Autogrid analysis

A method of identifying the position and nominal outline in an image of a substantially four-sided, four-cornered grid of features, comprising:

• a) obtaining an image;
• b) identifying the significant features in the image;
• c) defining a centroid for each significant feature;
• d) placing a search line at a first point on the perimeter of the image and moving it across the image until it contacts a first centroid;
• e) defining the position of the first centroid as the first corner of the grid;
• f) placing a second search line which is substantially parallel to the first search line at a second point on the perimeter of the image substantially diametrically opposite from the first point and moving it across the image until it contacts a second centroid;
• g) defining the position of the second centroid as the second corner of the grid;
• h) if the grid is known to be square, defining a nominal outline of the four sides of the grid by defining a square with diagonally opposite corners oriented at the first and second corners of the grid.

A method of identifying the position in an image of each of a plurality of features in a grid, where the orientation of sides of the grid are known, the method comprising:

• a) obtaining an image;
• b) identifying the significant features in the image;
• c) defining a centroid for each significant feature;
• d) placing a first integration line parallel to a first side of the grid;
• e) recording a centroid integrated intensity of each feature that has its centroid within a predetermined region on either side of the first integration line;
• f) stepping the first integration line across the image towards a side of the grid opposite to the first side;
• g) repeating steps (e) and (f) until the first integration line passes entirely outside of a portion of the grid to be analyzed;
• h) analyzing the recorded integrated intensities to identify a set of best fit rows of the centroids substantially parallel to the first integration line;
• i) defining a second integration line parallel to a second side of the grid substantially orthogonal to the first side;
• j) recording the centroid integrated intensity of each feature that has its centroid within a predetermined region on either side of the second integration line;
• k) stepping the second integration line across the image towards a side of the grid opposite to the second side;
• l) repeating steps (j) and (k) until the second integration line passes entirely outside of a portion of the grid to be analyzed;
• m) analyzing the recorded integrated intensities to identify a set of best fit columns of the centroids substantially parallel to the second integration line;
• n) defining the nominal positions of the features in the grid as the intersections of the sets of best fit rows and columns.

A method of identifying an actual position of an object in an image, where a nominal position of the object is known, the method comprising:

• a) obtaining an image;
• b) identifying the significant features in the image;
• c) defining a centroid for each significant feature;
• d) identifying the position of all centroids in the image within a predetermined distance of the nominal position, and defining a centroid of such centroids;
• and
• e) identifying the position of the centroid of the centroids as the actual position of the object in the image.

A system for identifying the position in an image of a plurality of features in a substantially four-side, four-cornered grid of features, each feature having a centroid, the system comprising:

• a) an image capture device for capturing an image;
• b) a data storage device;
• and
• c) a central processing unit for receiving a captured image from the image capture device and which can write to and read from the data storage unit, the central processing unit being programmed to:
• i) obtain an image;
• ii) identify the significant features in the image;
• iii) define centroids for each significant feature;
• iv) place a first integration line contiguous to a first side of the image at an angle θ to the first side;
• v) record in the data storage device the centroid integrated intensity of each feature that has its centroid within a predetermined region on either side of the first integration line;
• vi) step the first integration line across the image;
• vii) repeat steps (v) and (vi)until the first integration line has crossed at least a portion of the image to be analyzed;
• viii) analyze the recorded integrated intensities to find the slope of the first peak in the integrated intensities recorded for the first integration line;
• ix) repeat steps (iv) through (viii) for a second integration line at an angle θ+δ to the side of the image, and for a third integration line at an angle θ−δ to the side of the image;
• x) determine the difference in the slopes of the first peak in the integrated intensities recorded for the first, second and third integration lines;
• xi) if the difference is within a predetermined tolerance limit, define and record in the data storage device the one of the first, second or third integration line having its first peak with the highest slope among the three lines as the closest match, and define and record in the data storage device the angle of the first column in the grid to match the angle of the closest match, and the position of the first column in the grid to match the location of the first peak in the integrated intensities for closest match;
• xii) if the difference is not within the predetermined tolerance limit, iterate steps (iv) through (xii) with varying values of θ and δ until the difference in the slopes is within the predetermined tolerance limit.

A system for identifying the position and nominal outline in an image of a substantially four-side, four-cornered grid of features, the system comprising:

• a) an image capture device for capturing an image;
• b) a data storage device;
• and
• c) a central processing unit for receiving a captured image from the image capture device and which can write to and read from the data storage unit, the central processing unit being programmed to:
• i) obtain an image;
• ii) identify the significant features in the image;
• iii) define a centroid for each significant feature;
• iv) place a search line at a first point on the perimeter of the image and moving it across the image until it contacts a first centroid;
• v) define the position of the first centroid as the first corner of the grid;
• vi) place a second search line which is substantially parallel to the first search line at a second point on the perimeter of the image substantially diametrically opposite from the first point and moving it across the image until it contacts a second centroid;
• vii) define the position of the second centroid as the second corner of the grid;
• viii) if the grid is known to be square, defining a nominal outline of the four sides of the grid by defining a square with diagonally opposite corners oriented at the first and second corners of the grid and recording the nominal outline in the data storage device.

A system for identifying the position in an image of a plurality of features in a grid, where the orientation of sides of the grid is known, the system comprising:

• a) an image capture device for capturing an image;
• b) a data storage device;
• and
• c) a central processing unit for receiving a captured image from the image capture device and which can write to and read from the data storage unit, the central processing unit being programmed to:
• i) obtain an image;
• ii) identify the significant features in the image;
• iii) define a centroid for each significant feature;
• iv) place a first integration line parallel to a first side of the grid;
• v) record in the data storage device a centroid integrated intensity of each feature that has its centroid within a predetermined region on either side of the first integration line;
• vi) step the first integration line across the image towards a side of the grid opposite to the first side;
• vii) repeat steps (v) and (vi) until the first integration line passes entirely outside of a portion of the image to be analyzed;
• viii) analyze the recorded integrated intensities to identify a set of best fit rows of the centroids substantially parallel to the first integration line;
• ix) define a second integration line parallel to of a second side of the grid substantially orthogonal to the first side;
• x) record in the data storage device the centroid integrated intensity of each feature that has its centroid within a predetermined region on either side of the second integration line;
• xi) step the second integration line across-the image towards a side of the grid opposite to the second side;
• xii) repeat steps (x) and (xi) until the second integration line passes entirely outside of portion of the image to be analyzed;
• xiii) analyze the recorded integrated intensities to identify a set of best fit columns of the centroids substantially parallel to the second integration line;
• xiv) define the nominal positions of the features in the grid as the intersections of the sets of best fit rows and columns.

A system for identifying an actual position of an object in an image, where a nominal position of the object is known, the system comprising:

• a) an image capture device for capturing an image;
• b) a central processing unit for receiving a captured image from the image capture device, the central processing unit being programmed to:
• i) obtain an image from the image capture device;
• ii) identify the significant features in the image;
• iii) define a centroid for each significant feature;
• iv) identify the position of all centroids in the image within a predetermined distance of the nominal position;
• v) define a centroid of such centroids;
• and
• vi) identify the position of the centroid of the centroids as the actual position of the object in the image.