JP2010085133A - Distance measuring apparatus, distance measuring method, and projector - Google Patents

Abstract

A distance to an object is calculated more quickly.
Laser light beams La, Lb, Lc are simultaneously irradiated from laser light sources 2a, 2b, 2c toward a screen 100 (step S1). Thus, since the laser beams La, Lb, and Lc are simultaneously irradiated from the laser light sources 2a, 2b, and 2c, the distance to the screen 100 and the angle of the screen 100 described later can be measured more quickly. In step S5, the phase difference detection circuits 5a, 5b, and 5c are operated to detect the phase differences between the laser beams La, Lb, and Lc and the reflected light components Ra, Rb, and Rc. The distance is calculated (step S6). Further, the angle of the screen is calculated using these distances (step S7), and keystone correction is executed (step S8).
[Selection] Figure 4

Description

  The present invention relates to a distance measuring device and a distance measuring method for measuring a distance to a measurement object using a laser beam, and a projection device using them.

The thing of patent document 1 is known as a conventional distance measuring device. This distance measuring device irradiates an object with light from two optically different irradiation positions, and reflects light reflected from the object by the light irradiated from the two irradiation positions at either of the two irradiation positions. Each photo is taken at the same optical position. Then, by calculating the distance to the measured part based on the measured part of the object and the reflected light from the vicinity of the measured part, the error factor due to the inclination of the object surface is eliminated, and the object is more accurately It is assumed that the distance information can be acquired.
JP 2002-81908 A

  However, in the above-described conventional distance measuring device, the object is irradiated from the irradiation light irradiated from the two optically different positions and the reflected light thereof, that is, the two optically different irradiation positions. The distance to the object is calculated using the first irradiation light, the second irradiation light, and the reflected light corresponding to the first and second irradiation lights.

  Therefore, in order to accurately calculate the distance to the object, it is necessary to irradiate both irradiation lights with a time difference so that the first irradiation light and the second irradiation light are not mixed. The distance is calculated with this time difference still occurring. For this reason, it takes time to calculate the distance to the object due to the time difference between the irradiation times of the two irradiation lights, and the distance to the object cannot be calculated quickly.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a distance measuring device, a distance measuring method, and a projection device that can calculate the distance to an object more quickly.

  In order to solve the above-mentioned problem, in the distance measuring device according to the first aspect of the present invention, irradiation means for simultaneously irradiating the measurement target with a plurality of light beams each having a different modulation frequency, and reflection on the measurement target And a light receiving means for receiving reflected light including a plurality of light beams having different modulation frequencies, and an extracting means for extracting a light beam component for each predetermined frequency from the reflected light received by the light receiving means. And a distance calculation means for calculating a distance to the measurement object based on a phase difference between the light beam component of each frequency extracted by the extraction means and a light beam of the corresponding frequency irradiated by the irradiation means. Features.

  In the distance measuring device according to the second aspect of the present invention, the light beam is any one of a light emitting element such as a laser beam and an LED.

  In the distance measuring apparatus according to the invention described in claim 3, the irradiating means is constituted by a plurality of laser light sources that irradiate laser beams having different predetermined frequencies.

  Further, in the distance measuring device according to the invention of claim 4, the extracting means comprises a band pass means for separating the reflected light received by the light receiving means into laser light components for each predetermined frequency. It is characterized by providing.

  Further, in the distance measuring device according to the invention of claim 5, the distance calculating means is a laser having a corresponding frequency irradiated by the irradiating means for each laser light component of each frequency extracted by the extracting means. A plurality of phase difference detecting means for detecting a phase difference with light is provided.

  Further, in the distance measuring device according to the invention of claim 6, the distance calculating means calculates a distance to the measurement object for each laser beam having the different frequency, and is calculated by the distance calculating means. An angle calculating means for calculating an angle of the measurement object based on a plurality of distances is further provided.

  According to a seventh aspect of the present invention, there is provided a projection apparatus for projecting an image onto a screen, comprising the distance measuring apparatus according to any one of the first to sixth aspects, and the distance measuring apparatus. The image processing apparatus includes processing means for executing a process related to the projection of the image based on at least one of the distance to the screen or the angle of the screen calculated by the above.

  In the projection apparatus according to an eighth aspect of the present invention, the process related to the projection of the image is a trapezoid correction process for correcting the keystone of the projected image.

  In the distance measuring method according to the ninth aspect of the invention, an irradiation step of simultaneously irradiating the measurement target with a plurality of light beams each having a different modulation frequency, and the modulation frequency reflected by the measurement target A light receiving process for receiving reflected light including a plurality of different light beams, an extraction process for extracting a light beam component for each predetermined frequency from the reflected light received by the light receiving process, and the extraction process. And a distance calculating step of calculating a distance to the measurement object based on a phase difference between the extracted light component of each frequency and a light beam of a corresponding frequency irradiated by the irradiation unit.

  In the distance measuring method according to the invention of claim 10, any one of a light emitting element such as a laser beam or an LED is used as the light beam.

  According to the distance measuring device and the distance measuring method of the present invention, the distance to the measuring object can be measured more quickly. Further, according to the projection device of the present invention, the distance to the screen and the angle of the screen can be measured more quickly, and the processing related to the projection of the image can be performed quickly.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an electrical configuration of a projector 1 according to an embodiment of the present invention. The projector 1 has a function of measuring a distance and an angle to a screen 100 (see FIG. 3) described later, and includes a distance / angle measuring device 28, a control unit 11, an input / output interface 12, and an image conversion unit. 13, display encoder 14, display drive unit 15, and the like.

  In addition, an input / output connector unit 16 is provided. The image signals (image data) of various standards input from the input / output connector unit 16 are unified into image signals of a predetermined format suitable for display by the image conversion unit 13 via the input / output interface 12 and the system bus 17. After being converted in this way, it is sent to the display encoder 14. The display encoder 14 develops and stores the transmitted image signal in the video RAM 18, generates a video signal from the stored contents of the video RAM 18, and outputs the video signal to the display driving unit 15.

  The display driving unit 15 to which the video signal is input from the display encoder 14 drives the display element 19 which is a spatial light modulation element (SOM) at an appropriate frame rate in accordance with the transmitted image signal. Then, the light bundle emitted from the light source device 20 having a lamp is incident on the display element 19 through the light source side optical system, thereby forming an optical image with the reflected light of the display element 19, and the projection side optical system. An image is projected and displayed on the screen 100 (see FIG. 3) via the movable lens group 21. The movable lens group 21 of the projection side optical system is driven by a lens motor 22 for zoom adjustment and focus adjustment.

  The image compression / decompression unit 23 performs recording processing for compressing the luminance signal and the color difference signal in the image signal by processing such as ADTC and Huffman coding, and writing the data onto a memory card 24 that is a detachable recording medium. The image data recorded in the memory card 24 is read out, the individual image data constituting a series of moving images is expanded in units of one frame, sent to the display encoder 14 via the image conversion unit 13, and stored in the memory card 24. Based on the above, it is possible to display a moving image or the like.

  The control unit 11 controls the operation of each circuit including the distance / angle measuring device 28 in the projector 1 and includes a CPU and its peripheral circuits, a ROM 111, a RAM 112, and the like. The ROM 111 stores programs such as various settings, programs and data shown by flowcharts described later, and the RAM 112 is used as a work memory or the like.

  The key / indicator unit 25 includes a main key and an indicator provided in a main body case or the like, a lamp that is turned on when the projector 1 is started up, and the like. These indicators and the like are displayed and blinked by the control unit 11, and operation signals for various keys are sent to the control unit 11. The key operation signal from the remote controller is received by the Ir receiver 26, demodulated by the Ir processor 27, and the code signal is sent to the controller 11.

  The control unit 11 controls the light source control circuit 32 to perform time-division control on the red light source, the green light source, and the blue light source according to the image signal. Further, the cooling fan drive control circuit 33 performs temperature detection by a plurality of sensors provided in the light source device 20 and the like to control the rotation speed of the cooling fan, and cools the projector body even after the power is turned off by a timer or the like. Control of turning off the power of the projector main body is also performed depending on the result of temperature detection by the temperature sensor by continuing the rotation of the fan.

  2 and 3 are diagrams showing details of the distance / angle measuring device 28. FIG. The distance / angle measuring device 28 includes three pulse generators 1a, 1b, 1c, laser light sources 2a, 2b, 2c, band-pass filters 4a, 4b, 4c, and phase difference detection circuits 5a, 5b, 5c. And a single light receiving unit 3 and a distance / angle calculation circuit 6. First, frequency modulation is performed by shifting the pulse frequency by three. The pulse generators 1a, 1b, and 1c generate pulse signals Pa, Pb, and Pc having different modulation frequencies and output them to the corresponding laser light sources 2a, 2b, and 2c.

  The laser light sources 2a, 2b, and 2c are laser light emitting elements, and laser light (irradiation light) La, Lb, and Lc having frequencies of pulse signals Pa, Pb, and Pc input from the pulse generators 1a, 1b, and 1c. Are generated and irradiated to the outside. Further, as shown in FIG. 3, the laser light sources 2a, 2b, and 2c have different irradiation directions, and laser beams La, Lb, and Lc are irradiated to different positions on the screen 100 on which the image is projected and displayed. It is configured as follows.

  The light receiving unit 3 includes a light receiving element, and receives reflected light LR including reflected light components Ra, Rb, and Rc, which are light reflected by the laser light La, Lb, and Lc on the screen 100. At this time, since the reflected light components Ra, Rb, and Rc arrive at different positions of the projector 1 from different directions according to the directions of the laser light sources 2a, 2b, and 2c, the light receiving unit 3 receives all of them. It has such a wide light receiving area as possible.

  The bandpass filters 4a, 4b, and 4c have a characteristic of filtering the frequencies of the corresponding laser beams La, Lb, and Lc. The phase difference detection circuits 5a, 5b and 5c are respectively provided with the reflected light components Ra, Rb and Rc filtered through the bandpass filters 4a, 4b and 4c and the corresponding pulse signals Pa generated by the pulse generators 1a, 1b and 1c. , Pb, and Pc are detected. The distance / angle calculation circuit 6 calculates the distance to the screen 100 for each phase difference based on the phase differences detected by the phase difference detection circuits 5a, 5b, and 5c, and 3 on the screen 100 obtained thereby. Based on the distance to the point, the angle of the screen 100 is calculated.

  In the present embodiment having the above-described configuration, the control unit 11 of the projector 1 executes processing as shown in the flowchart of FIG. 4 based on the program stored in the ROM 111 when the power is turned on. That is, the control unit 11 controls the distance / angle measuring device 28 to simultaneously irradiate the laser light La, Lb, Lc from the laser light sources 2a, 2b, 2c toward the screen 100 (step S1).

  Thus, since the laser beams La, Lb, and Lc are simultaneously irradiated from the laser light sources 2a, 2b, and 2c, the distance to the screen 100 and the angle of the screen 100 described later can be measured more quickly.

  Next, it is determined whether or not the light receiving unit 3 has received the reflected light LR of the laser light (step S2). If the light receiving unit 3 receives the reflected light LR, the bandpass filters 4a, 4b, and 4c are operated, and the reflected light LR is filtered and separated for each frequency (step S3). Thereby, the reflected light components Ra, Rb, and Rc having frequencies corresponding to the laser beams La, Lb, and Lc can be separated with high accuracy. Subsequently, it is determined whether or not the reflected light components of the reflected light separated by the bandpass filters 4a, 4b, and 4c have reflected light components Ra, Rb, and Rc having frequencies corresponding to the laser beams La, Lb, and Lc. (Step S4).

  When the reflected light components Ra, Rb, and Rc are all present, that is, the reflected light component Ra is obtained from the bandpass filter 4a, the reflected light component Rb is obtained from the bandpass filter 4b, and the reflected light component Rc is obtained from the bandpass filter 4c. In that case, the process proceeds from step S4 to step S5. In step S5, the phase difference detection circuits 5a, 5b, and 5c are operated to detect each phase difference described above. Therefore, the phase difference between the laser beams La, Lb, and Lc and the reflected light components Ra, Rb, and Rc can be accurately detected by the phase difference detection circuits 5a, 5b, and 5c.

  Subsequently, the distance / angle calculation circuit 6 is operated to calculate each distance based on each phase difference detected by the phase difference detection circuits 5a, 5b, and 5c (step S6). Thereby, the distance between the projector 1 and the three points A, B, and C on the screen 100 shown in FIG. 3 is obtained.

  Next, the angle of the screen 100 is calculated (step S7). In other words, since the distance between the projector 1 and the three points A, B, and C on the screen 100 is obtained in step S6, the distance to the projector 1 is determined based on the distance between these three points A, B, and C. The angle of the screen 100 can be calculated.

  Thereafter, trapezoid correction is executed (step S8). This trapezoid correction may be performed using any of the known trapezoid correction methods (for example, see (1) Japanese Patent Laid-Open No. 2003-324669, (2) Japanese Patent Laid-Open No. 2007-94036, etc.). The trapezoid correction may be performed using only the angle calculated in step S7 (see the publication (1)), or may be performed using the angle calculated in step S7 and the distance calculated in step S6. (Refer to publication (1)).

  At this time, as described above, by simultaneously irradiating the laser beams La, Lb, and Lc from the laser light sources 2a, 2b, and 2c, the distance to the screen 100 and the angle of the screen 100 can be measured more quickly. This trapezoidal correction can also be performed quickly.

  In the present embodiment, the keystone correction is executed in step S8. However, the process executed in step S8 is not limited to the keystone correction process, and the focus adjustment is performed by controlling the lens motor 22, for example. Any other process may be used as long as it is a process related to the function of the projector 1 such as a process.

  Furthermore, in the present embodiment, the case where the distance / angle measuring device 28 is applied to a projector has been shown. However, the distance / angle measurement is not limited to the projector, and the distance / angle measurement is applied to various devices that detect and control the target distance and angle. Of course, the device 28 can be applied.

  In this embodiment, the distance to the screen is measured using a laser beam, which is one of the light beams. However, not only the laser beam but also a reference signal transmitted at a predetermined frequency to a target is used. Any light beam that can measure the distance to the target by irradiating the modulated light beam and detecting the phase difference between the received light-receiving signal and the reference signal that has returned. For example, there are light emitting elements such as LEDs. This is possible as long as it can be irradiated with modulation, and light sources based on these light emitting elements can be used instead of the laser light sources 2a, 2b, 2c.

  The present invention is not limited to the above-described embodiments, and can be freely changed and improved without departing from the gist of the invention.

1 is a block diagram showing a circuit configuration of a projector according to an embodiment of the present invention. It is a block diagram which shows the circuit structure of the distance and angle measuring apparatus which concerns on one embodiment of this invention. It is explanatory drawing which shows a part detail of the same distance and angle measuring device. It is a flowchart which shows the process sequence in one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2a, 2b, 2c Laser light source 3 Light-receiving part 4a, 4b, 4c Band pass filter 5a, 5b, 5c Phase difference detection circuit 6 Distance and angle calculation circuit 11 Control part 12 Input / output interface 13 Image conversion part 14 Display encoder 15 Display drive unit 19 Display element 20 Light source device 21 Movable lens group 22 Lens motor 28 Distance / angle measuring device 100 Screen 111 ROM
112 RAM

Claims (10)

Irradiating means for simultaneously irradiating a measurement object with a plurality of light beams each having a different modulation frequency;
A light receiving means for receiving reflected light that is reflected by the measurement object and includes a plurality of light beams having different modulation frequencies;
Extraction means for extracting a light beam component for each predetermined frequency from the reflected light received by the light receiving means;
Distance calculating means for calculating the distance to the measurement object based on the phase difference between the light ray component of each frequency extracted by the extracting means and the light ray of the corresponding frequency irradiated by the irradiating means; A distance measuring device.   The distance measuring device according to claim 1, wherein the light beam is one of a light emitting element such as a laser beam and an LED.   2. The distance measuring apparatus according to claim 1, wherein the irradiating means includes a plurality of laser light sources that irradiate laser beams having different predetermined frequencies.   4. The distance measuring device according to claim 1, wherein the extracting unit includes a band pass unit that separates the reflected light received by the light receiving unit into laser light components for each predetermined frequency.   The distance calculating means includes a plurality of phase difference detecting means for detecting a phase difference from the laser light of the corresponding frequency irradiated by the irradiating means for each laser light component of each frequency extracted by the extracting means. The distance measuring apparatus according to claim 1, wherein the distance measuring apparatus is characterized in that: The distance calculation means calculates a distance to the measurement object for each laser beam of the different frequency,
6. The distance measuring device according to claim 1, further comprising angle calculating means for calculating an angle of the measurement object based on a plurality of distances calculated by the distance calculating means. A projection device that projects an image on a screen,
The distance measuring device according to any one of claims 1 to 6,
A projection apparatus comprising: processing means for executing a process related to projection of the image based on at least one of a distance to the screen or an angle of the screen calculated by the distance measuring apparatus.   The projection apparatus according to claim 7, wherein the process related to the projection of the image is a trapezoid correction process for correcting a keystone of the image to be projected. An irradiation step of simultaneously irradiating a measurement object with a plurality of light beams each having a different modulation frequency;
A light receiving step for receiving reflected light that is reflected by the measurement object and includes a plurality of light beams having different modulation frequencies;
An extraction step of extracting a light ray component for each predetermined frequency from the reflected light received by the light receiving step;
A distance calculation step of calculating a distance to the measurement object based on a phase difference between the light beam component of each frequency extracted by the extraction step and the light beam of the corresponding frequency irradiated by the irradiation unit. Distance measuring method.   The distance measuring method according to claim 9, wherein any one of a light emitting element such as a laser beam or an LED is used as the light beam.

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