OPTICAL MEASURING METHOD AND OPTICAL MEASURING DEVICE

Abstract

The invention relates to an optical measuring method for three-dimensionally capturing the surface of an object by means of an optical capturing unit, wherein the optical capturing unit is moved relative to the object during a first measurement time period, the object is illuminated by the capturing unit with an illumination beam having a light intensity, height images are captured by the capturing unit in succession at a capturing frequency, at least some of the captured height images during the measurement tune period are added to form a total height image and the total height image is displayed, and the light intensity and/or the capturing frequency are controlled during the measurement time period by control signals, the control signals being produced at time intervals during the measurement time period and each control signal being produced on the basis of at least one sensor signal of a temperature sensor.

Claims

1. Optical measuring method for the three-dimensional detection of the surface of an object using an optical recording unit, comprising: moving the optical recording unit is relative to the object during a first measurement time interval; illuminating the object, by the recording unit, during the first measurement time interval, using an illumination beam with a light intensity; successfully detecting, by the recording unit, height maps, at a recording frequency during the first measurement time interval; adding at least a portion of the detected height maps to an overall height map (b.sub.ges) during the measurement time interval and the overall height map is displayed, wherein the light intensity and/or the recording frequency are regulated during the measurement time interval by means of control signals; wherein the control signals are generated at time intervals during the measurement time interval, and wherein each control signal is generated on the basis of at least one sensor signal of at least one temperature sensor.

2. Optical measuring method according to claim 1, wherein the control signal is additionally generated on the basis of at least one parameter of the recording unit and/or of at least one already detected height map.

3. Optical measuring method according to claim 2, wherein for generating each control signal for the respectively last detected height map, a statistic of an overlap of the last detected height map with a height map detected immediately before, and/or a statistic of an overlap of the last detected height map with the overall height map (b.sub.ges) is determined and a control signal corresponding to the statistic is then generated.

4. Optical measuring method according to claim 3, wherein the sensor signal of the at least one sensor is taken into account in the determination of the statistic of the overlap.

5. Optical measuring method according to claim 2, wherein for generating each control signal for the respectively last detected height map, a surface increase of a total surface contained in the overall height map is determined by means of a surface contained in the last detected height map and a control signal corresponding to the surface increase is generated.

6. Optical measuring method according to claim 3, wherein a sampling density or a speed of the optical recording unit is determined from the statistic of the overlap or from the surface increase and is used for generating the control signal.

7. Optical measuring method according to claim 2, wherein, for generating each control signal for the respectively last detected height map, the overall intensity and/or the maximum intensity and/or the contrast and/or the number of extracted data points and/or a quality of extracted data points and/or the signal-to-noise ratio and/or the contrast of an additionally generated color image is determined and used for generating the control signal.

8. Optical measuring method according to claim 2, wherein the parameter of the recording unit is detected with another sensor, wherein the parameter is a speed of the optical recording unit and/or an acceleration of the optical recording unit and/or a spatial position of the optical recording unit and/or a movement of the optical recording unit.

9. Optical measuring method according to claim 1, wherein, before adding a height map to the overall height map, a registration method for the addition is selected as a function of the recording frequency.

10. Optical measurement system, comprising an optical recording unit, a computer-readable storage unit, a computing unit, and a display unit, wherein the optical measurement system is designed to carry out the optical measuring method according to claim 1.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0041] Exemplary embodiments of the invention are shown in the drawing. The following is shown:

[0042] FIG. 1 a schematic representation of a first embodiment of a recording method according to the invention.

EXEMPLARY EMBODIMENTS

[0043] FIG. 1 schematically illustrates a first embodiment of a recording method according to the invention.

[0044] According to the exemplary embodiment, a lower jaw 1 with teeth 2 is measured as an object by means of an optical recording unit 3. The optical recording unit 3 is designed as an intraoral camera and comprises a light source 4 and a light detector 6 and is connected to a computing unit 7 with a display means 8.

[0045] The measurement is carried out during a time interval T1, wherein the intraoral camera 3 is moved over the teeth 2 of the lower jaw 1 and/or empty spaces in the lower jaw I. The light source 4 provides an illumination beam 5 and the light detector 6 detects reflected light. The reflected light is detected at a recording frequency f.sub.A, wherein a data set is respectively detected by the light detector 6 and transmitted to the computing unit at a time interval dt=1/f.sub.A. For each data set, the computing unit respectively calculates a height map b.sub.i, i=1 . . . N and stores the latter in a storage medium of the computing unit 8. The recording frequency f.sub.A can be changed so that the time intervals dt between successively recorded height maps b.sub.i are not necessarily identical.

[0046] The generated height maps bi are already gradually assembled during the measurement time interval T1 to form an overall height map b.sub.ges, wherein the overall height map b.sub.ges is already displayed by means of the display means 8 during the formation.

[0047] It goes without saying that, where applicable, not all generated height maps are used for the overall height map, but that individual height maps are sorted out due to lack of quality, for example. For this purpose, a first height map b.sub.i is stored as an overall height map b.sub.ges and displayed. Then, further recorded height maps b.sub.i, i=2 . . . N are continuously added to the overall height map b.sub.ges and the new overall height map b.sub.ges is displayed, wherein a relative alignment of the height map b.sub.i to the overall height map b.sub.ges is determined based on an overlap (shown in a hatched fashion) of the height map b.sub.i with the overall height map b.sub.ges, i.e., the previously recorded height maps b.sub.i, in particular the height map b.sub.i−1 recorded immediately before.

[0048] In addition, the recording frequency f.sub.A in the illustrated exemplary embodiment is calculated based on the determined overlap. For the overlap of the last recorded height map b.sub.i with the overall height map b.sub.ges, a first statistic M.sub.i, e.g., the area size of the overlap, is respectively determined and a first control signal S=S.sub.i(M.sub.i) for controlling the recording frequency f.sub.A is generated based on the first statistic Mi. The recording frequency f.sub.A of the light detector 6 is then regulated, i.e., changed where applicable, by means of the control signal S by means of a control unit 10, which is part of the optical recording unit 3 in the illustrated exemplary embodiment. The next height map b.sub.i+1 is detected accordingly at a time interval dt.sub.i+1=1/f.sub.A, wherein f.sub.A refers to the regulated recording frequency.

[0049] Furthermore, a second statistic for a quality of the height map bi, e.g., an overall intensity or a contrast, is determined based on the last recorded height map bi. A second control signal for controlling the light intensity of the illumination beam 5 is generated based on the second statistic and the light intensity is regulated accordingly or by means of the second control signal. In an alternative embodiment or additionally, a sensor signal of a sensor 9 (shown dashed) is used to calculate the control signal S. For example, the movement of the intraoral camera 3 is tracked by means of an integrated inertial measurement system, wherein the alignment of the individual height maps he relative to one another can be deduced from the movement of the camera 4.

LIST OF REFERENCE SIGNS

[0050] 1 Object [0051] 2 Tooth [0052] 3 Recording unit [0053] 4 Light source [0054] 5 illumination beam [0055] 6 Light detector [0056] 7 Computing unit [0057] 8 Display unit [0058] 9 Sensor [0059] 10 Control unit [0060] b.sub.ges Overall height map [0061] b.sub.i Height maps [0062] f.sub.A Recording frequency [0063] dt Time interval [0064] M.sub.i Statistic [0065] S Control signal [0066] T1 Recording time interval