KR102149377B1 - Time of flight camera apparatus - Google Patents

Abstract

The TOF camera device according to an embodiment of the present invention includes an optical output unit, an optical input unit including a plurality of pixels each including a first receiving unit and a second receiving unit, and a surface meeting the optical axis of the light output unit. A beam splitter and an operation unit that calculates a distance of an object using light received by the light input unit, the light output unit outputs IR light that flashes with a period, and the first receiving unit is turned on while the light source is turned on. Is activated, and the second receiving unit is activated while the light source is turned off.

Description

TOF camera device {TIME OF FLIGHT CAMERA APPARATUS}

The present invention relates to a TOF (Time of Flight) camera device, and more particularly, to the depth information extraction of the TOF camera device.

A technology for obtaining a 3D image using a photographing device is developing. In order to obtain a 3D image, depth information (Depth Map) is required. Depth information is information representing a distance in space, and represents perspective information of another point with respect to one point of a 2D image.

One of the methods of obtaining depth information is a method of projecting IR (Infrared) structured light onto an object and analyzing the reflected light from the object to extract depth information. According to the IR structured light method, there is a problem in that it is difficult to obtain a desired level of depth resolution for a moving object.

The TOF (Time of Flight) method is drawing attention as a technology that replaces the IR structured light method. According to the TOF method, the distance to the object is calculated by measuring the flight time, that is, the time that light is emitted and reflected.

In general, a camera according to the TOF method (hereinafter, a TOF camera) includes a scanner that adjusts an angle of light irradiated to an object and a mirror that adjusts a path of light. Since such a TOF camera includes at least one folding mirror to control the path of light, the structure is complicated and it is difficult to implement it in a small size.

The technical problem to be achieved by the present invention is to provide a TOF camera device for extracting depth information.

The TOF camera apparatus according to the embodiment includes an optical output unit, an optical input unit including a plurality of pixels each including a first receiving unit and a second receiving unit, a beam splitter including a surface meeting an optical axis of the light output unit, and the The optical input unit includes a calculation unit that calculates the distance of the object by using the received light, the light output unit outputs IR light that flashes with a period, and the first receiving unit is activated while the light source is turned on, and the The second receiving unit may be activated while the light source is turned off.

The light output unit may include a light conversion unit that modulates the input light and a light source that outputs light converted from the light conversion unit.

The light output unit may further include a light transmission member that transmits the output light to the beam splitter.

The light reception period may vary according to a distance between the first and second reception units and the object.

The calculating unit may measure a distance to the object by using a difference between the amount of light received by the first receiving unit and the second receiving unit.

The beam splitter is disposed between the light output unit and the light input unit, transmits part of the light, reflects the remaining part, and causes at least part of the light output from the light output unit to be incident on the object and reflected from the object. Light may be received, and a part of the transmitted light may be transmitted to be incident on the light input unit.

The beam splitter and the light input unit may be arranged on an optical axis through which the light is transmitted.

The light transmitted through the beam splitter may be directly incident on the light input unit.

The ratio of transmittance to reflectance of the beam splitter may be 0.4 or more and 2.3 or less.

The TOF camera device further includes a scanner, and the scanner may adjust an angle of IR light incident on the object.

The scanner may adjust the angle of light reflected from the object.

The beam splitter may cause at least a portion of the light output from the light output unit through the scanner to be incident on the object so that the light reflected from the object is incident on the light input unit.

The TOF camera device according to the embodiment includes an optical output unit, an optical input unit including a plurality of pixels each including a first receiving unit and a second receiving unit, a scanner for adjusting an angle of light incident on an object, and the light input unit. It includes an operation unit that calculates the distance of the object using the received light, the light output unit outputs IR light flashing with a period, the first receiving unit is activated while the light source is turned on, the second receiving The unit can be activated while the light source is turned off.

The scanner may cause at least a portion of the light output from the light output unit to be incident on the object so that the light reflected from the object is incident on the light input unit.

According to an embodiment of the present invention, a TOF camera can be implemented in a small size. In addition, due to high light efficiency, depth information of a long distance can be accurately extracted, and power consumption can be reduced.

1 is a block diagram of a TOF camera device according to an embodiment of the present invention.
2 is a block diagram of an optical output unit of a TOF camera device according to an embodiment of the present invention.
3 is a structure of an optical input unit of a TOF camera device according to an embodiment of the present invention.
4 is a diagram illustrating a method of calculating an object distance by an operation unit of a TOF camera device according to an embodiment of the present invention.
5 shows the structure of a TOF camera device according to an embodiment of the present invention.

The present invention is intended to illustrate and describe specific embodiments in the drawings, as various changes may be made and various embodiments may be provided. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers, such as second and first, may be used to describe various elements, but the elements are not limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a second element may be referred to as a first element, and similarly, a first element may be referred to as a second element. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, but the same reference numerals are assigned to the same or corresponding components regardless of the reference numerals, and redundant descriptions thereof will be omitted.

1 is a block diagram of a TOF camera device according to an embodiment of the present invention, FIG. 2 is a block diagram of an optical output unit of a TOF camera device according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. A structure of an optical input unit of a TOF camera apparatus according to an example, and FIG. 4 is a diagram illustrating a method of calculating a distance of an object by an operation unit of the TOF camera apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the TOF camera apparatus 100 includes an optical output unit 110, an optical control unit 120, an optical input unit 130, and an operation unit 140.

The light output unit 110 outputs IR (infrared) light. The IR light may be light having a wavelength band of 800 nm or more, for example. Referring to FIG. 2, the light output unit 110 includes a light source 112 and a light conversion unit 114. The light source may include at least one laser diode or a light emitting diode (LED) that projects infrared rays. In addition, the light conversion unit 114 may modulate the light output from the light source 112. The light conversion unit 114 may, for example, pulse-modulate or phase-modulate the light output from the light source 112. Accordingly, the light output unit 110 may flash and output the light source at predetermined intervals.

Referring back to FIG. 1, the light control unit 120 controls modulation of light output from the light output unit 110. For example, the light controller 120 may control pulse or phase modulation of light. The light controller 120 may control the pulse or phase modulation of light according to a reference set in advance by a user. For example, the light controller 120 may control the pulse or phase modulation of light according to the brightness around the TOF camera device.

Meanwhile, the light input unit 130 receives light reflected from the object after being output from the light output unit 110. The light input unit 130 may convert the received light into an electric signal. The light input unit 130 may be an image sensor including a photo diode or a complementary metal-oxide semiconductor (CMOS).

Referring to FIG. 3, the light input unit 130 includes a plurality of pixels 132 arranged. Each pixel may include an In Phase receiving unit 132-1 and an Out Phase receiving unit 132-2. Referring to FIG. 4, the in phase receiving unit 132-1 may be activated while the light source is turned on, and the out phase receiving unit 132-2 may be activated while the light source is turned off. In this way, when the In-Phase receiving unit 132-1 and the Out-Phase receiving unit 132-2 are activated with a time difference, a difference occurs in the amount of received light according to the distance to the object. For example, if the object is in front of the TOF camera device (i.e., when the distance is 0), the time it takes for the light to be reflected after the light is output from the light output unit 110 is 0, so the flashing period of the light source is As it is, it becomes the light reception period. Accordingly, only the in-phase receiving unit 132-1 receives light, and the out-phase receiving unit 132-2 cannot receive the light. As another example, when the object is located a predetermined distance away from the TOF camera device, it takes time to be reflected off the object after the light is output from the light output unit 110, so that the blinking period of the light source is different from the light reception period. do. Accordingly, a difference occurs in the amount of light received by the in phase receiving unit 132-1 and the out phase receiving unit 132-2.

Referring back to FIG. 1, the calculating unit 140 calculates the distance of the object by using the difference between the amount of light input to the in phase receiving unit 132-1 and the out phase receiving unit 132-2.

According to an embodiment of the present invention, the TOF camera device further includes a scanner for adjusting an angle of light irradiated onto an object, and a transflective member that reflects part of the light and transmits the remaining part. Accordingly, the optical layout distance can be minimized and the system can be slimmed.

5 shows the structure of a TOF camera device according to an embodiment of the present invention.

Referring to FIG. 5, the light source 500 outputs IR light. The output IR light may be pulsed or phase modulated light by the light conversion unit 502. The light source 500 may include, for example, a laser diode (LD) that outputs short wavelength light, a light emitting diode (LED), a light emitting diode having a multi-cell structure, and the like. .

The IR light output from the light source 500 reaches the transflective member 520. The transflective member 520 is disposed between the light source 500, the light output unit 540, and the scanner 530, and may transmit a part of the light that reaches and reflect the remaining part.

In this case, the transflective member 520 may be a beam splitter.

The ratio of the transmittance to the reflectance of the transflective member 520 (transmittance/reflectivity) may be 0.4 or more and 2.3 or less, preferably 0.7 or more and 1.5 or less. When the ratio of the transmittance to the reflectance of the transflective member 520 is out of this range, the depth resolution may be degraded due to a large amount of noise.

The transflective member 520 adjusts at least a part of the path of the IR light output from the light source 500 to enter the scanner 530. Further, the scanner 530 adjusts the angle of the IR light output from the light source 500 and reflected by the transflective member 520. Accordingly, the angle of the IR light incident on the object can be adjusted, the entire surface of the object can be scanned, and light efficiency can be improved.

Also, the scanner 530 adjusts the angle of light reflected from the object. Accordingly, the light reflected from the object may efficiently reach the light input unit 540.

To this end, a separate driving device 532 may be connected to the scanner 530. The driving device 532 may rotate the scanner 530 at a high speed.

The light reflected from the object reaches the light input unit 540. The light input unit 540 may include, for example, a photo diode (PD).

The light reaching the light input unit 540 is converted into an electric signal, and the calculation unit 542 calculates the distance of the object by using the converted electric signal.

Meanwhile, according to an embodiment of the present invention, the transflective member 520 may be disposed between the light source 500, the scanner 530, and the light input unit 540. Accordingly, a part of the light output from the light source 500 may be reflected and transmitted to the scanner 530, and a part of the light transmitted from the scanner 530 after being reflected from an object may be transmitted to the light input unit 540. .

In this case, one surface of the transflective member 520 may be disposed to meet the optical axis output from the light source 500. In addition, the scanner 530, the transflective member 520, and the light input unit 540 may be arranged on an optical axis of light whose angle is adjusted by the scanner 530 after being reflected from an object. In this case, the light input unit 540 may be arranged so that the light transmitted through the transflective member is directly incident without passing through the additional reflective member. Accordingly, it is possible to reduce optical loss by minimizing the optical path. In addition, the spatial alignment between the pixels of the optical input unit 540 and the optical axis is easy, and the internal structure of the system can be made slim.

Meanwhile, between the light source 500 and the transflective member 520, a light transmission member 510 for transmitting the IR light output from the light source 500 to the transflective member 520 may be further disposed. The light transmitting member 510 may be, for example, a focusing lens.

According to an embodiment of the present invention, if the transflective member is disposed between the light output unit, the light input unit and the scanner, there is no need to arrange a folding mirror to adjust the path of light. Accordingly, light loss occurring on the optical path can be minimized, and the device can be implemented in a small size.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. You will understand that you can do it.

100: TOF camera unit
110: optical output unit
120: optical control unit
130: optical input unit
140: operation unit
500: light source
510: focusing lens
520: transflective member
530: scanner
540: PD

Claims (17)

Light output unit;
An optical input unit including a plurality of pixels each including a first receiving unit and a second receiving unit;
A beam splitter including a surface meeting the optical axis of the light output unit; And
And a calculation unit that calculates a distance of an object using light received by the light input unit,
The light output unit outputs IR light that flashes with a period,
The first receiving unit is activated while the light source is turned on,
The second receiving unit is a TOF camera device that is activated while the light source is turned off. The method of claim 1,
The light output unit,
A light conversion unit that modulates the input light; And
A TOF camera apparatus comprising a light source for outputting light converted from the light conversion unit. The method of claim 2,
The light output unit,
TOF camera apparatus further comprising a light transmission member for transmitting the output light to the beam splitter. The method of claim 1,
The first receiving unit and the second receiving unit
The TOF camera device in which the light reception period is changed according to the distance to the object. The method of claim 4,
The calculation unit,
A TOF camera device that measures a distance to the object by using a difference between the amount of light received by the first receiving unit and the second receiving unit. The method of claim 1,
The beam splitter,
Is disposed between the light output unit and the light input unit to transmit a part of light and reflect the remaining part,
At least part of the light output from the light output unit is incident on the object to receive the light reflected from the object,
A TOF camera device that transmits a part of the transmitted light and enters the light input unit. The method of claim 1,
The beam splitter and the light input unit are arranged on an optical axis through which the light is transmitted. The method of claim 1,
A TOF camera device in which light transmitted through the beam splitter is directly incident on the light input unit. The method of claim 1,
The ratio of transmittance to reflectance of the beam splitter is 0.4 or more and 2.3 or less. The method of claim 1,
A TOF camera apparatus further comprising a scanner, wherein the scanner adjusts an angle of IR light incident on the object. The method of claim 10,
The scanner is a TOF camera device that adjusts the angle of light reflected from the object. The method of claim 10,
The beam splitter,
A TOF camera apparatus for injecting at least a portion of the light output from the light output unit through the scanner onto the object and causing the light reflected from the object to enter the light input unit. Light output unit;
An optical input unit including a plurality of pixels each including a first receiving unit and a second receiving unit;
A scanner that adjusts the angle of light incident on the object; And
And a calculation unit that calculates a distance of an object using light received by the light input unit,
The light output unit outputs IR light that flashes with a period,
The first receiving unit is activated while the light source is turned on,
The second receiving unit is a TOF camera device that is activated while the light source is turned off. The method of claim 13,
The scanner,
A TOF camera apparatus for injecting at least a portion of the light output from the light output unit onto the object and causing the light reflected from the object to enter the light input unit. The method of claim 13,
The scanner is a TOF camera device that adjusts the angle of light reflected from the object. The method of claim 13,
The first receiving unit and the second receiving unit
The TOF camera device in which the light reception period is changed according to the distance to the object. The method of claim 16,
The calculation unit,
A TOF camera device that measures a distance to the object by using a difference between the amount of light received by the first receiving unit and the second receiving unit.

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