signal and determine the presence and the colour shade of the egg shell of the egg present in the seat based on the determination sensor output signal. The determination controller may be the exposure controller or may comprise the exposure controller of the imaging system according to the first aspect of the invention. The exposure controller of the imaging system according to the first aspect of the invention may also comprise the determination controller.

[0049] In an embodiment of the determination system, the determination controller is configured to determine a determination signal amplitude of the determination sensor output signal, wherein the determination controller is configured to determine the presence of an egg in the seat based on the determination signal amplitude with respect to a first threshold value, wherein the determination controller is configured to determine that an egg is present in the seat if the determination signal amplitude exceeds the first threshold value and wherein the determination controller is configured to determine that an egg is not present in the seat if the determination signal amplitude does not exceed the first threshold value. The determination signal amplitude is representative of the amount of electromagnetic radiation received by the determination sensor. If little or no electromagnetic radiation is received by the determination sensor, there is no egg in the seat, as otherwise that egg would have reflected and / or scattered electromagnetic radiation from the determination source of electromagnetic radiation to the determination sensor. The first threshold value is not necessarily zero, since there may be some stray electromagnetic radiation which reaches the determination sensor even if no egg is present, for example due to reflection or scattering from other parts of the imaging system, or from ambient background radiation.

[0050] In an embodiment of the determination system, the determination controller is configured to determine a determination signal amplitude of the determination sensor output signal, wherein the exposure controller is configured to determine the colour shade of an egg present in the seat based on the determination signal amplitude, wherein a lower determination signal amplitude is indicative of a darker colour shade of the egg and wherein a higher determination signal amplitude is indicative of a lighter colour shade of the egg. The determination signal amplitude is representative of the amount of electromagnetic radiation received by the determination sensor. As a darker egg reflects and / or scatters less electromagnetic radiation than a lighter egg, a lower determination signal amplitude thus indicates a darker egg, whereas a higher determination signal amplitude indicates a lighter egg.

[0051] In an embodiment of the determination system, the determination controller comprises a memory in which one or more calibration signal amplitude values are stored, wherein the stored calibration amplitude values are associated with reference colour shades of eggs, wherein the determination controller is configured to determine the colour shade of the egg by comparing the determination signal amplitude of the determination sensor output signal to the calibration signal amplitude values, wherein optionally the determination controller is configured to associate a determination signal amplitude below a calibration signal amplitude associated with a darkest possible colour shade of an egg with absence of an egg in the seat. The determination controller can then compare the determination signal amplitude with values stored in the memory.

[0052] The determination signal amplitude is compared to calibration signal amplitude values stored in memory. If one of the stored calibration signal amplitude values matches the determination signal amplitude, the determination system determines that the egg has the same colour shade as the reference colour shade associated with that calibration signal amplitude.

[0053] If none of the stored calibration signal amplitude values matches the determination signal amplitude, the closest calibration signal amplitude may be used to determine the colour shade of the egg as the reference colour shade associated with said closest calibration signal amplitude. Alternatively, a (weighted) average of the two closest calibration signal amplitude values may be used to determine the colour shade of the egg as an intermediate colour shade of the two reference colour shades associated with said two closest calibration signal amplitude values.

[0054] It is envisaged that a fitting function may be used to generate a calibration curve based on the calibration signal amplitude values. Then, the parameters of the fitting function may be stored in the memory instead of the calibration signal amplitude values. Furthermore, the fitting function may be used to determine the colour shade of the egg based on the determination signal amplitude.

[0055] In an embodiment of the determination system, the determination source of electromagnetic radiation may comprise a visible light source such as red light, blue light, green light, or white light, the visible light source preferably comprising an LED light source.

[0056] In an embodiment of the determination system, the determination sensor comprises a photosensitive element such as a photo resistive sensor.

[0057] In an embodiment of the determination system, the determination system comprises a radiation shield arranged between the determination source of electromagnetic radiation and the determination sensor, wherein the radiation shield is configured to prevent radiation travelling in a straight path from the determination source of electromagnetic radiation from reaching the determination sensor directly, without scattering or reflecting prior to reaching the determination sensor. The radiation shield prevents radiation travelling in a straight path from the determination source of electromagnetic radiation from reaching the determination sensor directly, such that the determination signal amplitude is not or at least less determined by radiation that did not scatter or reflect from the egg. This increases accuracy of the measurement of egg colour shade and / or presence.

[0058] In an embodiment of the determination system, the determination source of electromagnetic radiation is arranged below the seat and / or the determination sensor is arranged below the seat. By arranging the determination source of electromagnetic radiation and / or the determination sensor below the seat, space above the seat is kept free for other parts and devices.

[0059] In order to achieve at least one of the above mentioned objects, the invention provides, in a third aspect, a method for imaging an egg, the method comprising the steps of:

[0060] - establishing a presence of the egg in a seat,

[0061] - if the egg is present in the seat, irradiating the egg,

[0062] - imaging the egg while it is being irradiated,

[0063] - wherein prior to irradiating the egg a colour shade of the egg is determined and said colour shade is used to control the irradiation and / or imaging of the egg.

[0064] In an embodiment of the method for imaging an egg according to the invention, the method comprises controlling an irradiation energy amount of the egg, wherein darker coloured eggs are irradiated with a higher irradiation energy amount than lighter coloured eggs, wherein preferably if no egg is present in the seat, the seat is not irradiated.

[0065] By irradiating darker coloured eggs with more irradiation energy than lighter coloured eggs, the additional absorption of radiation by darker coloured eggs as compared to lighter coloured eggs is compensated. This way, images of both darker coloured eggs and lighter coloured eggs can have the appropriate brightness and contrast required to detect shell defects such as cracks and other damage.

[0066] In an embodiment of the method for imaging an egg according to the invention, the irradiation energy amount is controlled by controlling an irradiation time of the egg.

[0067] By controlling the irradiation time, the intensity of the radiation source used for imaging can be kept constant. This can simplify the system and control logic. Alternatively, the irradiation time can be kept constant while the intensity of the radiation is controlled. This way, the irradiation time can be kept shorter, such that the system can operate faster, enabling a larger throughput of eggs. An advantage of this method is that the operation of the imaging device does not need to be adapted to the presence and / or colour shade of the eggs in the seats, simplifying the system and control logic.

[0068] In an embodiment of the method for imaging an egg according to the invention, imaging of the egg is controlled by controlling an exposure time of an imaging device such as a camera, such as a shutter time.

[0069] By controlling the exposure time, the amount of radiation such as light received by the imaging device is controlled. This way, the brightness and contrast of the resulting image can be controlled. An advantage of this method is that the irradiation conditions of all eggs can be kept constant, simplifying the system and control logic.

[0070] In an embodiment of the method for imaging an egg according to the invention, the step of determining the colour shade and presence of the egg comprises the steps of:

[0071] - irradiating the seat and the egg present in the seat from a determination side of the seat, preferably using electromagnetic radiation, measuring scattered and / or reflected radiation on the determination side of the seat, wherein said measuring is preferably performed using a determination sensor,

[0072] - determining a determination signal amplitude of the reflected radiation,

[0073] - determining the presence and colour shade of the egg based on the determination signal amplitude.

[0074] The determination signal amplitude is representative of the amount of electromagnetic radiation scattered and / or reflected by the egg. As a darker egg reflects and / or scatters less electromagnetic radiation than a lighter egg, a lower determination signal amplitude thus indicates a darker egg, whereas a higher determination signal amplitude indicates a lighter coloured egg. If little or no electromagnetic radiation is scattered and / or reflected, it can be determined that an egg is not present.

[0075] In an embodiment of the method for imaging an egg according to the invention, the method comprises blocking radiation used in irradiating the egg from reaching a determination sensor directly, without scattering or reflecting prior to reaching the determination sensor.

[0076] By preventing radiation travelling in a straight path from the determination source of electromagnetic radiation from reaching the determination sensor directly (e.g. by using a shield), the determination signal amplitude is not or at least less determined by radiation that did not scatter or reflect from the egg. This increases accuracy of the measurement of egg colour shade and / or presence.

[0077] In an embodiment of the method for imaging an egg according to the invention, the method comprises the step of determining the presence of an egg in the seat by comparing a determination signal amplitude to a first threshold value, wherein the method comprises determining that an egg is present in the seat if the determination signal amplitude exceeds the first threshold value and wherein the method comprises determining that an egg is not present in the seat if the determination signal amplitude does not exceed the first threshold value.

[0078] The determination signal amplitude is representative of the amount of electromagnetic radiation received by the determination sensor. If little or no electromagnetic radiation is received by the determination sensor, there is no egg in the seat, as otherwise that egg would have reflected and / or scattered electromagnetic radiation from the determination source of electromagnetic radiation to the determination sensor. The first threshold value is not necessarily zero, since there may be some stray electromagnetic radiation which reaches the determination sensor even if no egg is present, for example due to reflection or scattering from other parts of the imaging system, or from ambient background radiation.

[0079] In an embodiment of the method for imaging an egg according to the invention, the method comprises the step of determining the colour shade of an egg in the seat based on a determination signal amplitude, wherein a lower determination signal amplitude is indicative of a darker colour shade of the egg and wherein a higher determination signal amplitude is indicative of a lighter colour shade of the egg.

[0080] As discussed above, the determination signal amplitude is representative of the amount of electromagnetic radiation scattered and / or reflected by the egg. As a darker egg reflects and / or scatters less electromagnetic radiation than a lighter egg, a lower determination signal amplitude thus indicates a darker egg, whereas a higher determination signal amplitude indicates a lighter egg.

[0081] In an embodiment of the method for imaging an egg according to the invention, the method comprises comparing the determination signal amplitude to one or more calibration signal amplitude values, wherein the calibration amplitude values are associated with reference colour shades of eggs, wherein the method comprises determining that an egg is not present in the seat if a determination signal amplitude is below a calibration signal amplitude associated with a darkest possible colour shade of an egg.

[0082] The determination signal amplitude may be compared to calibration signal amplitude values stored in a memory. If one of the stored calibration signal amplitude values matches the determination signal amplitude, it is determined that the egg has the same colour shade as the reference colour shade associated with that calibration signal amplitude.

[0083] If none of the stored calibration signal amplitude values matches the determination signal amplitude, the closest calibration signal amplitude may be used to determine the colour shade of the egg as the reference colour shade associated with said closest calibration signal amplitude. Alternatively, a (weighted) average of the two closest calibration signal amplitude values may be used to determine the colour shade of the egg as an intermediate colour shade of the two reference colour shades associated with said two closest calibration signal amplitude values.

[0084] It is envisaged that a fitting function may be used to generate a calibration curve based on the calibration signal amplitude values. Then, the parameters of the fitting function may be stored in the memory instead of the calibration signal amplitude values. Furthermore, the fitting function may be used to determine the colour shade of the egg based on the determination signal amplitude.

[0085] In an embodiment of the method for imaging an egg according to the invention, the method is executed using an imaging system according to the first aspect of the invention and / or a determination system according to the second aspect of the invention.

[0086] In order to achieve at least one of the above mentioned objects, the invention provides, in a fourth aspect, a method for determining a presence and a colour shade of an egg in a seat, the method comprising the steps of:

[0087] - irradiating the seat from a first side of the seat, preferably using electromagnetic radiation measuring scattered and / or reflected radiation on the first side of the seat,

[0088] - determining a signal amplitude of the reflected radiation,

[0089] - determining the presence and colour shade of the egg based on the signal amplitude.

[0090] This method has the same advantages as the determination system according to the second aspect. Optionally, this method may be performed using a determination system according to the second aspect.

[0091] In an embodiment of the method of determining a presence and a colour shade of an egg, the step of determining the colour shade and presence of the egg comprises the steps of: irradiating the seat and the egg present in the seat from a determination side of the seat, preferably using electromagnetic radiation, measuring scattered and / or reflected radiation on the determination side of the seat, wherein said measuring is preferably performed using a determination sensor, determining a determination signal amplitude of the reflected radiation, determining the presence and colour shade of the egg based on the determination signal amplitude.

[0092] In an embodiment of the method of determining a presence and a colour shade of an egg, the method comprises blocking radiation used in irradiating the egg from reaching a determination sensor directly, without scattering or reflecting prior to reaching the determination sensor. By preventing radiation travelling in a straight path from the determination source of electromagnetic radiation from reaching the determination sensor directly (e.g. by using a shield), the determination signal amplitude is not or at least less determined by radiation that did not scatter or reflect from the egg. This increases accuracy of the measurement of egg colour shade and / or presence.

[0093] In an embodiment of the method of determining a presence and a colour shade of an egg, the method comprises the step of determining the presence of an egg in the seat by comparing a determination signal amplitude to a first threshold value, wherein the method comprises determining that an egg is present in the seat if the determination signal amplitude exceeds the first threshold value and wherein the method comprises determining that an egg is not present in the seat if the determination signal amplitude does not exceed the first threshold value. The determination signal amplitude is representative of the amount of electromagnetic radiation received by the determination sensor. If little or no electromagnetic radiation is received by the determination sensor, there is no egg in the seat, as otherwise that egg would have reflected and / or scattered electromagnetic radiation from the determination source of electromagnetic radiation to the determination sensor. The first threshold value is not necessarily zero, since there may be some stray electromagnetic radiation which reaches the determination sensor even if no egg is present, for example due to reflection or scattering from other parts of the imaging system, or from ambient background radiation.

[0094] In an embodiment of the method of determining a presence and a colour shade of an egg, the method comprises the step of determining the colour shade of an egg in the seat based on a determination signal amplitude, wherein a lower determination signal amplitude is indicative of a darker colour shade of the egg and wherein a higher determination signal amplitude is indicative of a lighter colour shade of the egg. As discussed above, the determination signal amplitude is representative of the amount of electromagnetic radiation scattered and / or reflected by the egg. As a darker egg reflects and / or scatters less electromagnetic radiation than a lighter egg, a lower determination signal amplitude thus indicates a darker egg, whereas a higher determination signal amplitude indicates a lighter egg.

[0095] In an embodiment of the method of determining a presence and a colour shade of an egg, the method comprises comparing the determination signal amplitude to one or more calibration signal amplitude values, wherein the calibration amplitude values are associated with reference colour shades of eggs, wherein the method comprises determining that an egg is not present in the seat if a determination signal amplitude is below a calibration signal amplitude associated with a darkest possible colour shade of an egg. The determination signal amplitude may be compared to calibration signal amplitude values stored in a memory. If one of the stored calibration signal amplitude values matches the determination signal amplitude, it is determined that the egg has the same colour shade as the reference colour shade associated with that calibration signal amplitude.

[0096] If none of the stored calibration signal amplitude values matches the determination signal amplitude, the closest calibration signal amplitude may be used to determine the colour shade of the egg as the reference colour shade associated with said closest calibration signal amplitude. Alternatively, a (weighted) average of the two closest calibration signal amplitude values may be used to determine the colour shade of the egg as an intermediate colour shade of the two reference colour shades associated with said two closest calibration signal amplitude values.

[0097] It is envisaged that a fitting function may be used to generate a calibration curve based on the calibration signal amplitude values. Then, the parameters of the fitting function may be stored in the memory instead of the calibration signal amplitude values. Furthermore, the fitting function may be used to determine the colour shade of the egg based on the determination signal amplitude.

[0098] These and other aspects of the invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts.

[0099] It will be clear to the skilled person that the features of any of the above embodiments can be combined.

[0100] Brief description of the figures

[0101] Figure 1 Shows a schematic depiction of an imaging system of an embodiment according to the first aspect of the invention.

[0102] Figure 2 shows a schematic depiction of a determination system of an embodiment according to the second aspect of the invention.

[0103] Detailed description of the figures

[0104] Figure 1 shows an embodiment of an imaging system 1 for imaging an egg 2 according to the invention. The system 1 comprises multiple seats 3, each configured to hold an egg 2. In Figure 1 , an egg 2 is shown in only one of the seats 3. In practice, the other seats 3 may or may not hold eggs 2. The seats 3 are arranged between holding members 24A of a transport device 24.

[0105] An imaging irradiator 4 is arranged on an imaging irradiation side 5 of the seats 3. In the imaged embodiment, the imaging irradiation side 5 is the underside of the seats 3, such that the imaging irradiator 4 is arranged below the seats 3.

[0106] The imaging irradiator 4 comprises an imaging source 10 of electromagnetic radiation. The imaging irradiator 4 is configured to expose the egg 2 in the seat 3A between the imaging irradiator 4 and an imaging device 6 to electromagnetic radiation from the imaging source 10.

[0107] The imaging device 6 is arranged on an imaging side 7 of the seats 3. The imaging device 6 may comprise a camera 28, for example a monochrome camera or a colour camera. In the imaged embodiment, the imaging side 7 is opposite to the imaging irradiation side 5 with respect to the seats 3. Thus, the imaging device 6 receives radiation transmitted through the egg 2 in the seat 3A between the imaging irradiator 4 and the imaging device 6 to image said egg 2. In an alternative embodiment, the imaging irradiator 4 and the imaging device 6 could be arranged on a same side of the seats 3, such that the imaging device 6 would received light scattered from the egg 2.

[0108] The imaging system 1 comprises a determination system 8 to determine whether or not an egg 2 is present in a seat 3, specifically in the seat 3B at the determination system 8. If an egg 2 is present in the seat 3B at the determination system 8, the determination system 8 determines its colour shade. The determination system is connected via a determination connection 8A to an exposure controller 9. The exposure controller 9 is connected to the imaging irradiator 4 via an exposure connection 9A and is configured to control the imaging irradiator 4 based on the determination of presence and colour shade of the egg 2 in the seat 3B at the determination system 8 performed by the determination system 8. In an alternative embodiment, the exposure controller 9 may instead or additionally be connected to the imaging device 6.

[0109] In the imaged embodiment, the exposure controller 9 is configured to control an irradiation energy amount with which the imaging irradiator 4 irradiates the egg 2 in the seat 3A between the imaging irradiator 4 and the imaging device 6. To achieve this, the exposure controller controls irradiation time of the imaging irradiator 4. For example, a darker egg gets a longer irradiation time than a lighter egg, because a lighter egg transmits more light than a darker egg. By modifying the irradiation energy amount via the irradiation time, a similar amount of energy is received by the imaging device 6 for each egg 2, regardless of its colour shade. This prevents overexposure of the imaging device 4 while simultaneously preventing images of darker eggs being too dark to discern any deficiencies such as cracks in the egg shell 14 of the egg 2.

[0110] The determination system 8 comprises a determination source 11 of electromagnetic radiation. The determination source 11 of electromagnetic radiation comprises a visible light source 19 providing light such as red light, blue light, green light, or white light. The visible light source 19 preferably comprises an LED light source 20. The determination system 8 also comprises a determination sensor 13 sensitive to electromagnetic radiation. The determination sensor 13 comprises a photosensitive element 21 such as a photo resistive sensor 22.

[0111] The determination source 11 sends first electromagnetic radiation 29 towards the egg 2. This electromagnetic radiation is then scattered and / or reflected by the shell 14 of the egg 2. Subsequently, second electromagnetic radiation 30 is received by the determination sensor 13.

[0112] The determination system 8 also comprises a radiation shield 23 arranged between the determination source 11 of electromagnetic radiation and the determination sensor 13. The radiation shield 23 is configured to prevent radiation travelling in a straight path from the determination source 11 of electromagnetic radiation from reaching the determination sensor 13 directly, without scattering or reflecting prior to reaching the determination sensor 13. This increases the difference in the amount of second electromagnetic radiation 30 received by the determination sensor 13 as a function of presence and colour shade of the egg 2, in particular of its shell 14, in the seat 3B at the determination system 8. This enhances sensitivity and accuracy of the determination system 8.

[0113] The determination source 11 of electromagnetic radiation is arranged on a determination side 12 of the seat 3B at the determination system 8 and a determination sensor 13 sensitive to electromagnetic radiation. The determination sensor 13 is also arranged on the determination side 12 of the seat 3B at the determination system 8. Both the determination source 11 and the determination sensor 13 are arranged on the determination side 12 of the seat 3B at the determination system 8. The determination side 12 is below said seat 3B in the imaged embodiment, such that the determination system 8 does not intrude on the space above the seats 3. This space above the seats 3 then remains free for other uses. In the imaged embodiment, the determination side 12 is the same as the imaging irradiation side 5, i.e. below the seats 3.

[0114] The determination source 11 is configured to irradiate the seat and the egg 2 present in the seat 3B at the determination system 8 with electromagnetic radiation (the first electromagnetic radiation 29 shown in figures 1 and 2), and the determination sensor 13 is configured to receive electromagnetic radiation (the second electromagnetic radiation 30 shown in figures 1 and 2) reflected and / or scattered from the egg shell 14 of the egg 2 present in the seat 3B at the determination system 8. The determination sensor 13 is furthermore configured to provide a determination sensor output signal representative of an intensity of received radiation to the exposure controller 9 via the determination connection 8A. The exposure controller 9 is configured to receive this sensor output signal and to determine the presence and the colour shade of the egg shell 14 of the egg 2 present in seat 3B at the determination system 8, based on the determination sensor output signal.

[0115] Specifically, the exposure controller 9 is configured to determine a determination signal amplitude of the determination sensor output signal. The exposure controller 9 is configured to determine the presence of an egg 2 in the seat 3B at the determination system 8 based on the determination signal amplitude with respect to a first threshold value. The exposure controller 9 is configured to determine that an egg 2 is present in said seat 3B if the determination signal amplitude exceeds the first threshold value. The exposure controller 9 is configured to determine that an egg 2 is not present in said seat 3B if the determination signal amplitude does not exceed the first threshold value. The background of this is that if the determination signal amplitude is below the first threshold value, this indicates that very little light was received by the determination sensor 13. This means that no egg 2 was present in said seat 3B, because otherwise more radiation would have been received by the determination sensor 13 by scattering and / or reflection off the egg shell 14 of the egg 2.

[0116] Besides determining egg presence, the exposure controller 9 is also configured to determine the colour shade of an egg 2 in the seat 3B at the determination system 8 based on the determination signal amplitude. A lower determination signal amplitude is indicative of a darker colour shade of the egg (in particular of the egg shell 14 of the egg 2) and a higher determination signal amplitude is indicative of a lighter colour shade of the egg 2 (again, in particular of its shell 14). To this end, the exposure controller 9 comprises a memory 9B in which one or more calibration signal amplitude values are stored. The stored calibration amplitude values are associated with reference colour shades of eggs 2, and the exposure controller 9 is configured to determine the colour shade of the egg 2 in the seat 3B at the determination system 8 by comparing the determination signal amplitude of the determination sensor output signal to the calibration signal amplitude values. The exposure controller 9 may be configured to associate a determination signal amplitude below a calibration signal amplitude associated with a darkest possible colour shade of an egg 2 with absence of an egg 2 in the seat 3B at the determination system 8.

[0117] The imaging system 1 comprises a transport device 24 comprising multiple seats 3 arranged between holding members 24A of the transport device 24. Each seat 3 is configured to hold an egg 2. The seats are open on an upper seat side 3C and lower seat side 3D, such that radiation may pass through the seats in a substantially vertical direction 3E. The transport device 24 moves the seats 3 in a horizontal transport direction 25 along a transport trajectory 26. The transport trajectory 26 extends past the determination sensor 13 and the determination source 11 of electromagnetic radiation. The imaging irradiator 4 and the imaging device 6 are also positioned along the transport directory 26, downstream along the transport direction 25 of the determination sensor 13 and the determination source 11 of electromagnetic radiation. The determination sensor 13 is stationary with respect to an environment 27 such as a machine room or other environment where the imaging system is located, such that the transport device 24 moves the seats 3 past the determination sensor 13. The determination source 11 of electromagnetic radiation is stationary with respect to the determination sensor 13 and thus is also stationary with respect to the environment 27.

[0118] It is noted that, in the imaged embodiment, the determination of the presence and colour shade of the egg 2 is performed at a different location than where the actual image of the egg 2 is made for assessing deficiencies of the egg shell 14. The presence and colour shade of the egg 2 is determined upstream from the position where the egg 2 is imaged with respect to a transport direction 25 along which the egg is transported by the transport device 24. The transport device 24 comprises the seats 3. The seats are disposed between holding members 24A of the transport device 24. The exposure controller 9 is synchronised with the movement of the transport device 24. This is done in such a way that the exposure controller 9 controls the imaging irradiator 4 to provide the appropriate amount of irradiation energy when the seat 3 which was at the determination system 8 at the time at which the determination system 8 made the determination of the presence and colour shade of the egg 2 is between the imaging irradiator 4 and the imaging device 6. To this end, a delay memory or delay device may be provided in the exposure controller 9.

[0119] In use, the imaging system 1 is used to establish a presence of an egg 2 in a seat 3, and if an egg is present, irradiating the egg 2 and imaging the egg 2 while it is being irradiated. Prior to irradiating the egg 2, a colour shade of the egg is determined and said colour shade is used to control the irradiation and / or imaging of the egg 2. The an irradiation energy amount of the egg 2 is controlled, wherein darker coloured eggs 2 are irradiated with more a higher irradiation energy amount than lighter coloured eggs 2. The irradiation energy amount is controlled by controlling an irradiation time of the egg 2, wherein if no egg 2 is present in the seat 3, the seat 3 is not irradiated. The irradiation time is thus zero. This prevents overexposing the imaging device 6. Alternatively, imaging of the egg may be controlled by controlling an exposure time of the imaging device 6 (e.g. a camera 28), such as a shutter time.

[0120] Fig. 2 shows the determination system 8 in an application separate from the imaging system 1 . In this case, the determination system 8 may be used to determine a presence and / or colour shade of an egg 2 in other context than in an imaging system 1 . This may for example be useful in a device for sorting eggs based on their colour shade or in an egg boxing device. Therein, it is desired to put the same amount of eggs 2 in each box, such that it is necessary to know whether or not a seat 3 holds an egg 2. In this case, the determination sensor 13 communicates with a determination controller 9C which determines egg presence and / or colour in a similar manner as the exposure controller 9 discussed above. However, in this case the determination controller 9Cdoes not control an imaging irradiator 4.

[0121] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.

[0122] The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and / or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention.

[0123] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

CLAIMS1 . Imaging system for imaging an egg, the system comprising:- a seat for holding the egg,- an imaging irradiator arranged on an imaging irradiation side of the seat, wherein the imaging irradiator is configured to irradiate the egg present in the seat,- an imaging device arranged on an imaging side of the seat, wherein the imaging side of the seat is preferably substantially opposite to the imaging irradiation side with respect to the seat, wherein the imaging device is configured for imaging the egg present in the seat,- a determination system for determining a presence and a colour shade of an egg in a seat,- an exposure controller configured to control the imaging irradiator and / or the imaging device based on a determination of a presence and colour shade of an egg in a seat performed by the determination system.

2. Imaging system according to the preceding claim, wherein the exposure controller is configured to control an irradiation energy amount of the imaging irradiator and / or an exposure time of the imaging system based on the determination of a presence and a colour shade of an egg in a seat performed by the determination system, wherein the exposure controller is preferably configured to control the irradiation energy amount by controlling an irradiation time of the imaging irradiator.

3. Imaging system according to any of the preceding claims, wherein the imaging irradiator comprises an imaging source of electromagnetic radiation, wherein the imaging irradiator is configured to expose the egg in the seat to electromagnetic radiation from the imaging source, wherein the imaging device is preferably configured to image electromagnetic radiation which is scattered by the egg and / or electromagnetic radiation which is passed through the egg.

4. Imaging system according to any of the preceding claims, wherein the determination system comprises:- a determination source of electromagnetic radiation arranged on a determination side of the seat, wherein the determination source is configured to irradiate the seat and the egg present in the seat with electromagnetic radiation,- a determination sensor sensitive to electromagnetic radiation, wherein the determination sensor is configured to receive electromagnetic radiation reflected and / or scattered from an egg shell of the egg present in the seat, wherein the determination sensor is configured to provide a determination sensor output signal representative of an intensity of received radiation, wherein the determination sensor is preferably arranged on the determination side of the seat, wherein the determination side of the seat is preferably the same as the imaging irradiation side of the seat, wherein the exposure controller is configured to receive the sensor output signal and determine the presence and the colour shade of the egg shell of the egg present in the seatbased on the determination sensor output signal.

5. Imaging system according to the preceding claim, wherein the determination source of electromagnetic radiation is arranged below the seat and / or the determination sensor is arranged below the seat.

6. Imaging system according to claim 4 or 5, wherein the exposure controller is configured to determine a determination signal amplitude of the determination sensor output signal, wherein the exposure controller is configured to determine the presence of an egg in the seat based on the determination signal amplitude with respect to a first threshold value, wherein the exposure controller is configured to determine that an egg is present in the seat if the determination signal amplitude exceeds the first threshold value and wherein the exposure controller is configured to determine that an egg is not present in the seat if the determination signal amplitude does not exceed the first threshold value.

7. Imaging system according to any of claims 4 - 6, wherein the exposure controller is configured to determine a determination signal amplitude of the determination sensor output signal, wherein the exposure controller is configured to determine the colour shade of an egg present in the seat based on the determination signal amplitude, wherein a lower determination signal amplitude is indicative of a darker colour shade of the egg and wherein a higher determination signal amplitude is indicative of a lighter colour shade of the egg.

8. Imaging system according to the preceding claim, wherein the exposure controller comprises a memory in which one or more calibration signal amplitude values are stored, wherein the stored calibration amplitude values are associated with reference colour shades of eggs, wherein the exposure controller is configured to determine the colour shade of the egg by comparing the determination signal amplitude of the determination sensor output signal to the calibration signal amplitude values, wherein optionally the exposure controller is configured to associate a determination signal amplitude below a calibration signal amplitude associated with a darkest possible colour shade of an egg with absence of an egg in the seat.

9. Imaging system according to any of claims 4 - 8, wherein the determination source of electromagnetic radiation comprises a visible light source such as red light, blue light, green light, or white light, the visible light source preferably comprising an LED light source.

10. Imaging system according to any of claims 4 - 9, wherein the determination sensor comprises a photosensitive element such as a photo resistive sensor.

11. Imaging system according to any of claims 4 - 10, comprising a radiation shield arranged between the determination source of electromagnetic radiation and the determination sensor, wherein the radiation shield is configured to prevent radiation travelling in a straight path from the determinationsource of electromagnetic radiation from reaching the determination sensor directly, without scattering or reflecting prior to reaching the determination sensor.

12. Imaging system according to any of claims 4 - 11 , comprising a transport device configured to move the seat in a transport direction along a transport trajectory, wherein the transport trajectory passes the determination sensor and / or the determination source of electromagnetic radiation, wherein the determination sensor is preferably stationary with respect to an environment, wherein the determination source of electromagnetic radiation is preferably stationary with respect to the determination sensor, wherein the transport direction is preferably substantially horizontal, wherein the transport device optionally comprises multiple seats, each configured to hold an egg.

13. Determination system for determining a presence and a colour shade of an egg in a seat, the determination system comprising:- a seat for holding an egg,- a determination source of electromagnetic radiation arranged on a determination side of the seat, configured to irradiate the seat and the egg present in the seat with electromagnetic radiation,- a determination sensor sensitive to electromagnetic radiation configured to receive electromagnetic radiation reflected and / or scattered from an egg shell of the egg present in the seat, wherein the determination sensor is configured to provide a determination sensor output signal representative of an intensity of received radiation, wherein the determination sensor is preferably arranged on the determination side of the seat, wherein the determination side of the seat is preferable the same as the imaging irradiation side of the seat.

14. Method for imaging an egg, the method comprising the steps of:- establishing a presence of the egg in a seat,- if the egg is present in the seat, irradiating the egg,- imaging the egg while it is being irradiated, wherein prior to irradiating the egg a colour shade of the egg is determined and said colour shade is used to control the irradiation and / or imaging of the egg.

15. Method according to the preceding claim, comprising controlling an irradiation energy amount of the egg, wherein darker coloured eggs are irradiated with a higher irradiation energy amount than lighter coloured eggs, wherein preferably if no egg is present in the seat, the seat is not irradiated.

16. Method according to the preceding claim, wherein the irradiation energy amount is controlled by controlling an irradiation time of the egg.

17. Method according to claim 15 or 16, wherein imaging of the egg is controlled by controlling an exposure time of an imaging device such as a camera, such as a shutter time.

18. Method according to any of the preceding method claims, wherein the step of determining the colour shade and presence of the egg comprises the steps of:- irradiating the seat and the egg present in the seat from a determination side of the seat, preferably using electromagnetic radiation, measuring scattered and / or reflected radiation on the determination side of the seat, wherein said measuring is preferably performed using a determination sensor,- determining a determination signal amplitude of the reflected radiation,- determining the presence and colour shade of the egg based on the determination signal amplitude.

19. Method according to any of the preceding method claims, wherein the method comprises blocking radiation used in irradiating the egg from reaching a determination sensor directly, without scattering or reflecting prior to reaching the determination sensor.

20. Method according to any of the preceding method claims, wherein the method comprises the step of determining the presence of an egg in the seat by comparing a determination signal amplitude to a first threshold value, wherein the method comprises determining that an egg is present in the seat if the determination signal amplitude exceeds the first threshold value and wherein the method comprises determining that an egg is not present in the seat if the determination signal amplitude does not exceed the first threshold value.

21. Method according to any of the preceding method claims, wherein the method comprises the step of determining the colour shade of an egg in the seat based on a determination signal amplitude, wherein a lower determination signal amplitude is indicative of a darker colour shade of the egg and wherein a higher determination signal amplitude is indicative of a lighter colour shade of the egg.

22. Method according to the preceding claim, wherein the method comprises comparing the determination signal amplitude to one or more calibration signal amplitude values, wherein the calibration amplitude values are associated with reference colour shades of eggs, wherein the method comprises determining that an egg is not present in the seat if a determination signal amplitude is below a calibration signal amplitude associated with a darkest possible colour shade of an egg.

23. Method according to any of the preceding method claims, wherein the method is executed using an imaging system according to any of claims 1 - 12 and / or a determination system according to claim 13.

24. Method for determining a presence and a colour shade of an egg in a seat, the method comprising the steps of:- irradiating the seat from a first side of the seat, preferably using electromagnetic radiation measuring scattered and / or reflected radiation on the first side of the seat, - determining a signal amplitude of the reflected radiation,- determining the presence and colour shade of the egg based on the signal amplitud

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