Capturing handwriting
Motion of a writing instrument is tracked from sensors located in the vicinity. The signals generated from the sensors are processed and used in a wide variety of ways.
1 . A method comprising:
receiving light from a moving writing instrument at an array of sensing elements of a sensor;
reading the sensing elements in sequence to generate a sequence of signals indicative of light sensed by the elements of the array; and
resetting each elements after it is read and before at least some of the other elements in the array are read.
2 . The method of claim 1 in which the array comprises a CMOS or CCD position sensor.
3 . The method of claim 1 in which each of the elements is reset before the next element in the sequence is read.
4 . The method of claim 1 in which all of the elements are read before all of the elements are reset.
5 . A method comprising:
conveying light from a moving hand-held instrument;
sensing the light at two or more sensors, each of the two or more sensors comprising a two-dimensional array of sensing elements;
generating signals representing the two-dimensional locations on the arrays of light that is sensed; and
determining a sequence of three-dimensional positions of the moving writing instrument based on the signals.
6 . Apparatus comprising:
a writing instrument system that can track three-dimensional motion of the writing instrument.
7 . The apparatus of claim 6 in which the system includes sensors having 3 linear arrays.
8 . The apparatus of claim 6 in which the system includes sensors that are a two-dimensional array or a one-dimensional array.
9 . A method comprising:
sending light from a moving writing instrument, the light being indicative of a position and path of the writing instrument; and
directly sensing, at one or more sensors spaced from the writing instrument, angles from which light is received from the writing instrument.
10 . The method of claim 9 in which the angles are directly sensed by an array of sensitive elements of a sensing device.
11 . The method of claim 10 in which the sensing device comprises a CMOS or CCD device.
12 . The method of claim 10 in which the sensing device comprises a PSD.
13 . Apparatus comprising:
a writing instrument;
an element that enables wireless transmission of a signal associated with motion of the writing instrument and tracking of the writing motion based on the signal; and
the element being built into a cell phone, a PDA, a webpad, or a clipboard.
14 . Apparatus comprising:
two optical sensors separated by a known distance and arranged to, receive light from a source associated with a writing instrument, determine directions from which the light is received relative to a known direction, and provide signals representing the directions for use in determining a sequence of locations of the writing instrument; and
at least one of the two sensors comprising a CMOS of CCD array.
15 . The apparatus of claim 14 in which the CMOS or CCD array comprises a linear array of sensor elements.
16 . The apparatus of claim 14 in which the CMOS or CCD array comprises a two-dimensional array of sensor elements.
17 . Apparatus comprising:
a holder for a writing instrument, the writing instrument including electronic circuitry configured to be used in conjunction with tracking writing motion of the writing instrument, the writing instrument including a rechargeable battery connected to power the electronic circuitry, and the holder including a receptacle for the writing instrument and a recharging circuit connected to recharge the battery when the writing instrument is in the receptacle.
18 . Apparatus comprising: a CMOS sensor adapted to receive light associated with motion of a writing instrument and to provide signals indicative of an angle of receipt of the light with respect to a known direction; and
a lens aligned to direct the received light to the CMOS array.
19 . The apparatus of claim 18 in which the lens comprises a half-ball lens.
20 . The apparatus of claim 18 in which the lens comprises an aspherical lens.
21 . The apparatus of claim 18 in which the lens is optimized for collection of light from an area in which the motion of the writing instrument occurs.
22 . The apparatus of claim 18 in which the lens comprises a flat field lens.
23 . The apparatus of claim 18 in which the lens comprises a Fresnel lens.
24 . The apparatus of claim 18 in which the lens system is configured to collect light in a dimension normal to a plane of motion of the writing instrument and to project the light onto the sensor in a direction parallel to the plane of motion.
25 . A method comprising:
modulating light that is conveyed from a moving writing instrument to light sensors spaced from the writing instrument at a predetermined frequency; and
using a phase locked loop associated with the sensors to lock onto the phase of the modulated light.
26 . Apparatus comprising: circuitry for tracking writing motion of a writing instrument using wireless transmission of signals between the writing instrument and a stationary element, the stationary element including a main processor and a separate preprocessor, the preprocessor being connected to perform at least data capture with respect to motion of the writing instrument, and the main processor being connected to perform at least data communication with respect to the tracking.
27 . The apparatus of claim 26 in which the preprocessor is also connected to perform user interface functions and sub-pixel data storage.
28 . The apparatus of claim 26 in which the main processor is also connected to perform background cancellation and sub-pixel calculation.
29 . The apparatus of claim 26 in which the main processor is also connected to perform conversion of sub-pixel data into paper coordinates.
30 . The apparatus of claim 27 in which data storage is done in the form of paper coordinates.