US 5,694,478 A · Method and apparatus for detecting and identifying microbial colonies

Abstract

A method and system for detecting and identifying microbial colonies in an inoculated growth medium first acquires a first image of the inoculated growth medium. After a selected incubation time interval, a second image of the growth medium is acquired. A difference image is produced by taking the difference between corresponding pixels in the first and second images. Potential colonies are identified within the difference image by locating peak pixels having local maximum pixel intensities within the difference image and having decreasing gradients in a predetermined number of directions. The potential colonies are validated as actual colonies by eliminating those potential colonies that are noise spikes or noise around previously validated colonies.

Claims32

Dependent claims

A method for detecting and identifying microbial colonies in an inoculated growth medium, said method comprising the steps of:

a) imaging said growth medium to obtain first colony image data;
b) incubating said growth medium for a selected time interval;
c) imaging said growth medium to obtain second colony image data;
d) processing said first and second colony images to produce a difference image wherein said difference image is obtained by taking a difference between said first colony image data and said second colony image data;
e) identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius;
and
f) validating each said potential colony to ensure said potential colony is a validated colony by a method comprising the steps of:
i) eliminating said potential colony if said potential colony is a noise spike;
and
ii) eliminating said potential colony if said potential colony is noise around the perimeter of a validated colony.

7 more elements

A method for detecting and identifying microbial colonies in an inoculated growth medium, said method comprising the steps of:

a) imaging said growth medium to obtain first colony image data;
b) incubating said growth medium for a selected time interval;
c) imaging said growth medium to obtain second colony image data;
d) processing at least one of said images to determine a growth medium center;
and
e) processing said first and second colony images to produce a difference image wherein said difference image is obtained by taking a difference between said first colony image data and said second colony image data;
f) identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius;
and
g) validating each said potential colony to ensure said potential colony is a validated colony.

6 more elements

A method for detecting and identifying microbial colonies in an inoculated growth medium, said method comprising the steps of:

a) imaging said growth medium to obtain first colony image data;
b) incubating said growth medium for a selected time interval;
c) imaging said growth medium to obtain second colony image data;
d) processing said first and second colony images to produce a difference image wherein said difference image is obtained by taking a difference between said first colony image data and said second colony image data;
e) identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius, by a method comprising the steps of:
i) locating said peak pixel within said difference image, said peak pixel having a local maximum pixel intensity and further exceeding a threshold peak intensity value;
ii) determining gradients from said peak pixel in a predetermined number of directions;
iii) labeling said peak pixel as a potential colony if at least a minimum number of said gradients decrease over a minimum gradient distance;
iv) determining said colony radius for said peak pixel;
v) placing a first mask of predetermined size over said first colony image, said mask centered over said peak pixel;
and
vi) repeating steps i) through v) for pixels that are not covered by said masks centered over any of said peak pixels;
and
f) validating each said potential colony to ensure said potential colony is a validated colony.

11 more elements

A method for detecting and identifying microbial colonies in an inoculated growth medium, said method comprising the steps of:

a) imaging said growth medium to obtain first colony image data;
b) incubating said growth medium for a selected time interval;
c) imaging said growth medium to obtain second colony image data;
d) processing said first and second colony images to produce a difference image wherein said difference image is obtained by taking a difference between said first colony image data and said second colony image data;
e) identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius;
f) comparing a peak pixel intensity value of said peak pixel of said potential colony with a spike peak threshold value;
g) comparing said colony radius of said potential colony with a spike radius threshold value;
h) validating said potential colony if said peak pixel intensity value does not exceed said spike peak threshold value or said colony radius exceeds said spike radius threshold value;
i) sorting said potential colonies according to the value of said peak pixel associated with said potential colony;
j) identifying a validated colony closest to said potential colony having the largest peak pixel intensity value;
k) computing a noise radius for said closest validated colony;
l) validating said potential colony if said potential colony is outside said noise radius of said closest validated colony;
m) computing a computed peak value derived from peak pixel values of said potential colony and said closest validated colony;
n) computing a computed radius value derived from radius values of said potential colony and said closest validated colony;
o) validating said potential colony if said computed radius value exceeds a threshold radius value, said computed peak value exceeds a threshold peak value, said peak pixel value of said potential colony exceeds a threshold peak validation value and said radius of said potential colony exceeds a threshold radius validation value;
and
p) eliminating said potential colony if said potential colony is not a validated colony.

14 more elements

A method for detecting and identifying microbial colonies growing on an inoculated growth medium, said method comprising the steps of:

a)incubating said inoculated growth medium for a selected time interval;
b) imaging said growth medium to obtain first colony image data;
c) imaging said growth medium after a selected time interval to obtain second colony image data;
d) processing said first and second colony images to produce a difference image wherein said difference image is obtained by taking a difference between said first colony image data and said second colony image data, said processing comprising the steps of:
i) locating a peak pixel within said first colony image, said peak pixel having a local maximum pixel intensity and further exceeding a threshold peak intensity value;
ii) determining gradients from said peak pixel in a predetermined number of directions;
iii) labeling said peak pixel as a potential colony if at least a minimum number of said gradients decrease over a minimum gradient distance;
iv) determining a colony radius for said peak pixel;
v) placing a first mask of predetermined size over said first colony image, said mask centered over said peak pixel;
and
vi) repeating steps i) through v) for pixels that are not covered by said masks centered over any of said peak pixels;
and
e) identifying potential colonies within said first colony image data, each said potential colonies having a peak pixel and a colony radius;
and
f) validating each said potential colony to ensure said potential colony is a validated colony.

12 more elements

A system for detecting and identifying microbial colonies on an inoculated growth medium, said system comprising:

an incubation chamber for incubating said growth medium;
image acquisition means for acquiring images of said growth medium, said image acquisition means acquiring a first colony image at a first time and a second colony image at a second time;
processing means for producing a difference image wherein said difference image is obtained by taking a difference between said first colony image and said second colony image;
means for identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius;
and
validation means for validating each said potential colony to ensure said potential colony is a validated colony, said validation means comprising means for eliminating said potential colony if said potential colony is a noise spike and means for eliminating said potential colony if said potential colony is noise around the perimeter of a validated colony.

3 more elements

A system for detecting and identifying microbial colonies on an inoculated growth medium, said system comprising:

an incubation chamber for incubating said growth medium;
image acquisition means for acquiring images of said growth medium, said image acquisition means acquiring a first colony image at a first time and a second colony image at a second time;
processing means for producing a difference image wherein said difference image is obtained by taking a difference between said first colony image and said second colony image;
means for identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius;
means for determining a growth medium center of said growth medium;
and
validation means for validating each said potential colony to ensure said potential colony is a validated colony.

4 more elements

A system for detecting and identifying microbial colonies on an inoculated growth medium, said system comprising:

an incubation chamber for incubating said growth medium;
image acquisition means for acquiring images of said growth medium, said image acquisition means acquiring a first colony image at a first time and a second colony image at a second time;
processing means for producing a difference image wherein said difference image is obtained by taking a difference between said first colony image and said second colony image;
means for identifying potential colonies within said difference image, each said potential colony having a peak pixel and a colony radius, wherein said means for identifying potential colonies comprises:
a) means for locating said peak pixel within said difference image, said peak pixel having a local maximum pixel intensity and further exceeding a threshold peak intensity value;
b) means for determining gradients from said peak pixel in a predetermined number of directions;
c) means for labeling said peak pixel as a potential colony if at least a minimum number of said gradients decrease over a minimum gradient distance;
d) means for determining said colony radius for said peak pixel;
and
e) means for placing a first mask of predetermined size over said first colony image, said mask centered over said peak pixel;
and
validation means for validating each said potential colony to ensure said potential colony is a validated colony.

9 more elements

Dependencies are inferred from the claim text.

Method and apparatus for detecting and identifying microbial colonies

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Method and apparatus for detecting and identifying microbial colonies

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Abstract

Claims32