Detection of eosinophil cells on a blood smeared slide

Claim 2

Automated apparatus for identifying an eosinophil blood cell on a blood smeared slide comprising: a high resolution microscope forming an optical image of a blood cell on said slide, two filters having different color characteristics, an optical system having a dual split optical path with one of said filters in each path, said eosinophil cell producing different optical density images from said two filters, a detector for converting the optical images from each path into electrical signals, an analog to digital converter producing digitized words representing the optical density of points in each image, means for generating optical density histograms of the two images from said two different filters, a comparator for comparing one histogram to the other, and means for producing an output indicating an eosinophil cell if one histogram is optically denser than another.

Claim 3

The apparatus recited in claim 1 wherein said means for generating optical density histograms includes: counters for counting the number of points in each image having a particular optical density, said counTers producing a histogram exhibiting a minimum number representing an optical density corresponding generally with the threshold of the cytoplasm and the nucleus of said eosinophil cell, a minimum determining comparator, the outputs of said counters being applied to said minimum determining comparator, and ratio circuitry forming the ratio of the sum of the counts in the counters above the minimum in each histogram, said means for producing an output indication being responsive to the output of said ratio circuit when said output is greater than one.

Claim 4

The apparatus recited in claim 1 wherein one filter is a blue filter producing a blue filtered image and the other filter is a yellow filter producing a yellow filtered image, the eosinophil cell having red granules in the nucleus, which, when imaged on said filters projects an optically brighter image through said yellow filter than through said blue filter.

Claim 5

The apparatus recited in claim 3 wherein said means for generating optical density histograms comprises: decoding means, each of said digitized words being applied to said decoding means which produce different outputs in accordance with the optical density represented by each digital word, and first and second sets of counters, the outputs of the decoders for said blue filtered image being applied to one set of counters and the outputs of the decoding means for the yellow filtered image being applied to the other set of counters, said counters producing counts representing the number of digitized words in each image representing an optical density of a particular level.

Claim 6

The apparatus recited in claim 4 wherein said means for comparing comprises: a minimum count comparator comparing all counts in one set of counters to determine a minimum, first and second summing means, all of the counts above a minimum in one set of counters being applied to the first summing means to form a blue filtered sum, and all of the counts above said minimum in the second set of counters being applied to the second summing means to form a yellow filtered sum, a divider, said blue filtered sum and said yellow filtered sum being applied to said divider to produce a ratio signal, and an output comparator, said ratio being applied to said output comparator, said output comparator producing an output indication if said ratio signal is greater than one.

Claim 7

The new use of automated apparatus for identifying blood cell types on a blood smeared slide, said apparatus being of the type comprising: a high resolution microscope forming an optical image of a blood cell on said slide, two filters having different color characteristics, an optical system having a dual split optical path with one of said filters in each path, a detector for converting the optical images from each path into electrical signals, an analog to digital converter producing digitized words representing the optical density of points in each image, and digital computing means for storing and automatically processing digital words, said new use being the identification of the eosinophil cell which produces different optical density images from said two filters comprising: generating optical density histograms of the two images from said two different filters, comparing said histograms one to the other, and producing an output indicating an eosinophil cell if one histogram is optically denser than another.

Claim 8

The new use of automated apparatus for identifying blood cell types on a blood smeared slide, said apparatus being of the type comprising: a high resolution microscope forming an optical image of a blood cell on said slide, two filters having different color characteristics, an optical system having a dual split optical path with one of said filters in each path, a detector for converting the optical images from each path into electrical signals, an analog to digital converter producing digitized words representing the optical density of points in each image, and digital computing means for storing and automatically processing digital words, said new use being the identification of the eosinophil cell which produces different optical density images from said two filters comprising: generating optical density histograms of the two images from said two different filters, comparing said histograms one to the other, and producing an output indicating an eosinophil cell if one histogram is optically denser than another.

Claim 9

The new use of claim 6 wherein one filter is a blue filter producing a blue filtered image and the other is a yellow filter producing a yellow filtered image, the eosinophil cell having red granules in the cytoplasm which, when imaged on said filters projects an optically brighter image through said yellow filter than through said blue filter.

Claim 10

The new use recited in claim 6 wherein each histogram indicates the number of points in each image having a particular optical density, each histogram exhibiting a minimum numbeR at a particular optical density corresponding generally with the optical density threshold of the cytoplasm and the nucleus of said cell, the step of comparing one histogram to another including: determining the minimum in each histogram, and forming the ratio of the histogram from one filter above its minimum to the histogram from the other filter above its minimum, said output indication being produced when said ratio is greater than one.

Claim 11

The new use recited in claim 6 wherein the step of generating optical density histograms comprises: decoding each of said digitized words to produce different outputs in accordance with the optical density represented by each digitized word, and counting each different output to produce counts representing the number of digitized words in each image representing an optical density of a particular level.

Claim 12

The new use recited in claim 6 wherein the step of comparing comprises: comparing said counts to determine a minimum, summing all counts above the minimum for the blue filtered image and for the yellow filtered image to form a blue filtered sum and a yellow filtered sum, dividing said blue filtered sum by said yellow filtered sum to produce a ratio signal, said output indication being produced if said ratio is greater than one.