Heart rhythm monitoring device that reduces motion interference

Abstract

A heart rhythm detection device includes an image sensor. The image sensor generates a first mixed signal during a first period and a second mixed signal during a second period. The first mixed signal includes light information of a first plurality of light wavelengths having a first intensity ratio relative to one another, and the second mixed signal includes light information of a second plurality of light wavelengths having a second intensity ratio relative to one another, wherein the second intensity ratio is different from the first intensity ratio.

Description

Technical Field

[0001] The present invention relates to a detection module and a detection method, and more particularly to a heart rhythm detection module and a detection method. Background Art

[0002] Generally speaking, photoplethysmography (PPG) systems use a pulse oximeter to illuminate the skin and measure changes in light absorption, thereby detecting heart rhythm based on light brightness (light absorption). During cardiac contraction, peripheral blood volume and light absorption are maximized, resulting in minimal light intensity. During diastole, light intensity is maximized, allowing heartbeats to be determined. Therefore, a heart rhythm detection system with a dynamic range capable of detecting light intensity from maximum to minimum is required.

[0003] Conventional PPG systems typically include a light source and a detector and use a single pixel. However, a single pixel typically does not have sufficient dynamic range and can result in a low signal-to-noise ratio, reducing detection accuracy.

[0004] Therefore, how to reduce noise interference and improve detection accuracy is an important task in this field. Summary of the Invention

[0005] To address the aforementioned issues, the present invention proposes a heart rhythm detection module comprising an image sensor and a processor. By using an image sensor with a complementary metal oxide semiconductor (CMOS) detection array to generate light intensity center of gravity displacement information and using the processor to calculate light intensity variations, a wider dynamic range can be achieved.

[0006] To achieve the above objectives, one embodiment of the present invention provides a heart rhythm detection device comprising a first light source, a second light source, and an image sensor. The first light source is configured to emit light of a first wavelength. The second light source is configured to emit light of a second wavelength. The image sensor is configured to generate a first mixed signal during a first period and a second mixed signal during a second period. The first and second wavelength light have a first intensity ratio during the first period and a second intensity ratio, different from the first intensity ratio, during the second period.

[0007] Another embodiment of the present invention provides a heart rhythm detection device comprising an image sensor. The image sensor is configured to generate a first mixed signal during a first period and a second mixed signal during a second period, wherein the first mixed signal comprises light information of a first plurality of light wavelengths having a first intensity ratio relative to one another, and the second mixed signal comprises light information of a second plurality of light wavelengths having a second intensity ratio relative to one another, the second intensity ratio being different from the first intensity ratio.

[0008] Another embodiment of the present invention provides a heart rhythm detection device comprising an image sensor. The image sensor is configured to generate a first mixed signal during a first period and a second mixed signal during a second period, wherein the first mixed signal includes light information of a first light combination of multiple light wavelengths, and the second mixed signal includes light information of a second light combination of multiple light wavelengths, wherein the second light combination includes at least one light wavelength not included in the first light combination.

[0009] Another embodiment of the present invention provides a heart rhythm detection device comprising an image sensor and a processor. The image sensor is configured to generate multiple image frames based on a first light combination of multiple light wavelengths or a second light combination of multiple light wavelengths emitted from an object. The processor is configured to output a heart rhythm value based on light intensity fluctuations in the multiple image frames associated with the first light combination or the second light combination.

[0010] In order to further understand the characteristics and technical contents of the present invention, reference numerals are attached to the following detailed description and accompanying drawings related to the present invention. However, the accompanying drawings are only for illustration and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of light passing through an object in a heart rhythm detection module according to an embodiment of the present invention;

[0012] Figure 2 is a schematic diagram of light reflected by an object in a heart rhythm detection module according to an embodiment of the present invention;

[0013] Figure 3 is a flow chart of a heart rhythm detection method according to an embodiment of the present invention;

[0014] Figure 4 is a schematic diagram of an image sensor according to an embodiment of the present invention;

[0015] Figure 5 is a schematic diagram of the configuration of an image sensor and a light source according to an embodiment of the present invention;

[0016] Figure 6A and 6B is a heart rhythm detection result measured by a heart rhythm detection module according to an embodiment of the present invention;

[0017] Figure 7 is a flow chart of a heart rhythm detection method according to a second embodiment of the present invention;

[0018] Figure 8 The configuration of the image sensor and multiple light sources of different wavelengths according to an embodiment of the present invention;

[0019] Figure 9 is a schematic diagram of the operation of a heart rhythm detection device according to a third embodiment of the present invention; and

[0020] Figure 10 FIG. 4 is a flowchart of an operating method of a heart rhythm detection device according to a third embodiment of the present invention.

[0021] Description of Reference Numerals

[0022] 10 Image Sensor

[0023] 301 First Light Source

[0024] 302 Second Light Source

[0025] 303 Third Light Source

[0026] 304 The Fourth Light Source

[0027] λ1 first wavelength

[0028] λ2 second wavelength

[0029] λ3 third wavelength

[0030] λ4 fourth wavelength DETAILED DESCRIPTION

[0031] The heart rhythm detection module and method of the embodiments of the present invention are illustrated below. Those skilled in the art can easily understand the advantages and effects of the present invention based on the description of this specification. The present invention can also be implemented and applied in other examples. Each detail in this specification can be applied based on different perspectives and can be modified and changed within the essence of the present invention. The drawings of the present invention are only used for brief description, but are not made according to actual size and do not reflect the actual size of the relevant structures. The following embodiments also detail the relevant technologies of the present invention, but the scope of the present invention is not limited to this.

[0032] First embodiment

[0033] Please refer to Figure 1 、 Figure 2 and Figure 4 . Figure 1 is a schematic diagram of light passing through an object in the heart rhythm detection module of the first embodiment of the present invention; Figure 2 is a schematic diagram of light reflected by an object in the heart rhythm detection module of the first embodiment of the present invention; Figure 4 FIG is a schematic diagram of an image sensor according to a first embodiment of the present invention. Figure 1 As shown, the heart rhythm detection module M of this embodiment includes an image sensor 10, a processor 20, and a light source 30. However, in other embodiments, the heart rhythm detection module M includes multiple image sensors 10, multiple processors 20, and multiple light sources 30, and the number of the multiple image sensors 10, multiple processors 20, and multiple light sources 30 can be selected according to needs. Figure 1In more detail, the image sensor 10 includes a detection array comprising a plurality of pixels and configured to generate a corresponding plurality of image frames F. In this embodiment, the detection array is a complementary metal oxide semiconductor (CMOS) detection array 100. The CMOS detection array 100 includes a plurality of pixels 1000 (shown in FIG. Figure 4 ), and the multiple pixels 1000 of the CMOS detection array 100 receive light passing through the object S (herein referred to as penetrating light LP) to generate an image frame F. In this embodiment, the processor 20 is a digital processor for outputting a heart rate value H. The light source 30 can be a light-emitting diode or a laser light source, which is used to emit light L toward the object S. The light L has a limited bandwidth to enhance the detection of the light L by the CMOS detection array 100. In addition, the processor 20 controls the light source 30 so that the light source 30 emits light continuously or intermittently. For example, the processor 20 controls the light source 30 to emit light L 20 times per second. In one embodiment, the CMOS detection array 100 of the image sensor 10 samples at a frequency synchronized with the lighting frequency of the light source 30 (i.e., the sampling rate), thereby receiving penetrating light LP 20 times per second and generating 20 image frames F. Figure 1 In the embodiment, the sampling rate of the CMOS detection array 100 of the image sensor 10 is synchronized with the lighting frequency of the light source 30 to improve the detection results, but the present invention is not limited thereto. In other embodiments, the sampling rate of the CMOS detection array 100 of the image sensor 10 is not synchronized with the lighting frequency of the light source 30.

[0034] like Figure 2 As shown, the image sensor 10 includes a detection array having a plurality of pixels and configured to generate a plurality of image frames F. Figure 1 In this embodiment, the detection array is a CMOS detection array 100, which includes a plurality of pixels 1000 (such as Figure 4 ), and the plurality of pixels 1000 of the CMOS detection array 100 receive reflected light (hereinafter referred to as reflected light LR) from the object S to generate an image frame F. The plurality of pixels 1000 of the CMOS sensor output intensity values ​​to generate an image and generate a plurality of image frames F, which is determined by the sampling rate of the image sensor 10.

[0035] In this embodiment, the processor 20 is a digital processor for outputting a heart rate value H. The light source 30 may be a light emitting diode or a laser light source, and is configured to emit light L toward the object S. Furthermore, the processor 20 controls the light source 30 so that the light source 30 can emit light continuously or intermittently. Figure 2 In the embodiment, the CMOS detection array 100 of the image sensor 10 samples at a frequency (ie, a sampling rate) that is synchronized with the lighting frequency of the light source 30 to receive the reflected light LR and generate an image frame F.

[0036] The present invention mainly describes how to calculate the heart rate based on the depth displacement of the measured surface (skin) (hereinafter referred to as displacement information). The change in the depth from the surface to the CMOS detection array 100 will cause the intensity center of gravity of the penetrating light LP or the reflected light LR to change. Therefore, the displacement information can be calculated by calculating the change in the intensity center of gravity of the penetrating light LP or the reflected light LR, and the method for calculating the change in the intensity center of gravity will be described below. In particular, please refer to Figure 3 and Figure 5 Steps S301 to S313. Figure 3 A flowchart showing the heart rhythm detection method according to the first embodiment of the present invention is shown, and Figure 5 A schematic diagram showing the configuration of the image sensor 10 and the light source 30. First, as Figure 3 and Figure 5 As shown, in steps S301 to S303, the processor 20 controls the light source 30 to emit light L toward the object S, and the image sensor 10 is placed at a distance D1 from the light source 30. In one embodiment, the distance D1 is selected from 1.8 mm to 4 mm, 2.8 mm to 4 mm, or 3.8 mm to 4 mm. Figure 5 In the figure, D1 is illustrated as 4 mm. In the next step S305, the image sensor 10 generates a plurality of image frames F based on the transmitted light LP or the reflected light LR. Then, in steps S307 to S313, the processor 20 calculates the position of the light intensity center of gravity based on at least two image frames F of the plurality of image frames F from the image sensor 10 (step S307). Based on the difference between the positions of the two light intensity centers of gravity, the processor 20 can calculate the displacement information of the light intensity center of gravity (step S309). Then, the processor 20 calculates the light intensity change based on the displacement information (step S311). In addition, the displacement information includes X displacement data, Y displacement data, and light volume change signal data. The displacement information is the difference between the positions of the light intensity center of gravity at two different times. The position of the light intensity center of gravity can be determined by the coordinates of each pixel and the corresponding intensity value, such as the following equation (I).

[0037] Σ(Pi×Ii) / ΣIi=PGC (I)

[0038] In equation (I), Pi represents the corresponding coordinates of each of the multiple pixels 1000, and includes an X coordinate and a Y coordinate. PGC can be determined by a two-dimensional coordinate system (including an X coordinate and a Y coordinate), but can also be determined by a one-dimensional coordinate system (including an X coordinate or a Y coordinate), wherein two one-dimensional PGCs (X coordinate and Y coordinate) can be combined into a two-dimensional PGC. Ii represents the intensity of the transmitted light LP or the reflected light LR received by each of the multiple pixels 1000. ΣIi represents the sum of the intensities of the transmitted light LP or the reflected light LR received by the multiple pixels 1000. PGC (center of gravity position) represents the light intensity center of gravity of each acquired image, wherein the displacement information is the difference between the two center of gravity positions of the two frames. Finally, the processor 20 outputs the heart rate value H based on the displacement information of the light intensity center of gravity of the multiple image frames F. In addition, there are multiple methods for calculating the light intensity center of gravity in the prior art, and the above equation cited here is only one of them. However, the method for calculating the light intensity center of gravity is not limited to that disclosed in the description of the present invention.

[0039] Please refer to Figure 6A and Figure 6B . Figure 6A and Figure 6B is the result of the motion-activated heart rhythm detection measured by the heart rhythm detection module M of the embodiment of the present invention. In other words, the result of the heart rhythm detection module M of the embodiment of the present invention is displayed on Figure 6A and Figure 6B . Figure 6A In FIG. 1 , the horizontal axis represents the number of image frames F. For example, the number 1000 represents the 1000th frame acquired by the image sensor 10 , which is obtained from the heart rhythm of a runner running on a treadmill over time. Figure 6A , from number 0 to approximately number 2200, the runner is resting, and then starts running at a speed of 5 km / h for 1 minute (from number 2200 to approximately number 3600). As shown from number 3600 to number 5500, the speed increases to 9 km / h and continues for 1 minute. Then, from number 5500 to number 6500, the speed decreases to 3 km / h and continues for 1 minute. Then, from number 6500 to number 7800, the speed increases to 7 km / h and continues for 1 minute, and after that the runner begins to rest (from number 7800). The vertical axis represents the displacement parameter, which is the change in height of the detected skin caused by the pulse beating, wherein the value from 0 to 1 represents the degree of change in height of the detected skin (the value 0 represents no displacement and the value 1 represents the maximum displacement). In particular, when the heart beats, blood is output and vibrations are generated, causing skin displacement, which is called the displacement parameter. Figure 6A The display includes displacement in the X direction (lower curve: line A) and displacement in the Y direction (upper curve: line B), wherein the maximum value of the displacement parameter is 1, and the maximum displacement parameter occurs at the number 7800.

[0040] like Figure 6B As shown, the conditions for heart rhythm detection are the same as above Figure 6A The horizontal axis represents the number of image frames F, and the vertical axis represents the change in light intensity, with values ​​from 0 to 1 representing the degree of intensity change during the acquisition of the image frame (0 represents no change, while 1 represents maximum change). In particular, when the heart beats, it pumps blood, generating vibrations that cause changes in light intensity on the skin. Figure 6B Only the PPG (photoplethysmography) signal (line A) is displayed. Figure 6B , the maximum change in light intensity is 1, and the maximum change in light intensity occurs at the number 7800.

[0041] Based on the above, it is shown that the heart rhythm detection module M of the present invention can measure X displacement, Y displacement and PPG, and the results can be compensated to reduce the interference signal of movement (such as hand shaking when running) and improve the detection accuracy.

[0042] Since the heart rhythm detection module M of the present invention can generate not only PPG data but also X displacement data and Y displacement data, interference can be reduced to output a highly accurate heart rhythm result.

[0043] Therefore, if the detection module, such as a conventional detection module, can only output PPG data and uses only one pixel to receive light, its dynamic range is insufficient and the variation of PPG is limited, making it difficult to reduce the noise of the heart rhythm detection signal.

[0044] Compared to prior art, the heart rhythm detection module M of the present invention comprises a CMOS detection array 100 composed of multiple pixels 1000. Each pixel 1000 receives reflected light LR or transmitted light LP, and the resulting results can be summed, resulting in a wider dynamic range. Furthermore, the displacement data contains two-dimensional information, including X-displacement data and Y-displacement data. Therefore, noise in the displacement detection signal (e.g., motion signal) can be effectively reduced, thereby increasing the accuracy of the heart rhythm results.

[0045] Second embodiment

[0046] The heart rhythm detection module M of the second embodiment of the present invention includes an image sensor 10 and a processor 20. The image sensor 10 generates a plurality of laser spots according to laser light from an object S. The processor 20 outputs a heart rhythm value H based on a change in at least one displacement of the plurality of laser spots.

[0047] Please refer to Figure 7 . Figure 7 FIG is a flow chart of a heart rhythm detection method according to a second embodiment of the present invention. The heart rhythm detection method according to the second embodiment is a light spot pixel positioning method. In particular, it comprises the following steps: Figure 7As shown in steps S701 to S711, the heart rhythm detection method of the second embodiment includes the following steps. First, in steps S701 and S703, the light source 630 emits laser light toward the object S, and then the image sensor 10 receives the laser light that passes through the object S or is reflected from the object S (the transmitted light LP and the reflected light LR, respectively). Next, in step S705, the image sensor 10 generates a plurality of laser spots based on the laser light from the object S. Next, in steps S707 and S709, the processor 20 is used to compare and analyze the plurality of laser spots and calculate the changes in the plurality of laser spots, that is, the processor 20 calculates at least one displacement of the plurality of laser spots. Finally, the processor 20 outputs the heart rhythm value H based on one or more changes in at least one displacement of the plurality of laser spots.

[0048] In the second embodiment of the present invention, except for the above-mentioned heart rhythm detection module M and its detection method, other technical features obtained thereby are the same as those of the first embodiment of the present invention, and thus will not be described in detail here.

[0049] Third embodiment

[0050] Please refer to Figure 8 , which is a schematic diagram illustrating the configuration of an image sensor 10 and multiple light sources (here, four light sources 301-304) in a heart rhythm detection device according to an embodiment of the present invention. The heart rhythm detection device includes the aforementioned heart rhythm detection module M. The details of the image sensor 10 have been described above and will not be repeated here. The heart rhythm detection device can be configured in a portable device, wearable device, or accessory.

[0051] The first light source 301 emits light of a first wavelength λ1. The second light source 302 emits light of a second wavelength λ2. The third light source 303 emits light of a third wavelength λ3. The fourth light source 304 emits light of a fourth wavelength λ4. In the present invention, λ1, λ2, λ3, and λ4 are not identical.

[0052] Please refer to Figure 9 , which is a schematic diagram of the operation of the heart rhythm detection device according to the third embodiment of the present invention. Assume that the sum of the intensities of multiple light sources illuminating an object (eg, the user's skin) has an intensity sum. Figure 9 The ratio of the light intensity of the first wavelength λ1 to the sum of the intensities and the ratio of the light intensity of the second wavelength λ2 to the sum of the intensities in different periods T1 to T4 are shown.

[0053] Also refer to Figure 8 and Figure 9 The following description takes two light sources, such as 301 and 302, as an example.

[0054] In one embodiment, the first wavelength of light emitted by the first light source 301 is green light and the second wavelength of light emitted by the second light source 302 is red light. In another embodiment, the first wavelength of light is green light and the second wavelength of light is infrared light. Different combinations of light can be selected.

[0055] The first light source 301 and the second light source 302 are in different periods, for example Figure 9 The displayed T1, T2, T3, and T4 emit light of different intensities (e.g., with different drive currents). Each period is, for example, 5 to 20 seconds, but is not limited thereto. The image sensor 10 samples at a sampling rate during all or part of the periods T1 to T4.

[0056] The image sensor 10 generates a first mixed signal during a first period T1 and a second mixed signal during a second period T2. In the third embodiment, the signal generated by the image sensor 10 is referred to as a mixed signal because the first light source 301 and the second light source 302 emit light together during each period (i.e., form a sum of intensities), and thus the transmitted or reflected light contains information related to both λ1 and λ2. As described above, the mixed signal is generated based on the multiple image frames F generated by the image sensor 10.

[0057] For example, Figure 9 The first wavelength light and the second wavelength light have a first intensity ratio (e.g., λ1 / λ2 = 4) during the first period T1; a second intensity ratio (e.g., λ1 / λ2 = 1.5) different from the first intensity ratio during the second period T2; a third intensity ratio (e.g., λ1 / λ2 = 2 / 3) during the third period T3; and a fourth intensity ratio (e.g., λ1 / λ2 = 1 / 4) during the fourth period T4. In other words, the intensity of the first wavelength light is either stronger or weaker than the intensity of the second wavelength light during different periods.

[0058] As described above, the processor 20 (eg, DSP, ASIC, or MCU) controls the first light source 301 and the second light source 302 to change the light intensity during the first period T1 and the second period T2. Figure 9 shown.

[0059] The processor 20 then decorrelates or decouples the first mixed signal and the second mixed signal (using both signals simultaneously) to obtain a first decorrelated signal and a second decorrelated signal. Decorrelation methods include, but are not limited to, independent component analysis (ICA) and blind source separation (BSS). Known methods such as ICA and BSS can be used to separate mixed signals. Therefore, one of the first decorrelated signal and the second decorrelated signal can be considered a motion signal (i.e., noise, as referred to herein), while the other can be considered a non-motion signal, which is used in calculating the heart rate value in this description. In other words, the non-motion signal is a PPG signal free of motion interference.

[0060] In one embodiment, the processor 20 identifies or distinguishes the non-motion signal by comparing the first decorrelated signal and the second decorrelated signal with the historical signal generated by the processor 10 .

[0061] For example, when there is no motion, the magnitudes of the first and second decorrelated signals differ significantly, for example, greater than a threshold. When the processor 20 determines that the magnitude difference (which can be in the time or frequency domain) is greater than or equal to the threshold, the processor 20 records (in memory) the signal distribution (i.e., the magnitude on the time axis) of the larger of the first and second decorrelated signals as a reference signal. In other words, the larger of the first and second decorrelated signals is considered the PPG signal. It will be appreciated that, if necessary, the processor 20 converts the first and second decorrelated signals to the frequency domain.

[0062] Then, during operation, when the difference in the magnitude values ​​becomes smaller than the threshold, the processor 20 compares the first decorrelated signal and the second decorrelated signal with the recorded reference signal, and regards the one of the first decorrelated signal and the second decorrelated signal that has a higher similarity (either in the time domain or the frequency domain) with the reference signal as a non-motion signal.

[0063] In another embodiment, the processor 20 identifies or distinguishes the non-motion signal in the first decorrelated signal and the second decorrelated signal by comparing (in the time domain or the frequency domain) the first decorrelated signal and the second decorrelated signal with the acceleration sensor signal, and the acceleration sensor signal is obtained simultaneously with the first mixed signal and the second mixed signal. That is, the heart rhythm detection device of the embodiment of the present invention further includes an acceleration sensor (such as a MEMS device) relative to different periods (such as Figure 9The processor 20 detects the acceleration sensor signal during the first and second decorrelation signals (T1 to T4) to generate an acceleration sensor signal relative to the first mixed signal and the second mixed signal. The processor 20 considers the one of the first decorrelation signal and the second decorrelation signal that has a higher similarity to the acceleration sensor signal as a motion signal, and considers the other of the first decorrelation signal and the second decorrelation signal that has a lower similarity to the acceleration sensor signal as a non-motion signal.

[0064] As mentioned above, in Figure 9 During each of the periods T1 to T4, the number of light sources emitting light is not limited to two. For example, the first mixed signal generated by the image sensor 10 includes a first light combination of multiple (at least two) light wavelengths, while the second mixed signal generated by the image sensor 10 includes a second light combination of multiple (at least two) light wavelengths. In one embodiment, the second light combination includes at least one light wavelength not included in the first light combination.

[0065] In one embodiment, if a certain light wavelength of the plurality of light wavelengths is included in both the first light combination and the second light combination, the certain light wavelength has different intensities in the first period and the second period.

[0066] The third embodiment can be combined with the first and second embodiments. Figure 6A and Figure 6B Frames 0 to 2200 are relative Figure 9 The period T1 shown is obtained with the first combination of light intensities of wavelengths λ1 and λ2; the 2200th to 3600th frames are relatively Figure 9 The period T2 shown is obtained with the second combination of light intensities of wavelengths λ1 and λ2; the 3600 to 5500 frames are relatively Figure 9 The period T3 shown is obtained with the third combination of light intensities of wavelengths λ1 and λ2; the 5500 to 6500 frames are relatively Figure 9 The illustrated period T4 is obtained with a fourth combination of light intensities of wavelengths λ1 and λ2, and so on.

[0067] In the third embodiment, the signal generated by the image sensor 10 (eg Figure 6A and Figure 6B The images A and B shown are not directly used as the displacement information or PPG in the first and second embodiments. The signal generated by the image sensor 10 is first decorrelated to obtain a non-motion signal (i.e., the motion component is removed). This non-motion signal is then used as the displacement information or PPG for calculating the heart rate value. For example, Figure 6A and Figure 6B The illustrated signals A and B are mixed signals, and the processor 120 performs a decorrelation operation to remove motion components from the mixed signals.

[0068] For example, please refer to Figure 3 In step S301, multiple light sources, such as a first light combination or a second light combination of multiple light wavelengths, emit light toward an object. In step S303, the image sensor 10 receives a light combination (i.e., the sum of intensities) that has penetrated or reflected from the object. In step S305, the image sensor 10 generates multiple image frames based on the first light combination or the second light combination of multiple light wavelengths from the object. Then, a heart rate value can be obtained based on the light intensity variation of the multiple image frames associated with the first light combination and the second light combination. For example, the processor 20 sequentially executes steps S307 to S313 using the multiple image frames associated with the first light combination to calculate the heart rate value based on the light intensity variation; or the processor 20 sequentially executes steps S307 to S313 using the multiple image frames associated with the second light combination to calculate the heart rate value based on the light intensity variation. The details of steps S307 to S313 have been described above and will not be repeated here.

[0069] In one embodiment, the first light combination has at least one light wavelength different from that of the second light combination. In another embodiment, the first light combination is completely different from the second light combination. In yet another embodiment, the first light combination is the same as the second light combination.

[0070] In one embodiment, the intensity ratio of the plurality of light wavelengths in the first light combination is different (partially or completely) from the intensity ratio of the plurality of light wavelengths in the second light combination.

[0071] In another embodiment, the processor 20 interactively outputs a heart rate value based on the light intensity changes associated with the first light combination and the second light combination. Figure 9 During the periods T1 and T3, the first light combination is used to illuminate the object, while Figure 9 During the periods T2 and T4, the second light combination is used to illuminate the object.

[0072] It is understood that the mixed signal generated by the image sensor 10 is not limited to only include light information of two wavelengths. If more light sources are used, the mixed signal can include light information of more wavelengths.

[0073] Please refer to Figure 10 , which is a flowchart of the operating method of the heart rhythm detection device of the third embodiment of the present invention, including the following steps: generating a first mixed signal during a first period and generating a second mixed signal during a second period (step S101); decorrelating the first mixed signal and the second mixed signal to obtain a first decorrelated signal and a second decorrelated signal (step S103); identifying a non-motion signal from the first decorrelated signal and the second decorrelated signal (step S105); and calculating a heart rhythm value using the non-motion signal (step S107).

[0074] Step S101: The first mixed signal comprises optical information of a first plurality of optical wavelengths having a first intensity ratio, and the second mixed signal comprises optical information of a second plurality of optical wavelengths having a second intensity ratio, wherein the second intensity ratio is different from the first intensity ratio.

[0075] In one embodiment, the first plurality of optical wavelengths is completely different from the second plurality of optical wavelengths. Figure 8 As shown, λ1, λ2, λ3 and λ4 are different from each other. For example, in the first period T1, the first light source 301 and the second light source 302 illuminate the object; but in the second period T2, the third light source 303 and the fourth light source 304 illuminate the object. In each period, as Figure 9 From T1 to T4, the light intensities of the different wavelengths λ1, λ2, λ3 and λ4 are completely different or partially different. The processor 20 performs decorrelation processing on the mixed signals obtained during the periods T1 and T2.

[0076] In another embodiment, the first plurality of optical wavelengths is partially different from the second plurality of optical wavelengths. Figure 9 During the three periods T1 to T3, wavelength λ1 is used throughout. However, during period T1, wavelengths λ1 and λ2 illuminate the object; during period T2, wavelengths λ1 and λ3 illuminate the object; and during period T3, wavelengths λ1 and λ4 illuminate the object. However, the present invention is not limited to this. Processor 20 performs decorrelation processing on the mixed signals obtained during periods T1, T2, and T3.

[0077] In another embodiment, during period T1, λ1 and λ2 illuminate the object; during period T2, λ2 and λ3 illuminate the object; and during period T3, λ3 and λ4 illuminate the object, but the present invention is not limited thereto. The processor 20 performs decorrelation processing on the mixed signals obtained during periods T1, T2, and T3.

[0078] In another embodiment, the first plurality of optical wavelengths are identical to the second plurality of optical wavelengths. Figure 9 Two light sources 301 and 302 are shown emitting light in each period, but with different intensities.

[0079] Step S103 : The processor 20 uses a decorrelation method, such as ICA and BSS, to separate the combined signal, ie, the PPG signal and the motion signal in this specification, to obtain a decorrelation signal.

[0080] Step S105: As described above, the processor 20 compares the decorrelation signal (e.g., including the first decorrelation signal and the second decorrelation signal) with the historical signal generated by the image sensor 10 to identify or distinguish the non-motion signal, or the processor 20 compares the decorrelation signal with the acceleration sensor signal to identify or distinguish the non-motion signal.

[0081] Step S107: After obtaining the non-motion signal, the processor 20 calculates the heart rate value using the methods of the first embodiment and the second embodiment.

[0082] It is understood that the number of periods used to generate the mixed signal for decorrelation by the processor 20 is not limited to Figure 9 It will be appreciated that there is no particular limitation on the number of light sources used to emit light in each period, and for example, 2, 3, or 4 light sources may be used.

[0083] Since different lights are affected differently by motion, using different intensity combinations during different periods helps the decorrelation process performed by processor 20 to correctly separate motion signals from non-motion signals.

[0084] In summary, the present invention's advantage lies in its ability to generate light intensity center of gravity displacement information and laser spot displacement using a heart rhythm detection module with a CMOS detection array of image sensors, and to calculate light intensity variations and laser spot displacement changes using a processor. This allows for a wider dynamic range, thereby reducing detection signal noise and improving detection accuracy.

[0085] The description shown above is only a preferred embodiment of the present invention; however, the features of the present invention are not limited thereto. All changes, adjustments or modifications that are easily conceivable by those skilled in the art are deemed to be included within the scope of the present invention defined by the claims.

Claims

1. A heart rhythm detection device, comprising: a first light source configured to emit light of a first wavelength; a second light source configured to emit light of a second wavelength; and an image sensor configured to generate a first mixed signal during a first period and a second mixed signal during a second period, in, The first wavelength light and the second wavelength light have a first intensity ratio during the first period and a second intensity ratio different from the first intensity ratio during the second period. The first mixed signal and the second mixed signal are the sum of the light intensities of the first wavelength light and the second wavelength light formed when the first light source and the second light source emit light simultaneously. 2 . The heart rhythm detection device according to claim 1 , further comprising a processor for controlling the first light source and the second light source to change light emission intensities during the first period and the second period.

3. The heart rhythm detection device according to claim 2, wherein: The processor is also used to decorrelating the first mixed signal and the second mixed signal to obtain a first decorrelated signal and a second decorrelated signal, and One of the first decorrelated signal and the second decorrelated signal is identified as a non-motion signal and the other of the first decorrelated signal and the second decorrelated signal is identified as a motion signal.

4. The heart rhythm detection device according to claim 3, wherein: The processor is configured to compare the first decorrelation signal and the second decorrelation signal with a historical signal generated by the image sensor to identify the non-motion signal.

5. The heart rhythm detection device according to claim 3, wherein: The processor is configured to compare the first decorrelation signal and the second decorrelation signal with an acceleration sensor signal to identify the non-motion signal.

6. The heart rhythm detection device according to claim 1, wherein: The first wavelength light is green light and the second wavelength light is red light, or The first wavelength light is green light and the second wavelength light is infrared light.

7. The heart rhythm detection device according to claim 1, wherein: During the first period, the first wavelength light is stronger than the second wavelength light, and During the second period, the first wavelength light is weaker than the second wavelength light.

8. A heart rhythm detection device, comprising: An image sensor is configured to generate a first mixed signal during a first period and a second mixed signal during a second period, wherein: The first mixed signal includes a first group of optical information having a first intensity ratio with respect to each other, and the second mixed signal includes a second group of optical information having a second intensity ratio with respect to each other, and the second intensity ratio is different from the first intensity ratio. The first mixed signal and the second mixed signal are respectively the sum of the light intensities of the first plurality of light wavelengths and the sum of the light intensities of the second plurality of light wavelengths detected by the image sensor.

9. The heart rhythm detection device according to claim 8, wherein: The first plurality of optical wavelengths is completely different from the second plurality of optical wavelengths.

10. The heart rhythm detection device according to claim 8, wherein: The first plurality of optical wavelengths is partially identical to the second plurality of optical wavelengths.

11. The heart rhythm detection device according to claim 8, wherein: The first plurality of optical wavelengths is identical to the second plurality of optical wavelengths.

12. The heart rhythm detection device according to claim 8, further comprising a processor for decorrelating the first mixed signal and the second mixed signal to obtain a first decorrelated signal and a second decorrelated signal, and One of the first decorrelated signal and the second decorrelated signal is identified as a non-motion signal and the other of the first decorrelated signal and the second decorrelated signal is identified as a motion signal.

13. The heart rhythm detection device according to claim 12, wherein: The processor is configured to compare the first decorrelation signal and the second decorrelation signal with a historical signal generated by the image sensor to identify the non-motion signal.

14. The heart rhythm detection device according to claim 12, wherein: The processor is configured to compare the first decorrelation signal and the second decorrelation signal with an acceleration sensor signal to identify the non-motion signal.

15. A heart rhythm detection device, comprising: An image sensor is configured to generate a first mixed signal during a first period and a second mixed signal during a second period, wherein: The first mixed signal includes optical information of a first optical combination of multiple optical wavelengths, and the second mixed signal includes optical information of a second optical combination of multiple optical wavelengths, and the second optical combination includes at least one optical wavelength not included in the first optical combination. The first mixed signal and the second mixed signal are respectively the sum of light intensities of a first light combination of the plurality of light wavelengths and the sum of light intensities of a second light combination of the plurality of light wavelengths detected by the image sensor. 16 . The heart rhythm detection device according to claim 15 , wherein a light wavelength simultaneously included in the first light combination and the second light combination has different intensities in the first period and the second period.

17. A heart rhythm detection device, comprising: an image sensor for generating a plurality of image frames based on a first light combination of a plurality of light wavelengths or a second light combination of a plurality of light wavelengths from an object; and A processor is configured to output a heart rhythm value based on the light intensity of the first light combination and / or the light intensity of the second light combination and the associated light intensity variations of the plurality of image frames.

18. The heart rhythm detection device according to claim 17, wherein: The first light combination comprises at least one light wavelength different from that of the second light combination. 19 . The heart rhythm detection apparatus according to claim 17 , wherein an intensity ratio of the plurality of light wavelengths of the first light combination is different from an intensity ratio of the plurality of light wavelengths of the second light combination. 20 . The heart rhythm detection device according to claim 17 , wherein the processor is configured to interactively output the heart rhythm value based on the light intensity variation associated with the first light combination and the second light combination.

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