Method and system for detecting at least one component of an optical element

Abstract

Method and system for detecting at least one component of an optical element The invention relates to a method for detecting at least one component of an optical element to be controlled by implementing a system comprising at least: a projection device, such as a screen or a display, of at least one luminous image onto an optical element to be controlled, a device for acquiring at least a part of the projected luminous image having passed through the optical element, characterized in that the method comprises: a step of projecting and acquiring through the optical element two series of luminous images emitted by the projection device and corresponding to a succession of sinusoidal fringes, each image of the same series having identical fringes with a phase shift relative to the other images of the series, the frequency of the sinusoidal fringes being different between the respective images of the two series,a measurement of a value of the light signal at a point with predefined coordinates identical to each light image having passed through the optical element, a correlation of the value of the light signal at the point identified and measured for each image having passed through the optical element, on the one hand, with the value of the light signal of the corresponding point of the corresponding projected light image and, on the other hand, with the value of the light signal of the corresponding identical point of another light image having passed through the optical element, a characterization of at least one component of the optical element. Figure to be published with the abstract: no figure.,

Description

Title of the invention: Method and system for detecting at least one component of an optical element

[0001] The present invention relates to the field of methods for detecting components of an optical element and more particularly to the field of methods for detecting components of an optical element implementing phase shift deflectometry.

[0002] In the context of quality control operations for an optical element, or even a transparent part, this verification is carried out, on the one hand, at the surface of the element being controlled and, on the other hand, in the thickness of the element by evaluating the optical properties of this element. Several control techniques have been developed to date, including in particular deflectometry. This technology, which can be implemented both in reflection and in transmission, allows for characterization of properties, expected or imperfect or even defective, of a transparent element, both at the surface and in the material itself, by evaluating deformation phenomena of a light signal projected onto and / or through the transparent element.This phenomenon of deviation of a light signal then allows the identification of technical specificities of the transparent element controlled by comparison with perfect or theoretically predictable reflection and / or transmission phenomena.

[0003] However, if quality control operations based on deflectometry projecting a simple sinusoidal pattern have obvious advantages, it should be noted that this technology shows its limits in easily characterizing one or other of the properties of the optical or transparent element being controlled. Furthermore, this technology alone is not capable of allowing a precise and effective determination of any optical distortions produced by the optical or transparent element being controlled.

[0004] The present invention aims to overcome these drawbacks by proposing a solution capable of effectively carrying out a precise and detailed characterization of the optical distortion phenomena generated by a controlled optical or transparent element while allowing easier implementation of this solution.

[0005] The invention thus relates to a method for detecting at least one component of an optical element by implementing a system comprising at least: - a projection device, such as a screen or display, of at least one light image on an optical element to be controlled, - a device for acquiring at least part of the light image having passed through the optical element to be controlled and coming from the projected light image, characterized in that the method comprises: - a step of projecting through the optical element a first series of at least three light images emitted by at least one projection device and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the first series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, - a step of acquiring each light image having passed through the optical element to be controlled and resulting from the projected light images of the first series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image having passed through the optical element of the first series, - a step of correlating the value of the light signal of the identified and measured point of each image of the first series having passed through the optical element with the value of the light signal of the corresponding point of identical coordinates of another light image of the first series having passed through the optical element, - a step of characterizing the modification of the phase shift of the first series of images at each point of the optical element to be controlled crossed by each image of the first series, - a step of projecting through the optical glass a second series of at least three light images emitted by at least one projection device and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the second series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the frequency of the sinusoidal fringes of the first series being different from the frequency of the sinusoidal fringes of the second series, the axes of the succession of sinusoidal fringes of the images of the first series and of the second series being identical, - a step of acquiring each light image having passed through the optical element to be controlled and resulting from the projected light images of the second series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image of the second series having passed through the optical element, - a step of correlating the value of the light signal of the identified and measured point of each image of the second series having passed through the optical element with the value of the light signal of the corresponding point of identical coordinates of another light image of the second series having passed through the optical element, - a step of characterizing the modification of the phase shift of the second series of images at each point of the optical element to be controlled crossed by each image of the second series, - a step of correlating the value of the phase shift of the first series of images at an identified point of the optical element with the value of the phase shift of the second series of images of the corresponding point of identical coordinates.

[0006] The invention also relates to a system for detecting at least one component of an optical element intended for implementing a detection method according to the invention, characterized in that the system comprises at least: - a device for supporting at least one optical element to be controlled, - a projection device, such as a screen or a display, of at least two series of successive light images through the optical element to be controlled, each series of light images comprising a defined pattern integrating in particular at least one succession of light and dark sinusoidal fringes with a different respective frequency, each light image of the same series comprising a light and dark sinusoidal signal with an identical frequency and a phase shift relative to the other light images of the same series, - a device for acquiring at least one value of the light signal at at least one point with predefined coordinates identical to each light image having passed through the optical element to be controlled and originating from the projected light image, - a calculation unit configured to determine at least one component of an optical element, on the one hand, from different measurements of at least one point with predefined coordinates identical to each light image of the same series of light images having passed through the optical element or, on the other hand, from different measurements of at least one point with predefined coordinates identical to each light image of two series of light images having passed through the optical element.

[0007] The invention will be better understood from the following description, which relates to the preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, in which: - [Fig.l] is a schematic representation illustrating an example of a detection system according to the invention, - [Fig.2] is a schematic illustration of an example of a first and second series of light images emitted by a projection device within the framework of the invention, - [Fig.3] is a schematic illustration of an example of a third and fourth series of light images emitted by a projection device within the framework of a variant of the invention.

[0008] It should be noted that, in the present document, the term “optical element” refers to any transparent or opaque element capable of being crossed by a light ray; this light ray preferably belonging to the visible light spectrum. This optical element 1 is thus likely to correspond to an optical glass but also to a mask or helmet visor, or even to a watch glass, a porthole or a windshield.

[0009] The invention relates to a method for detecting at least one component of an optical element 1 by implementing a system comprising at least: - a projection device 2, such as a screen or a display, of at least one luminous image onto an optical element 1 to be controlled, - a device 3 for acquiring at least part of the light image having passed through 42 the optical element 1 to be controlled and coming from the projected light image 41, characterized in that the method comprises: - a step of projecting through the optical element 1 a first series of at least three light images 41 emitted by at least one projection device 2 and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the first series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, - a step of acquiring each light image having passed through 42 the optical element 1 to be controlled and coming from the projected light images 41 of the first series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image having passed through the optical element 1 of the first series, - a step of correlating the value of the light signal of the identified and measured point of each image of the first series having passed through the optical element 1 with the value of the light signal of the corresponding point of identical coordinates of another light image of the first series having passed through the optical element 1, - a step of characterizing the modification of the phase shift of the first series of images at each point of the optical element 1 to be controlled crossed by each image 41 of the first series, - a step of projecting through the optical glass 1 a second series of at least three light images emitted by at least one projection device 2 and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the second series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the frequency of the sinusoidal fringes of the first series being different from the frequency of the sinusoidal fringes of the second series, the axes of the succession of sinusoidal fringes of the images of the first series and of the second series being identical, - a step of acquiring each light image having passed through 42 the optical element 1 to be controlled and resulting from the projected light images 41 of the second series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image of the second series having passed through the optical element 1, - a step of correlating the value of the light signal of the identified and measured point of each image of the second series having passed through 42 the optical element 1 with the value of the light signal of the corresponding point of identical coordinates of another light image of the second series having passed through 42 the optical element 1, - a step of characterizing the modification of the phase shift of the second series of images at each point of the optical element 1 to be controlled crossed by each image 41 of the second series, - a step of correlating the value of the phase shift of the first series of images at an identified point of the optical element 1 with the value of the phase shift of the second series of images of the corresponding point of identical coordinates.

[0010] The method according to the invention is based on a projection through an optical element 1 of two sequences of images corresponding respectively to series of at least three images, preferably at least four images, in each of which the images comprise identical sinusoidal fringes, i.e. having a frequency identical and specific to each of the series of images. In each of these series of projected images 41, the sinusoidal fringes of these images, although being identical, have, from one image to the other, a phase shift. The projection of two series of images through the optical element 1 allows the realization of a double acquisition with, between the different images projected through the optical element 1, on the one hand, a spatial phase shift and, on the other hand, a temporal phase shift.

[0011] Also, in the context of the method according to the invention, for each projected light image 41, from the value of the light signal at at least one point with predefined and identical coordinates of the image 41, the corresponding point of the light image having passed through 42 the optical element 1 as well as its signal value are identified. The phase shift between several projected images 41 of the same series then leads to variations in the value of the light signal at the same point of images having passed through 42 the optical element 1. This phase shift then makes it possible to operate a link between the respective values ​​of the light signal at the same point with identical coordinates of the corresponding images having passed through 42 the optical element 1.By comparing the different values ​​of the light signal at a point with identical coordinates of the images of the same series having passed through 42 the optical element 1, on the one hand, with each other and, on the other hand, with the corresponding value of the projected light signal 41, it is possible to evaluate the modification of the phase shift brought to the transmission or reflection of the light signal by the optical element 1 and to characterize the phase generated by the optical element 1 at the point crossed by said point with identical coordinates of the images having passed through 42 the optical element 1. It is thus possible to carry out a characterization of the shape of the surface of the optical element 1. It should be noted that the greater the number of images of the same series, the more the quality of the characterization will be enhanced.Furthermore, by comparing the different values ​​of the light signal at a point with coordinates identical to each of the images having passed through the optical element 1 and coming from different series, that is to say images having different frequencies of the sinusoidal fringes, it is then possible to carry out a refined identification of at least one defect of the surface or of the thickness of the optical element 1 and present in the field of the acquisition device 3. The difference in frequency of the sinusoidal fringes between each of the two series of projected images makes it possible, by comparing the acquisitions carried out within the framework of each of these projections, to operate an optimization of the sensitivity in the identification of defects by analysis of the light signals transmitted or reflected by the optical element 1.

[0012] It should be noted that, in the context of the implementation of the detection method of the invention, when the light signal is transmitted by the optical element 1, the characterization of the position of a defect of the optical element 1, on the surface or in its thickness, is likely to be carried out by an adjustment of the depth of field of the acquisition device 3, in particular by reducing the depth of this depth of field.

[0013] According to an example corresponding to a variant of implementation of the method according to the invention, the step of correlating the value of the phase shift of the first series of images at an identified point of the optical element 1 with the value of the phase shift of the second series of images of the corresponding point of identical coordinates involves: - a step of restoring the physical continuity of the succession of phases by removing the phase jumps of the modifications characterized by phase shift for each of the two series of images, - a step of determining the signal difference between the two phase shift signals whose physical continuity of the phase sequence is restored.

[0014] According to an example corresponding to a variant implementation of the method according to the invention, the phase shift of the sinusoidal fringes of the images of the same series is of the order of 360° / N where N is the number of images of the series. Also, within the same series of projected images 41, the spatial phase shift is carried out in an identical and uniform manner between the different images of the series. Thus, the successive phase shifts carried by the different images of the same series are distributed at regular intervals according to a shift of the order of 360° / N so as to allow a distribution of the images of the same series over the entire wavelength of the sinusoidal fringes carried by the images of this series. The coverage of the entire wavelength is thus carried out in a substantially homogeneous manner by the distribution of the phase shifts of the different images.

[0015] According to an example corresponding to a specific variant of the variant of implementation of the method according to the invention detailed above, the phase shift of the sinusoidal fringes of the images of at least one series is of the order of 90°. Also, according to this specific variant, such a series comprises four images with phase shifts distributed at regular intervals of 90° over the entire wavelength of the sinusoidal fringes of the images of the same series.

[0016] According to an example corresponding to another variant of implementation of the method according to the invention and capable of being combined with one or other of the previously detailed variants of implementation, the absolute value of the difference of the respective frequencies of the sinusoidal fringes between the first series and the second series is at most 10 hertz. According to an example corresponding to a preferred implementation of the method, the absolute value of the difference in the respective frequencies of the sinusoidal fringes between the first series and the second series is of the order of one or two pixels of the projected image. Such a small absolute value of the difference between the respective frequencies of the sinusoidal fringes between the first series and the second series makes it possible to achieve an optimization of the sensitivity of the signal obtained after processing by correlation of the phase shift values ​​characterized by each acquisition series.A reduction in the absolute value of the difference in the respective frequencies of the sinusoidal fringes between the first series and the second series provides an increase in sensitivity in detecting defects in the optical element 1 present in the field of the acquisition device 3.

[0017] According to an example corresponding to another variant of implementation of the method according to the invention and capable of being combined with one or other of the previously detailed variants of implementation, the method also comprises: - a step of projecting through the optical element 1 a third series of at least three light images 41 emitted by at least one projection device 2 and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the third series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the axis of the succession of sinusoidal fringes of the images of the third series having an inclination relative to the axis of the succession of sinusoidal fringes of the images of the first series, - a step of acquiring each light image having passed through 42 the optical element 1 to be controlled and resulting from the projected light images 41 of the third series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image having passed through the optical element 1 of the third series, - a step of correlating the value of the light signal of the identified and measured point of each image of the first series having passed through the optical element 1 with the value of the light signal of the corresponding point of identical coordinates of another light image of the third series having passed through the optical element 1, - a step of characterizing the modification of the phase shift of the third series of images at each point of the optical element 1 to be controlled crossed by each image 41 of the third series, - a step of projecting through the optical glass 1 a fourth series of at least three light images emitted by at least one projection device 2 and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the fourth series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the frequency of the sinusoidal fringes of the third series being different from the frequency of the sinusoidal fringes of the fourth series, the axes of the succession of sinusoidal fringes of the images of the third series and of the fourth series being identical, - a step of acquiring each light image having passed through 42 the optical element 1 to be controlled and resulting from the projected light images 41 of the fourth series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image of the fourth series having passed through the optical element 1, - a step of correlating the value of the light signal of the identified and measured point of each image of the fourth series having passed through 42 the optical element 1 with the value of the light signal of the corresponding point of identical coordinates of another light image of the fourth series having passed through 42 the optical element 1, - a step of characterizing the modification of the phase shift of the fourth series of images at each point of the optical element 1 to be controlled crossed by each image 41 of the fourth series, - a step of correlating the value of the phase shift of the third series of images at an identified point of the optical element 1 with the value of the phase shift of the fourth series of images of the corresponding point of identical coordinates. According to this variant implementation of the method of the invention, the detection involves projections of at least two pairs of series of images whose respective sinusoidal fringes of each pair of series are distributed along different axes, that is to say along axes arranged with each other with an inclination. This projection of images whose respective sinusoidal fringes are oriented along different axes makes it possible to carry out an optimized identification of possible defects in the optical element 1. A search for defects in the optical element 1 from projections of images whose respective sinusoidal fringes are oriented along a second axis makes it possible to detect defects in the optical element 1 which, by their characteristics, their positions and / or their configurations, would not have been identified or which would not be identifiable in the context of the search for defects carried out from the projections of images whose respective sinusoidal fringes are oriented along the first axis.

[0018] According to an example corresponding to an alternative implementation of the method according to the invention capable of being combined with the previously detailed alternative implementation, the axis of the succession of sinusoidal fringes of the images of the third series has an inclination of 90° relative to the axis of the succession of sinusoidal fringes of the images of the first series. This 90° inclination of the axes of succession of sinusoidal fringes of the images of the pairs of series between them is a preferred configuration. Such an inclination makes it possible to optimize the sensitivity of the search for defects of the optical element 1 from projections of images whose respective sinusoidal fringes are oriented along the second axis relative to the search carried out from projections of images whose respective sinusoidal fringes are oriented along the first axis.

[0019] According to an example corresponding to another variant of implementation of the method according to the invention and capable of being combined with one or other of the previously detailed variants of implementation, within the framework of the implementation of the method, series of at least three different light images 41 projected during projection steps are produced in different wavelength intervals. The use of light signals relating to differences in wavelength intervals makes it possible to carry out detection adapted to the technical specificities of the optical element 1.

[0020] The invention also relates to a system for detecting at least one component of an optical element 1, characterized in that the system comprises at least: - a device for supporting at least one optical element 1 to be controlled, - a projection device 2, such as a screen or a display, of at least two successive series of light images 41 through the optical element 1 to be controlled, each series of light images comprising a defined pattern integrating in particular at least one succession of light and dark sinusoidal fringes with a different respective frequency, each light image of the same series comprising a light and dark sinusoidal signal with an identical frequency and a phase shift relative to the other light images of the same series, - a device 3 for acquiring at least one value of the light signal at at least one point with predefined coordinates identical to each light image having passed through 42 the optical element 1 to be controlled and originating from the projected light image 41, - a calculation unit configured to determine at least one component of an optical element 1, on the one hand, from different measurements of at least one point of predefined coordinates and identical to each light image of the same series of light images having passed through 42 the optical element 1 or, on the other hand, from different measurements of at least one point of predefined coordinates and identical to each light image of two series of light images having passed through 42 the optical element 1.

[0021] According to an example corresponding to an alternative implementation of the detection system according to the invention, the acquisition device 3 is configured with a depth of field whose depth covers most of the distance which separates the acquisition device 3 from the optical element 1. Such a depth of field of the acquisition device 3 makes it possible to ensure sharpness during the acquisition of the image having passed through the optical element 1 without it being necessary to adjust the optical element 1 relative to the acquisition device. Also, the system according to the invention is able to be used in the context of an automation of the detection method according to the invention, in particular when several optical elements 1 must be successively controlled.Thus, the successive installation of the optical elements 1 on the support device can be automated without it being necessary to check and adjust the position of these optical elements 1 relative to the acquisition device 3.

[0022] Of course, the invention is not limited to the embodiments described and shown in the attached drawings. Modifications remain possible, particularly from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

1. Claims Method for detecting at least one optical distortion of an optical element (1) by implementing a system comprising at least: - a projection device (2), such as a screen or a display, of at least one luminous image (41) through an optical element (1) to be controlled, - a device (3) for acquiring at least part of the light image having passed through (42) the optical element (1) to be controlled and coming from the projected light image (41), characterized in that the method comprises: - a step of projecting through the optical element (1) a first series of at least three light images (41) emitted by at least one projection device (2) and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the first series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, - a step of acquiring each light image having passed through (42) the optical element (1) to be controlled and coming from the projected light images (41) of the first series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image having passed through (42) the optical element (1) of the first series, - a step of correlating the value of the light signal of the identified and measured point of each image of the first series having passed through (42) the optical element (1) with the value of the light signal of the corresponding point of identical coordinates of another light image of the first series having passed through the optical element (1), - a step of characterizing the modification of the phase shift of the first series of images at each point of the optical element (1) to be controlled crossed by each image (41) of the first series,

2. - a step of projecting through the optical element (1) a second series of at least three light images emitted by at least one projection device (2) and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the second series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the frequency of the sinusoidal fringes of the first series being different from the frequency of the sinusoidal fringes of the second series, the axes of the succession of sinusoidal fringes of the images (41) of the first series and of the second series being identical, - a step of acquiring each light image having passed through (42) the optical element (1) to be controlled and resulting from the projected light images (41) of the second series, - a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image of the second series having passed through (42) the optical element (1), - a step of correlating the value of the light signal of the identified and measured point of each image of the second series having passed through (42) the optical element (1) with the value of the light signal of the corresponding point of identical coordinates of another light image of the second series having passed through (42) the optical element (1), - a step of characterizing the modification of the phase shift of the second series of images at each point of the optical element (1) to be controlled crossed by each image (41) of the second series, - a step of correlating the value of the phase shift of the first series of images at an identified point of the optical element (1) with the value of the phase shift of the second series of images of the corresponding point of identical coordinates. Detection method according to claim 1, characterized in that the step of correlating the value of the phase shift of the first series of images at an identified point of the optical element (1) with the value of the phase shift of the second series of images of the corresponding point of identical coordinates involves: - a step of restoring the physical continuity of the succession of phases by removing the phase jumps of the characterized modifications of phase shift for each of the two series of images, - a step of determining the signal difference between the two phase shift signals whose physical continuity of the succession of phases is restored.

3. Detection method according to one of the preceding claims, characterized in that the phase shift of the sinusoidal fringes of the images of the same series is of the order of 360° / N where N is the number of images in the series.

4. Detection method according to claim 3, characterized in that the phase shift of the sinusoidal fringes of the images of at least one series is of the order of 90°.

5. Detection method according to one of the preceding claims, characterized in that the absolute value of the difference in the respective frequencies of the sinusoidal fringes between the first series and the second series is at most 10 hertz.

6. Detection method according to one of the preceding claims, characterized in that the method also comprises: - a step of projecting through the optical element (1) a third series of at least three light images (41) emitted by at least one projection device (2) and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the third series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the axis of the succession of sinusoidal fringes of the images of the third series having an inclination relative to the axis of the succession of sinusoidal fringes of the images of the first series, a step of acquiring each light image having passed through (42) the optical element (1) to be controlled and resulting from the projected light images (41) of the third series, a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image having passed through (42) the optical element (1) of the third series, a step of correlating the value of the light signal of the identified and measured point of each image of the first series having passed through (42) the optical element (1) with the value of the light signal of the corresponding point with identical coordinates of another light image of the third series having passed through the optical element (1), a step of characterizing the modification of the phase shift of the third series of images at each point of the optical element (1) to be controlled crossed by each image (41) of the third series, a step of projecting through the optical element (1) a fourth series of at least three light images emitted by at least one projection device (2) and corresponding to at least one succession of light and dark sinusoidal fringes, each image of the fourth series having identical sinusoidal fringes with a phase shift relative to the other images of the series, the shift being less than the phase of the sinusoids, the frequency of the sinusoidal fringes of the third series being different from the frequency of the sinusoidal fringes of the fourth series, the axes of the succession of sinusoidal fringes of the images of the third series and the fourth series being identical, a step of acquiring each light image having passed through (42) the optical element (1) to be controlled and coming from the projected light images (41) of the fourth series,a step of identifying and measuring a value of the light signal at at least one point with predefined coordinates identical to each light image of the fourth series having passed through (42) the optical element (1), - a step of correlating the value of the light signal of the identified and measured point of each image of the fourth series having passed through (42) the optical element (1) with the value of the light signal of the corresponding point of identical coordinates of another light image of the fourth series having passed through (42) the optical element (1), - a step of characterizing the modification of the phase shift of the fourth series of images at each point of the optical element (1) to be controlled crossed by each image (41) of the fourth series, - a step of correlating the value of the phase shift of the third series of images at an identified point of the optical element (1) with the value of the phase shift of the fourth series of images of the corresponding point of identical coordinates.

7. Detection method according to claim 6, characterized in that the axis of the succession of sinusoidal fringes of the images of the third series has an inclination of 90° relative to the axis of the succession of sinusoidal fringes of the images of the first series.

8. Detection method according to one of the preceding claims, characterized in that, in the context of implementing the method, series of at least three different light images (41) projected during projection steps are produced in different wavelength intervals.

9. System for detecting at least one component of an optical element intended for implementing a detection method according to one of claims 1 to 8, characterized in that the system comprises at least: - a device for supporting at least one optical element (1) to be controlled, - a projection device (2), such as a screen or a display, of at least two series of successive light images (41) through the optical element (1) to be controlled, each series of light images comprising a defined pattern integrating in particular at least one succession of light and dark sinusoidal fringes with a different respective frequency, each light image of the same series comprising a light and dark sinusoidal signal with an identical frequency and a phase shift relative to the other light images of the same series, - an acquisition device (3) of at least one value of the light signal at at least one point with predefined coordinates and identical to each light image having passed through (42) the optical element (1) to be controlled and coming from the projected light image (41), - a calculation unit configured to determine at least one component of an optical element (1), on the one hand, from different measurements of at least one point with predefined coordinates and identical to each light image of the same series of light images having passed through (42) the optical element (1) or, on the other hand, from different measurements of at least one point with predefined coordinates and identical to each light image of two series of light images having passed through (42) the optical element (1).

10. Detection system according to claim 9, characterized in that the acquisition device (3) is configured with a depth of field whose depth covers most of the distance which separates the acquisition device (3) from the optical element 1.

Images