Abstract: Methods for dispensing a fluid sample on a substrate include obtaining an image of a sample applicator in proximity to the substrate, where the image includes a first image of the sample applicator and a second image of the sample applicator, determining a height of the sample applicator relative to a surface plane of the substrate based on a distance between common portions of the first and second images, and dispensing the fluid sample onto the substrate using the sample applicator, where the dispensing includes: translating the sample applicator, translating the substrate, or translating both the sample applicator and the substrate to effect a relative translation between the sample applicator and the substrate; and maintaining the sample applicator within 2 microns of a target height relative to the surface plane of the substrate during the translating.

Abstract: This document describes methods, systems and computer program products directed to imaging blood cells. The subject matter described in this document can be embodied in a method of classifying white blood cells (WBCs) in a biological sample on a substrate. The method includes acquiring, by an image acquisition device, a plurality of images of a first location on the substrate, and classifying, by a processor, objects in the plurality of images into WBC classification groups. The method also includes identifying, by a processor, objects from at least some classification groups, as unclassified objects, and displaying, on a user interface, the unclassified objects and at least some of the classified objects.

Abstract: Systems and methods for positioning a sample applicator relative to a substrate include: (a) obtaining an image of the sample applicator in proximity to the substrate, where the image includes a direct image region corresponding to the sample applicator and a first reflected image region corresponding to an image of the sample applicator reflected from a surface of the substrate; (b) determining a position of an edge of the sample applicator in the direct image region; (c) determining a position of a reflected edge of the sample applicator in the first reflected image region; (d) determining a distance between the edge of the sample applicator and the reflected edge of the sample applicator; and (e) determining the position of the sample applicator relative to the substrate based on the distance between the edges.

Abstract: Methods and systems for identifying reticulocytes in a blood sample deposited on a substrate include: illuminating the sample with incident light at two different wavelengths, obtaining a two-dimensional image of the sample corresponding to a first one of the wavelengths, and obtaining a two-dimensional image of the sample corresponding to a second one of the wavelengths; analyzing the images to identify a set of representative red blood cells; determining an area of each of the red blood cells in the set; determining a color value of each of the red blood cells in the set; and, for each one of the red blood cells in the set, identifying the red blood cell as a reticulocyte if the area of the red blood cell exceeds an area cutoff value and the color value of the red blood cell is less than a color cutoff value.

Abstract: Systems, methods and computer program products for mapping coordinates of various imaging stations are described. In some implementations, cells (e.g., red blood cells) in a biological specimen can be used for determining the mapping information between the imaging stations. The use of cells allows a target image (e.g., an image of a sub-region of cells in the biological specimen) taken by one imaging station to be pattern-matched to a reference image (e.g., an image showing a larger region of cells in the biological specimen that also includes the sub-region) taken by another imaging station. Once the target image is matched to the reference image, point by point correspondence (and therefore coordinates) between the target image and the reference image can be established for computing the coordinate transformation to map the imaging stations.

Abstract: Systems and methods for positioning a sample applicator relative to a substrate include: (a) obtaining an image of the sample applicator in proximity to the substrate, where the image includes a direct image region corresponding to the sample applicator and a first reflected image region corresponding to an image of the sample applicator reflected from a surface of the substrate; (b) determining a position of an edge of the sample applicator in the direct image region; (c) determining a position of a reflected edge of the sample applicator in the first reflected image region; (d) determining a distance between the edge of the sample applicator and the reflected edge of the sample applicator; and (e) determining the position of the sample applicator relative to the substrate based on the distance between the edges.

Abstract: The disclosure relates to methods and systems for automatically focusing multiple images of one or more objects on a substrate. The methods include obtaining, by a processor, a representative focal distance for a first location on the substrate based on a set of focal distances at known locations on the substrate. The methods also include acquiring, by an image acquisition device, a set of at least two images of the first location. The images are each acquired using a different focal distance at an offset from the representative focal distance. The methods further include estimating, by a processor, an ideal focal distance corresponding to the first location based on comparing a quality of focus for each of the images, and storing the estimated ideal focal distance and the first location in the set of focal distances at known locations.

Abstract: Systems, methods and computer program products for mapping coordinates of various imaging stations are described. In some implementations, cells (e.g., red blood cells) in a biological specimen can be used for determining the mapping information between the imaging stations. The use of cells allows a target image (e.g., an image of a sub-region of cells in the biological specimen) taken by one imaging station to be pattern-matched to a reference image (e.g., an image showing a larger region of cells in the biological specimen that also includes the sub-region) taken by another imaging station. Once the target image is matched to the reference image, point by point correspondence (and therefore coordinates) between the target image and the reference image can be established for computing the coordinate transformation to map the imaging stations.

Abstract: The disclosure relates to methods and systems for automatically focusing multiple images of one or more objects on a substrate. The methods include obtaining, by a processor, a representative focal distance for a first location on the substrate based on a set of focal distances at known locations on the substrate. The methods also include acquiring, by an image acquisition device, a set of at least two images of the first location. The images are each acquired using a different focal distance at an offset from the representative focal distance. The methods further include estimating, by a processor, an ideal focal distance corresponding to the first location based on comparing a quality of focus for each of the images, and storing the estimated ideal focal distance and the first location in the set of focal distances at known locations.

Abstract: A method for determining a mean cell volume for a blood sample includes: illuminating the sample with incident light at a plurality of illumination wavelengths and obtaining a two-dimensional image of the sample at each of the plurality of illumination wavelengths; identifying a plurality of cells that appear in each of the images; for each one of the plurality of cells, determining an integrated optical density corresponding to each of the plurality of illumination wavelengths; for each one of the plurality of cells, determining a cell volume based on the integrated optical densities corresponding to each of the plurality of illumination wavelengths; and determining the mean cell volume for the blood sample from the cell volumes for each one of the plurality of cells.

Abstract: Methods and systems for identifying reticulocytes in a blood sample deposited on a substrate include: illuminating the sample with incident light at two different wavelengths, obtaining a two-dimensional image of the sample corresponding to a first one of the wavelengths, and obtaining a two-dimensional image of the sample corresponding to a second one of the wavelengths; analyzing the images to identify a set of representative red blood cells; determining an area of each of the red blood cells in the set; determining a color value of each of the red blood cells in the set; and, for each one of the red blood cells in the set, identifying the red blood cell as a reticulocyte if the area of the red blood cell exceeds an area cutoff value and the color value of the red blood cell is less than a color cutoff value.

Abstract: A method for determining a mean cell volume for a blood sample includes: illuminating the sample with incident light at a plurality of illumination wavelengths and obtaining a two-dimensional image of the sample at each of the plurality of illumination wavelengths; identifying a plurality of cells that appear in each of the images; for each one of the plurality of cells, determining an integrated optical density corresponding to each of the plurality of illumination wavelengths; for each one of the plurality of cells, determining a cell volume based on the integrated optical densities corresponding to each of the plurality of illumination wavelengths; and determining the mean cell volume for the blood sample from the cell volumes for each one of the plurality of cells.

Abstract: Methods for dispensing a fluid sample on a substrate include obtaining an image of a sample applicator in proximity to the substrate, where the image includes a first image of the sample applicator and a second image of the sample applicator, determining a height of the sample applicator relative to a surface plane of the substrate based on a distance between common portions of the first and second images, and dispensing the fluid sample onto the substrate using the sample applicator, where the dispensing includes: translating the sample applicator, translating the substrate, or translating both the sample applicator and the substrate to effect a relative translation between the sample applicator and the substrate; and maintaining the sample applicator within 2 microns of a target height relative to the surface plane of the substrate during the translating.

Abstract: A method for determining a mean cell volume for a blood sample includes: illuminating the sample with incident light at a plurality of illumination wavelengths and obtaining a two-dimensional image of the sample at each of the plurality of illumination wavelengths; identifying a plurality of cells that appear in each of the images; for each one of the plurality of cells, determining an integrated optical density corresponding to each of the plurality of illumination wavelengths; for each one of the plurality of cells, determining a cell volume based on the integrated optical densities corresponding to each of the plurality of illumination wavelengths; and determining the mean cell volume for the blood sample from the cell volumes for each one of the plurality of cells.

Abstract: A method for determining a mean cell volume for a blood sample includes: illuminating the sample with incident light at a plurality of illumination wavelengths and obtaining a two-dimensional image of the sample at each of the plurality of illumination wavelengths; identifying a plurality of cells that appear in each of the images; for each one of the plurality of cells, determining an integrated optical density corresponding to each of the plurality of illumination wavelengths; for each one of the plurality of cells, determining a cell volume based on the integrated optical densities corresponding to each of the plurality of illumination wavelengths; and determining the mean cell volume for the blood sample from the cell volumes for each one of the plurality of cells.

Abstract: A method of determining a volume of a platelet includes: (a) illuminating the platelet with incident light at a plurality of illumination wavelengths; (b) obtaining at least one two-dimensional image of the platelet corresponding to each illumination wavelength; (c) for each illumination wavelength, determining a mean optical density and a maximum optical density for the platelet; (d) determining an area of the platelet; (e) for each illumination wavelength, determining a volume of the platelet; (f) for each illumination wavelength, determining an integrated optical density for the platelet; and (g) determining the volume of the platelet based on a weighted combination of the area of the platelet, the volumes of the platelet corresponding to each of the illumination wavelengths, and the integrated optical densities for the platelet corresponding to each of the illumination wavelengths.

Abstract: Systems and methods for positioning a sample applicator relative to a substrate include: (a) obtaining an image of the sample applicator in proximity to the substrate, where the image includes a direct image region corresponding to the sample applicator and a first reflected image region corresponding to an image of the sample applicator reflected from a surface of the substrate; (b) determining a position of an edge of the sample applicator in the direct image region; (c) determining a position of a reflected edge of the sample applicator in the first reflected image region; (d) determining a distance between the edge of the sample applicator and the reflected edge of the sample applicator; and (e) determining the position of the sample applicator relative to the substrate based on the distance between the edges.

Abstract: Methods and systems for identifying reticulocytes in a blood sample deposited on a substrate include: illuminating the sample with incident light at two different wavelengths, obtaining a two-dimensional image of the sample corresponding to a first one of the wavelengths, and obtaining a two-dimensional image of the sample corresponding to a second one of the wavelengths; analyzing the images to identify a set of representative red blood cells; determining an area of each of the red blood cells in the set; determining a color value of each of the red blood cells in the set; and, for each one of the red blood cells in the set, identifying the red blood cell as a reticulocyte if the area of the red blood cell exceeds an area cutoff value and the color value of the red blood cell is less than a color cutoff value.

Abstract: Methods and systems for displaying images of cells in a sample include obtaining a plurality of images of cells in the sample, where each image corresponds to one of the cells in the sample, determining values of at least one property for each of the cells based on the plurality of images, arranging the plurality of images to form a first image array, where the images are ordered in the first image array based on the values of the at least one property, displaying the first image array, sorting the plurality of images to form a second image array in which an ordering of the images is different from the first image array, and displaying the second image array, where the sample includes blood and the cells include red blood cells.

Abstract: A method of determining a hemoglobin content value of a red blood cell includes: (a) illuminating the cell with incident light at a plurality of illumination wavelengths; (b) obtaining at least one two-dimensional image of the cell corresponding to each illumination wavelength; (c) for each illumination wavelength, determining a mean optical density and a maximum optical density for the cell; (d) determining an area of the cell; (e) for each illumination wavelength, determining a volume of the cell; (f) for each illumination wavelength, determining an integrated optical density for the cell; and (g) determining the hemoglobin content value of the cell based on the area of the cell, the volumes of the cell corresponding to each of the illumination wavelengths, and the integrated optical densities for the cell corresponding to each of the illumination wavelengths.