Machine vision system and method with multispectral optical assembly
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- COGNEX CORP
- Filing Date
- 2026-02-04
- Publication Date
- 2026-06-09
Smart Images
Figure 2026094153000001_ABST
Abstract
Claims
1. A lighting assembly for a machine vision system, It comprises multiple multispectral optical assemblies, each of which is a multispectral optical assembly. A multispectral light source configured to generate light of multiple different wavelengths, A light pipe having an incident surface and an outgoing surface, positioned in front of the multispectral light source with respect to the illumination direction, and configured to receive two or more of the multiple different wavelengths of light generated by the multispectral light source and to mix the two or more of the multiple different wavelengths of light, A diffusing surface is provided on the emission surface of the light pipe and receives the mixed-color light emitted from the light pipe, A projection lens positioned in front of the diffusion surface, configured to receive the mixed-color light from the diffusion surface and project a light beam containing the mixed-color light onto an object, It is equipped with, The lighting system further includes a processing unit configured to communicate with the plurality of multispectral light assemblies and to control the driving of the multispectral light source of each of the plurality of multispectral light assemblies. A lighting assembly characterized by the following features.
2. The multispectral light source comprises a plurality of color light-emitting diodes (LEDs) configured to output light of different wavelengths separately. The lighting assembly according to claim 1.
3. The multispectral light source is one of RGBW LED, RGB IR LED, or RGBBY LED. The lighting assembly according to claim 2.
4. The system further includes an illumination sensor that communicates with the processing device and is configured to receive light of at least one wavelength generated by the multispectral light source and measure the intensity of the light of that wavelength. The lighting assembly according to claim 1.
5. The processing apparatus is configured to receive the measured intensity of the light of at least one wavelength and, based on the measured intensity, perform one or more of the following: adjust the intensity of the light of at least one wavelength or adjust the exposure time of the light of at least one wavelength. The lighting assembly according to claim 4.
6. The processing apparatus is configured to adjust the intensity of light of at least one wavelength based on a comparison between the measured intensity and the target intensity. The lighting assembly according to claim 5.
7. The diffusion surface is configured to control the angle of the light emitted from the light pipe. The lighting assembly according to claim 1.
8. The diffusion surface is configured to control the shape of the light emitted from the light pipe. The lighting assembly according to claim 7.
9. The projection lens is one of the following lens shapes: aspherical lens, spherical lens, toroidal lens, cylindrical lens, or free-form lens, or a combination of multiple lens shapes. The lighting assembly according to claim 8.
10. The shape of the light beam projected onto the object is approximately equal to the shape of the field of view (FOV) of the machine vision system. The lighting assembly according to claim 8.
11. The shape of the light beam projected onto the aforementioned object is rectangular. The lighting assembly according to claim 10.
12. The diffusion surface is a holographic diffuser positioned on the emission surface of the light pipe. The lighting assembly according to claim 1.
13. The diffusion surface is the diffusion texture of the emission surface of the light pipe. The lighting system according to claim 1.
14. The shape of the light pipe and the ratio of the area of the incident surface to the exit surface of the light pipe are optimized for color mixing. The lighting assembly according to claim 1.
15. An optical system assembly having at least one lens, A sensor assembly equipped with an imaging sensor, An illumination assembly comprising a plurality of multispectral light assemblies symmetrically arranged around at least one lens, It is equipped with, Each of the plurality of multispectral optical assemblies is A multispectral light source comprising multiple color LED dies, each generating light of a different wavelength, wherein the orientation of the multiple color LED dies is set to provide a balanced color distribution in the illumination area. A light pipe having an emission surface is positioned in front of the multispectral light source, A diffusion surface arranged on the emission surface of the light pipe, A projection lens positioned in front of the diffusion surface and configured to project the illumination area onto an object, It is equipped with, The machine vision system further comprises a processing unit configured to communicate with the optical system assembly, the sensor assembly, and the illumination assembly, and to control the driving of each of the plurality of color LED dies. A machine vision system characterized by the following features.
16. The machine vision system according to claim 15, wherein the processing apparatus is configured to sequentially drive each of the plurality of color LED dies.
17. The processing apparatus is configured to sequentially drive each of the plurality of color LED dies during one exposure time. The machine vision system according to claim 16.
18. A housing arranged around the optical system assembly, the sensor assembly, the illumination assembly, and the processing apparatus, A diffuse light assembly, which is detachably mounted to the housing in front of the lighting assembly, and is configured to convert light emitted from the lighting assembly into diffuse light, The machine vision system according to claim 15, further comprising:
19. Each of the aforementioned plurality of color LED dies has a plurality of lighting positions corresponding to each of the plurality of color LED dies, each containing an LED of a different color. The plurality of multispectral light assemblies as a whole have an equal number of different colors at each of the plurality of lighting positions. The machine vision system according to claim 15.
20. A method for controlling a lighting system for a machine vision system used to acquire images of symbols present in an object, Using at least one multispectral light source and a corresponding light pipe, a first light beam having a first wavelength associated with a first color channel is projected over a first period of time. The intensity of the first light beam is measured using an illumination sensor, Using a processing apparatus, the measured intensity of the first light beam is compared with the first target intensity, Using the apparatus, the amount of light from the first light beam is adjusted based on the comparison result between the measured intensity of the first light beam and the first target intensity, until the measured intensity of the first light beam becomes equal to the target intensity. After the first period, the at least one multispectral light source and the corresponding light pipe are used to project a second light beam having a second wavelength associated with the second color channel over a second period. The intensity of the second light beam is measured using the illumination sensor, Using the apparatus, the measured intensity of the second light beam is compared with the second target intensity, Using the apparatus, the amount of light from the second light beam is adjusted based on the comparison result between the measured intensity of the second light beam and the second target intensity, until the measured intensity of the second light beam becomes equal to the second target intensity. A method characterized by including the following.
21. The first light beam and the second light beam are projected sequentially. The method according to claim 20.
22. The first period and the second period are included in the same single exposure time. The method according to claim 21.
23. Adjusting the amount of light from the first light beam includes adjusting the duration of the first period, or adjusting the amount of light from the second light beam includes adjusting the duration of the second period. The method according to claim 21.
24. An imaging sensor assembly equipped with an imaging sensor, A lens assembly coupled to the aforementioned imaging sensor assembly, A lighting assembly coupled to the aforementioned lens assembly, It is equipped with, The aforementioned lighting assembly comprises multiple multispectral light assemblies, Each of the plurality of multispectral optical assemblies is A multispectral light source comprising multiple color LED dies configured to generate light of at least two different wavelengths, A light pipe having an emission surface is positioned in front of the multispectral light source, A diffusion surface arranged on the emission surface of the light pipe, A projection lens positioned in front of the diffusion surface, It is equipped with, The machine vision system further comprises a removable front cover positioned in front of the lighting assembly. A machine vision system characterized by the following features.
25. It further comprises a passive optical accessory located in front of the removable front cover and detachably attached to the machine vision system, The machine vision system according to claim 24.
26. The passive light accessory is a diffuse light assembly configured to convert light emitted from the lighting assembly into diffuse light. The machine vision system according to claim 25.
27. A portion of the front cover is configured to diffuse light from the lighting assembly. The machine vision system according to claim 24.
28. A portion of the front cover is configured to provide orthogonal polarization. The machine vision system according to claim 24.
29. A lighting sensor is positioned to detect light emitted from the aforementioned lighting assembly, Distance sensor and It also has, The machine vision system according to claim 24.
30. The aforementioned distance sensor is a time-of-flight (TOF) sensor. The machine vision system according to claim 29.
31. The lens assembly further comprises a manual focusing mechanism for adjusting the focus of the lens assembly. The machine vision system according to claim 24.
32. The lens assembly further comprises a multi-aperture assembly positioned in front of the aforementioned lens assembly. The machine vision system according to claim 24.
33. An imaging sensor assembly equipped with an imaging sensor, A lens assembly coupled to the image sensor assembly, comprising a plurality of lenses and a first gear arranged around the lens assembly, A lighting assembly coupled to the aforementioned lens assembly, It is equipped with, The aforementioned lighting assembly is Housing and A gear mechanism that movably engages with the first gear of the lens assembly, An outer surface having an opening configured to receive a tool for adjusting the focus of the lens assembly, A front plate having multiple openings, Multiple multispectral optical assemblies, It is equipped with, The machine vision system further comprises a removable front cover positioned in front of the lighting assembly. A machine vision system characterized by the following features.
34. Each of the plurality of multispectral optical assemblies is A multispectral light source comprising multiple color LED dies configured to generate light of at least two different wavelengths, A light pipe having an emission surface is positioned in front of the multispectral light source, A diffusion surface arranged on the emission surface of the light pipe, A projection lens positioned in front of the diffusion surface, It is equipped with The machine vision system according to claim 33.
35. Each of the plurality of apertures in the front plate of the illumination assembly is configured to receive a projection lens for each corresponding multispectral light assembly among the plurality of multispectral light assemblies. The machine vision system according to claim 34.
36. It further comprises a passive optical accessory located in front of the removable front cover and detachably attached to the machine vision system, The machine vision system according to claim 33.
37. The gear mechanism described above is The lens assembly comprises a second gear that movably engages with the first gear, A third gear that is movablely engaged with the second gear, It is equipped with The machine vision system according to claim 33.
38. The rotation of the third gear drives the rotation of the second gear and the first gear, causing movement of at least one lens of the lens assembly. The machine vision system according to claim 37.
39. The movement of the at least one lens is either approaching or moving away from the imaging sensor assembly. The machine vision system according to claim 38.
40. The third gear is configured to be rotated by a tool for adjusting the focus of the lens assembly. The machine vision system according to claim 38.
41. A portion of the front cover is configured to perform at least one of the following: (1) diffusing light from the lighting assembly, or (2) providing orthogonal polarization. The machine vision system according to claim 33.
42. A lighting sensor is positioned to detect light emitted from the aforementioned lighting assembly, Distance sensor and It also has, The machine vision system according to claim 33.
43. The lens assembly further comprises a multi-aperture assembly positioned in front of the aforementioned lens assembly. The machine vision system according to claim 33.