JPH0981765A - Method and device for coordinate input - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the coordinate input device which enables a host device to receive coordinate information with arbitrary resolution within an arbitrary range of arbitrary input stroke information at need. SOLUTION: A coordinate processing means 202 generates coordinate information by detecting coordinate information on existent stroke input from a coordinate input means 201 at specific sampling intervals and a curve approximating means 204 performs curve approximation according to need and stores the result in a data storage means 203. Then when a request to transfer a specific range in response to the existent stroke input is received from the host device 300, coordinate information on the received transfer request specific range is read out of the data storage means 203, curve approximation is performed by the curve approximating means 204 according to need, and the result is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input method and device, for example, a coordinate input method and device for calculating coordinate data and re-outputting it in accordance with a request from a connected host device.

[0002]

2. Description of the Related Art Conventionally, the following method has been adopted as a method for sending input coordinates from a coordinate input device to a host device.

Various information centered on the coordinate information obtained by the coordinate input device has been transmitted from the coordinate input device to the host device at constant sampling rates.

From the host device to the coordinate input device,
The reset signal to the coordinate input device and the instruction means for the protocol of information transmission from the coordinate input device are the main ones.Under normal use conditions, unidirectional data supply from the coordinate input device to the host device is possible. It was only done.

At this time, when the host device requires more detailed coordinate point sequence data, the host device instructs the coordinate input device to send the coordinates at a finer sampling rate. After that, the operator again inputs coordinates using the coordinate input device. Alternatively, the host device performs curve approximation processing on the coordinate point sequence already obtained from the coordinate input device, and uses the data stored as a result to generate more detailed coordinate point sequence data. .

[0006]

However, in the above configuration, when the coordinate input device is requested to output the coordinate at a finer sampling rate, the operation input is required again, which is very troublesome. At the same time, as all information is detailed, the amount of information as a whole also increases,
In addition, the amount of processing is large, the load on the host device to be processed is increased, and other processes in the host device are often reduced or data is often lost. In many cases, there was a problem that the coordinate data of could not be obtained.

Further, when curve approximation processing or the like is performed on the host device side from the already obtained coordinate point sequence and the data interpolated by this is used, the load on the host device is also increased, and In some cases, the curve-approximated data was significantly different from the coordinate input actually made to the coordinate input device due to the lack of feature points due to the coarse sampling rate.

[0008]

In order to solve the above problems, in the present invention, the host side sets a specific point or a specific range in the coordinate point sequence to the coordinate point sequence output to the host side. A means for designating to the coordinate input device side is provided, and on the coordinate input device side that receives this, the characteristic points of the coordinate point sequence obtained by performing internal oversampling beforehand are used to perform a more accurate curve approximation. The present invention is characterized in that means is provided for finely re-outputting the specific point or the coordinate point sequence of the specific range.

That is, in a coordinate input device for outputting coordinates at a constant sampling rate, a storage means for detecting coordinate information of a stroke input at a predetermined sampling interval to generate and store the coordinate information, and the storage means from the outside. It is characterized by further comprising: a receiving unit for receiving a transfer request of a specific range stored in the previous stroke input, and an output unit for outputting the coordinate information of the transfer request specific range received by the receiving unit to the outside.

Further, for example, the receiving means is capable of accepting a coordinate information transfer request at a resolution higher than a sampling rate for a specific range, and the output means is capable of receiving a coordinate information transfer request for a specific range at a resolution higher than the sampling rate. The feature is that coordinate information is generated and can be output. Alternatively, the specific range may be coordinate information corresponding to a specific position or a specific section. Further, the storage means is characterized in that the curve is interpolated using a curve approximation function to generate and store coordinate information. Further, for example, it is characterized in that oversampling data detected inside the apparatus is used as data when using the curve approximation function.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the embodiments of the present invention will be described below with reference to the drawings. (First Example of Embodiment of the Invention) FIG. 1 is a block diagram showing a configuration of a coordinate input device and a host device according to an example of an embodiment of the present invention.

In FIG. 1, reference numeral 200 is a coordinate input device of the first embodiment of the present invention, and 300 is a host device to which the coordinate input device 200 is connected. Send and receive various information at.

In the coordinate input device 200, 201 is a coordinate input means by which the operator can input a desired locus and can be constituted by, for example, a digitizer.
Reference numeral 202 denotes coordinate processing means for performing various processes of the coordinate input device 200 of this example and communication with the host device 300, and 203 denotes data for continuously storing coordinate points and feature points obtained by the coordinate input means 201 in a limited range. The storage means 204 is a curve approximation calculation means for performing a curve approximation calculation from coordinate points and feature points.

The coordinate input device 2 of the present example having the above configuration
An overview of the operation of 00 will be described below with reference to FIG. FIG. 2 is a drawing best showing the operation of this example, in which 1 is input from the coordinate input means 201 of the coordinate input device 200 of this example.
It represents the locus of the stroke.

In FIG. 2, reference numeral 101 indicates the locus of actual input, and PS (103) is the host device 300.
It is an input start point of a locus sampled and output at every predetermined timing for outputting in the normal input mode, and is the first position coordinate output to the host device 300 side. P1 (104) is the next sampling coordinate to be output to the host side, and similarly P2 to the host side.
(105), P3 (106), and PE (107) which is the input end point of the locus are sequentially output.

At this time, on the side of the host device 300 which has received the point sequence information from PS to PE, when the locus information of one stroke is to be continuously reproduced, 10
The linear interpolation as shown in 2 or the curve interpolation by the spline curve approximation calculation as shown in 109 is performed.

Even in such a case, in this example, any position from PS to PE, here P
By designating X by the position parameter T (111) on the linear interpolation line, it is possible to output more accurately. The details will be described below.

FIG. 3 shows the coordinate input means 201 in this example.
6 is a diagram for explaining a method of extracting a feature point of trajectory information by using an oversampling method in FIG. In FIG. 3, reference numeral 301 denotes the locus in which the input is actually made.
02 and 303 are coordinate data sent to the host side, 30
4 and 305 are the sampling points of 302 and 303,
Immediately after this, it is difference vector information of the tent sampled at the timing of oversampling after a fixed time, and pseudo tangent vector information holding the characteristic of the curve.

Here, the fixed time is set to 304 and 305.
It is possible to treat the pseudo tangent vector information as substantial tangent vector information by setting the time sufficiently small as compared with the sampling interval and obtaining the information of the sufficient quantization unit amount as the difference vector information. Become.

FIG. 4 shows an operation flowchart of the coordinate input device of the present example which realizes the above processing. FIG. 4 is a diagram showing a flow of processing that is performed in units of one normal sampling coordinate point when coordinate input is being performed in the coordinate processing means 202 of the coordinate input device 200 according to the present example.

First, in step 402, the locus to be sent to the host device 300 is input from the coordinate input means 201. The input locus is captured by the coordinate processing means 202 and stored in the data storage means 203. Then, in step 403, the coordinates immediately after the previously obtained coordinates, which are also obtained by the coordinate input means 201, are read. Then, in step 404, step 402 and step 403.
The difference of the coordinate information obtained by is calculated, and this is made pseudo tangent vector information.

Next, at step 405, it is judged whether or not this normal one sampling coordinate information is the first information after pen down. If this normal one-sampling coordinate information is the first information after pen down, the process proceeds to step 406, and the same assigned ID number is assigned to the continuous strokes and recorded. Then, the process proceeds to step 407.

On the other hand, in step 405, if this normal one-sampling coordinate information is not the information of the first shot after pen down, the process proceeds directly to step 407. In step 407, the coordinates acquired in step 402 are stored in the data storage means 203. Then, in step 408, the pseudo tangent vector information calculated in step 404 is recorded in the data storage means 203.

Next, in step 409, the host device 300
The coordinate information fetched in step 402 is output. Then, in step 410, it is determined whether the one sampling coordinate point is a pen-up point. If the one sampling coordinate point is not the pen-up point, the process ends.

On the other hand, if the one sampling coordinate point is the pen-up point in step 411, step 411
Go to step 1 and set the ID number to be assigned for each stroke to 1
The unit is incremented and the process ends. Here, the ID number assigned to the stroke uses a finite counter means, and may be constituted by a counter or the like that can identify a sufficient amount of stroke expected to be requested from the host side. Accordingly, when the counter means exceeds the maximum value that can be counted, the stroke ID number automatically returns to the initial value.

Next, the processing when the host device 300 makes an inquiry about the input coordinate information to the coordinate input device 200 of this example will be described. FIG. 5 is a flowchart showing a flow of interrupt processing performed when the host device 300 makes an inquiry about coordinate information to the coordinate processing means 202.

In FIG. 5, first, in step 502, inquiry information from the host device 300 side is read. Then, in step 503, the data about the stroke inquired in step 502 is read from the data storage means 203. Then, in step 504, the curve approximation calculation is executed using the data read in step 503. Then step 505
From the result calculated in step 504 in step 502,
Outputs the answer to the query read by.

The details of the operation of this embodiment described above will be described in detail below with reference to a specific example.

In the following description, as shown in the configuration of FIG. 1, the coordinate input device 200 and the host device 300 are connected, and in the coordinate input means 201, there are various types as shown in FIG. 2 and FIG. It is performed assuming that stroke information including a curve is input. At this time, in the coordinate processing means 202, the processing shown in FIG. 4 is executed for each sampling point.

First, in step 402, the coordinate information detected by the coordinate input means 201 is fetched by the coordinate processing means 202. Subsequently, in step 403, similarly, the coordinate information acquired after the fixed time immediately after step 402 is acquired by the coordinate processing means 202. Next, in step 404, the difference between the two coordinate information read in the above two steps is calculated.

Further, in step 405, it is determined whether or not it is the first point after pen down. If it is the first point after pen down, data storage is performed in order to determine the stroke input in which the stroke ID counted by the specific counter means, which indicates a new stroke in step 406, is continuously input. It is stored in the means 203 in association with the stroke input. On the other hand, if it is not the first point after pen down, it is regarded as a part of a continuous stroke and the process proceeds to the next step.

In either case, the process proceeds to step 407, and the coordinate information fetched in step 402 is stored in the data storage means 203. Then, in step 408, the difference information calculated in step 404 is recorded in the data storage means 203 as pseudo tangent vector information. Next, in step 409, the coordinate information fetched in step 402 is output to the host device 300. In step 410, it is determined whether the one sampling point is a pen-up point. If the one sampling point is the pen-up point, the process proceeds to step 411, and the stroke ID number is incremented in preparation for the next stroke input.

Next, a case will be described in which, in the above-mentioned cycle, the host device 300 issues an inquiry for detailed coordinate information regarding a specific range of the specific stroke locus shown in FIG. To do. The following processing is the most characteristic configuration of this example.

When an inquiry is generated from the host device 300, the coordinate processing device 200 starts an interrupt process as shown in FIG.

First, in step 502, inquiry information is read from the host device 300. Here, the inquiry information is the number of previous pieces of inquiry information.
Information such as the stroke information sent to the host device 00, the number of coordinate points between the coordinate points in the stroke, and the step size.
Any information can be requested as long as the information can specify the position of the coordinate information required by the 0 side.

FIG. 6 shows an example of a format for requesting detailed coordinate information from the host device 300.

In FIG. 6, reference numeral 601 is stroke specifying information for requesting detailed coordinates. Here, there is a method for specifying a stroke based on the above-mentioned stroke ID information, and how many strokes before the stroke information sent so far. Any method of identifying the stroke with information indicating whether it is stroke information may be adopted. In the following description, a case will be described in which a method of identifying a stroke with information indicating how many strokes of stroke information has been sent so far is used.

Reference numeral 602 is specification information of a start point of requesting the information of the number of the stroke sent to the host device 300 of the stroke specified by the stroke specification information, and 603 is the specification information of the end point thereof. Further, reference numeral 604 is required resolution information for specifying the required resolution of the detailed coordinate information,
It is information indicating how much information is requested between the requested coordinate information start point information 602 and the requested coordinate information end point information 603.

The following description will be given taking the case shown in FIG. 2 as an example. In the example of the stroke locus shown in FIG. 2, the coordinate portion required by the host device 300 is between the coordinate points P1 and P2 which are the stroke loci sent three times before, and the coordinate divided into approximately 10 equal parts. This is the case when there is an information transfer request that is necessary. The inquiry information shown in FIG. 6 described above is, for example, as follows.

(3,2,3,10) where the symbol 3 is
It represents the stroke three times before, and the following symbols 2 and 3 indicate that coordinate information between the second and third strokes of the stroke is required, and the last symbol 10 indicates that the coordinate information is approximately 10. It indicates that the coordinate information divided equally is necessary.

Next, in step 503 of FIG. 5, the stroke information of three strokes before the current stroke ID number is read from the data storage means 203, and in step 504, curve approximation calculation is performed.

Here, the stroke data used for the calculation is searched based on the stroke ID number recorded in step 406 of FIG. 4, and thereafter, step 407.
And the point sequence information based on the coordinate information and the pseudo tangent vector information recorded in step 408.

The curve function used in step 504 is a cubic spline curve function here. However, for example, a curve function such as a B-spline curve function or a Bezier curve function that can generally express a curve is used. It goes without saying that you can substitute for it.

The cubic spline curve function is based on some data points originally given, and passes through the data points.
This is to generate a quadratic curve. However, since it is necessary to calculate the tangent vector of each data point passing at that time,
Generally, it is not suitable for high-speed calculation. However, in this example, since the pseudo tangent vector information calculated in step 404 can be used as a feature point, it is possible to generate a curve extremely accurately and at high speed.

Since the cubic spline curve function is not directly related to this example, continuous 2
To give a general formula for a three-dimensional spline curve given two coordinate points and their tangent vectors,
A cubic spline and a curve passing through this designated n position vector Pk (where 1≤k≤n) with the tangent vectors P'1 and P'n of the end points can be expressed as follows.

[0046]

[Equation 1]

If the chord length is tk + 1,

[0048]

[Equation 2]

Next, in step 505, step 5
Host device 30 based on the curve function calculated in 04.
Calculate the corresponding coordinate sequence data that 0 made an inquiry,
Output to the host device 300.

As described above, according to this example, the host device 300 can receive more detailed data on an arbitrary portion of an arbitrary stroke by sending an inquiry to the coordinate input device 200. Become.

(Second Example of Embodiment of the Invention) In the first example of the embodiment of the invention described above,
Although detailed data is requested for the stroke section from the coordinate point P1 to the coordinate point P2 in FIG. 2, when the position or section of the stroke data is designated, linear interpolation as shown by 102 in FIG. 2 is performed. Alternatively, the position or section of the stroke data may be designated by using a normalization parameter in which each chord length is 1.

For example, when coordinate data at the position of the approximate PX in FIG. 2 is required in the host device 300, the approximate PX in the ratio between the coordinates P1 and P2.
A distance point T111 from P1 where 108 is located is derived, and this is designated by the ratio T / L (where L is the chord length between the coordinate P1 and the coordinate P2) to the chord tone between the coordinate P1 and the coordinate P2.

In this case, the stroke data designation from the host device 300 and the position designation in the stroke data are as follows: (3, 2, 0.3) ) Can be Here, the symbol 3 indicates that the stroke data is three strokes before, and the symbol 2 indicates the second coordinate point. The symbol 0.3 is the above-mentioned T / L calculation result.

By using such a designation method, the coordinate P
Between one coordinate P2, the normalized position parameter of the curve approximation operation in step 504 of FIG. 5 can be made the same as the designation method instructed by the host device 300, and a more efficient curve approximation operation can be performed. Is possible.

As described above, according to the embodiment of the invention described above, only when necessary, only for a necessary portion,
By inquiring the coordinate input device 200 from the host device 300 about the detailed coordinate data with respect to the stroke data received in the past, the coordinate input device 200 allows the host device 300 to perform a detailed coordinate data inquiry without any load. Even if the coordinate data can be retransmitted to 300, and the host device 300 does not have a recording means for the stroke data, or if the data is modified, it is obtained from the coordinate input device 200 in the past. The information can be reused.

Further, by performing the curve interpolation, it is possible to obtain the intermediate coordinates of the stroke locus which the host device 300 has not obtained in the past without burdening the host device.

Further, by using the oversampling data stored only in the coordinate input device when performing the curve interpolation, more accurate detailed data can be retransmitted.

The present invention may be applied to either a system composed of a plurality of devices or an apparatus composed of a single device. Needless to say, the present invention can be applied to a case where the present invention is implemented by supplying a program to a system or an apparatus. In this case, the storage medium storing the program according to the present invention constitutes the present invention. Then, by reading the program from the storage medium to a system or an apparatus, the system or the apparatus operates in a predetermined manner.

[0059]

As described above, according to the present invention, the external device allows detailed coordinates for stroke data received in the past with respect to the coordinate input device only when necessary. By inquiring about data,
It is possible to receive desired coordinate data from the coordinate input device without applying any load. Therefore, if the external device does not have a means for recording stroke data,
Even if the data is modified, the information obtained from the coordinate input device in the past can be reused.

Further, by performing the curve interpolation on the coordinate information, it is possible to obtain more detailed intermediate coordinates of the stroke locus for the external device without imposing a load on the external device. Further, by using the oversampling data stored only in the coordinate input device when performing the curve interpolation, more accurate detailed data can be retransmitted.

[Brief description of drawings]

FIG. 1 is an overall block diagram of a coordinate input device showing an example of an embodiment of the present invention.

FIG. 2 is a diagram illustrating stroke trajectory data used in this example.

FIG. 3 is a diagram illustrating pseudo tangent vector information in stroke trajectory data according to the present example.

FIG. 4 is a flowchart illustrating a normal process of the coordinate processing unit shown in FIG. 1 according to the present example.

FIG. 5 is a flowchart illustrating request interrupt processing of detailed coordinate information from the host device according to the present example.

FIG. 6 is a diagram showing a format example in a request for detailed coordinate information from a host device in this example.

[Explanation of symbols]

 101 Stroke locus actually input 102 Linearly interpolated stroke locus 103 Input start point 104, 105, 106 Coordinate point 107 Input end point 109 Normal curve interpolated stroke locus 200 Coordinate input device 201 Coordinate input means 202 Coordinate processing means 203 Data storage means 204 Curve approximation calculation means 300 Host device

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Jun Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (10)

[Claims] 1. A coordinate input device for outputting coordinates at a constant sampling rate, wherein: storage means for detecting coordinate information of a stroke input at a predetermined sampling interval to generate and store coordinate information; and externally, the storage means. Coordinate input, comprising: receiving means for receiving a transfer request of a specific range for the stroke input already stored, and output means for outputting coordinate information of the transfer request specific range received by the receiving means to the outside. apparatus. 2. The receiving means is capable of accepting a coordinate information transfer request at a resolution of a sampling rate or higher for a specific range, and the output means is a coordinate at a resolution of a sampling rate or higher for the specific range. Information is generated and output is enabled.
Coordinate input device as described. 3. The coordinate input device according to claim 1, wherein the specific range is coordinate information corresponding to a specific position or a specific section. 4. The coordinate input device according to claim 1, wherein the storage means stores the coordinate information by performing curve interpolation using a curve approximation function. 5. The coordinate input device according to claim 4, wherein oversampling data detected inside the device is used as data when using the curve approximation function. 6. A coordinate input method in a coordinate input device for outputting coordinates at a constant sampling rate, wherein coordinate information of a stroke input is detected at predetermined sampling intervals to generate and store coordinate information, and A coordinate input method characterized in that, when a stored transfer request for a specified range for a stroke input is received, coordinate information of the received transfer request specific range is output to the outside. 7. The reception from the outside is capable of accepting a coordinate information transfer request at a resolution higher than the sampling rate for a specific range, and generating coordinate information at a resolution higher than the sampling rate for the specific range. 7. The coordinate input method according to claim 6, wherein the coordinate input method is capable of outputting. 8. The coordinate input method according to claim 6, wherein the specific range is coordinate information corresponding to a specific position or a specific section. 9. The coordinate input method according to claim 6, wherein in the storing, coordinate information is generated by performing curve interpolation using a curve approximation function and stored. 10. The coordinate input method according to claim 9, wherein oversampling data detected inside the apparatus is used as data when using the curve approximation function.