Motion sensor using time difference pixels and navigation device

Abstract

A light sensor includes a pixel matrix and a read circuit. The pixel matrix includes a plurality of pixels arranged in a matrix, and each of the plurality of pixels outputs time difference pixel data. And the reading circuit is used for reading the pixel matrix in sequence by a reading frame and carrying out hybrid differential operation on the time difference pixel data of the pixels in the reading frame. Therefore, the output of the reading circuit is the data of which the time difference and the space difference are completed.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number 202110409888.4, application date April 16, 2021, and name “Motion sensor and navigation device using time differential pixels”. Technical Field

[0002] The present invention relates to a sensor using time-differential pixels, and more particularly to a motion sensor using time-differential pixels and lift detection of a navigation device. Background Art

[0003] In a sensor having a pixel matrix, for motion detection, a readout circuit reads out a first image frame of the pixel matrix at a first time and stores it in a first frame buffer. Then, at a second time, the readout circuit reads out a second image frame of the pixel matrix and stores it in a second frame buffer.

[0004] When performing motion recognition, the processor accesses the first image frame from the first frame buffer and accesses the second image frame from the second frame buffer for calculation.

[0005] That is, the sensor must have at least two frame buffers.

[0006] In view of this, a motion sensor is needed which does not need to store pixel data acquired at different times in frame buffers before performing pixel operations. Summary of the invention

[0007] The present invention provides a motion sensor which performs spatial difference calculation between a plurality of pixels when reading time difference data of the plurality of pixels.

[0008] The present invention also provides a navigation device which is provided with a lift detection pixel matrix outside the navigation pixel matrix.

[0009] The present invention provides a motion sensor including a pixel matrix and a reading circuit. The pixel matrix includes a plurality of pixels arranged in a matrix, and each of the plurality of pixels is used to output time-differential pixel data. The reading circuit is used to sequentially read at least a portion of the pixel matrix using a reading frame, and calculate a mixed difference of the time-differential pixel data of a central pixel of the reading frame and pixels surrounding the central pixel.

[0010] The present invention also provides a navigation device comprising a first pixel region, at least one second pixel region, a reading circuit and a processor. The first pixel region is used to output first pixel data. The at least one second pixel region is arranged on one side of the first pixel region and comprises a plurality of pixels arranged in a matrix, and each of the plurality of pixels is used to output time differential pixel data. The reading circuit is used to read at least a portion of the at least one second pixel region with a reading frame, and calculate a mixed difference of the time differential pixel data of a central pixel of the reading frame and pixels surrounding the central pixel. The processor is used to calculate a displacement according to the first pixel data, and determine whether the navigation device is lifted according to the mixed difference.

[0011] In order to make the above and other purposes, features and advantages of the present invention more obvious, the following will be described in detail with reference to the accompanying drawings. In addition, in the description of the present invention, the same components are represented by the same symbols, which are hereby described together. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figures 1A-1D is a schematic diagram of the operation of a light sensor according to an embodiment of the present invention;

[0013] Figure 2 is a schematic diagram of the operation of a light sensor according to another embodiment of the present invention;

[0014] Figure 3 is a block diagram of a navigation device according to an embodiment of the present invention; and

[0015] Figure 4 It is a block diagram of a navigation device according to another embodiment of the present invention.

[0016] Description of Reference Numerals

[0017] 100 pixel matrix

[0018] 11 Reading Circuit

[0019] 111 Spatial Differential Circuit

[0020] 13. Comparator

[0021] 15. Counter

[0022] 21 Host

[0023] A1, A2, A35, A36 reading frame DETAILED DESCRIPTION

[0024] The motion sensor and navigation device of the embodiment of the present invention respectively judges motion and lift based on the pixel data which has undergone temporal differentiation and spatial differentiation in sequence. The temporal differentiation and spatial differentiation of the present invention are performed during the period of reading pixel data from the pixel, so as to complete the hybrid differential operation in the simulation stage.

[0025] Reference Figure 1A , which is a schematic diagram of an optical sensor (such as, but not limited to, a CMOS image sensor) according to an embodiment of the present invention. The optical sensor is suitable for, for example, but not limited to, a security system as a motion sensor for sending an activation signal S when a motion is detected. trig To the host 21, to start the video recording process, increase the frame rate of the pixel matrix, turn on the light source, increase the frame size of the pixel matrix output image frame, etc., but not limited to these. In some embodiments, when the light sensor does not detect any action, the host 21 enters a sleep mode or a power saving mode to reduce energy consumption.

[0026] The host 21 is, for example, separately disposed from the optical sensor (eg, disposed in a camera) but coupled to each other to transmit control signals and image data therebetween.

[0027] The optical sensor comprises a pixel matrix 100, a read circuit 11, a comparator 13, a counter 15 and a timing controller 17. Figures 1A to 1D The comparator 13 and the counter 15 are shown as independent circuits, but the present invention is not limited thereto. In other embodiments, the comparator 13 and the counter 15 may be included in the reading circuit 11 of the light sensor or a processor (not shown), wherein the processor is, for example, a microprocessor (MCU), a digital signal processor (DSP) or an application-specific integrated circuit (ASIC).

[0028] The pixel matrix 100 includes a plurality of pixels ( Figures 1A to 1D The plurality of pixels are arranged in a matrix (8×8 pixels are used as an example), and each of the plurality of pixels is used to output time differential pixel data. The time differential pixel data is, for example, the difference in charge generated by the photodiode of each of the plurality of pixels at the current time and the reference time (for example, a new reference time is set every predetermined time during operation); or the difference in charge generated by the photodiode of each of the plurality of pixels at the current time and the previous time one frame period ago.

[0029] The pixel structure that can calculate and output the temporal differential pixel data is known, and the pixel structure is not the main purpose of the present invention. For example, see https: / / arxiv.org / pdf / 1904.08405, Figure 1(a) entitled "Event-based Vision: A Survey", the entire contents of which are incorporated herein by reference. The present invention is to use temporal differential pixel data to achieve action detection and lift detection.

[0030] The time differential pixel data is determined according to the pixel circuit used. In a non-limiting embodiment, when the charge value generated by the photodiode increases between two times and exceeds a predetermined threshold, a high potential (for example, represented by "1") is output as the time differential pixel data; and when the charge value generated by the photodiode decreases between two times and is lower than the predetermined threshold, a low potential (for example, represented by "0") is output as the time differential pixel data; the reverse can also be done. That is, the time differential pixel data is the voltage difference caused by the charge generated by the photodiode between two times (for example, the current time and the reference time or the current time and the previous time).

[0031] The reading circuit 11 sequentially reads the pixel matrix 100 using a reading frame, and calculates the spatial difference of the time-differential pixel data between the central pixel of the reading frame and the pixels surrounding the central pixel.

[0032] For example, Figure 1A In the first time, the reading circuit 11 simultaneously reads the time difference pixel data of the central pixel P10 of the reading frame A1 and the surrounding pixels P11 to P18 of the central pixel P10, a total of 9 pixels. The pixel data that can be read by the reading circuit 11 is determined according to the control signal of the timing controller 17 (for example, including the row selection signal and the reading signal, etc.).

[0033] In a non-limiting embodiment, when the reading circuit 11 reads the 9 time-differential pixel data, the difference between the time-differential pixel data of the central pixel P10 and the time-differential pixel data of each of the surrounding pixels P11 to P18 can be calculated as a way to calculate the spatial difference. Then, the reading circuit 11 calculates the sum of the 8 absolute values ​​of the 8 differences obtained as the mixed difference of the 9 pixels. The comparator 13 compares the sum with a predetermined value (for example, a voltage value, a current value, or a charge / discharge time according to different applications) to determine the brightness change within the reading frame A1. When the mixed difference of the reading frame A1 is greater than or equal to the predetermined value, the count value of the counter 15 is increased by 1, otherwise the count value does not increase.

[0034] Next, the reading frame moves one pixel distance toward the right of the pixel matrix 100 to reach the position shown in FIG. Figure 1BThe display position A2. The reading circuit 11 simultaneously reads the time difference pixel data of the central pixel P20 of the reading frame A2 and the surrounding pixels P21 to P28 of the central pixel P20, a total of 9 pixels. The reading circuit 11 calculates the sum of the 8 absolute values ​​of the 8 differences obtained as the mixed difference of the 9 pixels in the reading frame A2, which is similar to the above-mentioned calculation of the mixed difference of the reading frame A1. The comparator 13 also compares the sum of the reading frame A2 calculated by the reading circuit 11 with the predetermined value. The counter 15 also increases the count value by 1 when the mixed difference of the reading frame A2 is greater than or equal to the predetermined value; otherwise, the count value is not increased.

[0035] The timing controller 17 sequentially controls the pixels that can be read in the pixel matrix 100 so that the reading circuit 11 reads all the pixels of the pixel matrix 100 sequentially (for example, first rightward and then downward) until the reading frame A36 (such as Figure 1D The mixed difference of the read frames A1 to A36 is compared with the predetermined value by the comparator 13. In this embodiment, the mixed difference associated with the read frames A1 to A36 is a value that has been sequentially subjected to time and space differences.

[0036] The counter 15 counts / accumulates the number of read frames in the mixed difference in the pixel matrix 100 that are greater than or equal to the predetermined value. When the counted / accumulated number is greater than or equal to a predetermined number (e.g., a predetermined ratio of the number of pixels in the pixel matrix 100 as a counting threshold), it indicates that activity is detected, and the counter 15 sends an activation signal S trig To host 21.

[0037] It should be noted that in other implementations, as long as the counted / accumulated number is greater than or equal to the predetermined number, the scanning of the pixel matrix 100 can be stopped and the counter 15 transmits the activation signal S trig to the host computer 21. That is, if the predetermined number has been reached in any previous read frame, it is not necessary for the read circuit 11 to read all the way to the last read frame A36.

[0038] Figures 1A to 1D In the figure, only the readout line Lr between the readout circuit 11 and the readable pixels is shown to indicate that the time differential pixel data of the pixels are read out by the readout circuit 11 through the readout line Lr. Other unreadable pixels are not shown to be connected to the readout line Lr to simplify the figure. Figures 1A to 1D The arrows in the figure indicate the direction of shift of the reading frame.

[0039] It must be pointed out that although Figures 1A to 1DIn the embodiment, the reading frames A1 to A36 are shown as including a pixel range of 3×3 pixels, but the present invention is not limited thereto. In an embodiment where the pixel matrix 100 includes more pixels, the reading frame may include more pixels, such as a pixel range of 5×5 pixels.

[0040] Reference Figure 2 In another embodiment, the light sensor includes six comparators 13. The reading circuit 11 reads 3 rows of pixel data of the pixel matrix 100 at the same time, and obtains the mixed difference of each reading frame A1 to A6 using the same method as described above. The comparator 13 then compares the mixed difference with a predetermined value to determine the brightness change of each reading frame A1 to A6. For example, the leftmost comparator 13 compares the mixed difference associated with the reading frame A1 with the predetermined value; the second comparator 13 on the left compares the mixed difference associated with the reading frame A2 with the predetermined value; ...; the second comparator 13 on the right compares the mixed difference associated with the reading frame A5 with the predetermined value; and the rightmost comparator 13 compares the mixed difference associated with the reading frame A6 with the predetermined value. The counter 15 then counts the number of reading frames A1 to A6 whose mixed differences are greater than the predetermined value.

[0041] Next, the three rows of pixels read by the reading circuit 11 are moved downward one pixel at a time until the last row of pixels in the pixel matrix 100 is read or scanned, and the reading circuit 11, the comparator 13 and the counter 15 repeat the procedure in the previous paragraph. When the predetermined count value is reached (after scanning all or part of the pixels in the pixel matrix 100), the counter 15 sends an activation signal S trig It can be understood that when the pixel matrix 100 has more columns, more comparators 13 are required.

[0042] Please refer to Figure 3 , which is a schematic diagram of a navigation device according to an embodiment of the present invention. The navigation device is, for example, an optical mouse, whose optical sensor (such as, but not limited to, a CMOS image sensor) includes a first pixel region 300, at least one second pixel region (for example, four second pixel regions 301 to 304 are respectively arranged on four sides of the first pixel region 300), a read circuit 31, a timing controller 37, and a processor 39, wherein the processor 39 includes, for example, a microprocessor (MCU), a digital signal processor (DSP), or an application specific integrated circuit (ASIC). The timing controller 37 is used to generate a control signal (such as a row scanning signal and a read signal, etc.) so that the read circuit 31 can read the pixel data of each pixel.

[0043] It must be pointed out that although Figure 3The second pixel regions 301 to 304 are shown to be spaced apart from the first pixel region 300 , but the present invention is not limited thereto. In other implementations, the second pixel regions 301 to 304 are disposed adjacent to the first pixel region 300 .

[0044] It must be pointed out that although Figure 3 The first pixel region 300 and the second pixel regions 301 to 304 are shown to have their pixel data read by the same readout circuit 31, but the present invention is not limited thereto. In other embodiments, the first pixel region 300 and the second pixel regions 301 to 304 have their pixel data read by different readout circuits. In one embodiment, the first pixel region 300 and the second pixel regions 301 to 304 are disposed on the same base layer. Figure 4 As shown, the second pixel region (the region displayed with grid lines) and the first pixel region (the region displayed as blank) are different regions of the same pixel matrix 400 .

[0045] The following Figure 3 For example, the technical personnel in the technical field of the present invention will understand Figure 3 After the explanation, you can still understand Figure 4 How it works.

[0046] The first pixel region 300 is used to output first image data. The size of the first image data is determined by the number of pixels included in the pixel matrix of the first pixel region 300. The reading circuit 31 outputs the first image data I after reading the first pixel region 300. move To processor 39.

[0047] The second pixel regions 301 to 304 are arranged at four sides of the first pixel region 300. Each of the second pixel regions 301 to 304 is used to output the second image data. In more detail, after reading the second pixel regions 301 to 304, the reading circuit 31 outputs the second image data I to each of the second pixel regions 301 to 304. lift To processor 39. For example Figure 3 In the example, the reading circuit 31 outputs a first image data I in each frame period. move and four second image data I lift In one embodiment, the first image data I move and the second image data I lift The first image data I is generated by including pixel data acquired during the current exposure period of the pixel area, rather than time-differential pixel data. move and the second image data I lift The frame rates of the images may be the same or different from each other, and there is no particular limitation.

[0048] The processor 39 performs the processing according to the first image data I move Calculate the displacement of the navigation device. The method of calculating the displacement is known, so the details are not repeated here. For example, the processor 39 compares the first image data I move (eg, calculating a correlation) to calculate a displacement of a navigation device, which displacement is used, for example, to control a cursor on a display.

[0049] The processor 39 also performs the following operations according to the second image data I lift Determine whether the navigation device is lifted. In one embodiment, the processor 39 calculates the second image data I lift The processor 39 determines whether the navigation device is lifted according to the absolute value of the total or average pixel value. For example, when the absolute value is greater than or equal to a threshold value, it indicates that the navigation device is lifted.

[0050] In another embodiment, the processor 39 determines whether the navigation device is lifted according to the difference in absolute values ​​between two second pixel regions, such as between 301 and 303 or between 302 and 304. For example, when the difference is greater than or equal to a change threshold, it indicates that the navigation device is lifted; and when the difference does not exceed the change threshold, it indicates that the navigation device is not lifted.

[0051] The second average pixel value may be greater than or less than the first average pixel value, depending on whether the second pixel regions 301 to 304 can receive the light emitted by the light source when the navigation device is not lifted. When the processor 39 determines that the time difference (from the first time to the second time) of one of the second pixel regions 301 to 304 is greater than or equal to the change threshold, it indicates that at least one side of the navigation device is lifted by the user. For example, when the absolute value associated with the second pixel region 301 is greater than or equal to the change threshold, it indicates that the left side of the navigation device is lifted by the user; when the absolute value associated with the second pixel region 302 is greater than or equal to the change threshold, it indicates that the upper side of the navigation device is lifted by the user; and so on.

[0052] When the processor 39 determines that at least one side of the navigation device is lifted by the user, it sends a lifting signal S lift To perform corresponding control, for example, to stop the first image data I move The calculated displacement controls the cursor, enters a power saving mode to reduce the frame rate of the detection matrix 300, or turns off the light source, but is not limited thereto. In a non-limiting embodiment, the processor 39 performs different controls according to the different sides of the navigation device being lifted. For example, when it is determined that the upper side of the navigation device is lifted by the user, the processor 39 performs different controls according to the first image data I at different ratios or multiples. moveThe calculated displacement controls the cursor; and when it is determined that the lower side of the navigation device is lifted by the user, the movement according to the first image data I is stopped move The calculated displacement controls the cursor, but is not limited thereto.

[0053] In another embodiment, each pixel of the second pixel area 301 to 304 is respectively used to output time difference pixel data to form the second image data I lift As mentioned above, the time differential pixel data is the difference between the charge generated by the photodiode of each pixel at the current time and the reference time; or the difference between the charge generated by the photodiode of each pixel at the current time and the previous time one frame period ago. In this embodiment, the processor 39 is used to count the second image data I output by the second pixel regions 301 to 304. lift In each of the above, the time difference pixel data of a plurality of pixels is greater than or equal to the number of pixels of a predetermined threshold (eg, the number of pixels with count output "1"), and is used to determine whether the navigation device is lifted.

[0054] It should be noted that the processor 39 does not necessarily calculate the second image data I lift Once the pixel count with significant time difference pixel data (i.e., greater than or equal to the predetermined threshold) in a second pixel region is greater than or equal to the predetermined count threshold, the lifting is confirmed. After the lifting is confirmed, a lifting signal S is issued. lift And stop counting.

[0055] In other words, when the navigation device is lifted, the pixel values ​​at different times (i.e., time-differential pixel data) will change significantly. Therefore, in this embodiment, the processor 31 compares the time-differential pixel data with a predetermined threshold or a predetermined value, and counts the number of pixels that have a significant change (i.e., exceeds the predetermined threshold or the predetermined value) to determine the lifting event. The setting of the predetermined threshold or the predetermined value can eliminate noise interference.

[0056] As described above, when the processor 39 determines that a lifting event occurs, predetermined control is performed.

[0057] In the embodiment where each of the plurality of pixels in the second pixel region 301 to 304 is used to output temporal differential pixel data, the read circuit 31 further performs spatial differential on the temporal differential pixel data to form a mixed differential. The processor 39 (e.g., including a comparator and a counter) then determines whether the navigation device is lifted according to the mixed differential.

[0058] More specifically, the read circuit 31 uses a similar Figures 1A to 1DThe reading frame sequentially reads each of the second pixel regions 301 to 304, and calculates the spatial difference of the time difference pixel data of the central pixel of the reading frame and the surrounding pixels of the central pixel, which can be referred to the above description. At this time, in order to be able to use the reading frame to sequentially scan the second pixel regions 301 to 304, each of the second pixel regions 301 to 304 includes at least 3×3 pixels. It can be understood that when the reading frame is a pixel region including 5×5 pixels, each of the second pixel regions 301 to 304 includes at least 5×5 pixels.

[0059] Figure 3 In the illustrated embodiment, each of the second pixel regions 301 to 304 outputs four mixed differences, which are obtained by the reading circuit 31 according to four reading frames. As described above, the reading circuit 31 calculates the difference between the time difference pixel data of the central pixel of the reading frame and the time difference pixel data of each of the surrounding pixels of the central pixel, and calculates the sum of the eight absolute values ​​of the obtained differences as the mixed difference.

[0060] After receiving the mixed difference from the reading circuit 31, the processor 39 compares the mixed difference of each of the reading frames with a predetermined value. When the mixed difference of a certain reading frame is greater than or equal to the predetermined value, the count value is increased by 1; otherwise, the count value is not increased. The processor 39 accumulates the number of reading frames whose mixed difference is greater than or equal to the predetermined value for each of the second pixel regions 301 to 304, and when the number of one of the second pixel regions 301 to 304 is greater than or equal to the predetermined number, it is determined that the navigation device is lifted.

[0061] As described above, the processor 39 does not need to count all reading frames by scanning all pixels of each of the second pixel regions 301 to 304. As long as one second pixel region reaches a predetermined value, the lifting of the second pixel region can be confirmed and the scanning can be stopped.

[0062] For example, when the mixed difference of two or more (i.e., the threshold is 2) reading frames of the four reading frames of the second pixel region 301 (e.g., the second pixel region 301 is scanned vertically, which is determined by the control signal of the timing controller 37) is greater than or equal to the predetermined value, it indicates that the left side of the navigation device is lifted; and the lifting of other sides can be determined by analogy. The threshold can be set according to different applications, as long as it is less than or equal to the reading frame used by each second pixel region.

[0063] In this embodiment, the processor 39 also performs the operation according to the first image data I move The displacement of the navigation device is calculated. As the content has been described above, it will not be repeated here.

[0064] As described above, when the processor 39 determines that a lifting event occurs, predetermined control is performed.

[0065] Figure 3 and Figure 4 The ΔI shown in lift Indicates the change in average pixel value, the number of counted pixels, or the number of accumulated read frames to represent the time change of the charge generated by the photodiode.

[0066] It should be noted that the numerical values ​​in the above embodiments, such as the number of pixels, the number of matrices and the threshold value, are merely examples and are not intended to limit the present invention.

[0067] In summary, in the known sensors with pixel matrix, at least two frame buffers are required to temporarily store the image frames output by the pixel matrix at different times. Figures 1A to 1D ) and navigation devices (e.g. Figure 3 to Figure 4 ), which uses the time-differential pixel data output by the pixel matrix. Then, the time-differential pixel data at different positions in the reading frame are spatially differentiated to complete the hybrid differential operation when reading the pixel data without using a frame buffer. The processor can directly perform subsequent control based on the hybrid differential result without performing the time-differential operation in the digital stage.

[0068] Although the present invention has been disclosed through the above examples, they are not intended to limit the present invention. Any person skilled in the art with ordinary knowledge in the art to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the appended claims.

Claims

1. A motion sensor, comprising: a pixel matrix, the pixel matrix comprising a plurality of pixels arranged in a matrix, and each of the plurality of pixels is used to output time-differential pixel data; and A reading circuit is used to sequentially read at least a portion of the pixel matrix using a reading frame, and calculate a mixed difference of the time-differential pixel data of a central pixel of the reading frame and pixels surrounding the central pixel.

2. The motion sensor according to claim 1, in, The time difference pixel data is The difference between the charge generated by the photodiode of the pixel at the current time and the charge generated at the reference time, or The difference in charge generated by the pixel's photodiode at the current time and at the previous time one frame period ago.

3. The motion sensor according to claim 1, in, The reading frame includes a pixel range of 3×3 pixels or 5×5 pixels. 4 . The motion sensor according to claim 1 , further comprising a comparator for comparing the mixed difference of each of the read frames calculated by the read circuit with a predetermined value.

5. The motion sensor according to claim 4, further comprising a counter for Counting the number of the read frames in the pixel matrix where the mixed difference is greater than the predetermined value, and When the number of the reading frames is greater than a predetermined number, an activation signal is sent. in, When the number of the reading frames is greater than or equal to the predetermined value, the reading circuit stops reading the pixel matrix with the reading frames.

6. The motion sensor according to claim 5, in, The activation signal is used to start at least one of a video recording program, increase a frame rate of the pixel matrix, turn on a light source, and increase a frame size of an output image frame of the pixel matrix.

7. The motion sensor according to claim 1, in, The read circuit is used to calculating a difference between the temporal differential pixel data of the central pixel and the temporal differential pixel data of each of the surrounding pixels, and The sum of the absolute values ​​of the differences is calculated as the mixed difference.

8. A navigation device, comprising: A first pixel area, the first pixel area is used to output first pixel data; at least one second pixel region, the at least one second pixel region being disposed at one side of the first pixel region and comprising a plurality of pixels arranged in a matrix, and each of the plurality of pixels being used to output time-differential pixel data; a reading circuit for reading at least a portion of each of the at least one second pixel region with a reading frame and calculating a mixed difference of the time-differential pixel data of a central pixel of the reading frame and pixels surrounding the central pixel; as well as A processor is used to calculate the displacement according to the first pixel data and determine whether the navigation device is lifted according to the mixed difference.

9. The navigation device according to claim 8, in, The time-differential pixel data is the difference between the charge generated by the photodiode of the pixel at the current time and the reference time, or The difference in charge generated by the pixel's photodiode at the current time and at the previous time one frame period ago.

10. The navigation device according to claim 8, in, The at least one second pixel region includes at least 3×3 pixels.

11. The navigation device according to claim 8, in, The read circuit is used to comparing the mixed difference of each of the read frames calculated by the read circuit to a predetermined value, counting the number of the reading frames in which the mixed difference is greater than the predetermined value for each of the at least one second pixel region, and When the number of the reading frames of one of the at least one second pixel region is greater than or equal to the predetermined value, it is determined that the navigation device is lifted and the counting of the number of the reading frames is stopped.

12. The navigation device according to claim 8, in, The read circuit is used to calculating a difference between the temporal differential pixel data of the central pixel and the temporal differential pixel data of each of the surrounding pixels, and The sum of the absolute values ​​of the differences is calculated as the mixed difference.

13. The navigation device according to claim 8, in, The navigation device includes four second pixel areas respectively arranged on four sides of the first pixel area.

14. The navigation device according to claim 8, in, The at least one second pixel region and the first pixel region are respectively different regions of the same pixel matrix.

Images