TWI812493B - Ranging device and ranging method thereof - Google Patents

Abstract

A ranging device includes a light emitter for emitting detection light, a sensor for sensing reflected light to generate an image, and a calibration unit for performing correction according to at least one feature lookup table and outputting a distance value according to the image. The detection light is reflected from an object to form the reflected light. The at least one feature lookup table is pre-established according to a specific object. The ranging device is able to suppress imaging disturbance and distance disturbance, thereby improving ranging accuracy.

Description

Distance measuring device and distance measuring method

The present invention refers to a distance measuring device and a distance measuring method thereof, in particular to a distance measuring device and a distance measuring method that can improve the accuracy of distance measurement.

The distance measuring device emits light to the object to be measured, receives the reflected light, and uses the imaging result of the reflected light to calculate the distance between the object to be measured and the distance measuring device.

Figures 1A to 1D are partial schematic diagrams of imaging, in which the horizontal axis represents the photosensitive elements numbered 120 to 170 in the photosensitive array of the distance measuring device, and the vertical axis represents the brightness value corresponding to the photosensitive element. Curve C100 represents the imaging of an object with a certain reflectivity, curve C120 represents the imaging of such an object that is interfered by ambient light, curve C140 represents the imaging of an object with a higher reflectivity, and curve C160 represents the imaging of an object with a higher reflectivity that is interfered by ambient light. imaging. The part with a higher brightness value in the image (for example, the curve C100 corresponding to the area of the photosensitive element numbered 140 to 150) can constitute the light spot of the image. It can be seen from Figures 1A to 1D that the reflectivity of the object is high (that is, the reflected light formed after the light source emitter is projected near the reflection point may interfere with the imaging point) or the ambient light may cause the imaging point (such as No. 144 The position of the photosensitive element of the sensor is overly sensitive, causing imaging disturbance and thus affecting the accuracy of ranging.

In addition, even if the distance between the ranging device and the object to be measured remains unchanged, interference from optical or electrical noise may cause the distance value measured by the ranging device to fluctuate, causing distance disturbance and thus affecting the accuracy of ranging.

Accordingly, there is a need to improve existing distance measuring devices.

Therefore, the present invention mainly provides a ranging device and a ranging method to improve the ranging accuracy.

The invention discloses a distance measuring device, which includes a light source emitter for emitting a detection light, the detection light is reflected by an object to form a reflected light; a sensor for sensing the reflected light to generate an imaging; and a correction unit, coupled to the light source emitter and the sensor, for performing correction according to at least one feature lookup table and outputting a distance value according to the imaging, wherein the at least one feature lookup table is based on Pre-created for a specific object.

The invention discloses a distance measurement method, which includes emitting a detection light, the detection light is reflected by an object to form a reflected light; sensing the reflected light to generate an image; and performing correction according to at least one feature lookup table. A distance value is output according to the imaging, wherein the at least one feature lookup table is pre-established according to a specific object.

C100~C160: Curve

20,50,60:Ranging device

210:Light source emitter

230: Sensor

250: Imaging comparison unit

270:Control unit

290,490: Distance disturbance suppression unit

491:Subtraction unit

492:Switch unit

493,494: Parameter unit

495: Addition unit

496:State unit

620: Rotating mechanism

640:Rotation angle detector

660:Storage unit

BJ,BJ1~BJj: objects

D1, D4, D5: distance

d _k,i : degree of disturbance

G1~G8: Feature group

L300~L330: polyline

Ld: detection light

Lr: reflected light

r _i , 1-r _i : parameter value

Sct,Sct _k,i : control parameters

Sd,Sd _k,i : estimated distance value

Sf,Sf _k,i : distance value

Sf _k-1,i : The distance value of the previous output

Smg,Smg _k,i : imaging

th _i : angle

W1, W4, W5: spot width

Figures 1A to 1D are partial schematic diagrams of imaging.

Figure 2 is a schematic diagram of a distance measuring device according to an embodiment of the present invention.

Figure 3 is a schematic diagram of the relationship between spot width and distance according to the embodiment of the present invention.

Figure 4 is a schematic diagram of a distance disturbance suppression unit according to an embodiment of the present invention.

Figures 5 to 6 are respectively schematic diagrams of the distance measuring device according to the embodiment of the present invention.

Figure 2 is a schematic diagram of a distance measuring device 20 according to an embodiment of the present invention. The distance measuring device 20 may include a light source emitter 210, a sensor 230 and a correction unit. The correction unit may include an imaging comparison unit 250, a control unit 270 and a range disturbance suppression unit 290.

The light source emitter 210 can emit a detection light Ld, and the detection light Ld can be reflected on (a certain point on) the surface of an object BJ to form a reflected light Lr.

The sensor 230 may be a photosensitive array composed of a plurality of photosensitive elements for sensing the reflected light Lr to generate an image Smg. That is to say, the light source emitter 210 can project a light spot to the object BJ, and the sensor 230 The intensity distribution of the reflected light Lr can be captured to output an image Smg. The imaging Smg can be a one-dimensional or two-dimensional image.

The imaging comparison unit 250 can receive the imaging Smg, and can calculate the geometric characteristics (such as width, area, or centroid position) of the light spot imaging Smg according to the intensity distribution, and can compare the geometric characteristics of the light spot imaging Smg with a feature lookup table. (Can be called the first feature lookup table).

The first feature lookup table can be created by measuring a specific object (such as a whiteboard). The first feature lookup table may include the distance between the specific object and the distance measuring device 20 , the width of the light spot reflected after the detection light Ld is projected onto the specific object, and the area of the light spot reflected after the detection light Ld is projected onto the specific object. , information such as the centroid position (or geometric center) of the light spot reflected after the detection light Ld is projected onto a specific object, or feature groups.

For example, Table 1 lists an embodiment of the first feature lookup table. The imaging comparison unit 250 may use the centroid position of the light spot imaging Smg (for example, located between two photosensitive elements with a certain number) to query which feature group of the first feature lookup table it corresponds to. For example, when the centroid position Mq of the spot imaging Smg is between the spot centroid position M1 (i.e., one boundary of the feature group G1) and the spot centroid position M4 (i.e., the other boundary of the feature group G1) (for example, M1 <Mq<M4), therefore the light spot imaging Smg corresponds to the feature group G1. The center of mass position Mq can be a non-integer or an integer.

Then, the imaging comparison unit 250 can use the interpolation method to calculate the corresponding feature value corresponding to the spot centroid position according to the boundary value of the feature group, and then use the proportional relationship to calculate the upper limit and lower limit of the feature. For example, the boundary values of the feature group G1 are the spot widths W1 and W4, and the imaging comparison unit 250 can use the interpolation method to calculate the feature value Wref corresponding to the spot centroid position Mq (for example, Wref=W1+(Mq-M1)/(M4 -M1)×(W4-W1)), and then use the proportional relationship to calculate the characteristic upper limit UBw (for example, UBw=Wref+Δw) and the characteristic lower limit LBw (for example, LBw=Wref-Δw), where Δw satisfies Δw=ct×Wref, for example, ct can be less than 5% (for example, ct=1% or ct=2%), ct can be a function of distance, or Δw can be the size/width of the photosensitive element with a fixed magnification value (for example, Δw=width of y photosensitive elements, y is less than 3). For example, the boundary values of the feature group G1 are the spot areas A1 and A4, and the imaging comparison unit 250 can use the interpolation method to calculate the corresponding feature value Aref (for example, Aref=A1+(Mq-M1)/(M4-M1)×(A4 -A1)), and then use the proportional relationship to calculate the upper characteristic limit UBa (for example, UBa=Aref+ΔA) and the lower characteristic limit LBa (for example, LBa=Aref-ΔA), where ΔA satisfies ΔA=CT×Aref, and CT can be less than 5% ( For example, CT=1% or CT=2%), CT can be a function of distance.

Then, the imaging comparison unit 250 can compare the geometric characteristics of the light spot imaging Smg with the corresponding characteristic value, the upper characteristic limit, or the lower characteristic limit, and output a control parameter Sct. For example, when the geometric characteristics (such as width or area) of the light spot imaging Smg are greater than the upper characteristic limit (such as UBw or UBa) (or the characteristic value Wref or Aref), the control parameter Sct is output to reduce the next exposure time of the sensor 230 , adjust Adjust the next sensing mode of the sensor 230 to a lower sensitivity, or reduce the next emission intensity of the light source emitter 210 . When the geometric characteristics (such as width or area) of the light spot imaging Smg are less than the characteristic lower limit (such as LBw or LBa) (or the characteristic value Wref or Aref), the control parameter Sct is output to increase the next exposure time and adjustment of the sensor 230 The next sensing mode of the sensor 230 is set to a higher sensitivity, or the next emission intensity of the light source emitter 210 is increased.

In one embodiment, the control unit 270 can adjust the next exposure time of the sensor 230 according to the control parameter Sct (for example, increase/decrease a fixed length of time, or increase/decrease the difference related to the geometric feature compared to the feature value. a length of time). In another embodiment, the control unit 270 can adjust the next sensing mode or output gain of the sensor 230 according to the control parameter Sct, or adjust the next emission intensity of the light source emitter 210 .

In another embodiment, the imaging comparison unit 250 can use the spot centroid position of the spot imaging Smg to determine which two boundary values (for example, spot widths W1, W2) of the first feature lookup table it corresponds to. According to these two The boundary values are interpolated to calculate the characteristic value corresponding to the spot centroid position Mq (for example, Wref=W1+(Mq-M1)/(M2-M1)×(W2-W1) or Aref=A1+(Mq-M1)/( M2-M1)×(A2-A1)), and compare the geometric characteristics of the light spot with the characteristic value to output the control parameter Sct. When the geometric characteristics (such as width or area) of the light spot imaging Smg are greater than the characteristic value (such as Wref or Aref), the control parameter Sct is output to reduce the next exposure time of the sensor 230; when the geometric characteristics of the light spot imaging Smg are smaller than characteristic value, the control parameter Sct is output to increase the next exposure time of the sensor 230 .

As can be seen from the above, the imaging comparison unit 250 can output the control parameter Sct according to the proportional relationship between the imaging spot characteristics of the object BJ and the imaging spot characteristics of the specific object, so that the exposure time, sensing mode or output gain of the sensor 230, Or the emission intensity of the light source emitter 210 is adjusted to suppress imaging disturbance.

Feature groups can be grouped by using the first derivative of width (or area) with respect to distance (or centroid position). Figure 3 is a schematic diagram of the relationship between spot width and distance according to the embodiment of the present invention. Figure, where polyline L300 represents the relationship between the spot width and distance corresponding to a specific object (which can be used as the first feature lookup table), polyline L310 represents the relationship between the spot width and distance corresponding to a high reflectivity object, and the polyline L310 represents the relationship between the spot width and distance corresponding to a high reflectivity object. L330 represents the relationship between the spot width and distance corresponding to a low-reflectivity object. Taking polyline L300 as an example, the turning point of polyline L300 (for example, the position where the first derivative of the spot width versus distance is discontinuous) can be used as the boundary of the feature group, or the points near the turning point of polyline L300 can be used as the boundary of the feature group. That is, feature relationships within the same feature group are predictable (e.g. linear). The use of distinguishing feature groups can reduce the time and number of searches for feature values corresponding to the light spot imaging Smg (for example, the center of mass position Mq of the light spot imaging Smg is between the spot center of mass position M1 and the spot center of mass position M4 (for example, M1 < Mq<M4) or between the spot centroid position M1 and the spot centroid position M2 (for example, M1<Mq<M2), the spot widths W1 and W4, which are the boundary values of the feature group G1, can be used to calculate the spot centroid position. Mq corresponding eigenvalue, upper characteristic limit and lower characteristic limit).

As shown in FIG. 3 , when the high reflectivity object is at a certain distance (for example, 1000 mm) from the distance measuring device 20 , reducing the exposure time of the sensor 230 can reduce the width of the light spot imaging Smg (for example, from the first Curve C140 in Figure 1C is adjusted to curve C100 in Figure 1A) (for example, follow the arrow in Figure 3 from the point of polyline L310 to the point of polyline L300). When there is a certain distance (for example, 1000 mm) between the low-reflectivity object and the distance measuring device 20, increasing the exposure time of the sensor 230 can increase the width of the light spot imaging Smg (for example, following the arrow in Figure 3 from the broken line The point of L330 rises to the point of polyline L300). Accordingly, the ranging device 20 can suppress imaging disturbance caused by different reflectivities in the imaging Smg of the sensor 230 . When there is strong light interference in the environment, the width or area of the light spot of the image Smg of the object BJ may become wider due to the strong light interference. The distance measuring device 20 can monitor the width or area ratio of the light spot of the current object BJ and the specific object, and Accordingly, the exposure time of the sensor 230 is controlled to reduce the width of the light spot imaging Smg (for example, adjust from the curve C120 in Figure 1B to the curve C100 in Figure 1A) to suppress imaging disturbance. That is to say, since the exposure time is proportional to the width or area of the light spot imaging Smg, the exposure time can be used to adjust the width or area of the light spot imaging Smg. When the object BJ is close to the width or area of the light spot of a specific object (for example, from the Curve C160 in Figure 1D is adjusted to curve C100 in Figure 1A), and the ranging device 20 can more accurately determine the centroid position of the light spot imaging Smg, thereby improving the corresponding ranging accuracy.

In addition, the imaging comparison unit 250 can estimate an estimated distance value Sd (which can be called an original distance value) between the object BJ and the ranging device 20 based on the center of mass of the light spot imaging Smg. Specifically, the sensor 230 can sense a first image when the light source emitter 210 is turned on; the sensor 230 can sense a second image when the light source emitter 210 is turned off. By comparing the first image and the second image, the intensity distribution of the reflected light reflected from the surface of the object BJ to the sensor 230 can be identified. According to the position of the centroid of the reflected light spot of the sensor 230 imaging Smg, the distance between the object BJ and the distance measuring device 20 (ie, the estimated distance value Sd) can be calculated using the triangulation principle.

The distance disturbance suppression unit 290 can adjust the estimated distance value Sd to a distance value Sf (which can be called a corrected distance value) to suppress the current ranging disturbance, and the distance disturbance suppression unit 290 can output the distance value Sf as the distance measurement device 20 ranging output. Accordingly, it is ensured that the ranging output of the ranging device 20 at each time is stable to avoid fluctuate.

Figure 4 is a schematic diagram of a distance disturbance suppression unit 490 according to an embodiment of the present invention. The distance disturbance suppression unit 490 may receive the estimated distance value Sd _k,i and output the distance value Sf _k,i correspondingly. The distance disturbance suppression unit 490, the estimated distance value Sd _k,i , and the distance value Sf _k,i can be used to implement the distance disturbance suppression unit 290, the estimated distance value Sd, and the distance value Sf respectively. The distance disturbance suppression unit 490 may include a subtraction unit 491, a switching unit 492, parameter units 493, 494, an addition unit 495 and a status unit 496.

The subtraction unit 491 can determine the degree of disturbance d _k,i , and the degree of disturbance d _k,i can satisfy d _k,i =|Sd _k,i -Sf _k-1,i |, where Sf _k-1,i is the previous output The distance value (can be called the previous distance value), k represents the time number. That is to say, the subtraction unit 491 can determine the difference between the estimated distance value Sd _k,i and the previously output distance value Sf _k-1,i , thereby determining the degree of fluctuation of the distance value.

The switching unit 492 can adaptively adjust the parameter values ri _and 1- _ri of the parameter units 493 and 494 according to the degree of disturbance d _k,i . The parameter value r _i can range between 0 and 1. If the degree of disturbance d _k,i is smaller, the switching unit 492 can reduce the parameter value r _i and adjust it to a smaller value. The switching unit 492 can compare the disturbance degree d _k,i with a feature lookup table (which can be called a second feature lookup table) to determine how to adjust the parameter values ri _and 1- _ri of the parameter units 493 and 494.

The second feature lookup table can be established by measuring the aforementioned specific object. That is to say, the specific object is not limited to the whiteboard, as long as both the first feature lookup table and the second feature lookup table are made using the same object. The second feature lookup table may include information such as the distance (average) and the standard deviation of the distance between the specific object and the distance measuring device 20 .

For example, Table 2 lists an embodiment of the second feature lookup table. The distance (average value) Dx (ie, one of D1 to Dn) can be the distance between the specific object and the distance measuring device 20 measured by the distance measuring device 20 when the specific object and the distance measuring device 20 are separated by a certain distance. distance (average). The distance standard deviation STDx (ie, one of STD1 to STDn) can be the standard of the distance between the specific object and the distance measuring device 20 measured by the distance measuring device 20 when the specific object and the distance measuring device 20 are separated by this distance. Difference.

The switching unit 492 can find the distance standard deviation STDx corresponding to the estimated distance value Sd k _,i according to STDx=argmin(Sd _k,i -Dx). That is to say, the switching unit 492 can determine which distance (average value) Dx in the second feature lookup table the estimated distance value Sd _k,i is closest to, and then find out the corresponding distance standard based on the found distance (average value) Dx Bad STDx. For example, when the switching unit 492 determines that the estimated distance value Sd _k,i is close to the distance (average value) D3, the switching unit 492 determines that the degree of disturbance d _k,i corresponds to the distance standard deviation STD3, and the switching unit 492 can determine based on the distance standard deviation STD3 Parameter values _ri , 1- _ri of parameter units 493, 494.

STDx)時，參數值r_i可接近0，例如可等於0.125，而進行距離擾動抑制。但在易受初始的估計距離值Sd_0,i擾動的情境下(可稱作欲弱化抑制的擾動區間)，當擾動程度d_0,i小於等於距離標準差STDx(即d_0,i

STDx)時，參數值r_i可接近1，例如可等於0.7，以避免不佳的初始的估計距離值Sd_0,i影響距離擾動抑制功能，據此，能減低初始的估計距離值Sd_0,i對後續產生的距離值Sf_k,i的影響。換言之，在欲強化抑制的擾動區間，參數值r_i越小；在欲弱化抑制的擾動區間，參數值r_i越大。當擾動程度d_k,i大於距離標準差STDx且小於等於2倍的距離標準差STDx(即STDx<d_k,i

2×STDx)時，參數值r_i相對接近0，例如可等於0.25，而進行距離擾動抑制。當擾動程度d_k,i大於2倍的距離標準差STDx且小於等於3倍的距離標準差STDx(即2×STDx<d_k,i

3×STDx)時，可視作物件BJ處在相對移動與最大擾動的過渡，參數值r_i相對接近1，例如可等於0.7，而進行輕微地距離擾動抑制。當擾動程度d_k,i大於某一倍數(例如3倍)的距離標準差STDx(即d_k,i>3×STDx)時，物件BJ很可能相對測距裝置20正在移動，參數值r_i可等於1，而不進行距離擾動抑制。 For example, the switching unit 492 can compare the disturbance degree d _k,i of the object BJ and the distance standard deviation STDx obtained by querying the second feature lookup table to determine the parameter values ri _and 1- _ri of the parameter units 493 and 494. For example, when the degree of disturbance d _k,i is less than or equal to the distance standard deviation STDx (that is, d _k,i

STDx), the parameter value r _i can be close to 0, for example, equal to 0.125, to perform distance disturbance suppression. However, in a situation that is easily disturbed by the initial estimated distance value Sd _0,i (which can be called the disturbance interval where suppression is to be weakened), when the degree of disturbance d _0,i is less than or equal to the distance standard deviation STDx (that is, d _0,i

STDx), the parameter value r _i can be close to 1, for example, it can be equal to 0.7 to avoid the poor initial estimated distance value Sd _0,i from affecting the distance disturbance suppression function. Accordingly, the initial estimated distance value Sd _{0,i can be reduced.} The influence of _i on the subsequent distance value Sf _k,i . In other words, in the disturbance interval where the suppression is to be strengthened, the parameter value r _i is smaller; in the disturbance interval where the suppression is to be weakened, the parameter value r _i is larger. When the degree of disturbance d _k,i is greater than the distance standard deviation STDx and less than or equal to 2 times the distance standard deviation STDx (that is, STDx<d _k,i

2×STDx), the parameter value r _i is relatively close to 0, for example, it can be equal to 0.25, and distance disturbance suppression is performed. When the degree of disturbance d _k,i is greater than 2 times the distance standard deviation STDx and less than or equal to 3 times the distance standard deviation STDx (i.e. 2×STDx<d _k,i

3×STDx), it can be seen that the object BJ is in the transition between relative movement and maximum disturbance. The parameter value r _i is relatively close to 1, for example, it can be equal to 0.7, and slight distance disturbance suppression is performed. When the degree of disturbance d _k,i is greater than a certain multiple (for example, 3 times) of the distance standard deviation STDx (that is, d _k,i >3×STDx), the object BJ is likely to be moving relative to the distance measuring device 20, and the parameter value r _i Can be equal to 1 without distance disturbance suppression.

The parameter units 493 and 494 can respectively perform multiplication calculations on the estimated distance value Sd _k,i and the previously output distance value Sf _k-1,i corresponding to the parameter values ri _and 1- _ri , and output Sd _k,i × r _i and Sf _k-1,i ×(1-r _i ). The sum of parameter values ri _and 1- _ri of parameter units 493 and 494 is 1.

The adding unit 495 can add the received Sd _k,i × _ri and Sf _k-1,i ×(1-ri ₎ , and add Sd _k,i × _ri +Sf _k-1,i ×( 1-r _i ) is output as a distance value Sf _k,i . That is to say, the distance value Sf _k,i output this time is determined by the estimated distance value Sd _k,i according to the adaptive disturbance suppression switching rule (Adaptive Switch Rule) and the distance value Sf _k-1,i output last time. The values r _i are mixed in proportion. According to this, even if the interference of light or electrical noise causes the estimated distance value Sd _k,i measured by the distance measuring device 20 to fluctuate and cause distance disturbance (but the distance between the distance measuring device 20 and the object BJ may not change), the measured distance value Sd k,i may not change. The distance value Sf _k,i output from the device 20 may be relatively stable and will not change significantly with the estimated distance value Sd _k,i . When relative movement occurs between the object BJ and the distance measuring device 20, the distance value Sf _k,i can truly reflect the change in the distance between the object BJ and the distance measuring device 20.

The state unit 496 can be used to save the distance value Sf _k-1,i that was output last time (or the distance value Sf _k,i that was output this time), and convert the distance value Sf _k-1,i that was output last time this time ( Or the distance value Sf _k,i ) is transferred to the subtraction unit 491 and the parameter unit 494 next time. That is, state unit 496 may delay outputting. Status unit 496 may be implemented using storage circuits or registers.

Figure 5 is a schematic diagram of a distance measuring device 50 according to an embodiment of the present invention. The distance measuring device 50 can be used to implement the distance measuring device 20 . The distance measuring device 50 can move (such as the movement between (a) in Figure 5 and (b) in Figure 5), and can detect surrounding objects (such as BJ1~BJj) and measure distances when moving. The distance measuring device 50 may include a rotating mechanism so that the distance measuring device 50 can rotate (such as the rotation between (b) in Figure 5 and (c) in Figure 5), and can detect and measure surrounding objects when rotating. Measure distance. The rotation angle range of the distance measuring device 50 may be between 0 and 360 degrees.

Figure 6 is a schematic diagram of a distance measuring device 60 according to an embodiment of the present invention. The distance measuring device 60 can be used to implement the distance measuring device 50 . Compared with the distance measuring device 20 , the distance measuring device 60 may further include a rotation mechanism 620 , a rotation angle detector 640 and a storage unit 660 . The distance measuring device 60 can stably detect surrounding objects and measure distances with the distance measuring device 60 as the center through a time-division multiplexing method.

The rotation angle detector 640 can be used to detect the rotation angle of the distance measuring device 60 .

The storage unit 660 can be used to independently store corresponding information (such as a certain The previous distance value corresponding to the angle, the emission intensity of the light source emitter 210, the exposure time of the sensor 230, the sensing mode or the output gain). In another embodiment, the rotation angle range of the distance measuring device 60 (for example, 360 degrees) can be divided into multiple angle detection points (for example, 360 degrees is divided into 0 degrees, 120 degrees, and 240 degrees), and the rotation mechanism 620 can be used to detect From the device 60 to each angle detection point in sequence, the storage unit 660 can be used to independently store corresponding information for each angle detection point.

The storage unit 660 may include a plurality of state units 496. Each state unit 496 stores a previous distance value corresponding to an angle (such as an angle th _i ) (or an angle detection point) (such as the previous output distance value Sf _{k-1, i} ), where i represents the angle number. The distance disturbance suppression unit 290 can extract the corresponding previous distance value (such as the previous output distance value Sf _k-1,i ) from the storage unit 660 according to the angle detected by the rotation angle detector 640 (such as th _i ), and , according to the degree of disturbance d k,i between the estimated distance value Sd _k,i and the previous output distance value Sf _{k-1, i} , the estimated distance value Sd _k,i and the previous output distance value Sf _{k- 1,i} is mixed in proportion to the parameter value r _i to form the distance value Sf _k,i output this time, and the distance value Sf _k,i is stored in the storage unit 660 for use when turning to angle _thi next time.

When the distance measuring device 60 rotates to a certain angle, the distance measuring device 60 (the control unit 270 thereof) can extract the corresponding emission intensity from the storage unit 660 according to the angle (for example, th _i ) detected by the rotation angle detector 640 . exposure time, sensing mode or output gain to adjust the emission intensity of the light source emitter 210, the exposure time, sensing mode or output gain of the sensor 230. Accordingly, the sensor 230 can generate an image Smg _k,i with a light spot, the imaging comparison unit 250 can output the control parameter Sct _k,i , and the control unit 270 can extract the corresponding exposure time (or emission intensity) from the storage unit 660 , sensing mode, or output gain), and increase/decrease the extracted exposure time (or emission intensity, sensing mode, or output gain) to adjust the sensor 230 or light source emitter 210, and increase/decrease The final exposure time (or emission intensity, sensing mode, or output gain) is stored in the storage unit 660 for use when turning to angle _thi next time. The imaging Smg _k,i and the control parameter Sct _k,i can be used to realize the imaging Smg and the control parameter Sct respectively.

The ranging devices 20, 50, and 60 may be two-dimensional optical radar (light detection and ranging, LiDAR). The distance measuring devices 20, 50, 60 can be fixed-point optical distance measuring devices, mobile/rotary distance measuring devices, or synchronous positioning and mapping devices.

In one embodiment, the imaging comparison unit 250, the control unit 270, the distance disturbance suppression unit 290, the subtraction unit 491, the switching unit 492, the parameter units 493, 494, the addition unit 495, the status unit 496, the rotation angle detector 640, Or the storage unit 660 can be implemented using circuits, or can use hardware, software, or firmware (which is a combination of hardware devices and computer instructions and data, and computer instructions and data belong to read-only software on the hardware device) , or a combination of the above.

To sum up, the present invention adjusts the sensing exposure time based on the proportional relationship between the object to be measured and the imaging spot characteristics of the specific object to suppress imaging disturbance caused by the light source emitter or imaging not caused by the light source emitter. disturbance. Moreover, the present invention dynamically adjusts the reference ratio of the estimated distance value to the corrected distance value based on the degree of disturbance of the estimated distance value, so as to suppress the current ranging disturbance. Accordingly, the present invention can improve ranging accuracy for objects to be measured with different reflectivities, different distances to be measured, or different ambient light intensities.

The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the patentable scope of the present invention shall fall within the scope of the present invention.

20: Distance measuring device

210:Light source emitter

230: Sensor

250: Imaging comparison unit

270:Control unit

290: Distance disturbance suppression unit

BJ:object

Ld: detection light

Lr: reflected light

Sct: control parameters

Sd: estimated distance value

Sf: distance value

Smg:Imaging

Claims (9)

A distance measuring device includes: a light source emitter, used to emit a detection light, the detection light is reflected by an object to form a reflected light; a sensor, used to sense the reflected light to generate a Imaging; and a correction unit coupled to the light source emitter and the sensor for performing correction according to at least one feature lookup table and outputting a distance value according to the imaging, wherein the at least one feature lookup table is based on a Pre-established for a specific object, wherein the correction unit includes: an imaging comparison unit coupled to the sensor for comparing a geometric feature of a light spot of the image with a first element of the at least one feature lookup table A feature lookup table outputs a control parameter, wherein the control parameter is used to adjust the exposure time of the sensor, the sensing mode of the sensor, the output gain of the sensor, or the light source emitter Emission intensity; and a control unit coupled to the imaging comparison unit for adjusting the exposure time of the sensor, the sensing mode of the sensor, the output gain of the sensor, or The emission intensity of this light source emitter. The distance measuring device as claimed in claim 1, wherein the geometric feature is the width or area of the light spot, the first feature lookup table includes corresponding relationships between multiple light spot centroid positions and multiple feature values, the Multiple eigenvalues are spot width or spot area respectively. The distance measuring device according to claim 1, wherein the imaging comparison unit is used to determine which feature group of the first feature lookup table the light spot corresponds to by using a centroid position of a light spot of the image, according to The two boundary values of the feature group use the interpolation method to calculate a feature value corresponding to the centroid position of the light spot, use the proportional relationship to calculate an upper feature limit and a lower feature limit based on the feature value, and add the geometric feature of the light spot The control parameter is compared with the characteristic value, the upper limit of the characteristic, or the lower limit of the characteristic to output the control parameter. The distance measuring device as claimed in claim 1, wherein the imaging comparison unit is further used to estimate an estimated distance value between the object and the distance measuring device based on the imaging, and the correction unit further includes: a distance The disturbance suppression unit is coupled to the imaging comparison unit and used to adjust the estimated distance value to the distance value according to a second feature lookup table of the at least one feature lookup table. The distance measurement device of claim 4, wherein the distance disturbance suppression unit is used to adjust the estimated distance value and a previous distance value output by the distance measurement device according to a disturbance degree and the second feature lookup table, And the distance value is generated according to the adjusted estimated distance value and the previous distance value. The ranging device of claim 4, wherein the range disturbance suppression unit includes: a first parameter unit coupled to the imaging comparison unit for multiplying the estimated distance value by a first parameter value. Generate a scaled estimated distance value; a second parameter unit for multiplying a previous distance value previously output by the distance measuring device by a second parameter value to generate a scaled previous distance value; a switching unit, coupled Connected to the first parameter unit and the second parameter unit, used to adjust the first parameter value of the first parameter unit and the second parameter value of the second parameter unit according to a disturbance degree and the second feature lookup table. Parameter value, the range of the first parameter value or the second parameter value is between 0 and 1, the sum of the first parameter value and the second parameter value is equal to 1, the second feature lookup table includes multiple distances a corresponding relationship between standard deviation and a plurality of distances; and an adder unit, coupled to the first parameter unit and the second parameter unit, for summing the scaled estimated distance value and the scaled previous distance value. Produces this distance value. The distance measurement device of claim 6, wherein the distance disturbance suppression unit further includes: a subtraction unit coupled to the imaging comparison unit for determining a difference between the estimated distance value and the previous distance value. The degree of disturbance is generated by the difference, wherein the first parameter value is based on the disturbance Determined by degree. The ranging device of claim 6, wherein the distance disturbance suppression unit determines a corresponding distance standard deviation from the second feature lookup table based on the estimated distance value. When the distance disturbance suppression unit determines that the disturbance degree is greater than When the distance standard deviation is a certain multiple, the first parameter value is equal to 1, and the second parameter value is equal to 0. When the distance disturbance suppression unit determines that the degree of disturbance is less than a certain multiple of the distance standard deviation, the first parameter value is equal to 0. The parameter value is less than 1, and the second parameter value is greater than 0. The distance measuring device as described in claim 1, wherein the distance measuring device outputs multiple distance values corresponding to multiple angles, and the distance measuring device stores multiple previous distance values, multiple exposure times, respectively, corresponding to the multiple angles. Multiple sensing modes, multiple output gains, or multiple emission intensities.

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