Patent Description:
Roasting technology of coffee beans is a technology that requires a lot of operational experience to be skilled. Depending on the different demands for the flavor of the coffee, the coffee beans need to be roasted to different stage. Currently, there are two main technical methods for determining the roasting stages of the coffee beans during the roasting of the coffee beans. The first method determines the roasting stages by observing the color of the coffee beans during the roasting of the coffee beans, and the second method determines the roasting stages by the sound generated during the roasting of the coffee beans.

Specifically, for the method of determining the roasting stages by the sound, the coffee beans will generate different sounds at different roasting stages (e.g., the start of the first crack, the intensive stage of the first crack, the end of the first crack, the start of the second crack, the intensive stage of the second crack, the end of the second crack or the like) when the coffee beans expand and crack upon being heated during the roasting process. A roaster may decide a time point to offload the beans, control the fire, and adjust the damper or the like according to the sounds generated at different roasting stages. However, the conventional method to determine the roasting stage of the coffee beans is to listen to the sound generated by the roasting device by the human ear (e.g., the roaster's ear). Therefore, with the different experience and status of the different roasters, this method will cause many uncertain factors. Moreover, without specific and standardized values as a reference, it is hard to precisely duplicate the same flavor in the roasting process even by a same professional roaster. Furthermore, this method requires the roaster to wait beside the roasting device for a long time in order not to miss the bean offloading time point, so this method is quite labor consuming.

<CIT> discloses that real-time process and system control of coffee roasting by monitoring one or more acoustical characteristics of a coffee roasting device.

Besides, <CIT> discloses that a method and to an apparatus for roasting a food product, in particular coffee.

<CIT> describes a method of roasting coffee beans. The method consists of two steps: (<NUM>) a process of calculating an average value of the sound pressure during a first period, in measuring over time the sound of a frequency within the range of <NUM> to <NUM> generated from coffee beans and roasting equipment during roasting; and (<NUM>) a process of using the average value of the sound pressure as a threshold value and measuring the sound pressure from the point at which the average value of the sound pressure exceeds the threshold value.

Accordingly, an urgent need exists in the art to provide an assisting mechanism for bean roasting so as to precisely determine the bean roasting stages and maintain the roasting quality.

The invention is described in the independent claims. Preferred embodiments are described in the sub claims. An objective of the present invention is to provide an assisting mechanism for bean roasting, which generates a control signal by sensing sound inside the chamber of a conventional bean roasting device or the bean roasting apparatus of the present invention and analyzing the sensed sound, and informs a roaster of the current roasting stage of the coffee beans in various prompting manners. Different from the conventional technology, the assisting mechanism for bean roasting of the present invention can precisely determine the roasting stages of the coffee beans without human intervention and reduce the influence of artificial interferences to assist the roaster in learning the roasting stage of the coffee beans in real time during the roasting process, and the roaster can receive the roasting information of the conventional bean roasting device or the bean roasting apparatus of the present invention without the need of waiting beside the bean roasting device for a long time. Moreover, the assisting mechanism for bean roasting of the present invention may further achieve automatic roasting and perform a bean offloading operation depending on the roasting stage set by the roaster.

To achieve the aforesaid objective, the present invention discloses an assisting apparatus for bean roasting which comprises a microphone and a processor. The microphone is configured to sense sound in a chamber of a bean roasting device to generate an audio signal. The processor is electrically connected to the microphone and is configured to receive the audio signal from the microphone and generate a control signal by determining that an energy value of the audio signal crosses a threshold at a time point based on an observation time window.

To achieve the aforesaid objective, the present invention discloses a bean roasting apparatus which comprises a chamber, a microphone and a processor. The microphone is configured to sense sound in the chamber to generate an audio signal. The processor is electrically connected to the microphone, and is configured to receive the audio signal from the microphone and generate a control signal by determining that an energy value of the audio signal crosses a threshold at a time point based on an observation time window.

The detailed technology and preferred embodiments implemented for the present invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention.

In the following description, the present invention will be explained with reference to embodiments thereof. However, these embodiments are not intended to limit the present invention to any environment, applications or particular implementations described in these embodiments. Therefore, description of these embodiments is only for purpose of illustration rather than to limit the scope of the present invention. It shall be appreciated that, in the following embodiments and the attached drawings, elements unrelated to the present invention are omitted from depiction.

<FIG> is a schematic view of an assisting apparatus <NUM> for bean roasting according to an embodiment not according to the present invention. The assisting apparatus <NUM> for bean roasting comprises a microphone <NUM> and a processor <NUM>. The processor <NUM> is electrically connected to the microphone <NUM>. The microphone <NUM> may be any audio receiving device of the same function. The assisting apparatus <NUM> for bean roasting is disposed adjacent to a bean roasting device (e.g., disposed at a side or at the top or bottom of a chamber of the bean roasting device) to sense sound inside the chamber during the bean roasting process (i.e., the sound generated during the roasting process of coffee beans).

In this embodiment, the microphone <NUM> continuously senses sound and transforms the sound sensed from an analog signal into a digital signal according to a sample rate so as to generate an audio signal <NUM>. For example, as shown in <FIG>, the audio signal <NUM> may be represented in a time domain, wherein the horizontal axis is time and the vertical axis is amplitude. Moreover, in some embodiments, the microphone <NUM> may further comprise a high pass filter, which first performs noise reduction on the analog signal generated after sensing the sound to filter unnecessary interference noise in the environment, and then transforms the analog signal into a digital signal to generate the audio signal <NUM>, as shown in <FIG>.

However, as shall be appreciated by those of ordinary skill in the art, the aforesaid noise reduction may also be implemented by the processor <NUM> via software. For example, after receiving the audio signal <NUM> on which the noise reduction has not been performed, the processor <NUM> may first have the audio signal <NUM> pass through a high pass filter, which may be represented as follows if it is expressed by a frequency domain equation: <MAT>.

Accordingly, no matter the noise reduction is achieved via hardware or software, the processor <NUM> can obtain the audio signal <NUM> as shown in <FIG>. Next, the processor <NUM> analyzes the audio signal <NUM> based on an observation time window. It shall be appreciated that, the observation time window is an observation time unit that is used to retrieve N sample values of the audio signal <NUM> on different time segments, wherein the number of N may be <NUM> or <NUM>, and the time covered by each observation time window is about <NUM> milliseconds (ms) to <NUM>. In other words, the observation time window retrieves values of different time segments of the audio signal <NUM> as time goes by. In the present invention, each time segment retrieved from the audio signal <NUM> is called an audio frame.

For example, as shown in <FIG>, audio frames A1, A2,. , An comprise values of different time segments of the audio signal <NUM> that are retrieved in sequence on the timeline based on the observation time window. It is assumed that the sample rate of the audio signal <NUM> is <NUM> kilohertz (KHz), and the audio frames A1, A2,. , An respectively consist of <NUM> sample points, then the time length corresponding to each audio frame is <NUM>, i.e., (<NUM>*<NUM>)/<NUM>. Therefore, taking the audio frame A1 and the audio frame A2 as an example for illustration, in the case where adjacent audio frames are not overlapped with each other, the audio frame A1 comprises values of the audio signal <NUM> between <NUM> and <NUM>, and the audio frame A2 comprises values of the audio signal <NUM> between <NUM> and <NUM>.

However, in order to prevent the accuracy of determining the change in the audio signal <NUM> by the processor <NUM> from decreasing due to an excessive change between two adjacent audio frames, a partially overlapped area may exist between the adjacent audio frames (e.g., the overlapped area comprises M sample points), as shown in <FIG>. For the case where the sample rate of audio used for general voice identification is about <NUM> or <NUM>, the value of N is generally set to be <NUM> or <NUM>, the time covered by each observation time window is about <NUM> to <NUM>, and the value of M is usually set to be <NUM>/<NUM> or <NUM>/<NUM> of N.

Thereafter, according to the observation time window of each time point, the processor <NUM> determines an energy value (e.g., a value of the total amplitude) of the audio signal <NUM> within the time observation window. In other words, for the energy value of each of the audio frames, the processor <NUM> retrieves the audio signal <NUM> within the observation time window as a to-be-analyzed signal to calculate a total signal energy value of the to-be-analyzed signal in a time domain and takes the total signal energy value as the energy value of the audio frame. Thereafter, when the processor <NUM> determines that the energy value of an audio frame crosses a threshold, the processor <NUM> generates a control signal to indicate a specific time point (e.g., one of a crack start time point and a crack end time point) corresponding to the audio frame.

For example, as shown in <FIG>, when the processor <NUM> calculates the energy value in each frame sequentially and determines that the energy value in an audio frame Ap1 exceeds a first threshold for the first time, the processor <NUM> generates a corresponding control signal which indicates the start of the first crack,. After the start of the first crack, the total energy of the subsequent audio frames increases gradually, and when the processor <NUM> determines that the total amplitude energy in an audio frame Ap2 exceeds a second threshold for the first time, the processor <NUM> generates a corresponding control signal which indicates an intensive stage of the first crack. Next, after the intensive stage of the first crack, the total energy of the subsequent audio frames decreases gradually, and when the processor <NUM> determines that the total amplitude energy in an audio frame Ap3 is below a third threshold, the processor <NUM> generates a corresponding control signal which indicates the end of the first crack.

Moreover, if the coffee beans are still roasted continuously after the end of the first crack, then the total energy of the subsequent audio frames will again increase gradually when the coffee beans is close to the stage of second crack. Therefore, the processor <NUM> may determine the time points of the start of the second crack, the intensive stage of the second crack and the end of the second crack based on the aforesaid manner of determining the time points of the start of the first crack, the intensive stage of the first crack and the end of the first crack. Since people skilled in the art shall appreciate how to determine the time points of the start of the second crack, the intensive stage of the second crack and the end of the second crack based on the above description of determining the time points of the start of the first crack, the intensive stage of the first crack and the end of the first crack, and thus this will not be further described herein. Moreover, as shall be appreciated by those of ordinary skill in the art, the aforesaid second threshold is certainly greater than the first threshold and the third threshold, and the third threshold may be set to be the same as the first threshold depending on the actual design. Furthermore, the present invention may not need to set a threshold (i.e., the second threshold) for the intensive stage of the first crack, and instead infer the time point of the intensive stage of the first crack according to the time points of the start of the first crack and the intensive stage of the first crack that are determined previously.

Moreover, in an embodiment, the assisting apparatus <NUM> for bean roasting may further comprise a loudspeaker (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may transmit the generated control signal to the loudspeaker so that the loudspeaker generates a prompting signal. In this way, as the assisting apparatus <NUM> for bean roasting determines the roasting stages (i.e., the start of the first crack, the intensive stage of the first crack, the end of the first crack, the start of the second crack, the intensive stage of the second crack, the end of the second crack or the like), the user may decide the time point to offload the beans according to the prompting signal.

Furthermore, in an embodiment, the assisting apparatus <NUM> for bean roasting further comprises a display panel (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may transmit the generated control signal to the display panel so that the display panel displays a prompting picture. In this way, as the assisting apparatus <NUM> for bean roasting determines the roasting stages, the user may decide the time point to offload the beans according to the prompting picture.

Additionally, in an embodiment, the assisting apparatus <NUM> for bean roasting may further comprise a transceiver (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may transmit the generated control signal to the transceiver so that the transceiver transmits a prompting message to a user equipment according to the received control signal. For example, the user equipment may be a smartphone, and the manufacture of the assisting apparatus <NUM> for bean roasting may design an application that can be installed on the smartphone. Therefore, after the application is installed on the smartphone of the user, the smartphone may be connected to the assisting apparatus <NUM> for bean roasting directly (via wireless technology) or indirectly (via local area network or Internet or the like), and thus the smartphone can receive the prompting message from the assisting apparatus <NUM> for bean roasting. In this way, as the assisting apparatus <NUM> for bean roasting determines the roasting stages, the user may be informed of the roasting stages immediately and decide the time point to offload the beans.

Moreover, in an embodiment, the assisting apparatus <NUM> for bean roasting may further comprise a transceiver (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may transmit the generated control signal to the transceiver so that the transceiver further transmits another control signal to the bean roasting apparatus to enable the bean roasting apparatus to automatically perform an operation (e.g., a bean offloading operation). For example, the user equipment may set the assisting apparatus <NUM> for bean roasting to generate a control signal after it is determined that the first crack ends so that the bean roasting apparatus automatically performs the bean offloading operation.

Please further refer to <FIG> for an embodiment of the present invention. Different from the first embodiment not according to the invention, the processor <NUM> in this embodiment transforms the audio signal <NUM> in each audio frame from the time domain to the frequency domain and analyzes the energy value of each audio frame in the frequency domain.

Specifically, the processor <NUM> further retrieves the audio signal <NUM> within the observation time window as a to-be-analyzed signal and transforms the to-be-analyzed signal into a frequency-domain signal to calculate a total signal energy value of the frequency-domain signal in a particular frequency band. In other words, the processor <NUM> performs Fast Fourier Transform (FFT) operation on each audio frame to transform the audio frame into a frequency-domain signal, and calculates a total signal energy value of the frequency-domain signal in a particular frequency band and takes the total signal energy value as the energy value of the frame.

For example, <FIG> depicts a spectrogram of transforming the audio signal <NUM> within an audio frame into a frequency-domain signal of the frequency domain, wherein the horizontal axis is frequency (unit: hertz (Hz)) and the vertical axis is the value of amplitude (unit: decibel (dB)). The processor <NUM> may calculate a total signal energy value of the frequency-domain signal within a particular frequency band (e.g., from <NUM> to <NUM>), and take the total signal energy value as an energy value of the audio frame. Therefore, the processor <NUM> calculates the total signal energy value of each audio frame in a particular frequency band, compares the energy value with a threshold, and generates a control signal when the energy value crosses a threshold. Based on the aforesaid first embodiment, people skilled in the art shall appreciate how to determine the time points of the roasting stages by setting thresholds corresponding to the roasting stages based on the energy value obtained by calculating the frequency-domain signal, and thus will not be further described herein.

The following will describe how to determine the particular frequency band and the threshold in the present invention. First, the processor <NUM> takes an audio signal that is sensed and generated by the microphone <NUM> at an initial bean roasting stage (the stage at the beginning of bean roasting) as an environment audio signal, and transforms an audio frame during this stage to the frequency domain to obtain an environment audio frequency signal, and a spectrogram thereof is as shown in <FIG>. Next, a spectrogram (e.g., <FIG>) corresponding to a time frame within the interval from the start of the first crack to the intensive stage of the first crack of coffee beans is overlaid with a spectrogram of <FIG> to generate an overlaid spectrogram as shown in <FIG>. In <FIG>, the dark grey part corresponds to the spectrogram (i.e., <FIG>) of an audio frequency signal within the interval from the start of the first crack to the intensive stage of the first crack, and the light grey part corresponds to the spectrogram (i.e., <FIG>) of the environment audio frequency signal, and the dark part is the overlapped part therebetween. According to <FIG>, the processor <NUM> may calculate differences in energy values between the audio frequency signal and the environment audio signal in different frequency bands (i.e., the dark grey part), determine the frequency band having the obvious energy difference (e.g., around <NUM>), and accordingly set thresholds corresponding to different roasting stages.

The aforesaid process of determining the particular frequency band and the threshold may be implemented by labelling particular time points (e.g., the start of the first crack, the intensive stage of the first crack, the end of the first crack, the start of the second crack, the intensive stage of the second crack, the end of the second crack or the like) with user intervention and through machine learning so that the processor <NUM> may identify the frequency band having the obvious energy difference more precisely and set thresholds corresponding to different roasting stages. For example, the assisting apparatus <NUM> for bean roasting may further comprise a transceiver (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may receive a feedback signal from the user equipment via the transceiver to adjust the particular frequency band for calculating the energy value and the threshold.

Moreover, in an embodiment, the processor <NUM> may first multiply each audio frame with a Hamming Window before performing the Fast Fourier Transform (FFT) operation on the audio signal <NUM> in each audio frame, so as to increase the continuity of a left-end signal and a right-end signal of each audio frame. Thereafter, the processor <NUM> performs the Fast Fourier Transform (FFT) operation on the audio signal <NUM> of each audio frame multiplied with the Hamming Window. The Hamming Window is well known to those of ordinary skill in the art, and thus will not be further described herein.

Through the assisting apparatus <NUM> for bean roasting of the present invention, the user may record information about the time points of the roasting stages (e.g., the start of the first crack, the intensive stage of the first crack, the end of the first crack, the start of the second crack, the intensive stage of the second crack, and the end of the second crack or the like) according to the control signals and perform suitable operations (e.g., opening the fire damper, adjusting the temperature, turning off the fire, and performing the bean offloading operation or the like) in real time according to the information. Moreover, the user may further plot roasting curve graphs of various kinds of coffee beans according to the information and user feedback information to record information relevant to bean roasting (e.g., the bean roasting time, temperature and roasting stage or the like) as auxiliary reference for the next bean roasting. Thus, automatic roasting processes for different kinds of coffee beans can be designed according to the information and shared with other users via a cloud database as a reference.

As shall be known from the above descriptions, the assisting apparatus <NUM> for bean roasting of the present invention generates a control signal by sensing the sound inside the chamber of the bean roasting device and analyzing the sensed sound, and informs a roaster of the current roasting stage of the coffee beans in various prompting manners. Different from the conventional technology, the assisting apparatus <NUM> for bean roasting can precisely determine the roasting stage of the coffee beans without human intervention and reduce the influence of artificial interferences to assist the roaster in learning the roasting stage of the coffee beans in real time during the roasting process, and the roaster can receive the roasting information of the bean roasting device without the need of waiting beside the bean roasting device for a long time. Moreover, the assisting apparatus <NUM> for bean roasting of the present invention may further achieve automatic roasting and perform the bean offloading operation depending on the roasting stage set by the roaster.

A third embodiment not according to the present invention is a bean roasting apparatus as shown in <FIG>. Different from the first embodiment, the assisting apparatus <NUM> for bean roasting of the first embodiment is integrated into a bean roasting apparatus <NUM> in third embodiment. Specifically, the bean roasting apparatus <NUM> comprises a microphone <NUM>, a processor <NUM> and a chamber <NUM>, and the processor <NUM> is electrically connected to the microphone <NUM>.

Similarly, the microphone <NUM> senses sound inside the chamber <NUM> to generate the audio signal <NUM>. After receiving the audio signal <NUM> from the microphone <NUM>, the processor <NUM> determines that an energy value of the audio signal crosses a threshold at a time point based on an observation time window to generate a control signal. Similarly, the microphone <NUM> may further comprise a high pass filter, which first performs noise reduction on the analog signal generated after sensing the sound to filter unnecessary interference noise in the environment, and then transforms the analog signal into a digital signal to generate the audio signal <NUM>. Moreover, the noise reduction may also be achieved by the processor <NUM> through software.

In an embodiment, the bean roasting apparatus <NUM> may further comprise a loudspeaker (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may transmit the generated control signal to the loudspeaker so that the loudspeaker generates a prompting signal. In this way, as the bean roasting apparatus <NUM> determines the roasting stages (i.e., the start of the first crack, the intensive stage of the first crack, the end of the first crack, the start of the second crack, the intensive stage of the second crack, the end of the second crack or the like), the user may decide the time point to offload the beans according to the prompting signal.

Furthermore, in an embodiment, the bean roasting apparatus <NUM> further comprises a display panel (not shown) electrically connected to the processor <NUM>, and the processor <NUM> may transmit the generated control signal to the display panel so that the display panel displays a prompting picture. In this way, as the bean roasting apparatus <NUM> determines the roasting stages, the user may decide the time point to offload the beans according to the prompting picture.

According to the invention, the bean roasting apparatus <NUM> comprises a transceiver (not shown) electrically connected to the processor, and the processor <NUM> transmits the generated control signal to the transceiver so that the transceiver transmits a prompting message to a user equipment according to the received control signal. In this way, as the bean roasting apparatus <NUM> for bean roasting determines the roasting stages, the user may be informed of the roasting stages immediately and decide the time point to offload the beans.

In an embodiment not according to the invention, the processor <NUM> retrieves the audio signal <NUM> within the observation time window as a to-be-analyzed signal to calculate a total signal energy value of the to-be-analyzed signal in a time domain. Therefore, the processor <NUM> takes the total signal energy value as the energy value of the audio signal that is retrieved based on the observation time window.

In an embodiment according to the invention, the processor <NUM> retrieves the audio signal within the observation time window as a to-be-analyzed signal and transforms the to-be-analyzed signal into a frequency-domain signal to calculate a total signal energy value of the frequency-domain signal in a particular frequency band. Therefore, the processor <NUM> takes the total signal energy value as the energy value of the audio signal that is retrieved based on the observation time window.

In other embodiments, the bean roasting apparatus <NUM> further comprises a discharge port and a discharge port control element. The discharge port control element is electrically connected to the processor <NUM>. The processor <NUM> further transmits the control signal to the discharge port control element so that the discharge port control element opens the discharge port to discharge a plurality of coffee beans within the chamber <NUM>.

In addition to the aforesaid operations, the processor <NUM> of this embodiment can also execute all the operations and have all the corresponding functions of the processor <NUM> described in the aforesaid embodiment. How this embodiment executes these operations and has these functions will be readily appreciated by those of ordinary skill in the art based on the explanation of the aforesaid embodiment, and thus will not be further described herein.

According to the above descriptions, the present invention provides an assisting mechanism for bean roasting, which generates a control signal by sensing the sound inside the chamber of the bean roasting apparatus and analyzing the sound, and informs a roaster of the current roasting stage of the coffee beans in various prompting manners. Different from the conventional technology, the assisting mechanism for bean roasting of the present invention can precisely determine the roasting stage of the coffee beans without human intervention and reduce the influence of artificial interferences to assist the roaster in learning the roasting stage of the coffee beans in real time during the roasting process, and the roaster can receive the roasting information of the bean roasting apparatus without the need of waiting beside the bean roasting apparatus for a long time. Moreover, the assisting mechanism for bean roasting of the present invention may further achieve automatic roasting and perform the bean offloading operation depending on the roasting stage set by the roaster.

Claim 1:
An assisting apparatus (<NUM>) for bean roasting, comprising:
a microphone (<NUM>), being configured to sense sound in a chamber of a bean roasting device to generate an audio signal (<NUM>);
a transceiver;
a processor (<NUM>), being electrically connected to the microphone (<NUM>) and the transceiver, and being configured to receive the audio signal (<NUM>) from the microphone (<NUM>), generate a control signal by determining that an energy value of the audio signal crosses a threshold at a time point based on an observation time window, and transmit the control signal to the transceiver to make the transceiver transmit a prompting message to an external user equipment, wherein the control signal is configured to indicate the time point, and the time point represents one of a crack start time point and a crack end time point; characterised by
the processor (<NUM>) further being configured to retrieve the audio signal (<NUM>) within the observation time window as a to-be-analyzed signal and to transform the to-be-analyzed signal into a frequency-domain signal to calculate a total signal energy value of the frequency-domain signal on a particular frequency band, and the energy value is the total signal energy value;
the processor (<NUM>) further being configured to take the audio signal (<NUM>) at an initial bean roasting stage as an environment audio signal and to transform an audio frame during the initial bean roasting stage to a frequency domain to obtain an environment audio frequency signal; and
the processor (<NUM>) further being configured to calculate differences in energy values between an audio frequency signal and the environment audio frequency signal in different frequency bands, to take a frequency band having obvious energy difference as the particular frequency band, and accordingly to set the threshold corresponding to a roasting stage.