Process for extracting periodic features from images by template matching
A method for extracting array elements from an image of an array, the array being contained within a well of a substrate is provided. The method comprises detecting coordinate locations of frequency spectrum peaks in the image by establishing local regions of the image, each local region containing a distinct frequency spectrum peak of the image; determining grid spacing and rotational characteristics of the image by analyzing the detected coordinate locations of the frequency spectrum peaks with a Fourier transform analysis; using the grid spacing and rotational characteristics of the image to generate a well template, the well template accounting for each array element's relative location within the well; and cross-correlating the generated well template with the image of the array to determine matched locations, the cross-correlated well template accounting for each array element's actual coordinate location within the well.
1 . A method for extracting array elements from an image of an array, the array being contained within a well of a substrate, comprising:
detecting coordinate locations of frequency spectrum peaks in the image by establishing local regions of the image, each local region containing a distinct frequency spectrum peak of the image;
determining grid spacing and rotational characteristics of the image by analyzing the detected coordinate locations of the frequency spectrum peaks with a Fourier transform analysis;
using the grid spacing and rotational characteristics of the image to generate a well template, the well template accounting for each array element's relative location within the well; and
cross-correlating the generated well template with the image of the array to determine matched locations, the cross-correlated well template accounting for each array element's actual coordinate location within the well.
2 . The method of claim 1 , further comprising performing a pre-filtering operation to remove discontinuities from the image.
3 . The method of claim 2 , wherein performing a pre-filtering operation to remove discontinuities from the image comprises excising a pad from the image by selecting well pixels in the image having a value below a mean value of the well and further setting the well pixel values to equal an average of a lower 25% of the well pixels.
4 . The method of claim 2 , wherein performing a pre-filtering operation to remove discontinuities from the image comprises removing high-intensity streaks from the image.
5 . The method of claim 1 , wherein the substrate comprises a spinning disc substrate.
6 . The method of claim 1 , wherein the image is selected from at least one of a protein microarray image and a DNA microarray image.
7 . The method of claim 1 , further comprising maximizing a local cross-correlation operation by refining the actual location of each array element.
8 . The method of claim 1 , wherein the image is generated by an image detection device that is selected from at least one of a charge-coupled device detector, a complementary metal oxide semiconductor image sensor, a pixel array device and an atomic force microscopy device.
9 . The method of claim 1 , wherein the coordinate locations of the frequency spectrum peaks are detected by a peak-finding algorithm.
10 . The method of claim 9 , wherein the peak-finding algorithm includes a Fourier transform analysis.
11 . The method of claim 1 , wherein the local regions of the image are established using spot pattern geometric and sampling rate information, the information being used to find a maximum value in each local region to calculate grid parameters of the image from the locations of frequency spectrum peaks.
12 . The method of claim 1 , wherein using the grid spacing and rotational characteristics to generate a well template comprises setting and recording the relative position for each array element.
13 . The method of claim 1 , wherein cross-correlating the generated well template with the image of the array comprises shifting a distance of a pixel with a maximum pixel value from a center of a cross-correlation image between the generated well template and the actual coordinate location of each array element.
14 . A method for extracting array elements from an image, comprising:
generating an image of a well, the well containing an array of elements;
performing a pre-filtering operation to remove discontinuities from the image;
detecting coordinate locations of frequency spectrum peaks in the image by establishing local regions of the image, each local region containing a distinct frequency spectrum peak of the image;
determining grid spacing and rotational characteristics of the image by analyzing the detected coordinate locations of the frequency spectrum peaks with a Fourier transform analysis;
using the grid spacing and rotational characteristics of the image to generate a well template, the well template accounting for each array element's relative location within the well;
cross-correlating the generated well template with the image of the array to determine matched locations, the cross-correlated well template accounting for each array element's actual coordinate location within the well; and
maximizing a local cross-correlation operation by refining the actual location of each array element.
15 . The method of claim 14 , wherein the image is selected from at least one of a protein microarray image and a DNA microarray image.
16 . The method of claim 14 , wherein the image is generated by an image detection device that is selected from at least one of a charge-coupled device detector, a complementary metal oxide semiconductor image sensor, a pixel array device and an atomic force microscopy device.
17 . The method of claim 14 , wherein the coordinate locations of the frequency spectrum peaks are detected by a Fourier transform analysis.
18 . A method for extracting array elements from an image of an array, the array being contained within a well of a spinning disc substrate, comprising:
performing a pre-filtering operation to remove discontinuities from the image;
detecting coordinate locations of frequency spectrum peaks in the image by establishing local regions of the image, each local region containing a distinct frequency spectrum peak of the image and being established by using spot pattern geometric and sampling rate information;
determining grid spacing and rotational characteristics of the image by analyzing the detected coordinate locations of the frequency spectrum peaks with a Fourier transform analysis;
using the grid spacing and rotational characteristics of the image to generate a well template, the well template accounting for each array element's relative location within the well;
cross-correlating the generated well template with the image of the array to determine matched locations;
calculating each array element's actual coordinate location based on the matched locations by shifting a distance of a pixel with a maximum pixel value from a center of a cross-correlation image between the generated well template and the actual coordinate location of each array element; and
maximizing a local cross-correlation operation by refining the actual location of each array element.
19 . The method of claim 18 , wherein using the grid spacing and rotational characteristics to generate a well template comprises setting and recording the relative position for each array element.
20 . The method of claim 18 , wherein the image is generated by an image detection device that is selected from at least one of a charge-coupled device detector, a complementary metal oxide semiconductor image sensor, a pixel array device and an atomic force microscopy device.