Handwriting type input display device

• US 5,995,081 A
• Filed: 01/10/1997
• Issued: 11/30/1999
• Est. Priority Date: 01/12/1996
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kato, Kiyoshi
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US08/781,807
• Time in Patent Office: 1,054 Days
• Field of Search: 345/156, 345/173, 345/174, 345/179, 345/180, 178/18.01, 178/18.03, 178/19.01, 382/116, 382/160, 382/181, 382/187, 382/188, 382/189, 382/190, 382/228
• US Class Current: 345/156
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

A handwriting type input display device is provided with a display device for performing a two-dimensional display, an input device which constitutes a handwriting device in combination with the display device, and is adapted to detect a handwriting input operation by a user at a coordinate position corresponding to a position on a screen of the display device, a passing point predicting device for receiving the coordinate point sequence from the input device to insert a new coordinate point sequence between neighboring coordinate points of the coordinate point sequence, and outputting a coordinate point sequence for forming a smooth handwritten curved line, and a processing device for instructing an insertion method of coordinate points to the passing point predicting device, and performing processing of displaying on the display device a curved line based on the coordinate point sequence which is obtained by the passing point predicting device.

Claims

1. A handwriting type input display device comprising:

display means for performing a two-dimensional display;

input means which constitutes handwriting means in combination with said display means, and is adapted to detect a handwriting input operation by a user at a coordinate position corresponding to a position on a screen of said display means;

passing point predicting means for receiving the coordinate point sequence from said input means to insert a new coordinate point sequence between neighboring coordinate points of the coordinate point sequence, and outputting a coordinate point sequence for forming a smooth handwritten curved line;

processing means for instructing an insertion method of coordinate points to said passing point predicting means, and performing processing of displaying on said display means a curved line based on the coordinate point sequence which is obtained by said passing point predicting means; and

wherein said passing point predicting means comprises control vector generating means for generating an average speed vector and an average acceleration vector on two neighboring coordinate points of the received coordinate point sequence.

insertion point number determining means for determining the number of insertion points between the two neighboring coordinate points on the basis of the magnitude of the average acceleration vector generated by said control vector generating means.

2. The handwriting type input display device as claimed in claim 1, wherein said passing point predicting means further comprises:

passing point adding means for dividing the average speed vector generated by said control vector generating means into parts whose number is equal to the insertion point number determined by said insertion point number determining means to generate a divisional coordinate point sequence, and shifting the divisional coordinate point sequence in the direction of the average acceleration vector in accordance with an instruction of said processing means.

3. The handwriting type input display device as claimed in claim 2, wherein said passing point predicting means has continuity judgment means for judging whether the interpolative coordinate point sequence received from said passing point adding means forms a smoothly curved line, and said control vector generating means in said passing point predicting means corrects the calculation of the average speed vector and the average acceleration vector in accordance with the judgment result of said continuity judgment means.

4. A handwriting type input display device comprising:

display means for performing a two-dimensional display;

input means which constitutes handwriting means in combination with said display means, and is adapted to detect a handwriting input operation by a user at a coordinate position corresponding to a position on a screen of said display means;

next input point predicting means for generating predicted coordinate points for each coordinate point which is received from said input means to reduce a delay time from the time when a user performs a handwriting input operation until the time when a response display is performed;

passing point predicting means for receiving the coordinate point sequence from said next input point predicting means to insert a new coordinate point sequence between neighboring coordinate points of the coordinate point sequence, and outputting a coordinate point sequence for forming a smooth handwritten curved line;

processing means for instructing a calculation method for generating the predicted coordinate points to said next input point predicting means, and performing processing of displaying on said display means a curved line based on a coordinate point sequence which is obtained from said next input point predicting means; and

wherein said passing point predicting means comprises

control vector generating means for generating an average speed vector and an average acceleration vector on two neighboring coordinate points of the received coordinate point sequence,

insertion point number determining means for determining the number of insertion points between the two neighboring coordinate points on the basis of the magnitude of the average acceleration vector generated by said control vector generating means.

5. The handwriting type input display device as claimed in claim 4, wherein said next input point predicting means comprises:

proximate point storage means for storing a coordinate point sequence which is to be a proximate coordinate point sequence to the latest coordinate point;

direction vector generating means for reading out the proximate coordinate point sequence to the latest coordinate point from said proximate point storage means to generate a speed vector and an acceleration vector at the latest coordinate point from the proximate coordinate point sequence; and

next input point generating means for correcting the composite vector of the speed vector and the acceleration vector generated by said direction vector generating means in accordance with an instruction of said processing means to generate a shift vector, and shifting the latest coordinate point in the direction of the shift vector to generate a predicted coordinate point.

6. The handwriting type input display device as claimed in claim 5, wherein said next input point predicting means has position error judging means for detecting the position error in coordinate position between the predicted coordinate point generated by said next input point generating means and a coordinate point which is newly obtained after the prediction, and said direction vector generating means in said next input point predicting means corrects the calculation of the speed vector and the acceleration vector in accordance with the position error detected by said position error judging means.

7. A handwriting type input display device comprising:

display means for performing a two-dimensional display;

input means which constitutes handwriting means in combination with said display means, and is adapted to detect a handwriting input operation by a user at a coordinate position corresponding to a position on a screen of said display means;

next input point predicting means for generating predicted coordinate points for each coordinate point which is received from said input means to reduce a delay time from the time when a user performs a handwriting input operation until the time when a response display is performed;

passing point predicting means for receiving the coordinate point sequence from said next input point predicting means to insert a new coordinate point sequence between neighboring coordinate points of the coordinate point sequence, and outputting a coordinate point sequence for forming a smooth handwritten curved line;

processing means for instructing a calculation method for generating the predicted coordinate points to said next input point predicting means, instructing an insertion method of a coordinate point to said passing point predicting means, and performing processing of displaying on said display means a curved line based on a coordinate point sequence obtained from said passing point predicting means; and

wherein said passing point predicting means comprises

control vector generating means for generating an average speed vector and an average acceleration vector on two neighboring coordinate points of the received coordinate point sequence,

insertion point number determining means for determining the number of insertion points between the two neighboring coordinate points on the basis of the magnitude of the average acceleration vector generated by said control vector generating means.

8. The handwriting type input display device as claimed in claim 7, wherein said passing point predicting means further comprises:

passing point adding means for dividing the average speed vector generated by said control vector generating means into parts whose number is equal to the insertion point number determined by said insertion point number determining means to generate a divisional coordinate point sequence, and shifting the divisional coordinate point sequence in the direction of the average acceleration vector in accordance with an instruction of said processing means.

9. The handwriting type input display device as claimed in claim 8, wherein said passing point predicting means has continuity judgment means for judging whether the interpolative coordinate point sequence received from said passing point adding means forms a smoothly curved line, and said control vector generating means in said passing point predicting means corrects the calculation of the average speed vector and the average acceleration vector in accordance with the judgment result of said continuity judgment means.

10. The handwriting type input display device as claimed in claim 7, wherein said next input point predicting means comprises:

proximate point storage means for storing a coordinate point sequence which is to be a proximate coordinate point sequence to the latest coordinate point;

direction vector generating means for reading out the proximate coordinate point sequence to the latest coordinate point from said proximate point storage means to generate a speed vector and an acceleration vector at the latest coordinate point from the proximate coordinate point sequence; and

next input point generating means for correcting the composite vector of the speed vector and the acceleration vector generated by said direction vector generating means in accordance with an instruction of said processing means to generate a shift vector, and shifting the latest coordinate point in the direction of the shift vector to generate a predicted coordinate point.

11. The handwriting type input display device as claimed in claim 7, wherein said next input point predicting means has position error judging means for detecting the position error in coordinate position between the predicted coordinate point generated by said next input point generating means and a coordinate point which is newly obtained after the prediction, and said direction vector generating means in said next input point predicting means corrects the calculation of the speed vector and the acceleration vector in accordance with the position error detected by said position error judging means.