RU2763667C1 - Device for morphological analysis of blood smears - Google Patents

Abstract

FIELD: medical technology.

SUBSTANCE: invention relates to the field of medical technology and can be used for the classification of blood cells, morphological assessment of blood cells and their count. The device for morphological analysis of blood smears consists of an optical microscope with a trinocular attachment, an automated stage and a focusing drive, a digital camera and a computer controller with software. The controller is configured to calibrate the digital camera settings in two stages. At the first stage, the controller adjusts the camera in the area of ​​pure light; at the second stage, it aligns the color of the blood cells of the smear under study. The digital camera is made with the ability to automatically calibrate its settings before each scan of blood cell images for a series of blood smears under study, depending on their color. The focusing drive of the optical microscope is configured to move the stage in accordance with the control signals of the controller.

EFFECT: increasing the accuracy, reliability and speed of morphological analysis of a series of investigated blood smears due to automatic calibration of the chamber in order to standardize the color of cells in blood smears with different colors.

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Description

The invention relates to the field of medical technology and can be used for classifying blood cells, morphological evaluation of blood cells and their counting.

To perform the study, the blood is placed on a glass slide, dried, stained with a special dye and a blood smear is prepared. However, the cell color of various blood smears depends both on the method of preparation and on the cellular composition, just as the average background of the visual field depends on the thickness of the glass and the amount of dye used.

Traditionally, the evaluation of a blood smear is carried out using a microscope in a "manual" mode, while the doctor of laboratory diagnostics has to constantly move the microscope stage.

A device for analyzing blood composition is known, containing an optical microscope equipped with a mechanized object table (on which a dry stained blood smear is placed) with mechanisms for moving in its plane and a focusing mechanism made on the basis of stepper motors, a color television camera connected in series with the optical microscope, a block control of stepper motors and a system of functional blocks, including an analog-to-digital converter, a video signal encoding unit, a temporary storage device, a microcomputer and a digital-to-analog converter (RU 2122733, publ. 27.11.1998).

However, such a device is difficult and inconvenient to operate, is not automated and contains a number of separate functional blocks that require independent manual settings, and does not provide high information content of the cellular composition of the blood.

Closest to the claimed is a device for analyzing blood composition, containing a biological optical microscope with a trinocular nozzle and an automated object stage with scanning and focusing mechanisms made on the basis of stepper motors connected to the control unit, a color imaging device installed on the trinocular nozzle and connected to it and with a personal computer control unit, the color imaging device is made in the form of a digital video camera connected to the interface board for digitization and image input installed in the personal computer, and the control unit is made in the form of an interface board for controlling stepper motors installed in the personal computer (RU 32279, publ. .10.09.2003).

This device works as follows: the prepared stained blood smear in the form of a monolayer is placed on the movable part of the automated object table, the field of view of the smear is entered into the memory of a personal computer in the form of a series of digital frames, cells of all types and their intracellular structures are isolated (segmented) in each saved frame , the number of selected cells of each type (erythrocytes, leukocytes, platelets) is counted, their ratio is determined, the selected objects are measured with the ability to reproduce the shape of the object with a given accuracy, the images of erythrocyte and leukocyte cells are classified, normal and pathological forms of erythrocytes are distinguished and their ratio is calculated, the leukocyte formula is determined.

However, this known device does not allow to calibrate the settings of a digital camera for different colors of blood smears and, accordingly, to obtain reliable results of morphological analysis when scanning a series of blood smears of different colors.

EFFECT: improved accuracy, reliability and speed of morphological analysis of a series of blood smears under study due to automatic camera calibration in order to standardize the color of blood smear cells with different colors.

The technical result is achieved by the fact that in a device for morphological analysis of blood smears, consisting of an optical microscope with a trinocular attachment, an automated object stage and a focus drive, a digital camera and a computer controller with software, according to the invention, the controller is configured to calibrate the settings of the digital camera in two stages, at the same time, at the first stage, the controller adjusts the camera in the area of pure light, at the second stage, it aligns the color of the blood cells of the studied smear, while the digital camera is configured to automatically calibrate its settings before each scanning of blood cell images for a series of blood smears under study depending on their color, and the focusing drive of the optical microscope is made with the possibility of moving the object stage in accordance with the control signals of the controller.

Execution of the controller with the ability to calibrate the settings of the digital camera in two stages, while at the first stage the controller adjusts the camera in the area of pure light, at the second stage it aligns the color of the blood cells of the studied smear, as well as the execution of the digital camera with the possibility of automatically calibrating its settings before each scanning images of blood cells for a series of blood smears under study, depending on their color, when the focusing drive of the optical microscope is performed with the possibility of moving the object stage in accordance with the control signals of the controller, it allows in real time to determine the average background of the image of the field of view and the average color of the cells and bring them closer to "reference" values, regardless of the color of blood smears, because the average background and the average color of the cells will be the same for a blood smear, prepared by any known methods.

Since the reference values of the parameters are set by the program before scanning, the colors of the picture can be personalized for each doctor.

The device allows you to adjust the camera settings before each new scan so that the color of the cells and the background on each smear from the series is constant and approaches the reference values.

Automation of the process of setting up the microscope camera, eliminating the human factor and errors during manual adjustment allows you to quickly, accurately and reliably classify blood cells, regardless of the color of the smear.

A blood smear analysis device with automatic camera calibration for various smear staining conditions is more efficient than known similar devices due to the camera calibration function for standardizing the color of blood smear cells regardless of smear staining conditions, while allowing you to scan a series of blood smears without manually adjusting the lighting before every single blood smear and get more accurate cell classification and high speed. It is convenient to operate and can be widely used for complete blood count in diagnostic centers and laboratories.

The invention is illustrated by the following figures.

In FIG. 1 schematically shows the claimed device.

In FIG. 2 shows what the defocused and focused images of a blood cell look like.

In FIG. 3 shows a trinocular microscope with an object stage that can move in space along the X, Y, Z coordinates.

In FIG. 4 - images on the computer monitor, where a) - image from the camera; b) - a layer of erythrocytes; c) — layer without erythrocytes.

The claimed device contains:

1 - trinocular microscope;

2 - digital camera;

3 - focusing drive along the Z coordinate;

4 — block for controlling the object table along the X, Y coordinates;

5 - computer controller with software;

6 - computer monitor;

7 — microscope stage 2.

The principle of operation of the device is as follows.

The software of the controller 5 of the computer sets the control (reference) values of the following parameters:

- the value of the required average color of the image in the area of pure light:

;

;

- the value of the required average color of the image before background correction:

;

;

(The average color of an image is the sum of all flux intensity values for each pixel, divided by the number of pixels.)

- minimum and maximum values of the average image background:

;

;

(Medium image background is the average color of the image, in which all blood cells have been previously removed.)

- minimum and maximum values of the optical density of erythrocytes:

.

.

(Optical density is a measure of the opacity of a layer of matter to light rays).

Before the start of scanning, a slide with a blood smear (not shown) is placed on the stage 7.

Next, the scanner of the digital camera 2 is launched, and the process of scanning blood smears on the stage 7 begins. The drive 3, according to the given program of the controller 5, focuses the image along the Z coordinate in the thin part of the smear (Fig. 2).

Next, the controller 5 performs the first step, the so-called "pure light auto-calibration". This stage is performed on the first of a series of strokes to set the right lighting and background alignment.

. После этого столик 7 перемещается с помощью блока управления 4 в область чистого света, не меняя положение по оси

(положение сфокусированного изображения). Область чистого света — такое положение столика 7 микроскопа 1, в котором нет препятствия между объективом и осветителем, в частности стекла с мазком крови.The controller 5 remembers the current position of the stage 7, i.e. coordinates

. After that, the table 7 moves with the help of the control unit 4 to the area of pure light, without changing the position along the axis

(position of the focused image). The area of pure light is the position of the stage 7 of the microscope 1, in which there is no obstacle between the lens and the illuminator, in particular glass with a blood smear.

Next, controller 5 adjusts the exposure value of camera 2.

The concept of "exposure" characterizes the amount of light that hit the photosensitive material of the camera matrix during a certain time. Increasing the exposure increases the values of the average color, the average background of the image and vice versa, decreasing the exposure value of the camera decreases the values of these image indicators.

установлено программой контроллера 5 в зависимости от выставленного перед сканированием значения

, а именно 10 % от этого значения

. При этом оно не должно быть меньше минимального значения допустимого камерой -

и не больше достаточно маленького фиксированной числа -

.In this case, the initial exposure value

set by the controller program 5 depending on the value set before scanning

, namely 10% of this value

. At the same time, it should not be less than the minimum value allowed by the camera -

and at most a small enough fixed number -

.

, но не более достаточно маленького фиксированной величины

и не менее минимального значения допустимого камерой 2 (

) до тех пор, пока средний цвет изображения

с камеры 2 не превысит значение необходимого среднего цвета изображения в области чистого света (150): Next, controller 5 increases the exposure on camera 2 in steps of 20% of the current value

, but no more than a sufficiently small fixed value

and not less than the minimum value allowed by camera 2 (

) until the average color of the image

from camera 2 will not exceed the value of the required average color of the image in the area of pure light (150):

, где

, where

— интенсивность красного потока пикселя под номером

;

is the intensity of the red flux of the pixel under the number

;

— интенсивность зеленого потока пикселя под номером

;

is the intensity of the green flux of the pixel under the number

;

— интенсивность синего потока пикселя под номером

;

is the intensity of the blue flux of the pixel under the number

;

— количество пикселей на изображении.

is the number of pixels in the image.

After that, the controller 5 performs automatic white balance. White balance refers to the process of compensating for color losses when light is detected by a matrix in accordance with a predetermined color temperature. It follows from this that the white balance is designed to preserve natural colors in the image programmatically in order to compensate for the imperfection of the matrices. A neutral color in the camera view is a color that does not have any shades: white, gray. Taking this color as a reference point, the camera will be able to accurately represent the rest of the colors in the image.

Controller 5 increases the exposure on camera 2 with a minimum step of 20% of the current one, but no less than the minimum possible exposure and no more than 1:

с камеры не превысит значение необходимого среднего цвета изображения перед коррекцией фона (200):until the average color of the image

from the camera will not exceed the value of the required average image color before background correction (200):

Next, the controller 5 performs background correction. Background correction is a method of correcting the non-uniform illumination of the image from the camera by dividing it by the reference one.

To do this, controller 5 reduces the exposure on camera 5 with a minimum step of 20% from the current one, but not less than the minimum possible exposure of the camera and not more than 1:

с камеры максимально не приблизится к значению 245:until the average color of the image

from the camera will not approach the value of 245 as much as possible:

, и камера 2 фокусируется на изображении.At the signal of the controller 5, the focus drive 3 and the control unit 4 return the table 7 to its original position

, and camera 2 focuses on the image.

Next, the controller 5 performs the second stage of scanning, the so-called "cell color equalization". At this stage, by adjusting the gamma of the digital camera 2, the color of the cells is brought to the standard pink.

The second step is repeated before each new blood smear is scanned, with controller 5 increasing or decreasing the exposure in increments of 1:

,

,

until the average background of the image falls within the required range of minimum and maximum values of the average background of the image:

.

.

. и формирует новые изображения: из слоя, на котором только одни эритроциты, без фона -

и из слоя, на котором только фон, без эритроцитов —

(фиг. 4).Camera 2, at the signal of controller 5, takes a picture of the field of view -

. and forms new images: from a layer on which there are only erythrocytes, without a background -

and from the layer on which there is only a background, without erythrocytes -

(Fig. 4).

The calculation of the optical density of erythrocytes is carried out according to the formula:

Next, controller 5 changes the gamma of camera 2 in steps of 0.2

) таким образом, чтобы оптическая плотность эритроцитов приблизилась к заданному диапазону допустимых значений:(

) so that the optical density of erythrocytes approaches the specified range of acceptable values:

After that, the exposure increases or decreases in steps of 1:

,

,

until the average background of the image is as close as possible to the middle of the minimum and maximum values of the average background of the image:

Controller 5 corrects the gamma of camera 2 with a change in exposure until the optical density of erythrocytes falls within the specified range of acceptable values:

Gamma defines the relationship between the numerical value of a pixel and its actual luminosity. Gamma correction is a pre-correction of the brightness of the black-and-white or color-separated components of a color image.

After the performed manipulations at the first and second stages of scanning, the average background and the average color of the cells will become the same for smears prepared by any known methods.

Since the necessary parameters are pre-set before scanning by the program of the controller 5, the colors of the images can be personalized for a particular doctor. And the automation of the process of setting up the microscopy system and the exclusion of the human factor when manually setting the device allows you to quickly, accurately and reliably classify blood cells, regardless of the color of the smear.

Then it becomes possible to carry out the final stage - morphological analysis of cells. To do this, the image captured from camera 2 is analyzed by the CBC classifier, which stores and classifies all leukocytes, erythrocytes and platelets present in the image, then the field of view changes to the neighboring one.

The third stage is repeated until the number of cells required for analysis is found. Upon completion of the blood smear scan, the results will be stored in the computer database and are available for viewing by the doctor on monitor 6.

If further blood smears need to be examined, the controller 5 will start the scanning process from the second step. When restarted, the scan will start from the first step.

Since the necessary parameters are pre-set before scanning by the controller program, the colors of the images can be personalized for a particular doctor. And the automation of the process of setting up the microscopy system and the exclusion of the human factor when manually setting the device allows you to quickly, accurately and reliably classify blood cells, regardless of the color of the smear.

A blood smear analysis device with automatic camera calibration for various smear staining conditions is more efficient than known similar devices due to the camera calibration function for standardizing the color of blood smear cells regardless of smear staining conditions, while the device allows you to scan a series of blood smears without manually adjusting the lighting before each individual blood smear and get more accurate cell classification and high speed.

It is convenient to operate and can be widely used for complete blood count in diagnostic centers and laboratories.

Claims (1)

A device for morphological analysis of blood smears, consisting of an optical microscope with a trinocular attachment, an automated object stage and a focus drive, a digital camera and a computer controller with software, characterized in that the controller is configured to calibrate the digital camera settings in two stages, while on at the first stage, the controller adjusts the camera in the area of pure light, at the second stage it aligns the color of the blood cells of the studied smear, while the digital camera is configured to automatically calibrate its settings before each scanning of blood cell images for a series of blood smears under study, depending on their color, and the focus drive of the optical microscope is configured to move the object stage in accordance with the control signals of the controller.

Images