JPH03287002A - Movement detecting method for speckle pattern and position specifying device using same - Google Patents

Abstract

PURPOSE:To reduce the variance of movement information due to irregularity in the shape of a speckle by averaging the movement information on the speckle pattern at intervals of unit time. CONSTITUTION:When the rough surface of a moving body 1 is irradiated with a coherent electromagnetic wave Bm, the speckle pattern SP is formed with a scattered electromagnetic wave. This pattern is detected by an electromagnetic wave detector 2 and its detection signal is averaged by an averaging processing circuit at intervals of unit time. The variance of the movement information due to the irregularity in the shape of the speckle is reduced by this averaging processing and the moving direction M of the body 1 is detected with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a speckle pattern movement detection method for detecting movement information of a speckle pattern caused by scattering of coherent electromagnetic waves on a rough surface of an object, and a speckle pattern movement detection method using the same. The present invention relates to improvements in position specifying devices (position specifying devices useful for specifying positions on display screens in computer terminals, workstations, personal computers, etc., and for specifying positions for various controlled objects).

[Conventional technology]

As an example of a conventional position specifying device for computer input, a so-called mouse is widely used because it is inexpensive, easy to operate, and has high position specifying accuracy.

The current mainstream mechanical mouse has a ball that can be rotated in any direction protruding from a part of the housing, and the direction and amount of movement can be controlled by the direction and amount of rotation of this ball. This is to detect and specify the position to be specified.

[Problem to be solved by the invention]

However, since such conventional mechanical mice utilize contact rotation of a mechanical ball, there are problems in terms of durability, and there is also a limit to the improvement in positional accuracy. .

An optical mouse that optically detects movement information in a non-contact manner has already been provided as a solution to the drawbacks of mechanical mice.

This type of optical mouse is known, for example, from Japanese Patent Application Laid-Open No. 57-10792.
No. 9, as shown in Publication No. 57-207930,
It includes a main body in which a light source and a photodetector are housed,
Movement information is detected by moving the main body on a special underlay engraved with a regular grid pattern and counting the number of grids on the special underlay that it crosses during movement.

However, this type of optical mouse requires a special underlay, which not only limits the freedom of use, but also makes it unusable if the underlay gets dirty or damaged, which reduces its durability. Even points are not enough, and furthermore,
Since the resolution of movement detection information is determined by the fineness of the grid engraved on the dedicated underlay, it is not easy to increase the resolution of movement information detection without increasing cost.

As a solution to these drawbacks of optical mice,
The inventor of the present application has already provided a method using movement information of speckle patterns (Japanese Patent Laid-Open No. 116878/1983), but it was found that there was a problem that the position specification accuracy was slightly degraded.

Note that this problem is not limited to the mouse mentioned above.
The same problem occurs in position specifying devices such as robots, and also in various devices (movement detection devices, speed detection devices, etc.) that use detection of movement information from speckle patterns, detection of movement amount and movement speed. A problem may arise in that accuracy varies.

The inventor of the present application assumed that the above-mentioned problem was caused by the irregularity of the shape of speckles, and devised a method for detecting movement of speckle patterns, and also utilized this method for detecting movement of speckle patterns. This led to the devising of a position specifying device (the present invention).

[Means to solve the problem]

That is, as shown in FIG. 1(a), the present invention detects movement information M of a speckle pattern caused by scattering of a coherent electromagnetic wave B111 against a rough surface l of an object. is detected by the electromagnetic wave detector 2, and then the electromagnetic wave detector 2
The detection signals are averaged every unit time.

In such a method invention, in addition to the position specifying device described later, the method invention can be applied to the speed of a movement amount detection device, speed sensor, etc. that is necessary for controlling the position of a self-propelled cart, etc. Examples include a detection device.

In addition, the speckle pattern SP is shown in Fig. 1(a).
As shown in , it may be caused by so-called diffraction field speckles without an imaging system, which is caused by scattering of the object's rough surface 1, or
It may also be caused by so-called speckle in the image field, in which scattered light from the rough surface l of the object is imaged onto a predetermined portion by an imaging lens.

Furthermore, the electromagnetic wave detector 2 collects movement information M of the speckle pattern SP (in addition to movement amount, movement speed,
(including moving acceleration) may be selected as appropriate, and the design may be changed as appropriate for the averaging process of the detection signal from the electromagnetic wave detector 2, such as dividing the pulse signal as appropriate. I can do it.

Furthermore, regarding the electromagnetic wave detector 2, from the viewpoint of easy real-time processing and accurate determination of the movement information M including the positive/negative of the movement direction of the speckle pattern SP, the electromagnetic wave detector 2 shown in FIG. ), at least one set of electromagnetic wave detection elements 2 a and 2 b are arranged in parallel for each dimension of the direction component necessary for detecting the movement information M,
As shown in FIG. 1(c), a set of electromagnetic wave detection elements 2
Preferably, the configuration is such that the phase difference τ between the output signals from a and 2 b is detected.

In this case, when detecting -dimensional movement information M, one set of electromagnetic wave detection elements 2 is used for one direction component.
For example, two or three sets of electromagnetic wave detecting elements 2 may be arranged so that the straight lines connecting the electromagnetic wave detecting elements 2 a and 2 b are orthogonal to each other.
By using a and 2 b, it becomes possible to detect two-dimensional or three-dimensional movement information.

Furthermore, the set of electromagnetic wave detection elements 2a.

Although the processing system for processing the output signal from the electromagnetic wave detector 2 consisting of the electromagnetic wave detector 2b may be selected as appropriate, it is important to consider the influence of errors due to the irregularity of the speckle pattern SP on the obtained phase difference τ. From the viewpoint of reducing the number of electromagnetic wave detection elements 2a, 2 per dimension, multiple sets of electromagnetic wave detection elements 2a, 2
b (such as those assembled in an array) to average each phase difference τ obtained from each set of electromagnetic wave detection elements,
It is preferable to adopt a configuration in which the phase difference τ obtained from a pair of electromagnetic wave detection elements 2 a and 2 b is time-averaged, or in which both are used in combination.

Further, the invention of a position specifying device using the speckle pattern movement detection method described above includes a movable body 3 movable with respect to the rough surface 1 of the object, and a movable body 3 that On the other hand, there is an electromagnetic wave source 4 that irradiates a coherent electromagnetic wave Bm from a predetermined part of a movable body 3 to the rough surface l of the object; an electromagnetic wave detector 2 that detects relative movement information of the speckle pattern SP with respect to the movable body 3 generated from the electromagnetic wave detector 2; and an averaging processing means 5 that averages the relative movement information detected by the electromagnetic wave detector 2 for each unit time. The position to be designated is specified based on the relative movement information from the averaging means 5.

In such a device invention, the movable body 3 can house at least the electromagnetic wave source 4 and the electromagnetic wave detector 2, and can also move along a predetermined direction or an arbitrary direction of the rough surface l of the object. You may choose as appropriate as long as it is suitable.

Further, the electromagnetic wave source 4 may be appropriately selected, including a laser, as long as it emits a coherent electromagnetic wave B+n having a wavelength smaller than the degree of unevenness of the rough surface 1 of the object.

Furthermore, the detection signal from the electromagnetic wave detector 2 is averaged by averaging processing means 5.
The design of the signal processing system after averaging may be changed as appropriate, but from the point of view of simplifying the signal processing system of external equipment, the signal for binarizing the signal from the averaging means 5 It is preferable to add a processing system. Further, in order to accurately obtain the relative movement information from the averaging means 5, it is possible to use an array of electromagnetic wave detection elements arranged one-dimensionally, two-dimensionally, or three-dimensionally along the movement reference direction, and to use a cross-correlation method. It is preferable to
No. 78, Example 2).

In addition, regarding the location of the signal processing section, it is possible to select an external device, the movable body 3, or a device connected to the external device as appropriate. It is preferable to arrange a signal processing section in 3. Furthermore, from the viewpoint of effectively preventing deformation of the speckle pattern SP, the electromagnetic wave B
It is preferable to design such that a re-diffraction optical system is interposed between the rough surface l of the object to be irradiated and the electromagnetic wave detector 2 (see Example 4 of JP-A-63-116878). Furthermore, in order to further improve the operability of the position specifying device, it is preferable to design it so that the movement path between the movable body 3 and the specified object can be changed (as described in the example of JP-A-63-116878). (see 5).

[Effect]

In the above-mentioned technical means, according to the method invention shown in FIG. Output. Then, this detection signal is averaged for each unit time, and movement information M of the speckle pattern SP is detected based on the averaged signal.

At this time, the pulse width of the detection signal from the electromagnetic wave detector 2 will vary depending on the shape of the speckle, but the pulse width of each averaged signal obtained by averaging the detection signals from the electromagnetic wave detector 2 will be approximately equal. - set to something.

Further, according to the position specifying device invention shown in FIG. 1(d),
An electromagnetic wave Bm is irradiated from an electromagnetic wave source 4 such as a laser to the rough surface l of the object, and the movable body 3 moves at a velocity v4 relative to the rough surface 1 of the object U,
If the object rough surface 1 moves by a distance U at a speed V, the rough surface 1 of the object moves relative to the movable body 3 by a distance U.

The speckle pattern SP scattered by the object rough surface 1 moves proportionally by u8 at a speed V on the light receiving surface of the electromagnetic wave detector 2 as the object rough surface 1 moves relative to the object surface 1.

At this time, the electromagnetic wave detector 2 outputs detection signals with varying pulse widths depending on the intensity pattern of the speckle pattern SP moving on its light receiving surface.
The detection signal is averaged for each unit time by the averaging means 5 and converted into a substantially average pulse width signal.

Therefore, each averaged signal of the detection signals from the electromagnetic wave detector 2 detects the relative movement 1 of the object rough surface 1 with respect to the movable body 3 at approximately equal intervals, and the averaged detection signals Based on the signal, a specified object such as a cursor is moved at approximately equal intervals, and the position of the specified object is specified.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

2 and 3 show the present invention applied to a position specifying device (so-called mouse) for manual computer operation.

In the figure, 10 is a rough object surface, 11 is a movable housing having a sliding pressing pad lla at the bottom, 12 is a semiconductor laser housed in the movable housing II and serves as an electromagnetic wave source for emitting a laser beam, and 13 is a movable housing having a sliding pressing pad lla at the bottom. a semiconductor laser controller that controls on/off the semiconductor laser I2;
14 is a condensing lens made of a plastic lens, a Fresnel lens, etc. that guides the beam from the semiconductor laser 12 to the irradiation area Q of the rough object surface 10 with a predetermined spot diameter W; 15 is a condenser lens for ensuring the optical path length of the detection optical system. A reflecting mirror 16 that appropriately reflects the reflected beam from the object rough surface 10 is a detector disposed at the end position of the optical path of the detection optical system, and detects movement information of the speckle pattern SP generated in the reflected beam from the object rough surface 10. , 17 is a signal processing system that converts the output signal from this detector 16 into a movement control signal for computer input, 18 is an input switch for performing a position designation operation, and 19 is a signal for external equipment (not shown). It is a connection harness.

In this embodiment, the detector 16 is particularly
As shown in the figure, light-receiving cells 16a to 16d each consisting of a photodiode are arranged in parallel along the X and Y directions, which are movement reference directions, and are made of photodiodes spaced apart by a predetermined distance. In this case, the condenser lens 14 includes each light receiving cell 16a~! of the detector I6. The beam diameter is adjusted so that the average diameter of speckles becomes larger than that of 66.

Further, as shown in FIG. 5, the signal processing system 17 is arranged in parallel in the y direction with an xFt signal processing system 17X that processes signals from the light receiving cells 16a and 16b arranged in parallel in the x direction. and a y-component signal processing system 17y that processes signals from the light receiving cells 16a and 16c.

In this embodiment, the signal processing system 17 includes a corresponding set of light receiving cells 16a, 16b, or 16a.

an amplifier 21 that amplifies the output from the amplifier 2; a cut filter 22 that removes DC components, noise, and high frequency components from the output of the amplifier 2; and a binary filter that binarizes the output of the cut filter 22 with a threshold value of 0. It is composed of a converting circuit 23 and a frequency divider 24 that divides the frequency of the pulse output from the binarizing circuit 23 by, for example, 5.

The output of the signal processing system 17 is input to the mouse interface of the computer, and based on this, the display screen 2 is
The position of the cursor 27 on 6 is specified.

Next, the operation of the position specifying device according to this embodiment will be explained.

Now, the laser beam irradiated from the semiconductor laser 12 reaches the detector 16 after being reflected by the rough surface 10 of the object, and a speckle pattern SP is generated on the detector 16.

In this state, when the movable housing 11 is moved on the rough object surface 10, the detector 16
The speckle pattern S on each light receiving cell 16a to 16d of
P moves. This smoothness.

The X-direction component of the movement of the speckle pattern SP is caused by a pair of 16a and 16b arranged in parallel along the X direction, and the y-direction component of the movement of the speckle pattern SP is caused by the pair of 16a and 16b arranged in parallel along the y direction. It is detected by a pair of light receiving cells 16a and 16c.

Here, since the detection operations for each movement component of the speckle pattern SP are substantially the same, the movement detection operation for the X-direction component will be described below.

That is, in FIG. 5, the speckle pattern S
When P moves toward the light receiving cells 16a to 16b, the output signal of the light receiving cell 16a changes in accordance with the movement of the speckle pattern SP. At this time, speckle pattern SP
If the deformation of can be ignored, the adjacent light receiving cell 16b has
As shown in FIG. 6(a), a signal is obtained which is delayed by a time τX in the form of a time lag with the output signal of the light receiving cell 16a.

This output signal is input to the X component signal processing system 17x,
After being amplified by the amplifier 21, as shown in FIG. 6(b), it is converted into a signal that crosses the 0 line by the cut filter 22, and then, as shown in FIG. 6(c), the signal is converted to a signal that crosses the 0 line. 23, the signal is binarized with the 0 line as a reference and converted into a two-phase pulse signal.

As shown in FIG. 6(d), this two-phase pulse signal is frequency-divided by a frequency divider 24, for example, by 5, and converted into a temporally averaged pulse signal. Therefore, for each pulse signal before passing through the frequency divider 24, irregularities in the shape of speckles directly affect the pulse width of each pulse signal, and the pulse width of each pulse signal varies. However, in the frequency-divided pulse signal, the pulse width of each pulse signal is set to be approximately equal.

By the way, regarding the two-phase pulse signal from the binarization circuit 23, the moving direction of the speckle pattern SP can be determined from the time difference τX between the m-phase and the n-phase, and the number of pulses is the moving amount of the speckle pattern SP. It is proportional. Therefore, regarding the frequency-divided pulse signal as well, the moving direction of the speckle pattern SP can be determined from the phase difference between the two phases, and the number of pulses can be said to be proportional to the amount of movement of the speckle pattern SP.

Therefore, when this frequency-divided pulse signal is manually entered into the computer's mouse interface, the cursor 27
moves smoothly at a substantially constant rate with respect to the amount of movement of the mouse (movable)\Ujifugu 11).

In addition, in this embodiment, as shown in FIGS. 2 and 3, in order to avoid the situation where the light of the semiconductor laser 12 is directly or indirectly irradiated into the eyes of the user or people around him, A safety device 30 is attached.

This safety device 30 has an insertion hole 31 at the bottom of the movable housing 11, and the insertion hole 31 has a maximum dimension I2.
The detection protrusion 32 that can protrude by a certain amount (the dimension is set to be larger than the thickness of the pressing pad lla) is inserted so that it can move forward and backward, and the detection protrusion 32 is turned outward by the return spring 33 as appropriate. The detection protrusion 32
A limit switch 34 is provided on the proximal end side of the detector 34, which is turned off when the detection protrusion 32 is protruded to the maximum extent. It is designed to be linked.

Therefore, in this embodiment, when the device moves away from the object plane A, as shown in FIG. 7(a),
The detection protrusion 32 is arranged to protrude to the maximum extent by the return spring 33, so that the limit switch 3
4 is turned off, and the semiconductor laser 12 is turned off via the semiconductor laser controller 13 based on the off signal. Therefore, under such circumstances, the situation in which the light of the semiconductor laser 12 is irradiated onto the eyes of the user or those around him can be effectively avoided.

On the other hand, when this device is placed on the object plane A, as shown in FIG.
), the detection protrusion 32 is pushed into contact with the object surface A, and the limit switch 34 is turned on.
The semiconductor laser 1 via the semiconductor laser controller 13
2 is turned on and normal positioning operations can occur.

Note that this type of safety device at least detects whether or not there is an abnormal situation in which electromagnetic waves from an electromagnetic wave source such as the semiconductor laser 12 directly or indirectly reach the eyes of the user or people nearby. As long as it is equipped with an abnormal situation detection means and an electromagnetic wave stopping means for stopping the electromagnetic waves from being emitted to the outside of the movable housing 11, the design is not limited to that shown in the embodiments, and the design can be changed as appropriate. It is possible.

For example, among the abnormal situation detection means described above, as in the embodiment, a method for determining that an abnormal situation exists by detecting that the movable housing 11 has moved away from the object surface A by a predetermined distance may include an electromagnetic wave source (spec By utilizing the fact that the reflected intensity of electromagnetic waves irradiated to the object surface A changes depending on the distance from the electromagnetic wave source (whether the same or different from the electromagnetic wave source for generating the electromagnetic waves), the reflected intensity can be detected, and the irradiation of electromagnetic waves can be Spot Q (
One example is one that detects the position of the irradiation spot Q by utilizing the fact that the position of the irradiation spot (see FIG. 2) changes depending on the distance.

In addition, as another method of the abnormal situation detection means, the attitude of the movable housing 11 is detected, and if the apparatus itself is turned upside down or 90 degrees from the normal attitude.
It is determined that there is an abnormal situation when the tilting or the like is detected. For example, as shown in FIG. When it is in the N position, it is determined that the posture is normal, and the posture shown in Fig. 8 (b
) As shown in (c), the movable object 41 of the attitude detector 40
If the position is outside the normal position N, it may be determined that the position is abnormal.

On the other hand, the electromagnetic wave blocking means may be one that stops the generation of electromagnetic waves itself, such as stopping the power supply to the electromagnetic wave source such as the semiconductor laser 12, as in the embodiment, or a shutter, etc. The movable housing 11 may be designed to prevent electromagnetic waves from being irradiated to the outside of the movable housing 11.

〔Effect of the invention〕

As explained above, according to the speckle pattern movement detection method according to claim 1, since the movement information of the speckle pattern is averaged for each unit time, irregularities in the speckle shape can be detected. It is possible to reduce variations in the movement information caused by the movement information, and the detection accuracy of the movement information of the speckle pattern can be improved accordingly.

In particular, according to the speckle pattern movement detection method according to claim 2, at least one set of electromagnetic wave detection elements arranged in parallel in the moving speckle pattern detects the temporal fluctuation of the speckle pattern, and Since the movement information of the speckle pattern can be detected through simple processing such as determining the phase difference between the speckle patterns, real-time processing is easy, and various movement information including the movement direction of the speckle pattern can be easily obtained.

Further, according to the position specifying device according to claim 3, the relative movement information of the speckle pattern detected by the electromagnetic wave detector is averaged for each unit time, and the position of the specified object is determined based on this average relative movement information. This reduces the variation in the relative movement information of the speckle pattern due to the irregularity of the speckle shape, and improves the detection accuracy of the relative movement information of the speckle pattern. It is possible to reduce the variation in the moving distance of the specified object, and improve the position specification accuracy.

[Brief explanation of drawings]

FIG. 1(a) is an explanatory diagram showing a speckle pattern movement detection method according to the present invention, FIGS. 1(b) and (c) are explanatory diagrams showing one aspect of an electromagnetic wave detector and its detection operation diagram,
FIG. 1(d) is an explanatory diagram showing a schematic configuration of a position specifying device according to the present invention, FIG. 2 is an explanatory diagram showing an embodiment of a mouse to which this invention is applied, and FIG. 3 is a partially broken bottom view thereof. , 4th
The figure is an explanatory diagram showing the configuration of the detector according to the example,
The figure is a block diagram showing the signal processing system of the detector according to the embodiment, FIGS. 6(a) to (d) are timing charts showing the operation timing of the signal processing system, and FIG. 7(a) (
b) is an explanatory diagram showing an example of the operation of the safety device used in the embodiment, and FIGS. 8(a) to (c) are explanatory diagrams showing modified examples of the safety device. [Explanation of symbols] SP... Speckle pattern Bm... Electromagnetic wave M... Movement information l... Object rough surface 2... Electromagnetic wave detector 2 a, 2 b... Electromagnetic wave detection element 3. ...Movable body 4...Electromagnetic wave source 5...Averaging processing means

Claims (1)

[Claims] 1) When detecting movement information (M) of a speckle pattern caused by scattering of a coherent electromagnetic wave (Bm) on a rough object surface (1), time fluctuations of the speckle pattern (SP) are detected. A method for detecting movement of a speckle pattern, characterized in that after detection by an electromagnetic wave detector (2), the detection signal of the electromagnetic wave detector (2) is averaged every unit time. 2) In the device according to claim 1, the electromagnetic wave detector (2) has at least one set of electromagnetic wave detection elements (2a, 2b) arranged in parallel per one dimension, and The phase difference (τ) of the output signal of
A method for detecting movement of a speckle pattern, characterized in that a direction of movement is detected based on. 3) A movable body (3) that is movable with respect to the rough object surface (1), and a coherent electromagnetic wave that is built into this movable body (3) and is transmitted from a predetermined part of the movable body (3) to the rough object surface (1). (Bm)
an electromagnetic wave source (4) that irradiates an electromagnetic wave (Bm) that is incorporated into the movable body (3);
an electromagnetic wave detector (2) that detects relative movement information of a speckle pattern (SP) generated from the object's rough surface (1) with respect to the movable body (3) due to irradiation; and averaging processing means (5) for averaging the relative movement information for each unit time, and the position to be designated is specified based on the relative movement information from the averaging means (5). Characteristic positioning device.