Method and apparatus for particle size determination

1. A computer-implemented method of determining a particle size, comprising:

providing an apparatus including a background and a lens that is fixed at a predetermined distance above the background;

obtaining an image of a calibration mark physically positioned on the background by using the lens;

placing a plurality of particles on the background;

obtaining an image of the particles on the background, wherein the particles and the calibration mark were captured using the same lens;

correcting the image for distortion effects to generate a corrected image, wherein the same correction factor is applied to both the particles and the calibration mark;

characterizing size and shape of the particles with a set of parameters by using the corrected image, wherein the set of parameters comprises one or more of size distribution, area distribution, and volume distribution;

comparing the set of parameters with a target particle profile; and

determining a type of grinding action that brings the set of parameters closer to the target particle profile.

2. The method of claim 1 , wherein the calibration mark comprises straight lines extending in perpendicular directions.

3. The method of claim 1 , wherein the image includes a plurality of particles randomly positioned with respect to the calibration mark.

4. The method of claim 1 , wherein the image is a bitmap.

5. The method of claim 1 , wherein the determining of the size comprises separating a first portion of the image that includes the particle from a second portion of the image that includes the calibration mark in the image.

6. The method of claim 5 , wherein the separating comprises using chroma range extraction.

7. The method of claim 1 , wherein correcting the image for distortion effects comprises:

comparing a known actual dimension of the calibration mark with the dimension of the calibration mark obtained from the image;

generating a correction factor based on the comparing;

obtaining a measurement of the particle in the image; and

modifying the measurement of the particle by using the correction factor.

8. The method of claim 1 , wherein correcting the image for distortion effects comprises correcting at least one of lens distortion and perspective distortion.

9. A computer-implemented method of achieving a desired particle size for coffee grounds, comprising:

providing an apparatus including a background and a lens that is fixed at a predetermined distance above the background;

obtaining an image of a calibration mark on the background;

placing coffee grounds on the background;

obtaining an image of the coffee grounds dispersed on the background by using the same lens;

correcting the image for distortion effects to generate a corrected image, wherein the same correction factor is applied to both the coffee grounds and the calibration mark; and

characterizing size and shape of the coffee grounds with a set of parameters by using the corrected image, wherein the parameters comprise one or more of size distribution, area distribution, and volume distribution;

comparing the set of parameters with a target particle size profile; and

determining a type of grinding action that brings the set of parameters closer to the target particle profile.

10. The method of claim 9 , wherein the image is a bitmap.

11. The method of claim 9 , wherein the determining of the particle size comprises:

separating the image into a first portion that includes the coffee grounds and a second portion that includes the calibration mark;

computing a correction factor for the calibration mark by comparing the physical measurements of the calibration mark with the calibration mark in the second portion of the image; and

applying the correction factor for the calibration mark to the first portion of the image to obtain a corrected particle size for the coffee grounds.

12. The method of claim 9 , wherein the determining of the particle size comprises:

correcting the image for lens distortion; and

correcting the image for perspective distortion.

13. A non-transitory computer-readable medium storing instructions for determining a particle size, the instructions comprising:

obtaining an image of a plurality of particles and a calibration mark with an apparatus that includes a background and a lens that is fixed at a predetermined distance above the background, wherein the particles are placed on the background;

correcting the image for distortion effects to generate a corrected image, wherein the same correction factor is applied to both the particles and the calibration mark;

characterizing size and shape of the particles with a set of parameters by using the corrected image, wherein the set of parameters comprises one or more of size distribution, area distribution, and volume distribution;

comparing the set of parameters with a target particle profile; and

determining a type of grinding action that brings the set of parameters closer to the target particle profile.

14. The non-transitory computer-readable medium of claim 13 , wherein the image is a bitmap.

15. The non-transitory computer-readable medium of claim 13 , wherein the determining of the particle size comprises:

separating the image into a first portion that includes the particle and a second portion that includes the calibration mark;

computing a correction factor for the calibration mark by comparing the physical measurements of the calibration mark with the calibration mark in the second portion of the image; and

applying the correction factor for the calibration mark to the first portion of the image to obtain a corrected particle size for the coffee grounds.

16. The non-transitory computer-readable medium of claim 13 , wherein the determining of the particle size comprises:

correcting the image for lens distortion; and

correcting the image for perspective distortion.