High throughput and low cost height triangulation system and method

Patent metadata

Field	Value
Publication number	US-9756313-B2
Application number	US-201414284483-A
Country	US
Kind code	B2
Filing date	May 22, 2014
Priority date	Jun 9, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A triangulation system comprising an area camera, a communication interface, a first image processing module, a second image processing module; wherein the area camera is arranged to obtain, at an acquisition rate, a stream of images of illuminated regions of an object; wherein the area camera is prevented from performing height calculations; wherein the communication interface is arranged to convey, in real time thereby in correspondence to the acquisition rate, the stream of images from the area camera to the first image processing module; wherein the first image processing module is arranged to process, in real time, the stream of images to provide first compressed information; wherein the second image processing module is arranged to process, at a non-real time image processing rate, the first compressed information to provide height information indicative of heights of at least the illuminated regions of the object.

First claim

We claim:

1. A triangulation system comprising an area camera, a communication interface, a first image processing module, a second image processing module;
wherein the area camera is arranged to obtain, at an acquisition rate, a stream of images of illuminated regions of an object; wherein the area camera is prevented from performing height calculations;
wherein the communication interface is arranged to convey, in real time thereby in correspondence to the acquisition rate, the stream of images from the area camera to the first image processing module;
wherein the first image processing module is arranged to process, in real time, the stream of images to provide first compressed information, by:
(a) calculating first estimates of heights of the illuminated regions that are responsive to locations of peaks of pixel intensity distributions that are associated with radiation from the illuminated regions;
(b) calculating at least one attribute out of shape attributes and size attributes of the pixel intensity distributions, the shape and size attributes differ from the locations of the peaks;
wherein the first compressed information comprises the first estimates and the at least one attribute;
wherein the second image processing module is arranged to process, at a non-real time image processing rate, the first compressed information to provide height information indicative of heights of at least the illuminated regions of the object.

2. The system according to claim 1 wherein the first image processing module comprises a real time frame grabber and a real time image processor.

3. The system according to claim 1 wherein the system is arranged to perform, in response to one or more attributes of the shape and size attributes that differ from the locations of the peaks, at least one out of (a) a quality measurement of a reflected signal received by the area camera when generating one or more images of the stream of images, (b) a registration of the stream of images, (c) a selection of an area to be used as a base reference surface, and (d) simultaneous metrology and defects detection of selected objects.

4. The system according to claim 1 wherein shape and size attributes of a pixel intensity distribution are indicative of at least one out of a peak value, a width of the pixel intensity distribution, a symmetry of the pixel intensity distribution and a difference between peak and noise intensities.

5. The system according to claim 1 wherein at least one of the first and second image processing modules is arranged to determine a height of a features of the object, the feature comprising multiple illuminated regions, in response to (a) first estimates of heights of the multiple illuminated regions and to (b) at least one out of shape attributes and size attributes of pixel intensity distributions of images of the multiple illuminated regions.

6. The system according to claim 1 wherein the second image processing module is arranged to receive the first compressed information and to calculate second estimates of heights of the illuminated regions.

7. The system according to claim 1 wherein the second image processing module is arranged to receive the first compressed information and to re-calculate one or more attribute out of the shape attributes and size attributes of the pixel intensity distributions.

8. The system according to claim 1 wherein the first image processing module is arranged to select image portions that comprise pixels indicative of the heights of the illuminated regions to provide the first compressed information.

9. The system according to claim 1 wherein at least one of the first and second image processing modules is arranged to perform image registration in response to pixel intensity distributions that are associated with radiation from one or more illuminated regions.

10. The system according to claim 1 wherein at least one of the first and second image processing modules is arranged to select from an image of an illuminated area, pixels that represent a reference surface of the object, in response to values of pixels of a pixel intensity distribution of pixels of the image.

11. The system according to claim 1 wherein the at least one of the first and second image processing modules is arranged to select the pixels that represent a reference surface by differentiating between two groups of pixels that are located in proximity to each other but differ from each other by pixel value.

12. The system according to claim 1 wherein at least one of the first and second image processing modules is arranged to measure a dimension of a feature that comprises multiple illumination areas in response to values of pixels of a pixel intensity distribution of pixels of the image.

13. The system according to claim 1 wherein the area camera is prevented from calculating height information related to the heights of the illuminated regions.

14. The system according to claim 1 wherein the communication interface is a CoaXPress protocol compliant communication interface.

15. A triangulation system comprising an area camera, a communication interface, a first image processing module, a second image processing module;
wherein the area camera is arranged to obtain, at an acquisition rate, a stream of images of illuminated regions of an object; wherein the area camera is prevented from performing height calculations;
wherein the communication interface is arranged to convey, in real time thereby in correspondence to the acquisition rate, the stream of images from the area camera to the first image processing module;
wherein the first image processing module is arranged to process, in real time, the stream of images to provide first compressed information;
wherein the second image processing module is arranged to process, at a non-real time image processing rate, the first compressed information to provide height information indicative of heights of at least the illuminated regions of the object, by
(a) calculating second estimates of heights of the illuminated regions;
(b) calculating at least attribute out of shape attributes and size attributes of the pixel intensity distributions, the shape and size attributes differ from the locations of the peaks.

16. The system according to claim 15 wherein shape and size attributes of a pixel intensity distribution are indicative of at least one out of a peak value, a width of the pixel intensity distribution, a symmetry of the pixel intensity distribution and a difference between peak and noise intensities.

17. A triangulation method comprising:
obtaining by an area camera, at an image acquisition rate, a stream of images of illuminated regions of an object; wherein the area camera is prevented from performing height calculations;
conveying over a communication interface, in real time thereby in correspondence to the image acquisition rate, the stream of images from the area camera to a first image processing module;
real-time processing by the first image processing module, the stream of images to provide first compressed information; wherein the real-time processing of the stream of images comprises: calculating first estimates of heights of the illuminated regions that are responsive to locations of peaks of pixel intensity distributions that are associated with radiation from the illuminated regions; and calculating at least one attribute out of shape attributes and size attributes of the pixel intensity distributions, the shape and size attributes differ from the locations of the peaks; wherein the first compressed informatio

Assignees

• Camtek Ltd

Inventors

• Koren Shimon
• Langmans Eldad
• Regensburger Menachem
• Weinar Uri

Classifications

• G01N21/95

  characterised by the material or shape of the object to be examined (G01N21/89 - G01N21/91, G01N21/94 take precedence) · CPC title

• G01N2021/95638

  for PCB's · CPC title

• G01B11/0608 Primary

  Height gauges · CPC title

• H04N13/0253 Primary

  Electricity · mapped topic

• G01N2021/95676

  Masks, reticles, shadow masks · CPC title