A method for depth-scanning strip triangulation with wavelet signal generation with a strip triangulation arrangement for structured illumination of at least one measured object, wherein the strip triangulation arrangement comprises:
- a projection beam path,
- a detection beam path separated from the projection beam path,
- at least one rasterised light detector with pixels,
- at least one computer system, and
- a computer-controlled scanning device for the depth scan of the at least one measured object;
- and
- wherein the method comprises:
- (i) running a depth scan of the at least one measured object, the depth scan comprising:
- generating concurrently or sequentially at least two grating patterns with differing grating periods p_1 and p_2, wherein the at least two grating periods fulfill the relationships
- p_2≥1.01*p_1 and p_2≤100*p_1,
- projecting through the projection beam path onto the at least one measured object, so that a measured object illuminated in a structured manner exists, and
- recording with the rasterised light detector and by using the detection beam path of at least two sets of images, that respectively correspond to the at least two grating patterns, wherein each of the at least two sets of images comprises a sequence of images of the at least one measured object illuminated in a structured manner with a certain grating pattern,
- or
- (ii) producing a grating pattern with a period p and projecting the grating pattern with the period p onto the at least one measured object-through the projection beam path, so that a measured object illuminated in a structured manner exists;
- altering a triangulation angle of the strip triangulation arrangement so that at least two different effective triangulation angles beta_1 and beta_2 sequentially exist in the strip triangulation arrangement, which fulfil the relationships
- beta_2≥1.01*beta_1 and beta_2≤1.25*beta_1, and
- recording with the rasterised light detector and by using the detection beam path at least two sets of images, that respectively correspond to the triangulation angles, wherein each of the at least two sets of images comprises a sequence of images of the measured object illuminated in a structured manner at a corresponding given triangulation angle;
- producing at least two wavelets W1 and W2 with respectively different wavelet periods pw_1 and pw_2 from the at least two sets of images, wherein the at least two wavelets W1 and W2 respectively exhibit a contrast envelope (CE_1, CE_2);
- determining, using the computer system, a depth position of a measured measurement point i of the at least one measured object from the at least two wavelets W1 and W2 and considering reference phase values specified by pixel (phi_R_1, phi_R_2) of the at least two wavelet periods pw_1 and pw_2, comprising:
- by pixel evaluations of a center of gravity of at least one of the contrast envelopes (CE_1, CE_2);
- by pixel phase evaluations of both the wavelet period pw_1, which provides a phase value phi_1 modulo 2 Pi, and the wavelet period pw_2, which provides a phase value phi_2 modulo 2 Pi,
- calculating a phase value phi_O_1_i and phi_O_2 i modulo 2 Pi for a pixel i, which in the pixel i both the reference phase value phi_R_1_i modulo 2 Pi of the wavelet period pw_1 and the phase value phi_R_2_i modulo 2 Pi of the wavelet period pw_2 in the surroundings of the calculated center of gravity (CoG_W_1) correspond to the contrast envelope of the first wavelet W1 and/or the calculated center of gravity (CoG_w_2) of the contrast envelope of the second wavelet W2 at least approximately;
- and
- calculating the depth position for the measurement point i of the measured object from the calculated phase values phi_O_1_i and phi_O_2_i modulo 2 Pi for the pixel i.