WO2003049016A2

WO2003049016A2 - Method, and use of a finger scanner, for providing input to an electronic unit and such a unit comprising a finger scanner

Info

Publication number: WO2003049016A2
Application number: PCT/NO2002/000468
Authority: WO
Inventors: Sigmund AARØ; George Helmke
Original assignee: Idex Asa
Priority date: 2001-12-07
Filing date: 2002-12-06
Publication date: 2003-06-12
Also published as: WO2003049016A3; AU2002364495A8; NO20016009D0; AU2002364495A1; NO318294B1; NO20016009L

Abstract

Electronic unit, and method for providing input to the electronic unit, the unit comprising a sensor being capableof sensing direction of a movement over the sensor, and the method comprising the steps of: sensing the direction of a movement, categorising the sensed direction into a chosen number of categories, said categories each being related to one or more signs, e.g. characters, on the ending of said movement, providing the related sign or command to the electronic unit as input.

Description

NAVIGATION CONCEPT

This invention relates generally to a method for providing input to an electronic unit, the unit comprising a sensor being capable of sensing direction of a movement over the sensor and a display.

The market of biometrics is evolving rapidly, and the industry is becoming more mainstreamed. However, for biometrics to penetrate the consumer market, requirements are strict in respect to both price and performance (eg. power consumption) .

Currently finger scanners are typically pure capturing devices, hence the responsibility of any signal processing is left to the host. Thus, for implementation in eg. a mobile phone, requirements are also strict in respect to the use of processing power and memory of the signal processing. Nevertheless, as these processes mature and can be implemented in the finger scanner device, the requirements will still apply.

The size of a matrix finger scanner is typically restricted by the size of the finger images to be captured, due to the number of interconnects if the sensor where to be separated from the IC. Since the price is typically very much proportional to the size of the silicon die, the price of matrix finger scanner can not be expected to decrease significantly. For a stripe finger scanner, however, where the user wipes a finger over one or more arrays of sensor elements, the number of channels is reduced dramatically and separation of sensor and IC is possible, and the size of the IC is not restricted to the size of finger images. The reduction in channels of course also contributes to reduce the size of the die substantially. Since the price and the size of the IC are so related, stripe finger scanners have the potential of breaking the consumer market . International patent application no. PCT/NO98/00182 describes a stripe finger scanner requiring that the finger is moved over the scanner, which then samples information about the finger surface and generates a two dimensional representation of the finger image.

For stripe finger scanners, the user must be allowed to pull the finger over the scanner at various velocity. If the finger scanner samples at a fixed rate, this causes for a method that detects the speed of a finger and remaps the rows that are sampled, so that the axes of the remapped finger image are equal and linear.

Menu controlled electronic equipment, such as PDA's or some mobile phones, require some type of control device coupled to the display to enable to user to choose from the menus. This may be performed using pointer tools such as touch sensitive displays, navigation wheels or touch sensitive pads, also adding to the equipment costs. It is an object of this invention to provide a navigation tool based on a fingerprint sensor technology, the sensor thus obtaining an additional functionality without adding hardware or complicated software to the product.

In some cases, especially related to small units such as mobile phones, the menus on the displays are simplified, thus only requiring navigation in a limited number of direction, e.g. up, down, right and left.

This object is obtained using a method as described above comprising the steps of: sensing the direction of a movement, categorising the sensed direction into a chosen number of categories, said categories each being related to one or more signs, e.g. characters, indicating the direction category on the display, on the ending of said movement, providing the related sign to the electronic unit as input.

The typical method for determining the speed of a finger pulled over a stripe finger scanner would be to use auto correlation. This would require one or more additional arrays of sensor elements parallel to the image sensor elements, if the image sensor elements consist of only one array.

European patent application No 1,113,386 presents a device and method for sensing data input using a fingerprint skanner. This patent application suggests the use two lines of sensor elements that are oriented mutually perpendicular .

By comparing successive outputs from the sensing units of each of the lines, it is claimed that the movement in the direction of each of the lines can be detected. Based on these two "speed components" a composite direction and speed of finger movement can be determined.

However, when a finger is pulled in a direction which does not correspond to one of these two "main directions", a single point or structure on the finger surface does not pass over more than one sensing unit in each of the two lines. For arbitrary pull directions, this makes it difficult to perform the specified comparison or correlation of successive sensor outputs within a line to measure the movement. To be able to calculate the speed in the way it is described in this document, the geometrical features of the fingerpring sensor has to be known or assumed. This increases the complexity of or in the worst case inhibits speed measurement in the way described. On the contrary, the present invention includes an arrangement of sensor elements that define pairs of sensor constituting a closely spaced "array" of pull directions, with a fixed distance between the units within each pair. Regardless of pull direction it will therefore always be possible to detect a time-delayed correlation of the signal from the pads in those pairs that most closely correspond to the pull direction. These correlation measurements are then used to detect the speed and direction of movement. Important factors for a speed correction process to run on eg. a mobile phone, are that it should be fast, require little processing power and use little memory. Preferrably it should run in real-time, due to the amount of memory that would be required to buffer a finger image captured of fingers wiped at various velocities, if the speed correction is post-processed. Examples of such speed determinations are discussed in international patent applications No PCT/NO01/00241 and PCT/NO01/00242.

This invention is based mainly on the navigation tool described in international patent application No

PCT/NOOl/00243 , but sensors, e.g. the sensor described in International patent application no. PCT/NO98/00182 , being sensitive to movements along at least one axis, may also be used, e.g. the sensors suggested in PCT/NO01/00244. The invention will be described below with reference to the accompanying drawings, illustrating the invention by way of examples.

Figure 1 illustrates an essentially linear fingerprint scanner. Figure 2 illustrates the use of a fingerprint scanner for navigation purposes in at least two directions. Figure 3 illustrates a fingerprint sensor with a four directional navigation tool. Figure 4 illustrates one possible layout for a finger print scanner with navigation sensors .

Figure 5 illustrates one of the navigation sensors in figure 4. Figure 6 illustrates the use of one embodiment of the invention. Figure 7 illustrates the navigation concept according to the invention. Figure 8 illustrates an alternative navigation concept according to the invention. This invention describes a method for adding the functionality of a pointer into a finger scanner or similar by utilising the structure of the finger. While a touchpad detects a finger being moved over its surface, this method detects the movement of the sensor area over the finger surface. For a stripe finger scanner this requires som additional sensor elements, while for matrix finger scanners a selection of the already existing sensor elements is sufficient. As this mode will be active for a substantial amount of time during the use of a mobile phone or PDA, it is of importance that the number of sensor elements being used is reduced to a minimum, to keep the consumption of power, processor and memory of the host low.

For mobile phones with character based displays, the need for a pointer is restricted to a navigator that enables the user to browse menus. This is currently typically solved by the use of keys or a roller drum. Implementation of such a mode for finger scanners, can be done with much less requirements to power consumption, processing power and memory usage. Figure 1 illustrates the sensor in international patent application no. PCT/NO98/00182 comprising sensor elements for speed compensation 2,3. In addition to the detection of movements along the axis of the speed compensation sensor elements 2,3, neighbouring sensor elements 4 may be used to detect angular movements, and a sensitivity along the array may be provided by detecting the first sensor element detecting the presence of a finger. Thus the essentially line shaped sensor may be sensitive to movements in at least 4 directions. In addition differences in speed over the sensor may be interpreted as rotational movements of the finger.

Figure 2 illustrates an essentially linear finger scanner being capable of detecting movements in two dimensions, such as described in PCT/NOOl/00244. The principle of the pointer function is to determine the direction of the finger being moved and then calculate the distance on the basis of the speed of the finger. The measured directions may, according to this invention, be put into a number of predetermined categories, e.g. by dividing the circle into eight sections, each covering 45 degrees .

Figure 3 describes a method for a four directional navigation, based on four, or more, additional sensor elements on a stripe finger scanner. The sensor elements should be larger than the image sensor elements, because the structure of the finger surface is regarded as noise in this context. For matrix finger scanners, clusters of image sensor elements can be used to represent a large element . The purpose of the navigation sensor elements is purely to detect the presence of a finger or not, which simply can be solved by a signal level threshold. If a finger is wiped over the sensor area, the four navigation sensor elements will be triggered at certain points in time. A more detailed description of this solution is provided in PCT/NO01/00243.

In figure 4 and 5 a number of navigation sensor groups 19 are provided close to a fingerprint scanner. By monitoring the signals from the sensor elements in each group a time sequence may be provided containing the order in which the sensors 19 are activated is stored. Thus the direction of movement 20 may be obtained in a simple manner .

Referring to figure 6 the utilisation method according to the invention will in be referred to as a navi pie illustrating the image on the related display used to aid the user in providing input to the unit, e.g. the cellular phone. The name is derived for the functionality of navigating over a pie like structure where the omnidirectional functionality are made courser, and fitted into a subset of pie slices. These pie slices can be of any absolute number over the value of one (1) , and in this example the value of 12 is chosen to show general functionality. The method may be described as follows: 1. The core of the concept takes root in that all movement initiates from the centre of the pie and that any movement 20 will be forced into the pie slice 21 that is closest to the direction of this movement 20. 2. As the movement in one direction solidifies, the notification to the user will come in form of a growing pie or a line that grows towards the particular value allocated to the particular pie slice.

3. As the user lifts the finger from the navigation hardware, the value of the pie slice will be entered into a field.

4. The user will then again put the finger on the navigation hardware to initiate entering another value into the field. This will go on until the user has entered the complete value which may be a name, a phone number etc.

5. Note that one slice may also be divided into more than one piece. As the directional value grows it may grow through different values or characters. Suggested use may include allocating letters such as a-b-c. This means that in one pie slice you will grow from a to b to c as you move from center outward within the particular pie slice. In figure 6 the slice 21 contains an inner 22 and outer part 23 which may indicate different symbols or commands. This will give the user a simple way to enter any character from the alphabet only by selecting a slice direction and release the finger from the pointer hardware at the correct time within the particular slice. Figure 7 illustrates schematically the process of the method according to the invention.

As mentioned above the partitioning of the pie may vary in use. If in a certain menu on a display only two commands are valid the pie may be split only in two parts, e.g. up or down, while a writing process including selecting characters, words or symbols may require several slices, depending on the accuracy of the user movements.

If the sections are split radially the process illustrated in figure 8 may be used, thus allowing for a larger number of categories being directly accessible from the navigation pie depending on the length and/or speed of the movement over the sensor.

As mentioned above the categories may be correlated to a chosen set of signs, e.g. numbers, characters symbols or commands to the electronic unit. The categories may also be related to subsets so that a first movement over the sensor results in a change in the display letting the user choose from a new subset of signs or commands corresponding to a new set of categories.

As mentioned above the change in a direction may also be sensed, and thus classified. This way a number of commands may be associated with sequences of directions and changes. This may also be used to recognize certain movements over the sensor. Thus if the user performes movements making the character "L" this may be recognized as a certain command to the electronic unit or even be recognised as the written character as the sensor is capable of detecting the direction and length of each part of the movement . According to one embodiment of the invention the method thus also provides a method for recognising characters being written on the sensor by the user.

This invention is described here as primarily based on a finger print scanner of the type described in International patent application no. PCT/NO98/00182 thus primarily on capacitance measurements on a finger surface. It is, however, clear that the invention may used different sensor types, such as thermal or resistance sensors e.g. as described in US 6,052,475, within the scope of this invention.

Claims

C l a i m s

1. Method for providing input to an electronic unit, the unit comprising a sensor being capable of sensing direction of a movement over the sensor, comprising the steps of: sensing the direction of a movement, categorising the sensed direction into a chosen number of categories, said categories each being related to one or more signs, e.g. characters, - on the ending of said movement, providing the related sign or command to the electronic unit as input.

2. Method according to claim 1, wherein the length of the movement is measured, and in that each direction category comprises a number of subcategories being related to different lengths of said movement.

3. Method according to claim 1, wherein the duration of the movement is measured, and in that each direction category comprises a number of subcategories being related to different duration of said movement.

4. Method according to claim 1, wherein the electronic unit comprises a display and wherein the direction category on the display is indicated on the display.

5. Method according to claim 1, wherein the electronic unit comprises a display and the directions are indicated as circle sections on the display, the number of sections corresponding to the number of categories.

6. Method according to claim 5, wherein each circle section comprises a number of radially distributed parts, each indication a sub category within the direction category.

7. Method according to claim 1, wherein at least one of said categories is related to a subcategory comprising a number of choices each corresponding to a new category.

8. Method according to claim 1, wherein sequences of one or more changes in the directions are registered and related to a chosen set of categories.

9. Use of a finger scanner as a sensor in a method according to claims 1-8, said finger scanner being adapted to measure the direction of a movement along at least one axis.

10. Electronic unit comprising a finger skanner being adapted to measure the direction of a movement along at least one axis, means for measuring the direction of a finger moved over said skanner, means for categorising the movements of the finger into a set of categories corresponding to at least one sign or command, and a display, said display being adapted to indicate the measured movements and/or the corresponding sign or command.