METHOD AND APPARATUS FOR DETERMINING A LIQUID LEVEL IN A CONTAINER USING IMAGING

• US 20110268329A1
• Filed: 12/11/2009
• Published: 11/03/2011
• Est. Priority Date: 01/06/2009
• Status: Active Grant

• Current Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Original Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Inventors: Pronkine, Viatcheslav
• Granted Patent: US 9,002,096 B2
• Time in Patent Office: Days
• US Class Current: 382/128
• CPC Class Codes: G01F 23/292 Light , e.g. infrared or ultraviolet
• CPC Class Codes: G01F 23/804 containing circuits handling parameters other than liquid level

Abstract

Methods, systems and apparatus for determining a level of a sample are provided. An image of a sample housed in a container is captured, wherein the image is represented as a two dimensional array of intensities of light. An area of interest is extracted from the image. A filter is applied to the area of interest. The filtered area is collapsed into a one dimensional array. The one dimensional array is masked. The level of the sample in the container is determined based on the masked one dimensional array. Numerous other aspects are provided.

Claims

1. A method for determining a level of a sample comprising:

capturing an image of a sample housed in a container, wherein the image is represented as a two dimensional array of intensities of light;

extracting an area of interest from the image;

applying a filter to the area of interest;

collapsing the filtered area into a one dimensional array;

masking the one dimensional array; and

determining the level of the sample in the container based on the masked one dimensional array.

2. The method of claim 1, wherein filtering the area of interest emphasizes an air-sample interface in the sample.

3. The method of claim 1, wherein the filter is a differential filter.

4. The method of claim 1 wherein masking the one dimensional array accounts for noise in the sample, and wherein noise may include at least one of foam or dust on the surface of the sample and turbulence in the sample.

5. The method of claim 1 wherein extracting the area of interest from the image further comprises:

cropping the image.

6. The method of claim 1 wherein extracting the area of interest from the image further comprises:

adjusting the geometry of the image.

7. The method of claim 1 wherein masking the one dimensional array further comprises:

applying a threshold as a mask, wherein the threshold is comprised of the one dimensional array plus a constant to the one dimensional array.

8. The method of claim 7 wherein determining the level of the sample in the container further comprises:

searching the masked signal for local peaks.

9. The method of claim 1 wherein determining the level of the sample in the container further comprises:

determining a bottom of the container and a sample-air interface.

10. A system for determining a level of a sample comprising:

an image capture apparatus adapted to capture the image of a sample in a container, wherein the image is represented as a two dimensional array of intensities of light; and

a controller coupled to the image capture apparatus, wherein the controller is adapted to extract an area of interest from the image, apply a filter to the area of interest, collapse the filtered area of interest into a one dimensional array, apply a mask to the one dimensional array, and determine the level of the sample in the container based on the masked one dimensional array.

11. The system of claim 10 wherein the filter is a differential filter.

12. The system of claim 10 wherein the system includes one or more image capture apparatuses adapted to capture the image of a sample in one or more containers.

13. A method for determining a level of a sample comprising:

capturing an image of a sample housed in a container, wherein the image is represented as a two dimensional array of intensities of light;

extracting an area of interest from the image;

applying a filter to the area of interest;

splitting the image into more tha one narrower vertical arrays;

analyzing each vertical array for peaks;

counting and combining, per vertical unit, the peaks resulting from the analysis;

forming a histogram from the combined peaks;

analyzing the histogram for peak concentrations; and

determining the level of the sample in the container based on the analysis.

14. The method of claim 13, wherein determining the level of sample in the container further comprises:

determining a bottom of the container and a sample-air interface.

15. The method of claim 13 wherein extracting the area of interest from the image further comprises:

adjusting the geometry of the image.

16. A method for determining the presence and amount of foam on a surface of a sample comprising:

capturing an image of a sample housed in a container, wherein the image is represented as a two dimensional array of intensities of light;

extracting an area of interest from the image;

applying a filter to the area of interest;

collapsing the filtered area of interest into a one dimensional array;

masking the one dimensional array;

determining an interface of the sample and ambient air based on the masked one dimensional array; and

detecting a range of continuous concentration of peaks in the one dimensional array in at least one direction moving away from the interface, and wherein the continuous concentration is the foam.

17. The method of claim 16, wherein the continuous concentration of peaks is greater than or equal to a particular value.

18. The method of claim 17, further comprising:

determining the amount of foam based on a width of the range of continuous concentration of peaks and a height of the foam.

19. The method of claim 16, wherein the continuous concentration of peaks are separated by a distance, and the distance is less than or equal to a preset number.

20. The method of claim 19, wherein the preset number is defined by the maximum size of bubbles.