TW201623917A - Time of flight system capable of increasing measurement accuracy, saving power and/or increasing motion detection rate and method thereof - Google Patents

Abstract

A light source is used for transmitting an invisible light toward an object. The object reflects the invisible light and forms reflected light, and a sensor is used for receiving the reflected light. A processor is coupled to the sensor for recording a time interval of the invisible light traveling from the light source to the object and reflected from the object to the sensor. Then, the processor estimates a measurement distance of the object according to the time interval, and adjusts an emission period of the light source, an exposure period of the sensor, intensity of the invisible light, and/or a main sensing range of the sensor according to the measurement distance.

Description

Time difference ranging system and method thereof capable of improving measurement accuracy, power saving and/or improving motion detection efficiency

The present invention relates to a time difference ranging system and a method thereof, and more particularly to a time difference ranging system that improves measurement accuracy, saves power, and/or improves motion detection efficiency according to time when detecting light to and from an object to be tested. Its method.

In the prior art, a time difference (TOF) system emits detection light for an object to be detected, and receives reflected light generated by the object to be detected by the object to be detected. The time difference ranging system can estimate the distance between the time difference ranging system and the object to be tested by measuring the time required between the detecting light and the distance measuring device and the object to be tested. However, the prior art time difference ranging system does not dynamically adjust the range detection range of the time difference ranging system due to the distance of the object to be tested, nor does it dynamically adjust the exposure time of the sensor in the ranging system, so the range The accuracy of the measurement is low. In addition, the prior art time difference ranging system does not dynamically adjust the intensity of the projected light source due to the distance of the object to be tested, and thus consumes more power. In addition to the above shortcomings, the prior art time difference ranging system does not dynamically adjust the sensitive sensing range of the sensor in the ranging system due to the distance of the object to be tested, so the sensor needs to have a larger sensing range. , resulting in a lower motion detection rate.

An embodiment of the present invention provides a method for improving time-of-flight (TOF) measurement accuracy. The method includes: transmitting an invisible light to detect an object; recording a time interval during which the invisible light is reflected by the object and reaching a sensor; and adjusting an inactive period of the invisible light according to the time interval and the sensor The exposure period.

Another embodiment of the present invention provides a time difference ranging system that can improve measurement accuracy. The time difference ranging system comprises a light source, a sensor and a processor. The light source is configured to emit an invisible light toward an object; the sensor is configured to receive a reflected light from the object; and the processor is coupled to the sensor for recording the invisible light through the object The time interval after reaching the sensor after reflection, and adjusting the emission period of the light source and the exposure period of the sensor according to the time interval.

Another embodiment of the present invention provides a method of power saving time difference ranging. The method includes transmitting an invisible light to detect an object; recording a time interval during which the invisible light is reflected by the object and reaching a sensor; and adjusting an emission intensity of the invisible light according to the time interval.

Another embodiment of the present invention provides a power saving time difference ranging system. The time difference ranging system comprises a light source, a sensor and a processor. The light source is configured to emit an invisible light toward an object; the sensor is configured to receive a reflected light from the object; and the processor is coupled to the sensor for recording the invisible light through the object The time interval after reaching the sensor after reflection, and adjusting the intensity of the invisible light according to the time interval.

Another embodiment of the present invention provides a method for improving time difference ranging of motion detection efficiency. The method includes transmitting an invisible light to detect an object; recording a time interval during which the invisible light is reflected by the object and reaching a sensor; and adjusting a focus sensing range of the sensor according to the time interval.

Another embodiment of the present invention provides a time difference ranging system capable of improving motion detection efficiency. The time difference ranging system is a light source, a sensor and a processor. The light source is configured to emit an invisible light toward an object; the sensor is configured to receive a reflected light from the object; and the processor is coupled to the sensor for recording the invisible light through the object The time interval after reaching the sensor after reflection, and adjusting the focus sensing range of the sensor according to the time interval.

The invention provides a time difference ranging system, which comprises a processor for estimating the distance between the object to be tested and the time difference ranging system according to the time interval between the invisible light and the time difference ranging system and an object and the speed of light. . Then, the processor can adjust the emission period of the invisible light, the exposure period of a sensor, adjust the emission intensity of a light source, and/or the sensor according to the distance between the object and the time difference ranging system. Focus on sensing range. Therefore, the time difference ranging system can improve measurement accuracy, reduce noise, save power, and/or improve motion detection efficiency.

Please refer to FIG. 1. FIG. 1 is a schematic diagram showing a time difference ranging system 100 capable of improving measurement accuracy according to an embodiment of the present invention. The time difference ranging system 100 includes a light source 102, a sensor 104, and a processor 106. The light source 102 is configured to emit an invisible light toward an object to be tested 103. The light source 102 is an infrared light emitting diode or an infrared laser light source. The sensor 104 is a sensing array for receiving a reflected light from the object to be tested 103. When the light source 102 emits infrared light on the surface of the object to be tested 103, after the sensing array in the sensor 104 receives the reflected light, the appearance of the object to be tested 103 can be determined according to the reflected light. In addition, the sensor 104 further includes an infrared filter 1042 for blocking light other than infrared rays from entering the sensor 104. The processor 106 is coupled to the sensor 104 for recording the time interval T when the invisible light is reflected by the object to be tested 103 and reaches the sensor 104, and adjusting the emission period of the light source 102 according to the interval T and the sensor. The exposure period of 104.

When the light source 102 is an infrared light emitting diode, the differential ranging system 100 further includes a first lens 108 mounted between the light source 102 and the object to be tested 103 for collecting infrared light emitted by the light source 102 to the object to be tested. The surface of the 103, and the concentrated infrared light is reflected by the surface of the object to be tested 103 to form reflected light. In addition, the time difference ranging system 100 further includes a second lens 110 mounted between the sensor 104 and the object to be tested 103 for concentrating the reflected light to the sensor 104. However, when the light source 102 is an infrared laser light source, in this case, the time difference ranging system 100 does not need to condense with the first lens 108 and the second lens 110.

Referring to FIG. 2, FIG. 2 illustrates a time interval T during which the invisible light is reflected from the light source 102 and reflected by the object to be tested 103 and reaches the sensor 104, and the emission period and the sensor of the light source 102 are adjusted according to the time interval T. Schematic diagram of the exposure period of 104. When the light source 102 starts to continuously emit invisible light according to the emission period to detect the object to be tested 103, the sensor 104 is used to sense the reflected light from the object to be tested 103. Then, the processor 106 records the time interval T when the invisible light is emitted from the light source 102 and is reflected by the object to be tested 103 to reach the sensor 104, and adjusts the emission period of the light source 102 and the exposure period of the sensor 104 according to the time interval T, wherein The adjusted emission period of the light source 102 and the adjusted exposure period of the sensor 104 are slightly larger than the time interval T recorded by the processor 106.

The light source 102 continuously emits invisible light to detect the object to be tested 103, and the processor 106 recognizes the appearance of the object to be tested 103 (for example, the face of the user in the game) by the multiple reflected light sensed by the sensor 104, and according to the time. The interval T and the speed of light determine the distance D between the object to be tested 103 and the time difference ranging system 100. The time difference ranging system 100 initially detects a range after a predetermined distance in front of the sensor 104. For example, if the time difference ranging system 100 is an interactive game, the time difference ranging system 100 will be 60 cm from the front of the sensor. The distance is detected, but the application of the present invention is not limited to the interactive game, and is not limited to 60 cm, as long as the detection of 3D specific distance is performed by using the time difference ranging concept, which is the scope of the present invention. When the emission period of the invisible light is adjusted by the processor 106, the detection range of the time difference ranging system 100 will be limited to the position of the object to be tested 103 before and after, for example, the distance between the object to be tested 103 and the time difference ranging system 100 3m, the detection range of the time difference ranging system 100 will be limited to the range around 3m. In addition, the emission period of the invisible light adjusted by the processor 106 will be moderately shortened (that is, the emission frequency of the invisible light becomes high), so that the information obtained by the processor 106 via the reflected light can obtain the information of the object 103 to be tested. many. Furthermore, as shown in FIG. 2, the exposure period of the sensor 104 adjusted by the processor 106 is also moderately shortened, and only when the sensor 104 senses the reflected light, the shutter is opened, so that the reduction can be reduced. Receive outside noise.

Figure 3 is a flow chart showing a method for improving the measurement accuracy of the time difference ranging according to another embodiment of the present invention. The method of Figure 3 is illustrated by the time difference ranging system 100 shown in Figure 1, the steps of which are detailed below:

Step 300: Start;

Step 302: The light source 102 emits invisible light to detect the object to be tested 103, and the detection light is collected by the first lens 108 to the surface of the object to be tested 103;

Step 304: The second lens 110 converges the reflected light reflected from the surface of the object to be tested 103 to the sensor 104;

Step 306: The processor 106 records the time interval T when the invisible light is emitted from the light source 102 and reflected by the object to be tested 103 and reaches the sensor 104;

Step 308: The processor 106 estimates the distance D between the object to be tested 103 and the time difference ranging system 100 according to the time interval T and the speed of light;

Step 310: The processor 106 adjusts the emission period of the invisible light and the exposure period of the sensor 104 according to the distance D between the object to be tested 103 and the time difference ranging system 100;

Step 312: The processor 106 adjusts the working period of the sensor 104 according to a duty cycle of invisible light;

Step 314: End.

In step 304, the infrared filter 1042 included in the sensor 104 can block light other than the reflected light from entering the sensor 104. In step 310, the processor 106 adjusts the emission period of the invisible light and the exposure period of the sensor 104 according to the distance D. In this way, the emission period of the invisible light adjusted by the processor 106 will be moderately shortened (that is, the emission frequency of the invisible light becomes high), so the more information the processor 106 can obtain the object 103 to be tested via the reflected light. . In step 312 (as shown in FIG. 2), the processor 106 adjusts the duty cycle of the sensor 104 according to a duty cycle of invisible light, wherein the duty cycle of the invisible light is related to the operation of the sensor 104. The cycle is the same. After the duty cycle of the sensor 104 is adjusted, it is only necessary to open the shutter when the sensor 104 senses the reflected light, so that the noise of receiving the outside world can be reduced.

In addition, the embodiment of FIG. 3 can also use infrared laser light as a light source. In this case, it is not necessary to collect light by using the first lens 108 and the second lens 110.

Another embodiment of the present invention is directed to a power saving time difference ranging system by means of FIG. The time difference ranging system 100 is configured to record the time interval T of the invisible light emitted from the light source 102 after being reflected by the object to be tested 103 and reach the sensor 104, and estimate the object to be tested 103 and the time difference ranging system according to the time interval T and the speed of light. The distance D between 100. Processor 106 then adjusts the emission intensity of light source 102 based on distance D. Since the emission intensity of the light source 102 can be dynamically adjusted with the distance D, the time difference ranging system 100 can save power.

Figure 4 is a flow chart showing a method for power-saving time difference ranging according to another embodiment of the present invention. The method of Figure 4 is illustrated by the time difference ranging system 100 shown in Figure 1, the steps of which are detailed below:

Step 400: Start;

Step 402: The light source 102 emits invisible light to detect the object to be tested 103, and the detection light is collected by the first lens 108 to the surface of the object to be tested 103;

Step 404: The second lens 110 converges the reflected light reflected by the surface of the object to be tested 103 to the sensor 104;

Step 406: The processor 106 records the time interval T when the invisible light is emitted from the light source 102 and reflected by the object to be tested 103 and reaches the sensor 104;

Step 408: The processor 106 estimates the distance D between the object to be tested 103 and the time difference ranging system 100 according to the time interval T and the speed of light;

Step 410: The processor 106 adjusts the emission intensity of the light source 102 according to the distance D;

Step 412: End.

In addition, the embodiment of Fig. 4 can also use infrared laser light as a light source. In this case, it is not necessary to use the first lens 108 and the second lens 110 to collect light.

Another embodiment of the present invention provides a time difference ranging system capable of improving motion detection efficiency by means of FIG. The processor 106 of the time difference ranging system 100 records the time interval T at which the invisible light is emitted from the light source 102 and is reflected by the object to be tested 103 and reaches the sensor 104, and estimates the object to be tested 103 and the time difference according to the time interval T and the speed of light. The distance D from the system 100. Please refer to FIG. 5 , which is a schematic diagram illustrating the processor 106 determining the focus sensing range of the sensor 104 according to the size and range of motion of the object 103 to be tested. As shown in FIG. 5, after the processor 106 estimates the size of the object to be tested 103 and the distance D, the sensor can sense the focus of the sensor 104 according to the size of the object to be tested 103 and the range of motion of the object to be tested 103. a range in which the number of pixels sensed by the sensor 104 in the focus sensing range is greater than the number of pixels sensed by the sensor 104 outside the focus sensing range, and the focus sensing range of the sensor 104 varies with the object to be tested. 103 and move dynamically. Because the sensor 104 senses more pixels only in the focus sensing range, the number of pixels output by the sensor 104 can be reduced, power can be saved, and motion detection efficiency can be improved.

FIG. 6 is a flow chart showing a method for improving time difference ranging of motion detection efficiency according to another embodiment of the present invention. The method of Fig. 6 is illustrated by the time difference ranging system 100 shown in Fig. 1, and the steps are as follows:

Step 600: Start;

Step 602: The light source 102 emits invisible light to detect the object to be tested 103, and the detection light is collected by the first lens 108 to the surface of the object to be tested 103;

Step 604: The second lens 110 converges the reflected light reflected by the surface of the object to be tested 103 to the sensor 104;

Step 606: The processor 106 records the time interval T when the invisible light is emitted from the light source 102 and reflected by the object to be tested 103 and reaches the sensor 104;

Step 608: The processor 106 estimates the distance D between the object to be tested 103 and the time difference ranging system 100 according to the time interval T;

Step 610: The processor 106 determines the size and the active range of the object to be tested 103 according to the distance D.

Step 612: The processor 106 adjusts the focus sensing range of the sensor 104 according to the size and the range of motion of the object to be tested 103;

Step 614: End.

In addition, the embodiment of Fig. 6 can also use infrared laser light as a light source. In this case, it is not necessary to collect light by the first lens 108 and the second lens 110.

Another embodiment of the present invention illustrates a time difference ranging system that can improve measurement accuracy, save power, and/or improve motion detection efficiency by means of FIG. The processor 106 of the time difference ranging system 100 records the time interval T at which the invisible light is emitted from the light source 102 and is reflected by the object to be tested 103 and reaches the sensor 104, and estimates the object to be tested 103 and the time difference according to the time interval T and the speed of light. The distance D from the system 100. The processor 106 then adjusts the emission intensity of the light source 102, the emission period of the invisible light, the exposure period of the sensor 104, and/or the focus sensing range of the sensor 104 according to the distance D. The emission period of the invisible light adjusted by the processor 106 will be moderately shortened (that is, the emission frequency of the invisible light becomes high), and therefore, the more information the processor 106 can obtain the object 103 to be tested via the reflected light. After the duty cycle of the sensor 104 is adjusted, it is only necessary to open the shutter when the sensor 104 senses the reflected light, so that the noise of receiving the outside can be reduced. Since the emission intensity of the light source 102 can be dynamically adjusted with the distance D, the time difference ranging system 100 can save power. In addition, since the sensor 104 senses more pixels only in the focus sensing range, the number of pixels output by the sensor 104 can be reduced, power can be saved, and motion detection efficiency can be improved.

FIG. 7 is a flow chart showing a method for improving the accuracy of measurement, power saving, and/or time difference ranging capable of improving motion detection efficiency according to another embodiment of the present invention. The method of Fig. 7 is illustrated by the time difference ranging system 100 shown in Fig. 1, and the steps are as follows:

Step 700: Start;

Step 702: The light source 102 emits invisible light to detect the object to be tested 103, and the detection light is collected by the first lens 108 to the surface of the object to be tested 103;

Step 704: The second lens 110 converges the reflected light reflected by the surface of the object to be tested 103 to the sensor 104;

Step 706: The processor 106 records the time interval T when the invisible light is reflected from the light source 102 through the object to be tested 103 and reaches the sensor 104;

Step 708: The processor 106 estimates the distance D between the object to be tested 103 and the time difference ranging system 100 according to the time interval T;

Step 710: The processor 106 adjusts the emission intensity of the light source 102, the emission period of the invisible light, the exposure period of the sensor 104, and/or the focus sensing range of the sensor 104 according to the distance D;

Step 712: End.

In addition, the embodiment of Fig. 7 can also use infrared laser light as a light source. In this case, it is not necessary to collect light by the first lens 108 and the second lens 110.

In summary, the present invention provides a time difference ranging system capable of improving measurement accuracy, a power-saving time difference ranging system, a time difference ranging system capable of improving motion detection efficiency, and improving measurement accuracy, power saving, and / or a time difference ranging system capable of improving motion detection efficiency, wherein the included processor estimates the object to be tested and the time difference ranging system according to the time interval between the invisible light traveling time difference ranging system and the object to be tested and the speed of light The distance between them. Then, the time difference ranging system provided by the invention can improve the measurement accuracy, and the processor adjusts the emission period of the invisible light and the exposure period of the sensor according to the distance between the object to be tested and the time difference ranging system. Therefore, the measurement accuracy and the noise can be improved. The power-saving time difference ranging system provided by the invention adjusts the emission intensity of the light source according to the distance between the object to be tested and the time difference ranging system, so The utility model provides the time difference ranging system capable of improving the motion detection efficiency, wherein the processor adjusts the sensitive sensing range of the sensor according to the distance between the object to be tested and the time difference ranging system, so Saving power and improving motion detection efficiency; the time difference ranging system provided by the invention can improve measurement accuracy, save power and/or improve motion detection efficiency, and the processor is based on the object to be tested and the time difference ranging system The distance between the invisible light emission period, the exposure period of the sensor, the emission intensity of the light source, and/or the sensing range of the sensor, so Measurement accuracy and noise reduction can save energy and improve the efficiency of motion detection. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100‧‧‧Time difference ranging system
102‧‧‧Light source
103‧‧‧Articles to be tested
104‧‧‧Sensor
106‧‧‧ Processor
108‧‧‧ first shot
110‧‧‧second lens
1042‧‧‧Infrared filter
300-314, 400-412, 600-614, 700-712‧‧ steps

FIG. 1 is a schematic diagram showing a time difference ranging system capable of improving measurement accuracy according to an embodiment of the present invention. 2 is a schematic diagram showing the time interval during which the invisible light is reflected from the light source and reflected by the object to be tested, and the emission period of the light source and the exposure period of the sensor are adjusted according to the time interval. Figure 3 is a flow chart showing a method for improving the measurement accuracy of the time difference ranging according to another embodiment of the present invention. Figure 4 is a flow chart showing a method for power-saving time difference ranging according to another embodiment of the present invention. Figure 5 is a schematic diagram showing the processor's focus sensing range based on the size and range of motion of the object to be tested. FIG. 6 is a flow chart showing a method for improving time difference ranging of motion detection efficiency according to another embodiment of the present invention. FIG. 7 is a flow chart showing a method for improving the accuracy of measurement, power saving, and/or time difference ranging capable of improving motion detection efficiency according to another embodiment of the present invention.

100‧‧‧Time difference ranging system

102‧‧‧Light source

103‧‧‧Articles to be tested

104‧‧‧Sensor

106‧‧‧ Processor

108‧‧‧ first shot

110‧‧‧second lens

1042‧‧‧Infrared filter

Claims (11)

A method for improving time difference ranging of motion detection efficiency, comprising: transmitting an invisible light to detect an object; recording a time interval at which the invisible light is reflected by the object and reaching a sensor; and adjusting the time according to the time interval The sensor's focus sensing range. The method of claim 1, further comprising adjusting the emission period of the invisible light and the exposure period of the sensor according to the time interval, and adjusting the emission intensity of the invisible light according to the time interval. The method of claim 1, further comprising estimating the measured distance of the object by using the time interval; wherein adjusting the focus sensing range of the sensor according to the time interval is to adjust the sensor according to the measured distance of the object The focus of the sensing range. The method of claim 1, wherein adjusting the focus sensing range of the sensor according to the time interval determines the size and the range of the object by using the time interval, and determining the feeling according to the size and the range of the object. The focus of the detector is the sensing range. The method of claim 1, wherein the number of pixels sensed by the sensor in the focus sensing range is greater than the number of pixels sensed by the sensor outside the focus sensing range. The method of claim 1, wherein the invisible light is infrared light, and the sensor further comprises an infrared filter for blocking light other than infrared rays from entering the sensor. A time difference ranging system capable of improving motion detection efficiency, comprising: a light source for emitting an invisible light toward an object; a sensor for receiving a reflected light from the object; and a processor coupled The sensor is configured to record a time interval during which the invisible light is reflected by the object and arrive at the sensor, and adjust a focus sensing range of the sensor according to the time interval. The time difference ranging system of claim 7, wherein the processor estimates the measured distance of the object by using the time interval, and adjusts a focus sensing range of the sensor according to the measured distance of the object. The time difference ranging system according to claim 7, wherein the processor determines the size and the range of motion of the object by using the time interval, and determines a focus sensing range of the sensor according to the size and the range of motion of the object. The time difference ranging system of claim 7, wherein the number of pixels sensed by the sensor in the focus sensing range is greater than the number of pixels sensed by the sensor outside the focus sensing range. The time difference ranging system according to claim 7, wherein the light source is an infrared light emitting diode or an infrared laser light source, and the sensor further comprises an infrared filter for blocking light outside the infrared light. The sensor.