OPTICAL MEASURING METHOD AND OPTICAL MEASURING APPARATUS

Abstract

The invention relates to an optical measuring method for the three-dimensional detection of the surface of an object using an optical recording unit. The optical recording unit is moved relative to the object during a first measurement time interval, height maps are successively detected by the recording unit at a recording frequency, and at least some of the detected height maps are each added to an overall height map and displayed. The recording frequency is regulated by control signals during the measurement time interval. The control signals are generated spaced apart in time and for the purposes of producing each control signal, a statistic for the quality of the height map is determined for the respectively last detected height image and used for producing the control signal. The statistic is 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.

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 relative to the object during a first measurement time interval, successfully detecting by the recoding 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 during the measurement time interval and displaying the overall height map, wherein the recording frequency is 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, wherein for generating each control signal for the respectively last detected height map, a statistic for the quality of the height map is determined and used for generating the control signal, wherein wherein the statistic is 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.

2. Optical measuring method according to claim 1, wherein the additionally generated color image is generated by means of a color image camera.

3. Optical measuring method according to claim 1, wherein during the first measurement time interval, the object is illuminated by the recording unit using an illumination beam with a light intensity and the light intensity is regulated by means of the control signal during the measurement time interval.

4. Optical measuring method according to claim 1, wherein at least one sensor signal by at least one sensor is additionally used for generating each control signal.

5. Optical measuring method according to claim 1, wherein the time intervals between the generation of control signals during the measurement time interval are predetermined by a predetermined frequency.

6. Optical measuring method according to claim 1, wherein a control signal is determined for each detected height map, wherein the time intervals between the generation of control signals during the measurement time interval are predetermined by the recording frequency.

7. 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.

8. 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

[0033] Exemplary embodiments of the invention are shown in the drawing. The following is shown:

[0034] FIG. 1 a schematic representation of a first embodiment of a recording method according to the invention.

EXEMPLARY EMBODIMENTS

[0035] FIG. 1 schematically illustrates a first embodiment of a recording method according to the invention.

[0036] 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.

[0037] The measurement is carried out during a time interval TI, wherein the intraoral camera 3 is moved over the teeth 2 of the lower jaw 1 and/or empty spaces in the lower jaw 1. The light source 4 provides an illumination beam 5 and the light detector 6 detects reflected light.

[0038] 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.sub.i between consecutively recorded height maps b.sub.i, b.sub.i=1 are not necessarily identical.

[0039] The height maps b± generated are already gradually assembled during the measurement time interval TI 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. It goes without saying that, where applicable, not all generated height maps b.sub.i are used for the overall height map, but that individual height maps b.sub.i are sorted out due to lack of quality, for example.

[0040] First, a first height map b.sub.1 is stored and displayed as an overall height map b.sub.ges. Further recorded height maps b.sub.i, i=2 . . . N are then continuously added to the overall height map bges and the new overall height map bges is displayed in new form after adding each further height map. A relative orientation of the height map bi relative to the overall height map b.sub.ges is determined, for example, based on an overlap (shown in a hatched fashion) of the height map bi with the overall height map b.sub.ges, i.e., the height maps b.sub.i recorded up to now, in particular the height map b.sub.i-1 recorded immediately before.

[0041] In addition, in the exemplary embodiment shown, at least one statistic M.sub.i of the quality of the height map b.sub.i is determined for each height map bi, and the recording frequency f.sub.A is regulated based on the determined quality.

[0042] The quality statistic M.sub.i is 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.

[0043] Based on the first statistic M.sub.i, a first control signal S=S.sub.i(M.sub.i) for controlling the recording frequency f.sub.A is generated. 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.

[0044] In an alternative embodiment, a sensor signal of a sensor 9 (shown dashed) is sapplementally 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 b.sub.i relative to one another can be deduced from the movement of the camera 4.

LIST OF REFERENCE SIGNS

[0045] 1 Object

[0046] 2 Tooth

[0047] 3 Recording unit

[0048] 4 Light source

[0049] 5 Illumination beam

[0050] 6 Light detector

[0051] 7 Comptiting unit

[0052] 8 Display unit

[0053] 9 Sensor

[0054] 10 Control unit

[0055] b.sub.ges Overall height map

[0056] b.sub.i Height maps

[0057] f.sub.A Recording frequency

[0058] dt Time interval

[0059] M.sub.i Statistic for the quality of the height map b.sub.i

[0060] S Control signal

[0061] T1 Recording time interval