Programmable hair trimming system

Abstract

A programmable hair trimming system has a hair trimming device including a receiving element configured to receive an electromagnetic field and at least one source element having an electromagnetic field source. The hair cutting length of the hair trimming device is adjustable, and the at least one source element is external to the hair trimming device and arranged to be placed in a fixed relationship to the head of a person. The hair trimming system is arranged to detect, by an electromagnetic tracking system, the position of the hair trimming device in relation to the at least one source element. Further the hair trimming system relates this position to a previously generated hair length profile data regarding the desired hair trimming length at various positions. Based on the desired hair trimming length at the sensed position, the trimmer cutting length is automatically and dynamically adjusted.

Claims

1. A method of trimming hair using a programmable hair trimming system having a hair trimming device with a cutter, a receiving element configured to sense an electromagnetic field from at least one electromagnetic field source, and a hair length regulator to adjust a hair cutting length of the hair trimming device, the method comprising acts of: detecting, by an electromagnetic tracking system, a position of the hair trimming device in relation to the at least one electromagnetic field source; relating the position to a desired hair trimming length based on a previously generated hair length profile data including trimming lengths at individual position points; determining a fade shape of the trimming lengths between the individual position points by interpolation of the trimming lengths between the individual position points, wherein the interpolated trimming lengths are determined based on a default interpolation being a Bezier curve interpolation between the individual position points; receiving a fade shape modification of the fade shape to form a modified fade shape, wherein the interpolation of the trimming lengths between the individual position points for forming the modified fade shape is changed from the Bezier curve interpolation between the individual position points to a linear interpolation between the individual position points; and automatically and dynamically controlling the hair length regulator of the hair trimming device to adjust the hair cutting length of the hair trimming device according to the position of the hair trimming device and the interpolated trimming lengths and the modified fade shape.

2. The method of claim 1, comprising acts of: processing field data regarding the sensed electromagnetic field; determining the position and an orientation of the hair trimming device in relation to the at least one electromagnetic field source based on the field data.

3. The method of claim 1, wherein the at least one electromagnetic field source is configured to be placed in a fixed relationship with an ear of a person.

4. The method of claim 1, comprising acts of: storing the hair length profile data; obtaining field data regarding the sensed electromagnetic field; calculating a hair length from the stored hair length profile data and the obtained field data; and controlling the hair cutting length of the hair trimming device.

5. The method of claim 1, wherein the previously generated hair length profile data includes a number of changes of hair length, and wherein the previously generated hair length profile data includes different densities of the individual position points that change as a function of the number of changes of the hair length included in the previously generated hair length profile data.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A detailed description of the invention is provided below. The description is provided by way of a non-limiting example to be read with reference to the drawings in which:

(2) FIG. 1 illustrates schematically an overall system setup with a hair trimming device, two source elements and a base unit according to an exemplary embodiment of the current invention.

(3) FIG. 2 illustrates schematically a hair trimming device layout with a fixed distance between a user grip area and a distance comb according to an embodiment of the invention.

(4) FIG. 3A illustrates schematically a placement of centred and symmetrical position points according to an embodiment of the invention.

(5) FIG. 3B illustrates schematically calculated local hair lengths between position point lengths according to an embodiment of the invention.

(6) FIG. 3C illustrates schematically calculated smooth Bezier local hair lengths between position point lengths according to an embodiment of the invention.

(7) FIG. 3D illustrates schematically calculated linear local hair lengths between position point lengths according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(8) In figures showing the same embodiment or the same parts thereof, the same numbers are used for the same parts.

(9) In the following descriptions, the term user describes the person holding and guiding the hair trimming device during a calibration and/or hair trimming session, and/or is operating an integrated and/or connected external computer system.

(10) The term treated person describes the person on whom a hair trimming is being performed. These can be multiple persons or a single person. As the device according to the current invention is perfectly suited for creating one's own haircut, also known as do-it-yourself haircutting, the user and the treated person can be one and the same.

(11) FIG. 1 illustrates an embodiment of the invention wherein the programmable hair trimming system comprises two source elements (3), one of which is visible as being attached to an ear of the head (30). The second source element (3) is attached to the other ear at the from this perspective not visible part of the head (30). In alternative embodiments, the at least one source element may be fixed to other parts of the head such as e.g. the nose, one or more eyebrows, one or more lips, the chin, the teeth and so on. A combination of these fixation options is imaginable as well. It is to be noted that the precision of the position sensing correlates with the number of source elements being used. The more source elements are used by the programmable hair trimming system to determine the position of the hair trimming device, the higher the obtainable precision of the position detection. It will be appreciated that there is an optimal number of source elements as the costs of a further source element is to be offset against the gained precision.

(12) The trimming device (2) comprises a receiving element (1). The trimming device (2) is arranged to engage the head (30) at a touching position (35).

(13) The position and orientation of the trimming device (2) monitored using the electromagnetic fields generated by the source elements (3) and the receiving element (1). As the source elements (3) are in fixed relationship with a point on the head (30) they will follow potential movements of the head during a hair trimming session without this movements interfering with the hair trimming procedure.

(14) In an embodiment of the invention, source element (3) is in a shape similar to small audio headsets, and is placed inside the treated person's ear, thus preventing it from moving and turning while in use.

(15) Parts of the source element (3) that are placed inside the treated person's ear and that touch the treated person's ear channel can optionally be interchangeable for hygienic multiple user scenarios, and for adapting to different ear shapes.

(16) The source element (3) is powered by a battery (not shown) that can optionally be recharged while the device is placed in a base unit (5) or a hair trimming device (2).

(17) The performance of the electromagnetic tracking system can be adapted to the desired precision by modifying the at least one source element, the receiving element and the data calculation/transmission components.

(18) The strength, phase and orientation of the detected electromagnetic field is transmitted, wired or wirelessly, from the receiving element (1) and the at least one source element (3) to an embedded computer system.

(19) The embedded computer system can be placed in either a base unit (5), or in the hair-trimming device (2).

(20) The distance and orientation of the hair trimming device (2) and the at least one source element (3) with respect to each other, together with previously generated data regarding the treated person's head shape, provides sufficient data for an embedded computer system to calculate the position of the hair trimming device's (2) position in relation to the treated person's head (30), more precisely of the touching position (35).

(21) This position information is compared by the embedded computer system to previously generated data about the desired local hair length (21) at any given point on the treated person's head (30).

(22) The derived hair trimming length (21) is transmitted, wired or wirelessly (8), to the hair trimming device's (2) length regulation control system (11) and length regulation mechanism (18), see FIG. 2, which dynamically and automatically adjusts the hair trimming length accordingly.

(23) Head Shape Calibration Procedure:

(24) The hair trimming system can be adapted more precisely to the treated person's head (30) via an initial calibration procedure that generates a 3D representation of the treated person's head shape (30).

(25) This once-per-treated person procedure may be performed by setting a hair trimming device (2) in a calibration mode with its trimmer motor (16) turned off.

(26) The, in this embodiment, two source elements are placed in their use positions on the treated person's head, in this embodiment attached to the ears.

(27) The hair trimming device (2) in calibration mode is placed by the user at a number of predetermined points on the treated person's head (30).

(28) The calibration system software provides the user with a visual and/or acoustic feedback signal when a calibration point has been registered, and can also optionally show the points that the user has covered so far and the points where he still needs to position the hair trimming device (2) in calibration mode, as well as the sequence in which these points are to be touched.

(29) In some embodiments the calibration procedure is limited to obtaining the distance between two source elements and scaling a sphere shaped approximation of the head based on the distance between the two source elements. In further alternative embodiments other approximations may be used, e.g. an ellipsoid.

(30) Hair Length Profile (HLP):

(31) In an embodiment of the invention, the system can present a number of default HLPs for the user to choose from.

(32) In another embodiment of the invention, the user enters length values at a number of points on the treated person's head (30) into the HLP modification system. These values can be based on manually measured hair lengths on the treated person's head whilst having a desired hair length.

(33) A HLP contains a set of position points (20, 26), each with an accompanying hair length between zero mm and a maximum length determined by a hair trimming device's adjustment travel length.

(34) The number of position points (20, 26) for a HLP should be small enough to allow for a smooth HLP, while maintaining the resolution needed for hair length variation, preferably four to eight centred position points (20) and two to six pairs of symmetrical position points (26).

(35) The number of calculated steps between the positions (20, 26) can be adjusted by the HLP modification system with due respect for seamless steps, preferably not larger than one mm.

(36) As a HLP consists of said position points (20, 26) and accompanying position point lengths (20), the software of the embedded computer system will be calculating the local hair lengths (21), optimized for the precision of the length regulation mechanism (18) of its hair trimming device (2).

(37) The length selectable at any position point (20, 26) is limited by the maximum travel distance of the length regulation mechanism (18) of the hair trimming device (2) to be used.

(38) The fade shape between position lengths (20, 26) is by default set to a smooth Bezier curve (28), FIG. 3C, and can be modified by the user towards a sharper connection angle (29), FIG. 3D. In other embodiments a different fade shape algorithm may be implemented.

(39) A number of HLPs can be stored in the hair trimming device (2) or the base unit (5).

(40) Hair Trimming Start-Up Procedure:

(41) Prior to a trimming session, the user selects which HLP to use and attaches the source elements (3) in their predefined attachment positions.

(42) In order to verify the placement and orientation of the source elements (3), and to verify that the HLP selected is compatible with the current treated person (30), a start-up calibration procedure is performed by the user.

(43) At the beginning of the start-up calibration procedure, the source elements are switched on and mounted on the treated person (30).

(44) The hair trimming device (2) with its trimmer motor (16) switched off is placed by the user at a number of points on the treated person's head (30). The user can optionally confirm the placement by pressing a button (not shown) on the hair trimming device (2).

(45) The user can optionally follow the calibration procedure on e.g. an interactive display of the base unit (5) or an external display linked to the base unit (5), which display shows the areas where the user so far has and still needs to position the hair trimming device (2) in calibration mode.

(46) When sufficient points have been detected by the embedded computer system to verify the compatibility between the head of the treated person (30) and the HLP as well as the placement and orientation of the source elements (3) in relation to the treated person's head (30), the user is informed visually and/or acoustically by the embedded computer system, and the hair trimming can begin.

(47) The trimmer motor (16) can optionally be prevented from being switched on until a start-up calibration is completed.

(48) Hair Trimming Procedure:

(49) The user places the hair trimming device (2) on the treated person's head (30), with contact detected by a pressure sensitive sensor in the hair trimming device (not shown). The position of the hair trimming device (2) is detected and the trimming length adjusted according to the HLP for this position. Following this initial adjustment the trimming motor (16) starts automatically.

(50) During a hair trimming session, the user guides the hair trimming device (2) on the surface of the treated person's head (30) in the same way, as he would use a commercially available hair trimming device.

(51) If the system includes a head-tracking device (3) with built-in audio receiver (not shown) and loudspeaker (not shown), audio information regarding the current trimming length can optionally be provided to the treated person (30), which would be desirable if he is guiding the hair trimming device (2) himself, and/or if no hair trimming visualizing system is used during the trimming session.

(52) If, for whatever reason, the data stream from a receiving element (1) to the embedded computer system is interrupted, and/or the user moves the hair trimming device (2) too fast for the embedded computer system to calculate and transmit the current length to the hair trimming device's (2) embedded length regulation control system (11), and/or the transmission of trimming length data from the embedded computer system (4) to the hair trimming device (2) is interrupted, and/or the hair trimming device (2) is lifted from the treated person's head (30), then the trimmer motor (16) is automatically shut off, and/or the length regulation mechanism (18) is set to its maximum trimming length.

(53) In an embodiment of the invention, FIG. 3A, the hair trimming device (2) has a fixed distance between its user grip area (24) and its comb (19), while the cutting point (22) of the hair trimming device (2), shown in FIG. 2, is moved up and down inside the distance comb (19) by the length regulation mechanism (18).

(54) This allows the user to focus on guiding the hair trimming device (2) on the surface of the treated person's head (30) without paying attention the automatically adjusted trimming length.

(55) While the invention has been illustrated and described in detail in the drawings and in the foregoing description, the illustrations and the description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. It is noted that the programmable hair trimming system according to the invention and all its components can be made by applying processes and materials known per se. In the set of claims and the description the word comprising does not exclude other elements and the indefinite article a or an does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope. It is further noted that all possible combinations of features as defined in the set of claims are part of the invention.