TWI595445B - Anti-noise three dimensional scanning system - Google Patents

Description

Anti-noise stereo scanning system

The disclosure relates to a stereo scanning system.

With the advancement of technology, more and more electronic products are beginning to use metal materials as the shell to increase the aesthetics of the products. The metal casing can be machined (e.g., a milling machine or a lathe) to obtain the desired shape and features that can be imaged for inspection using optical instruments. However, after processing, the metal surface may become rough (for example, the stencil generated by the processing), so that the image captured by the optical instrument may contain information on the rough surface, making the measurement unstable or even impossible to measure. The characteristics to be detected.

One aspect of the disclosure provides a stereo scanning system including a polarized parallel line source, a telecentric image capturing device, and a first polarizing element. A polarized parallel line source provides a line of polarized light to the surface to be measured. The polarization beam has a spread angle of less than 10 degrees. The telecentric image capturing device is used to extract the polarized light beam on the surface to be measured. The first polarizing element is placed in the telecentric image capturing device and the surface to be tested between. The polarization state of the polarized beam and the polarization state of the first polarizing element are substantially textual.

In the above embodiment, the stereo scanning system utilizes a combination of a polarized light beam having a small diffusion angle, a first polarizing element, and a telecentric image capturing device to eliminate measurement errors caused by irregularities in the surface structure of the object to be tested.

110‧‧‧Polarized parallel line source

112, 115‧‧‧ polarized beam

114, 116‧‧‧ optical axis

122‧‧‧Polarized light source

123‧‧‧Polarized beam

124‧‧‧ lenticular lens

152‧‧‧ camera

154‧‧‧ telecentric lens

160‧‧‧First polarizing element

900‧‧‧ platform

905‧‧‧Test object

910‧‧‧To be tested

126, 136‧‧ ‧ collimating components

132‧‧‧Line light source

133‧‧‧Line beam

138‧‧‧Second polarizing element

150‧‧‧ telecentric image capture device

912‧‧‧ normal

C‧‧‧ area

D‧‧‧ Direction

θ, θ'‧‧‧ diffusion angle

FIG. 1 is a schematic diagram of a stereo scanning system, a platform, and an object to be tested according to an embodiment of the present disclosure.

Fig. 2 is a schematic view of a polarization parallel line source of Fig. 1 according to an embodiment.

Fig. 3 is a schematic view of a polarization parallel line source of Fig. 1 according to another embodiment.

Fig. 4 is a schematic view showing a polarization parallel line source of Fig. 1 according to still another embodiment.

The embodiments of the present disclosure are disclosed in the following drawings, and for the sake of clarity, many of the details of the practice will be described in the following description. However, it should be understood that these practical details are not intended to limit the disclosure. That is, in some embodiments of the disclosure, these practical details are not necessary. In addition, some of the conventional structures and elements are shown in the drawings in a simplified schematic manner in order to simplify the drawings.

1 is a schematic diagram of a stereo scanning system, a platform 900 and an object to be tested 905 according to an embodiment of the present disclosure, and FIG. 2 is a schematic diagram of a polarization parallel line source 110 according to FIG. 1 according to an embodiment. The stereo scanning system includes a polarization parallel line source 110, a telecentric image capturing device 150, and a first polarization element 160. The polarization parallel line source 110 provides a line of polarized beam 112 to the surface 910 to be tested. The diffusion angle θ of the polarized beam 112 (as shown in Fig. 2) is less than 10 degrees. In a preferred embodiment, the diffusion angle θ is less than 5 degrees. The telecentric image capturing device 150 is configured to capture the polarized light beam 115 on the surface 910 to be tested. The first polarizing element 160 is disposed between the telecentric image capturing device 150 and the surface to be tested 910. The polarization state of the polarized line beam 112 is substantially orthogonal to the polarization state of the first polarizing element 160.

In this context, the diffusion angle θ is the extent to which the beam diffuses as the propagation distance increases. The greater the degree of diffusion, the greater the diffusion angle θ, and vice versa. In FIG. 2, the polarized beam 112 propagates along an optical axis 114, and the beam edge of the polarized beam 112 is incident with the optical axis 114 by a diffusion angle θ. If the diffusion angle θ is 0 degrees, the polarization beam 112 is parallel light, that is, the parallel beam does not spread as the propagation distance increases.

In some embodiments, the surface to be tested 910 can be the surface of a platform 900. However, in the present embodiment, a test object 905 can be placed on the platform 900, and the stereoscopic scanning system is used to scan the three-dimensional shape of the object to be tested 905. If the stereo scanning system scans the object to be tested 905, the surface to be tested 910 is the surface on which the object to be tested 905 and the platform 900 are irradiated by the polarized light beam 112. If the stereo scanning system scans the surface of the platform 900, the surface 910 to be tested is the platform 900 illuminated by the polarized light beam 112. To the surface. For the sake of clarity, the surface to which the object to be tested 905 is irradiated with the polarized light beam 112 is taken as an example of the surface to be tested 910.

In the present embodiment, the stereo scanning system uses a combination of the polarized light beam 112 having a small diffusion angle θ, the first polarizing element 160, and the telecentric image capturing device 150 to eliminate the amount of the object 905 due to surface structure irregularities. Measure the error. Specifically, the object to be tested 905 may be a metal casing, for example, a metal casing that is machined and has a blade on the surface. For a rough surface of the object to be tested 905, measuring the surface topography is easy to generate irregular scattered light due to the rough surface. These scattered light will form noise on the captured image, which will improve the difficulty of subsequent analysis.

However, in the present embodiment, the polarization parallel line source 110 provides a polarization beam 112, i.e., the polarization beam 112 has a particular polarization state. The polarized light beam 112 forms a line on the surface 910 to be tested 905, and the undulation of the line reflects the topography of the surface 910 to be tested. As the object 905 and the polarization beam 112 move relative to each other, the polarization beam 112 scans the surface 910 to be measured, thereby reflecting the complete topography of the surface 910 to be measured. When the polarized line beam 112 is irradiated onto the surface to be tested 910, the grain defects of the surface to be tested 910 or other mechanical processing may cause irregular scattering of the polarized beam 112, and these irregular scattering may cause The polarization state of the polarized beam 112 produces an irregular change. When the polarized line beam 112 having an irregular polarization state reaches the first polarizing element 160, it is filtered by the first polarizing element 160, so that only the partially polarized line beam 115 having the stereoscopic information of the surface to be tested 910 can pass through the first The polarizing element 160 reaches the telecentric image capturing device 150. On the other hand, since the telecentric image capturing device 150 has a substantially flat reception The characteristics of the traveling light, therefore, can receive the polarized light beam 115 of a small diffusion angle scattered from the surface to be measured 910, and do not receive other light beams of a large diffusion angle irregularly scattered by the surface grain.

In summary, even if a part of the polarized light beam 112 is irradiated onto the surface to be tested 910, irregular scattering occurs due to the stencil, but these irregularly scattered beams can be passed through the first polarizing element 160 and the telecentric image capturing device 150. The filtering is performed, so that the features of the surface to be tested 910 can be enhanced, and the image of the rough surface is suppressed, so that the features of the object to be tested 905 can be highlighted to obtain a clear feature image of the object to be tested 905. In this way, the object to be tested 905 can be detected without surface treatment (for example, sand blasting), and the process can be greatly simplified.

Please refer to Figure 2. In some embodiments, the polarization parallel line source 110 includes a polarized light source 122, a lenticular lens 124, and a collimating element 126. The polarized light source 122 is used to provide a polarized light beam 123. The lenticular lens 124 is used to shape the polarized beam 123 into a polarized beam 112. The collimating element 126 is used to collimate the polarized line beam 112. Specifically, the polarized light source 122 may be, for example, a light source having a polarization state, such as a laser light source, or a combination of other light sources and polarizing elements. The polarized light source 122 can be a point source. In this paper, the spot of the polarized beam 123 provided by the point source is substantially non-linear, such as circular, rounded. The lens curved surface of the lenticular lens 124 is bent in a single direction, so that the polarized light beam 123 can be deformed in a single axial direction (for example, after convergence), so that the polarized light beam 123 becomes the polarized light beam 112. The collimating element 126 can collimate the polarized line beam 112 to converge the diffusion angle θ of the polarized line beam 112. In other words, the diffusion angle θ' of the polarization beam 112 that does not pass through the collimating element 126 is greater than The diffusion angle θ of the polarization beam 112 passing through the collimating element 126. In some embodiments, the collimating element 126 can be a lens, although the disclosure is not limited thereto.

The structure of the polarization parallel line light source 110 is not limited to the structure of FIG. Please refer to FIG. 3, which is a schematic diagram of a polarization parallel line source 110 according to FIG. 1 according to another embodiment. In the present embodiment, the polarization parallel line source 110 can omit the collimating element 126 of FIG. 2, that is, the polarization parallel line source 110 includes the polarization source 122 and the lenticular lens 124. In the present embodiment, the polarization beam 112 of the region C (i.e., the partial polarization beam 112 near the optical axis 114) has a small diffusion angle θ, so that only the polarization beam 112 of the region C can be utilized, for example, using a The baffle blocks the polarized line beam 112 outside of the area C, or the telecentric image capturing device 150 receives only the polarized line beam 112 of the area C. Other details of the present embodiment are the same as those of Fig. 2, and therefore will not be described again.

Fig. 4 is a schematic view of a polarization parallel line source 110 of Fig. 1 according to still another embodiment. In the present embodiment, the polarization parallel line source 110 includes a line source 132, a collimating element 136, and a second polarizing element 138. Line source 132 is used to provide line beam 133. The collimating element 136 is used for a quasi-linear beam 133. The second polarizing element 138 is used to polarize the collimated line beam 133 into a polarized beam 112. Specifically, the line source 132 can be a light bar comprising a plurality of point sources 134 arranged in a direction D. Point source 134 can be a light emitting diode or other suitable light source. The collimating element 136 can collimate the beam 133 to converge the angle of diffusion of the line beam 133. The back-line beam 133 is polarized to the polarized beam 112 by the second polarizing element 138. The polarization state of the second polarization element 138 and the first polarization element 160 (as shown in Figure 1) are substantially positive cross. Although in FIG. 4, the collimating element 136 is placed between the line source 132 and the second polarizing element 138, in other embodiments, the second polarizing element 138 can be placed between the line source 132 and the collimating element 136. The line beam 133 provided by the line source 132 may pass through the second polarizing element 138 and then pass through the collimating element 136. Other details of the present embodiment are the same as those of Fig. 2, and therefore will not be described again.

Please return to Figure 1. In the present embodiment, the polarized light beam 112 is incident on the surface 910 to be measured, and the telecentric image capturing device 150 obliquely draws the polarized light beam 115 on the surface 910 to be tested. Specifically, the surface to be tested 910 has a normal line 912. "Positive incidence" means that the optical axis 114 of the polarized line beam 112 supplied from the polarized parallel line source 110 is substantially parallel to the normal 912, and "obliquely drawn" indicates the polarized line beam 115 received by the telecentric image capturing device 150. The angle of intersection of the optical axis 116 with the optical axis 114 is greater than 0 degrees. The greater the angle of intersection, the better the effect of eliminating (or anti-noise) noise. In a preferred embodiment, the angle of intersection is greater than 20 degrees. Since the polarization beam 112 is positively incident on the surface 910 to be measured, and the telecentric image capturing device 150 obliquely extracts the polarization beam 115, the telecentric image capturing device 150 extracts the polarization line mainly scattered from the surface 910 to be measured. Beam 115.

In FIG. 1, the telecentric image capturing device 150 includes a camera 152 and a telecentric lens 154. The telecentric lens 154 is placed between the camera 152 and the first polarizing element 160. The telecentric lens 154 can include a plurality of lenses (not shown) that are designed to cause substantially parallel light to be incident such that the camera 152 is primarily imaged by parallel light. Such a design allows the imaging magnification of the object to be not changed by the distance of the object, and the beam of the large diffusion angle can be excluded from being imaged by the camera 152.

In summary, the polarized parallel line source provides a polarized line beam to form a line on the surface to be measured, the undulation of which reflects the topography of the surface to be measured. When the polarized light beam is irradiated onto the surface to be measured, the grain defects of the surface to be measured or other mechanical processing may cause irregular scattering of the polarized light beam. When the polarized light beam having an irregular polarization state reaches the first polarizing element, it is filtered by the first polarizing element, so that only a part of the polarized line beam having the stereoscopic information of the surface to be measured can reach the telecentricity through the first polarizing element. Image capture device. The telecentric image capturing device can receive a beam of polarized light having a small diffusion angle scattered from the surface to be measured, and does not receive a beam of a large diffusion angle that is irregularly scattered by the surface knife. In this way, the stereo scanning system can eliminate measurement errors caused by irregularities in the surface structure of the object to be tested.

The present disclosure has been disclosed in the above embodiments, and is not intended to limit the disclosure. Any one skilled in the art can make various modifications and retouchings without departing from the spirit and scope of the disclosure. The scope is subject to the definition of the scope of the patent application attached.

110‧‧‧Polarized parallel line source

112, 115‧‧‧ polarized beam

114, 116‧‧‧ optical axis

150‧‧‧ telecentric image capture device

152‧‧‧ camera

154‧‧‧ telecentric lens

160‧‧‧First polarizing element

900‧‧‧ platform

905‧‧‧Test object

910‧‧‧To be tested

912‧‧‧ normal

Claims (8)

A stereo scanning system comprising: a polarization parallel line source, providing a polarization beam to a surface to be measured, wherein the polarization beam has a diffusion angle of less than 10 degrees, the polarization parallel line source comprising: a polarization source for providing a polarized beam; a cylindrical lens for shaping the polarized beam into the polarized beam; and a collimating element for collimating the polarized beam; a telecentric image capturing device for capturing the beam a polarized light beam on the surface to be measured; and a first polarizing element disposed between the telecentric image capturing device and the surface to be tested, wherein the polarization state of the polarized light beam and the polarization of the first polarizing element The states are substantially orthogonal. The stereoscopic scanning system of claim 1, wherein the polarized light source is a laser light source. The stereo scanning system of claim 1, wherein the polarized light beam is incident on the surface to be tested. The stereo scanning system of claim 1, wherein the telecentric image capturing device obliquely captures the polarized light beam on the surface to be tested. The stereoscopic scanning system of claim 1, wherein the telecentric image capturing device comprises: a camera; and a telecentric lens disposed between the camera and the first polarizing element. A stereo scanning system comprising: a polarization parallel line source, providing a polarization beam to a surface to be measured, wherein the polarization beam has a diffusion angle of less than 10 degrees, and the polarization parallel line source comprises: a line source for providing a line a light beam; a collimating element for collimating the line beam; and a second polarizing element for polarizing the collimated line beam into the polarized line beam; a telecentric image capturing device for capturing The polarized light beam on the surface to be tested; and a first polarizing element disposed between the telecentric image capturing device and the surface to be tested, wherein the polarization state of the polarized light beam and the first polarizing element The polarization states are substantially orthogonal. The stereo scanning system of claim 6, wherein the line source comprises a plurality of point sources arranged in a direction. The stereoscopic scanning system of claim 6, wherein the point light sources are light emitting diodes.