JP4586487B2 - Distance measuring device and distance measuring method - Google Patents

Description

  The present invention relates to a distance measuring device and a distance measuring method.

  An autofocus camera or the like is provided with a distance measuring sensor that measures a distance to a subject. As such a distance measuring sensor, there is a passive type sensor (for example, see Patent Document 1). As shown in FIG. 11, the passive distance measuring sensor includes a pair of lenses 51a and 51b and photosensor arrays 52a and 52b.

  The lens 51a and the lens 51b are arranged with an interval b. C1 and C2 are center lines of the lenses 51a and 51b, respectively. The center lines C1 and C2 coincide with the light rays from the subject 53 existing at an infinite position with respect to the lenses 51a and 51b and are parallel to each other. The photosensor arrays 52a and 52b are arranged so as to be perpendicular to the center lines C1 and C2, respectively.

Video data strings L0 and R0 of the subject 53 are formed in the photosensor arrays 52a and 52b, respectively. In such a distance measuring sensor, the distance L from the lenses 51a and 51b to the subject 53 is obtained by the following equation (1).

  When the subject 53 is arranged at a position closer to the lenses 51a and 51b than an infinite position, a phase difference (x1 + x2) is generated. For example, the distance measuring sensor obtains a correlation value between the data string L1 and the data string R1 of the photosensor array 52a while shifting the data string R1 on the photosensor array 52b. The amount of deviation (shift) from the center lines C1 and C2 at which the correlation value is maximized is the phase difference (x1 + x2).

  In addition, in a projector, the projected image formed on the screen is distorted by the tilt angle of the screen on which the projection light is projected. Therefore, the tilt angle of the screen with respect to the optical axis of the projection light of the projector is used to correct this projected image. It becomes necessary. For this reason, there is a projector in which the tilt angle of the screen is obtained using the distance measuring device using the distance measuring sensor.

  In order to measure the distance to the screen, such a projector projects, as a distance measurement chart, light of a chart having an equidistant continuous pattern in which bright and dark portions are arranged as shown in FIG.

  In the figure, the white square of the chart represents the bright part of the chart, and the hatched part represents the background and the dark part of the chart. The interval from the center of the bright part of each chart to the center of the adjacent bright part is 1 pitch (p). In the figure, two distance measurement windows WL and WR indicated by frames indicate areas in which the distance measurement sensor performs distance measurement in the left-right direction of the projected image. The ranging windows WL and WR have widths w1 and w2, respectively.

The distance measuring sensor receives the reflected light from the two distance measuring windows WL and WR. The projector measures each phase difference when the distance measurement sensor receives reflected light from the two distance measurement windows WL and WR of the chart, and on the screen surface based on the obtained phase difference. Measure the distance to multiple ranging points. Further, the projector determines the tilt angle of the screen based on distance measurement data up to a plurality of distance measurement points on the screen surface.
JP 2003-057531 A (2nd page, 3rd page, FIG. 3)

  Many of such projectors have an optical variable zoom function as one of their functions. On the other hand, in the conventional distance measuring apparatus, as shown in FIG. 13A, the widths w1 and w2 of the distance measuring windows WL and WR are uniquely fixed to 72 pixels with respect to the chart to be used.

  Therefore, when the optical zoom magnification is changed using this optical variable zoom function, the pitch p of the chart projected on the range of the distance measurement windows w1 and w2 also changes, and as shown in FIG. As the magnification is changed, the pitch multiple m as the number of pitches p in the distance measurement windows WL and WR also changes.

  For example, as shown in FIG. 14, an image of the chart waveform Cw is formed on the sensor pixel Pix (photosensor array 52a, 52b) inside the sensor through the lens 51a, 51b of the sensor, and the chart image is formed by the formed image. Light / dark information is acquired.

  Here, the chart waveform Cw is a waveform representing the intensity of light and dark information imaged on the sensor pixel Pix (photosensor arrays 52a and 52b), and the light and dark period increases as the zoom magnification Zoom becomes wider. . Further, since the lens focus of the sensor is poor, the chart waveform Cw is a gentle curve.

  As shown in FIGS. 14A to 14C, when Zoom = z0 (tele end), the pitch multiple m = 9.3, and when Zoom = z7, the pitch multiple m = 8.5. When z = z15 (wide end), the pitch multiple m = 7.7. This pitch multiple m is the number of line pairs of the black and white chart in the distance measurement windows WL and WR, and is a number representing how many times the chart is repeated in the range of the distance measurement window widths w1 and w2.

  Therefore, as shown in FIG. 13B, the pitch multiple m also changes as the zoom magnification changes. When the pitch multiple m changes, the resulting phase difference also changes, making it impossible to accurately measure the distance.

  The present invention has been made in view of such conventional problems, and provides a distance measuring device and a distance measuring method capable of accurately measuring the distance between the projection points of the projection light. The purpose is to do.

In order to achieve this object, a distance measuring device according to the first aspect of the present invention provides:
In a distance measuring device that measures a distance between a projection point of projection light and a projection point on the projection surface that projects the projection light,
A chart drawing unit that generates a chart in which light and dark portions are continuously arranged at a set pitch, and projects the projection light of the generated chart on the projection surface to draw the chart;
A plurality of light receiving units arranged at intervals, and sensor units that receive reflected light from the chart drawn on the projection plane,
A window for setting the width of the window as a range in which each light receiving unit of the sensor unit receives light from the chart drawn on the projection plane to be an integral multiple of the pitch of the chart drawn on the projection plane A width setting section;
The distance between the projection point of the projection light and the projection point on the chart drawn on the projection surface based on the phase difference of the chart image received through the respective windows by the respective light receiving units of the sensor unit And a distance acquisition unit for obtaining.

The window width setting unit acquires zoom magnification information of an optical mechanism unit that projects projection light of a specified chart, and acquires the pitch of the light and dark part based on the acquired zoom magnification information. Good.

  The window width setting unit may acquire the pitch of the light and dark portions from image data formed by light received by each light receiving unit of the sensor unit.

The distance measuring method according to the second aspect of the present invention is:
A chart drawing step of generating a chart in which light and dark portions are continuously arranged at a set pitch, projecting the projection light of the generated chart and drawing the chart on a projection surface;
A window width setting step of the width of the window as a light receiving range of the light is set so as to be an integral multiple of the pitch of the charts drawn on the projection plane from the chart,
A light receiving step of receiving light from the chart through each window with a window width set at a plurality of distance measurement points;
A distance measuring step for obtaining a distance between the projection point of the projection light and the projection point on the chart drawn on the projection surface based on the phase difference of the chart image respectively received at each distance measurement point; It is characterized by that.

The window width setting step acquires zoom magnification information of an optical mechanism unit that projects projection light of a specified chart , acquires a pitch of the light and dark part based on the acquired zoom magnification information, and the window width May be set to be an integral multiple of the acquired pitch.

  The window width setting step acquires the pitch of the bright and dark portions from each image data formed by light received at the plurality of distance measurement points, and the window width is an integral multiple of the acquired pitch. It may be a step of setting.

  ADVANTAGE OF THE INVENTION According to this invention, the distance between the projection point of projection light and a projection point can be measured correctly.

  Hereinafter, a distance measuring device according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, a case where the distance measuring device is applied to a projector will be described.

FIG. 1 shows the configuration of the projector according to this embodiment.
The projector 1 according to the present embodiment includes a projector drawing unit 11, phase difference angle sensors 12 </ b> A and 12 </ b> B, an operation unit 13, and a projector control unit 14.

  The projector drawing unit 11 projects a projection image based on a chart or an input video signal onto the screen 2, and includes a scaler 21, a trapezoid correction unit 22, a signal selection unit 23, a projection light conversion device 24, An optical mechanism unit 25, a horizontal chart generation unit 26, and a vertical chart generation unit 27 are provided.

The scaler 21 adjusts the resolution of the input video signal.
The trapezoidal correction unit 22 performs trapezoidal correction on the video signal whose resolution has been corrected by the scaler 21.

  Based on the tilt angles θH and θV of the screen 2, the trapezoid correction unit 22 sets the position and shape of the corrected projection image inside the uncorrected projection image projected on the screen 2, and continuously Keystone correction is performed by projective transformation of the video signal. The tilt angle θH is the tilt angle in the horizontal direction of the screen 2 with respect to the optical axis of the projection light, and the tilt angle θV is the tilt angle in the vertical direction of the screen 2.

This trapezoid correction will be described.
Since a video signal of a quadrangle abcd image as shown in FIG. 2 (1) is supplied and the screen 2 is inclined by the inclination angles θH and θV with respect to the optical axis of the projection light, the projected image on the screen 2 Is a square a′b′c′d ′ as shown in FIG. The trapezoidal correction unit 22 cuts out the quadrangle p′q′r ′s ′ so as to be arranged in the quadrangle a′b′c′d ′. The trapezoidal correction unit 22 inversely transforms the quadrangle p′q′r ′s ′ to generate an inversely transformed image pqrs as shown in FIG. By projecting the inversely transformed image pqrs onto the screen 2, a projection image without distortion is formed on the screen 2. The trapezoidal correction unit 22 performs such trapezoidal correction.

  The signal selection unit 23 selectively outputs any one of the horizontal chart generated by the horizontal chart generation unit 26, the vertical chart generated by the vertical chart generation unit 27, and the projection image generated by the trapezoid correction unit 22. is there.

The projection light conversion device 24 converts the video signal selected and output by the signal selection unit 23 into projection light.
The optical mechanism unit 25 performs focus control so that an image is formed on the screen 2, and projects the projection light converted by the projection light conversion device 24 onto the screen 2. When the zoom instruction signal is supplied from the projector control unit 14, the optical mechanism unit 25 projects the projection light on the screen at a zoom magnification set based on the zoom instruction signal. The position of the optical mechanism unit 25 becomes a projection point.

  The horizontal chart generating unit 26 generates charts # 0 to # 7 as shown in FIG. 3 projected on the screen 2 in the horizontal direction. This horizontal chart is a chart projected to measure the distance to a plurality of distance measuring points in the horizontal direction with respect to the ground plane.

  Note that the pitch p is the number (interval) of line pairs in the respective light and dark portions of each chart # 0 to # 7, the size of the chart # 0 to # 7 projected on the screen 2, and the resolution of the distance measuring sensor 31A. Etc. are set based on the above.

  The patterns of the charts # 0 to # 7 are shifted little by little. That is, the light and dark part pattern of chart # 1 is shifted to the right in the drawing with respect to the light and dark part pattern of chart # 0. The same applies to the bright and dark portions of the charts # 2 to # 7. The reason why such charts # 0 to # 7 are sequentially projected onto the screen 2 is to cancel the error component of the chart and improve the accuracy of the inclination angles θH and θV.

The reason for this will be described.
The shift amount (shift amount) of each chart can be represented by a chart pitch (repetition interval). If one pitch of each chart is 360 degrees and the number of charts is 8 as shown in FIG. 3, the deviation amounts of the charts # 0 to # 7 are evenly distributed and 360 ÷ 8 = 45 degrees. Become.

  When the deviation of each chart is expressed by an angle with reference to the chart # 0, the deviation angles of the charts # 0 to # 7 are 0 degree, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, and 270 degrees. 315 degrees.

The error component shown in FIG. 4 (1) is almost decomposed into the error component shown in FIG. 4 (2) and the error component shown in FIG. 4 (3). This is obtained as an experimental result. The error component A shown in FIG. 4 (2) is an error component having the same cycle as the chart shift. Also, the error component B shown in FIG. 4 (3) is an error component having a period twice as long as the chart shift.
That is, the phase difference error component e is expressed by the following equation 2.

ただしｎはチャートの数で４以上の２の倍数、ｋはチャート番号０〜ｎ−１、θｋはチャート＃ｋのチャート＃０を基準としたときのずれの角度である。 However, the first term indicates the error component A, the second term indicates the error component B, θ is the angle of deviation _relative to the chart # 0, θ ₀₁ and θ ₀₂ are the initial deviation of the chart # 0, and a and b are It is a constant determined by the chart pitch and optical characteristics.
Further, if the chart is selected so that the relational expression shown in Equation 3 is established, the error can be reduced.

However, n is the number of charts and is a multiple of 2 greater than or equal to 4, k is a chart number 0 to n-1, and θk is an angle of deviation with reference to chart # 0 of chart #k.

  When the chart is selected in this way, the errors in the charts # 0 to # 7 are canceled by averaging both the error occurring in the same period as the shift period and the error occurring in the half period. If the errors in the charts # 0 to # 7 are reduced, the accuracy of the inclination angles θH and θV is increased.

Returning to FIG. 1, the vertical chart generator 27 generates a vertical chart (horizontal stripe) obtained by rotating eight charts (vertical stripes) projected on the screen 2 as shown in FIG. is there.
This vertical chart is a chart projected when measuring distances to a plurality of distance measuring points in a direction perpendicular to the ground plane.

  The phase difference angle sensors 12A and 12B measure the distances to a plurality of distance measuring points on the horizontal and vertical measurement lines on the screen 2, respectively, and based on the measured distances, the inclination angles θA, θB is acquired.

  The inclination angles θA and θB are both inclination angles between the virtual screen S1 represented by the angle θs in FIG. 5 and the actual screen 2 (a line connecting the measurement points P1 and P2 on the screen 2). The virtual screen S1 is a virtual screen in which the center line C0 penetrates vertically. The center line C0 is a line in the direction of the screen 2 of the phase difference angle sensors 12A and 12B (ranging sensors 31A and 31B), and is a line connecting equidistant points from the centers of the lenses 51a and 51b shown in FIG. Corresponding line.

  In the figure, R and L indicate distances between the projector 1 and distance measuring points P1 and P2 in the distance measuring window, respectively. The angle θw indicates the angle between the center line C0 of the distance measuring sensors 31A and 31B and the distance measuring points P1 and P2, and the angle θN corresponds to the distance measuring window widths w1 and w2 shown in FIG. The corresponding angle is shown.

  The phase difference angle sensor 12A includes a distance measurement sensor 31A and a sensor controller 32A, and the phase difference angle sensor 12B includes a distance measurement sensor 31B and a sensor controller 32B.

  The distance measuring sensors 31A and 31B are light receiving portions that receive the reflected light from the distance measuring window on the screen 2, and are used to measure the distance to the distance measuring point on the conventional screen 2 as shown in FIG. It ’s like that. The positions of the distance measuring sensors 31A and 31B become distance measuring points. The distance measuring sensors 31A and 31B are phase difference type sensors having a multi distance measuring function capable of measuring distances in a plurality of directions.

  When the signal selection unit 23 selects the horizontal chart, the distance measuring sensors 31A and 31B are, as shown in FIG. 5, the screen 2 positioned on the left and right with an angle θw with respect to the center line C0 of the distance measuring sensors 31A and 31B. The reflected light from the center points P1 and P2 of the upper two distance measuring windows WL and WR is received.

  In the case of the distance measuring sensor 31A, when the distance measuring sensor 31A receives the reflected light from the center point P1 of the right distance measuring window WR on the screen 2, the chart image in the right distance measuring window WR shown in FIG. It is formed on the photosensor arrays 52a and 52b shown in FIG.

  As shown in FIG. 6A, the distance measuring sensors 31A and 31B have their respective center lines (lines connecting the center points of the two photosensor arrays 52a and 52b) Ca and Cb orthogonal to each other in the vicinity of the projection lens 28. To be arranged.

  As shown in FIG. 6B, the elevation angle of the distance measuring sensors 31A and 31B with respect to the optical axis of the projection light of the projector 1 is θp. However, the elevation angle θp is not limited to a positive value but may be a negative value or may be zero.

When the elevation angle θp is zero, the optical axis of the projection lens 28 and the center line C0 of the distance measuring sensors 31A and 31B are parallel to each other, and the optical axis of the projection lens 28 intersects vertically. The two surfaces coincide with the virtual screen S1 surface of the distance measuring sensors 31A and 31B. However, when the elevation angle θp is not zero, the two screen surfaces do not coincide with the virtual screen S1 surface of the distance measuring sensors 31A and 31B.
The distance measuring sensors 31A and 31B supply the received light to the sensor controllers 32A and 32B as sensor data, respectively.

  The sensor controller 32A acquires the tilt angle θA by controlling the horizontal chart generation unit 26, the signal selection unit 23, and the distance measurement sensor 31A. The sensor controller 32B controls the vertical chart generation unit 27, the signal selection unit 23, and the distance measurement sensor 31B to acquire the inclination angle θB.

  When the sensor controller 32A acquires the inclination angle θA, the sensor controller 32A outputs a horizontal chart drawing instruction for sequentially drawing the horizontal charts # 0 to # 7 to the signal selection unit 23. Then, the sensor controller 32A outputs a sensor control signal to the distance measuring sensor 31A so that the distance measuring sensor 31A performs a sensor operation, and receives reflected light from the charts # 0 to # 7 from the distance measuring sensor 31A. Are acquired.

  The sensor controller 32A obtains a correlation value between two data strings of the two left and right photosensor arrays 52a and 52b as shown in FIG. 11 of the distance measuring sensor 31A based on each sensor data, and obtains a maximum value thereof. Each phase difference is obtained by The sensor controller 32A averages the eight phase differences to obtain an average phase difference, and obtains an average distance to the points P1 and P2 based on the obtained average phase difference.

さらに、センサコントローラ３２Ａは、図５に示すように、仮想スクリーンＳ１面と実際のスクリーン２との角度θsを、数５を用いて求める。

The distance to the distance measuring point is obtained from the average phase difference using the following equation (4).

Further, as shown in FIG. 5, the sensor controller 32 </ b> A obtains an angle θs between the virtual screen S <b> 1 surface and the actual screen 2 using Equation 5.

  The sensor controller 32A supplies the obtained angle θs to the projector control unit 14 as the inclination angle θA.

  Similarly to the sensor controller 32A, the sensor controller 32B also outputs a vertical chart drawing instruction for sequentially drawing the vertical charts # 0 to # 7 to the signal selection unit 23 when acquiring the inclination angle θB. Then, the sensor controller 32B acquires eight pieces of sensor data from the distance measuring sensor 31B, and obtains the angle θs similarly to the sensor controller 32A. The sensor controller 32B supplies the obtained angle θs to the projector control unit 14 as the inclination angle θB.

  The operation unit 13 includes switches and keys for operating the projector 1 and also includes a key for designating a zoom magnification.

  The projector control unit 14 controls the projector 1 and obtains the tilt angles θH and θV based on the tilt angles θA and θB supplied from the sensor controllers 32A and 32B, respectively. When determining the tilt angles θH and θV, the projector control unit 14 outputs sensor operation start commands to the sensor controllers 32A and 32B, respectively.

The inclination angles θH and θV are obtained by replacing the inclination angles θA and θB according to the relational expression shown in the following equation (6).

  Then, the projector control unit 14 obtains the inclination angles θH and θV according to Equation 6, and supplies the obtained inclination angles θH and θV of the screen 2 to the trapezoid correction unit 22.

  Further, the projector control unit 14 acquires information on the designated zoom magnification from the operation unit 13 and outputs a zoom instruction signal to the optical mechanism unit 25 of the projector drawing unit 11 based on the acquired zoom magnification information. Control zoom. Then, the projector control unit 14 sets the widths w1 and w2 and the pitch p of the distance measurement windows WL and WR based on the acquired zoom magnification information.

  Specifically, assuming that the designated zoom magnification is Zoom, the projector control unit 14 follows the relationship between the zoom magnification Zoom, the pitch multiple m (no unit), and the window widths w1 and w2 (unit: sensor pixel, integer). The window widths w1 and w2 are set.

  As shown in FIG. 7, the window widths w1 and w2 are set using the number of pixels of the distance measuring sensors 31A and 31B. The number of pixels of the distance measurement window widths w1 and w2 of this embodiment is increased or decreased with the specified zoom magnification Zoom so that the pitch multiple m approaches an integer. However, the number of pixels of the distance measurement window widths w1 and w2 needs to be set so as not to be too large or too small. The distance measurement window widths w1 and w2 of this embodiment are set to be in the range of 68 pixels to 76 pixels. The window widths w1 and w2 are set to 70 pixels when the zoom magnification Zoom is at the telephoto end, and to 75 pixels when the zoom magnification Zoom is at the wide end.

  For example, when Zoom = z0, the conventional pitch multiple m is 9.3 as shown in FIG. On the other hand, in the present embodiment, as shown in FIG. 8A, the distance measurement window widths w1 and w2 are reduced from the conventional 72 pixels to 70 pixels so that the pitch multiple m is about 9. It is.

  Similarly, when Zoom = z7, the conventional pitch multiple m is 8.5 as shown in FIG. 14B. On the other hand, in this embodiment, as shown in FIG. 8B, the distance measurement window widths w1 and w2 are reduced from the conventional 72 pixels to 68 pixels so that the pitch multiple m is about 8. It is.

  Further, when Zoom = z15, the conventional pitch multiple m is 7.7 as shown in FIG. 14 (c). On the other hand, in this embodiment, as shown in FIG. 8C, the distance measurement window widths w1 and w2 are increased from the conventional 72 pixels to 75 pixels so that the pitch multiple m is about 8. It is.

  Thus, in the present embodiment, the pitch multiple m is a value in the vicinity of 8 or 9. The zoom magnification Zoom changes continuously, and the chart pitch (unit: sensor pixel) also changes continuously. On the other hand, since the number of sensor pixels of the window widths w1 and w2 is an integer, the pitch multiple (= ranging window width ÷ chart pitch) is not necessarily an integer.

  The chart pitch here is not the actual chart pitch on the screen 2, but when the light / dark information of the chart on the screen 2 forms an image on the pixel column of the sensor (photosensor arrays 52a and 52b in FIG. 11). It is the pitch of the light and dark part.

  By setting the window widths w1 and w2 in this way, the window widths w1 and w2 are integer m times the pitch p (unit: sensor pixel, but not an integer) of the chart projected on the screen 2. (W1≈p × m, w2≈p × m).

  In order to set the window widths w1 and w2 as described above, the projector control unit 14 includes a conversion table as shown in FIG. 9 created based on the relationship as shown in FIG. The projector control unit 14 sets the window widths w1 and w2 of the distance measurement windows WL and WR with reference to this conversion table. The projector control unit 14 includes a memory such as a ROM and a RAM, and stores a conversion table as shown in FIG.

  Then, the projector control unit 14 causes the phase difference angle sensors 12A and 12B to receive light from the ranging windows WL and WR in which the window widths w1 and w2 are set, respectively.

Next, the operation of the projector 1 according to this embodiment will be described.
When obtaining the tilt angles θH and θV of the screen 2, the projector control unit 14 acquires the designated zoom magnification Zoom from the operation unit 13. The projector control unit 14 outputs a zoom instruction signal to the optical mechanism unit 25 of the projector drawing unit 11 based on the acquired zoom magnification Zoom.

  In addition, the projector control unit 14 sets the window widths w1 and w2 of the windows WL and WR based on the acquired zoom magnification Zoom. For example, if the acquired zoom magnification Zoom is z0 ≦ Zoom <z1, the projector control unit 14 refers to the conversion table shown in FIG. 9 and sets the window widths w1 and w2 of the distance measurement windows WL and WR to 70, respectively. Set to (pixel). As shown in FIG. 7B, the pitch multiple m of the distance measurement windows WL and WR is approximately 9 pixels.

  When the projector control unit 14 sets the window widths w1 and w2 of the distance measurement windows WL and WR as described above, the projector control unit 14 starts sensor operation using the distance measurement windows WL and WR of the set window widths w1 and w2, respectively. Thus, a start command is transmitted to the sensor controllers 32A and 32B.

  When the sensor controllers 32A and 32B receive the sensor operation start command from the projector control unit 14, the phase difference angle sensors 12A and 12B execute processing for obtaining the inclination angles θA and θB, respectively.

  First, the sensor controller 32A acquires the tilt angle θA based on the flowchart shown in FIG.

  The sensor controller 32A sets each phase difference when the distances to the points P2 and P1 are measured as BL and BR, respectively, and sets 0 to the total values SL and SR of the phase differences BL and BR (step S11).

  The sensor controller 32A sets 0 to the count number n (step S12). The count number n indicates the number of times the distance to the chart on the screen 2 is measured.

  The sensor controller 32A outputs a horizontal chart drawing instruction to the signal selection unit 23 so as to project the chart #n (step S13). The signal selection unit 23 receives a command from the sensor controller 32A, and selectively outputs the chart #n generated by the horizontal chart generation unit 26.

The projection light conversion device 24 converts the chart #n selected and output by the signal selection unit 23 into chart projection light.
The optical mechanism unit 25 performs focus control and the like. The chart projection light of the chart #n converted by the projection light conversion device 24 is projected toward the screen 2.

  The sensor controller 32A controls the distance measurement sensor 31A so as to perform distance measurement using the distance measurement windows WL and WR in which the window widths w1 and w2 are set by the projector control unit 14 (step S14). The distance measuring sensor 31A executes an operation of taking light into the two photosensor arrays therein for a certain period of time, and supplies sensor pixel data obtained by this operation to the sensor controller 32A.

  The sensor controller 32A acquires the pixel data of the two photosensor arrays inside the distance measuring sensor 31A (step S15).

  The sensor controller 32A calculates the phase differences BL and BR based on the acquired pixel data of the two photosensor arrays inside the sensor (step S16).

  The sensor controller 32A adds the phase differences BL and BR to the phase difference total values SL and SR, respectively, and holds the added values as new phase difference total values SL and SR (step S17).

The sensor controller 32A increments the count number n by one (step S18).
The sensor controller 32A determines whether or not the count number n is less than 8 (n <8) (step S19).

If it is determined that the count number n is less than 8 (Yes in Step S19), the sensor controller 32A executes the processes of Steps S13 to S18 again.
When the sensor controller 32A sequentially executes the processes of steps S13 to S18 so that the count number n becomes 8, the sensor controller 32A determines that the count number n is not less than 8 (No in step S19).

  If it is determined that the count number n is not less than 8, the sensor controller 32A divides the total phase difference values SL and SR by 8, and obtains average phase differences AL and AR as quotients (step S20).

  The sensor controller 32A calculates the distances L and R according to Equation 4 (step S21).

The sensor controller 32A calculates the angle θs according to Equation 5 (step S22).
The sensor controller 32A supplies the obtained angle θs as the tilt angle θA to the projector control unit 14 and ends this process.

  The sensor controller 32B also performs the same process as the sensor controller 32A. In other words, the sensor controller 32B controls the signal selection unit 23, controls the distance sensor 31B, and obtains the angle θs based on the sensor data obtained from the distance sensor 31B. Then, the sensor controller 32B supplies the angle θs as the inclination angle θB to the projector control unit 14.

  The projector control unit 14 replaces the tilt angles θA and θB supplied from the sensor controllers 32A and 32B with the tilt angles θH and θV according to the relational expression shown in Equation 6.

  The inclination angles θH and θV obtained by the projector control unit 14 are values obtained based on the average phase difference after performing the light capturing operation from the charts # 0 to # 7, so that the average value of the error e becomes almost zero. . Accordingly, the accuracy of the inclination angles θH and θV is increased.

  The projector control unit 14 supplies the tilt angles θH and θV of the screen 2 to the trapezoidal correction unit 22 of the projector drawing unit 11.

  The trapezoid correction unit 22 performs keystone correction based on the inclination angles θH and θV of the screen 2. When the signal selection unit 23 selects the output signal of the trapezoidal correction unit 22, the projection light conversion device 24 converts the video signal corrected by the trapezoidal correction unit 22 into projection light and applies it to the screen 2 via the optical mechanism unit 25. Project. A projected image corrected with high accuracy is formed on the screen 2.

  Next, when the zoom magnification Zoom is changed and the acquired zoom magnification Zoom becomes z1 ≦ Zoom <z2, the projector control unit 14 refers to the conversion table and refers to the respective window widths of the distance measurement windows WL and WR. Set w1 and w2 to 71 (pixels). As shown in FIG. 7B, the pitch multiple m of the distance measurement windows WL and WR is substantially 9 as well.

  The projector control unit 14 transmits a start command to the sensor controllers 32A and 32B so as to start the sensor operation using the distance measurement windows WL and WR having the set window widths w1 and w2. The sensor controllers 32A and 32B execute angle acquisition processing based on the flowchart shown in FIG. 10, and acquire the inclination angles θA and θB.

  Further, when the zoom magnification Zoom is changed and the acquired zoom magnification Zoom becomes z7 ≦ Zoom <z8, the projector control unit 14 refers to the conversion table, and each window width w1 of the distance measurement windows WL and WR. , W2 is set to 68 (pixels). As shown in FIG. 7B, the pitch multiple m of the distance measurement windows WL and WR is approximately 8.

  The projector control unit 14 transmits a start command to the sensor controllers 32A and 32B so as to start the sensor operation using the distance measurement windows WL and WR having the set window widths w1 and w2. The sensor controllers 32A and 32B execute angle acquisition processing based on the flowchart shown in FIG. 10, and acquire the inclination angles θA and θB.

  As described above, according to the present embodiment, the distance measurement window widths w1 and w2 are obtained from the acquired zoom magnification Zoom so that the distance measurement window widths w1 and w2 are an integral multiple of the chart pitch (period interval) p. I set it.

  Therefore, even if the zoom magnification Zoom changes, the average phase difference obtained by the chart shift is not affected, and the distance between the projection points of the projection light can be accurately measured. Further, the tilt angles θH and θV of the screen 2 with higher accuracy can be detected based on the measured distance.

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, in the above embodiment, the conversion table is used to set the distance measurement window widths w1 and w2. However, the distance measurement window widths w1 and w2 may be set based on a calculation formula representing the relationship between the zoom magnification Zoom and the distance measurement window widths w1 and w2.

  In the above embodiment, the pitch p is acquired from the zoom magnification Zoom. However, instead of obtaining from the zoom magnification Zoom, the pitch p can be obtained based on data of an image formed on the distance measuring sensor. For example, the window widths w1 and w2 may be selected such that the pitch multiple m is closest to an integer in the range of 68 to 76 pixels of pixel data.

  By setting the window width by such a method, the distance measurement window widths w1 and w2 are accurately set to be an integral multiple of the chart pitch p without being affected by the individual variations of the projector drawing unit 11 and the distance measurement sensors 31A and 31B. And the distance can be measured accurately.

It is a block diagram which shows the structure of the projector which concerns on embodiment of this invention. It is explanatory drawing which shows operation | movement of the trapezoid correction | amendment part shown in FIG. 1, (1) is an input image | video, (2) is a projection image, (3) shows an inverse transformation image. It is a figure which shows the horizontal chart which the horizontal chart production | generation part shown in FIG. 1 produces | generates. It is a figure which shows the error when the sensor controller shown in FIG. 1 calculates | requires an average phase difference. It is a figure which shows the positional relationship of the projector and screen of FIG. 2A and 2B are diagrams illustrating attachment positions of the projector and the distance measuring sensor illustrated in FIG. 1, in which FIG. 1A is a front view of the projector, and FIG. 2B is a side view of the projector. It is a figure which shows the relationship between zoom magnification, pitch multiple, and ranging window width. It is a figure which shows the relationship between the ranging window width of this embodiment, and a chart waveform. It is a figure which shows the conversion table with which a projector control part is provided. It is a flowchart which shows the angle acquisition process which a projector performs. It is a figure which shows the principle of a phase difference angle sensor. It is a figure which shows the conventional chart. It is a figure which shows the relationship between the zoom magnification at the time of ranging using a conventional chart, a pitch multiple, and a ranging window width. It is a figure which shows the relationship between the conventional ranging window width and a chart waveform.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Screen, 11 ... Projector drawing part, 12A, 12B ... Phase difference angle sensor, 14 ... Projector control part, 22 ... Trapezoid correction part, 23 ... Signal selection unit, 24 ... projection light conversion device, 25 ... optical mechanism unit, 26 ... horizontal chart generation unit, 27 ... vertical chart generation unit, 31A, 31B ... ranging sensor, 32A, 32B ... Sensor controller

Claims (6)

In a distance measuring device that measures a distance between a projection point of projection light and a projection point on the projection surface that projects the projection light,
A chart drawing unit that generates a chart in which light and dark portions are continuously arranged at a set pitch, and projects the projection light of the generated chart on the projection surface to draw the chart;
A plurality of light receiving units arranged at intervals, and sensor units that receive reflected light from the chart drawn on the projection plane,
A window for setting the width of the window as a range in which each light receiving unit of the sensor unit receives light from the chart drawn on the projection plane to be an integral multiple of the pitch of the chart drawn on the projection plane A width setting section;
The distance between the projection point of the projection light and the projection point on the chart drawn on the projection surface based on the phase difference of the chart image received through the respective windows by the respective light receiving units of the sensor unit A distance acquisition unit for obtaining,
A distance measuring device characterized by that. The window width setting unit acquires information on the zoom magnification of the optical mechanism unit that projects the projection light of the specified chart, and acquires the pitch of the light and dark part based on the acquired information on the zoom magnification.
The distance measuring device according to claim 1. The window width setting unit obtains the pitch of the light and dark portions from image data formed by light received by each light receiving unit of the sensor unit;
The distance measuring device according to claim 1. A chart drawing step of generating a chart in which light and dark portions are continuously arranged at a set pitch, projecting the projection light of the generated chart and drawing the chart on a projection surface;
A window width setting step of the width of the window as a light receiving range of the light is set to be an integer multiple of the pitch of the charts drawn on the projection plane from the chart,
A light receiving step of receiving light from the chart through each window with a window width set at a plurality of distance measurement points;
A distance measuring step for obtaining a distance between the projection point of the projection light and the projection point on the chart drawn on the projection surface based on the phase difference of the chart image respectively received at each distance measurement point; The
A distance measuring method characterized by this. The window width setting step acquires zoom magnification information of an optical mechanism unit that projects projection light of a specified chart , acquires a pitch of the light and dark part based on the acquired zoom magnification information, and the window width Is set to be an integral multiple of the acquired pitch,
The distance measuring method according to claim 4, wherein: The window width setting step acquires the pitch of the bright and dark portions from each image data formed by light received at the plurality of distance measurement points, and the window width is an integral multiple of the acquired pitch. Is the step to set,
The distance measuring method according to claim 4, wherein:

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