Simultaneous measurement and display of 3-D size distributions of particulate materials in suspensions

• US 6,873,725 B2
• Filed: 09/09/2002
• Issued: 03/29/2005
• Est. Priority Date: 09/09/2002
• Status: Expired due to Term

• Current Assignee: Coulter International Corp. (Danaher Corporation)
• Original Assignee: Coulter International Corp. (Danaher Corporation)
• Inventors: Xu, Renliang
• Primary Examiner(s): Ahmed, Samir
• Assistant Examiner(s): BHATNAGAR, ANAND P
• Application Number:
  US10/237,369
• Publication Number:
  US 20040047502A1
• Time in Patent Office: 932 Days
• Field of Search: 382/154, 345/419, 345/420, 345/421, 345/422, 345/581, 356/12
• US Class Current: 382/154
• CPC Class Codes: G01N 15/147 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/1497 Particle shape
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

An apparatus and method in which a still image, or still images, are obtained of a plurality of particles suspended in a fluid medium. Each still image is transferred to an image analyzing unit that measures a set of dimensional characteristics per particle for particles appearing in the image and determine an occurrence characteristic for particles having a matching set of dimensional characteristics. Preferably, a three dimensional representation of the characteristics is displayed in real time. More preferably, the displayed three-dimensional representation is continuously updated and further entries are accumulated on the display as image analysis is performed. The display provides information to a viewer enabling the viewer to determine a shape distribution of the particles within the suspension even when multiple particle shapes are present.

Claims

1. Apparatus for analyzing particles suspended in a fluid medium, comprising:

an image detector for obtaining at least one still image of a plurality of particles suspended in a fluid medium;

an image analyzing unit for measuring from said at least one still image at least two dimensional characteristics per particle for each of said plurality of particles appearing in said at least one still image and for determining an occurrence characteristic of particles which is related to the particles having a matching set of measured dimensional characteristics; and

a display unit for presenting a three dimensional representation of said measured dimensional characteristics and said occurrence characteristics of all said plurality of particles appearing in said image and providing information about said plurality of particles in a manner which permits a viewer of said three dimensional representation to determine a size and shape distribution of said plurality of particles appearing in said at least one still image.

2. An apparatus according to claim 1, wherein said display unit has a screen on which said three dimensional representation is provided as an x-y-z coordinate plot, and wherein two of said coordinates correspond to said dimensional characteristics and a third coordinate corresponds to said occurrence characteristic.

3. An apparatus according to claim 2, wherein said plot is continually updated in real-time such that said plot continues to accumulate and display further information as said at least one still image is processed by said image analyzing unit.

4. An apparatus according to claim 1, wherein at least one of said dimensional characteristics is selected from a group consisting of particle length, width, depth, diameter, sphericity, and aspect ratio.

5. An apparatus according to claim 1, wherein said occurrence characteristic is measured in terms of a parameter selected from a group consisting of particle number, particle area, particle volume, particle length, particle width, particle depth, particle diameter, particle sphericity, and particle aspect ratio.

6. An apparatus according to claim 1, wherein said image analyzing unit forms and stores a matrix table of data including at least said set of dimensional characteristics and said occurrence characteristics so that individual characteristics of each particle are saved and capable of representation in said three dimensional representation.

7. An apparatus according to claim 6, wherein said image analyzing unit is a computer having at least one image analysis computer software program which analyzes the still image, forms said matrix table, and causes said three dimensional representation to be displayed on said display unit.

8. An apparatus according to claim 1, further comprising a flow cell providing a path of flow for particles suspended in a fluid and defining a chamber in which said at least one still image is obtained by said image detector.

9. An apparatus according to claim 8, wherein said image detector is a camera for obtaining an optical image of said plurality of particles.

10. An apparatus according to claim 1, wherein one of said measured dimensional characteristics is particle depth.

11. An apparatus according to claim 1, further comprising a light source for directing a beam of light onto said plurality of particles when said image is obtained, said light source being positioned relative to said image detector such that said beam of light is directed substantially perpendicular to a direction in which said image is taken from said image detector.

12. Apparatus for analyzing particles suspended in a fluid, comprising:

a flow cell having a chamber providing a path of flow for particles suspended in a fluid;

a camera for obtaining at least one optical image of a plurality of particles located within said chamber;

a computer system in communication with said camera for enabling said at least one optical image to be analyzed, said computer including at least one image analysis computer program for measuring at least two dimensional characteristics per particle for each of said particles appearing in said image and determining an occurrence characteristic of particles having a matching set of measured dimensional characteristics; and

a monitor screen for displaying a three dimensional representation in real-time of said measured dimensional characteristics and said occurrence characteristics of all said plurality of particles appearing in said image as said characteristics are determined, said three dimensional representation having three coordinates such that two of said coordinates correspond to said measured dimensional characteristics and a third coordinate corresponds to said occurrence characteristic;

whereby said three dimensional representation provides information of said plurality of particles in a manner which permits ready determination of a size and shape distribution of said plurality of particles appearing in said at least one image.

13. An apparatus according to claim 12, wherein at least one dimensional characteristic set is selected from a group consisting of particle length, width, depth, diameter, sphericity, and aspect ratio.

14. An apparatus according to claim 13, wherein said occurrence characteristic is measured in terms of a parameter selected from a group consisting of particle number, particle area, particle volume, particle length, particle width, particle depth, particle diameter, particle sphericity, and particle aspect ratio.

15. An apparatus according to claim 14, wherein said camera is a CCD camera and said image is a still image.

16. A method of analyzing particles suspended in a fluid medium, comprising the steps of:

obtaining at least one still image of a plurality of particles suspended in a fluid medium;

measuring at least two dimensional characteristics per particle for each of said plurality of particles appearing in said image;

determining an occurrence characteristic of particles having a matching set of measured dimensional characteristics; and

displaying a three dimensional representation of said measured dimensional characteristics and said occurrence characteristics of all said plurality of particles appearing in said image, said three dimensional representation having three coordinates such that two of said coordinates correspond to said measured dimensional characteristics and a third coordinate corresponds to said occurrence characteristic such that said three dimensional representation provides information of said plurality or particles in a manner which permits a viewer to determine a size and shape distribution of said pluarality of particles appearing in said at least one image.

17. A method according to claim 16, wherein said measuring step is performed by an image analysis computer program after said at least one still image is obtained, and wherein said three dimensional representation is updated in real time as said image analysis computer program measures said dimensional characteristics.

18. A method according to claim 17, further comprising the step of forming a matrix table which correlates and stores said measured at least two dimensional characteristics and said associated occurrence characteristic.

19. A method according to claim 17, wherein said dimensional characteristic includes at least one parameter selected from a group consisting of particle length, width, depth, diameter, sphericity, and aspect ratio, and wherein said occurrence characteristic is measured in terms of a parameter selected from a group consisting of particle number, particle area, particle volume, particle length, particle width, particle depth, particle diameter, particle sphericity, and particle aspect ratio.

20. A method according to claim 19, further comprising the step of providing a path of flow for said plurality of particles suspended in the fluid, wherein said path of flow provides a location for obtaining said at least one still image.

21. A method according to claim 20, wherein said step of obtaining at least one still image is accomplished utilizing a camera to obtain an optical image.

22. A method according to claim 16, further comprising the step of directing a beam of light in a direction onto said plurality of particles in the fluid, and wherein said image is taken from a direction substantially perpendicular to the direction of the beam of light.