CN1641397A - Microscopic automatic focusing device and method suitable for space application - Google Patents

Abstract

This is a kind of microscopical focus self-adjusting device and method fit for spatial application. The device comprises the microscopical optical system which orderly compose optical couplings with dimensional objects, the system to obtain microscopical images, the image processing system which is used to process the microscopical images to ascertain the clear imaging position, the coupling image processing system, and the micro-displacement controlling system of the microscopical optical system, so as to form a closed loop controlling system and realize microscopical focus self-adjusting. The method is to obtain the microscopical images mainly depending on the micro-displacement controlling system to make the microscopical optical system move the distance with spatial objectives step by step in stated bound. Then calculate every image element in the way of gray difference and work out the gray maximum after doing a group of gray extremum. Ascertain the clear imaging position by the gray maximum and adjust the distance between the microscopical optical system and the spatial objectives by the micro-displacement system to realize focus self-adjusting.

Description

Be fit to microscopic automatic focusing device and the method that use in the space

Technical field:

The present invention relates to a kind of space microscopic automatic focusing device and method, the microscopic automatic focusing device and the method thereof of the space multistory distribution cell target that use in particularly a kind of suitable space.

Background technology:

Space life science be one brand-new, also be the field of present countries in the world active research, carry out significant to the space life science development of microexamination research in the space.The target of space microexamination is to be contained in the cell that the closed container neutral body distributes, and is very different with the ground microexamination target that is contained on the wave carrier piece.Owing to the effect of gravity, target is tiled into one deck, can treat as a plane on ground; Be close to disappearance at space gravity, cell suspension is space multistory and distributes in container.To carry out microexamination in the space, the microscopic automatic focusing device of the space multistory distribution cell target of using at the space at first must be arranged.

The existing various automatic focusing methods that are applied to different technical fields all can not be fit to the space microscopic automatic focusing fully.As camera telemetry that automatic focusing adopts commonly used, comprise range of triangle, infrared distance measurement and ultrasonic ranging etc.The weak point of this range finding automatic focusing method is that precision is not high, and can't eliminate the interference of chamber wall, is not suitable for the microscopic automatic focusing that use in the space.Other, as No. two space crystal finders of divine boat, belong to macroscopic observation, it adopts Spectrum Method to carry out automatic focusing, the main deficiency of this method is: threshold value is different with the difference of target, be not suitable for the automatic focusing under the complex background, especially be not suitable for automatic focusing at the micro-target of space multistory distribution.

Summary of the invention:

The objective of the invention is to adapt to the space life science features of experiment, the microscopic automatic focusing device that provides a kind of suitable space to use is realized the Real Time Observation to the space three-dimensional cultured cell, for scientific research provides the distinct image data.

Another object of the present invention provides the microscopic automatic focusing method that use in a kind of suitable space.

Technical scheme of the present invention is as follows:

The microscopic automatic focusing device that use in a kind of suitable space according to the present invention comprises: a micro optical system, and it becomes optical link and has microlens and travel mechanism with extraterrestrial target;

Be characterized in, also have: an image-taking system, it has a CCD image device that is installed on the imaging surface of this micro optical system, in order to obtain the target micro-image, convert micro-image the image digitazation module of analysis of digital microscopy images to one, and an image buffer storage module of depositing analysis of digital microscopy images; One image processing system connects the dsp interface circuit and the dsp processor of this image buffer storage module after it has successively, to the analysis of digital microscopy images processing of focusing, obtain the blur-free imaging position; An and micrometric displacement control system, it comprises control device, stepper motor and the ball screw that is connected successively, and connect image processing system and be connected micro optical system by ball screw by control device respectively, adjust the distance of micro optical system and extraterrestrial target according to image position that image processing system is specified to.

Particularly, the moving step length of described micrometric displacement control system is the 1 μ m/ step.

According to the extraterrestrial target microscopic automatic focusing method of said apparatus of the present invention, it comprises step:

A. first step-length of the microscope of mobile micro optical system gathered piece image by image-taking system, and converted a width of cloth analysis of digital microscopy images to;

B. to image processing system input digit micro-image, and by image processing system selected focus area in input picture;

C. image processing system is pressed the gray scale difference point-score to this selection area and is calculated the focusing amount, and memory location amount and focusing amount;

D. repeating step a, b, c in focusing range obtain desired location amount and corresponding focusing amount;

E. image processing system calculates extreme value to the one group of focusing amount that obtains, and obtains several extreme points, and these extreme points are represented several layers space of planes target blur-free imaging position respectively;

F. image processing system maximizing from these extreme points; And

G. image processing system send the micrometric displacement control system with maximum value information, the micrometric displacement control system moves to the maximal value position with the camera lens of micro optical system, obtain extraterrestrial target quantity maximum and details and enrich the blur-free imaging position of aspect most, finish focusing, or press customer requirements, move to other extreme point place by telecommand, obtain the blur-free imaging position of other aspect extraterrestrial target;

Further:

Microlens described in the step a moves a step-length, equals one micron/step;

The point-score of gray scale difference described in the step c is that each pixel in the focus area is carried out calculus of differences;

Ask maximizing in extreme value and the arbitrary group of extreme value described in step e and the step f, it uses functional relation:

$F\left(i\right)=\underset{(x,y)}{\mathrm{\Σ}}\left\{\right|f_i(x,y)-f_i(x,y-1)|+|f_i(x,y)-f_i(x-1,y)\left|\right\}$

(i＝0，1，…，M)

When image focusing, F (i) gets maximal value.

Advantage of the present invention is:

1. this automatic focusing device compact conformation is focused accurately, can reach the micron order precision;

2. this automatic focusing device can carry out automatic focusing to the target of space multistory distribution under complex background;

3. this automatic focusing device is fit to the space application, can realize microscopic automatic focusing to the space life science object of experiment.

4. this algorithm is simple, and calculated amount is little, is fit to the implementation space through engineering approaches;

5. this algorithm focusing accurately can reach the micron order precision;

6. this algorithm can carry out automatic focusing to the target of space multistory distribution under complex background, is particularly suitable for realizing automatic focusing under space environment.

Description of drawings:

Fig. 1 is that automatic focusing device of the present invention is formed synoptic diagram.

Fig. 2 is an automatic focusing program flow diagram of the present invention.

Fig. 3 is a target image synoptic diagram of the present invention.

Fig. 4 is the focusing curve of section target cell.

Fig. 5 is the focusing curve of double-deck Reishi sporule.

Fig. 6 is the focusing curve of multi-layer cellular.

Embodiment:

Provide better embodiment of the present invention according to Fig. 1～Fig. 6 below, further the present invention is elaborated in conjunction with this embodiment.

See also Fig. 1, present embodiment comprises micro optical system 40, image-taking system 10, image processing system 20 and micrometric displacement control system 30.Wherein, in image-taking system 10, CCD image device 11 is installed on the imaging surface of micro optical system 40, obtains the micro-image of target.This micro-image obtains the micro-image of numeral through image digitazation module 12, and deposits in the image buffer storage module 13.Image processing system 20 is read internal RAM with dma mode with the image in the image buffer storage module 13 by dsp interface circuit 21, again through dsp processor 22 processing of focusing, obtains the position of blur-free imaging.In micrometric displacement control system 30, control device 31 links to each other with image processing system 20, and control device 31 drive stepping motor 32 are rotated, and stepper motor 32 links to each other with ball screw 33, and ball screw 33 links to each other with micro optical system 40 again.Under the control of control device 31, ball screw 33 drives micro optical system 40 and does axially-movable, to adjust the distance between micro optical system 40 and the target.When beginning to focus, under the control of micrometric displacement control system 30, micro optical system 40 moves with fixed step size (1 μ m) from zero-bit, moves certain step number according to focusing range.Micro optical system 40 whenever moves a step-length, and image-taking system 10 is gathered a two field picture, and converts analysis of digital microscopy images to, and a series of analysis of digital microscopy images that will obtain are again sent into image processing system 20, obtains the position of blur-free imaging after the processing of focusing.By micrometric displacement control system 30, micro optical system 40 is moved to focusing handle the blur-free imaging position that obtains again, thereby realize automatic focusing.

Through experimental verification (as Fig. 4, shown in 5,6), show that this microscopic automatic focusing device has the focusing accuracy height, can obtain space multistory distribution purpose micro-image clearly, be adapted at the space and use.

See also the focusing Processing Algorithm that Fig. 1, Fig. 2, Fig. 3 and Fig. 4 set forth the cell target that space multistory is distributed.This algorithm is introduced the decision function of the method for grey scale difference as image definition; There is the aspect of a plurality of blur-free imagings in the cell target that distributes at space multistory simultaneously, this method utilizes the gray scale difference point-score in focusing range image to be handled, obtain one group of focusing numerical value, utilize the method for asking extreme value to obtain the position of each extreme point then, the position of these extreme points is exactly the blur-free imaging face of each confluent monolayer cells.Relatively each extreme point is obtained the maximal value place, and it is the abundantest aspect of cell details, and mobile then microscope is promptly finished the abundantest aspect automatic focusing of pair cell details to this position; Simultaneously according to demand, also can finish automatic focusing to other imaging surfaces.

In the present embodiment, the cell target that space multistory is distributed processings of focusing, by automatic focusing program 100 execution that reside in the image processing system 20, steps flow chart is as shown in Figure 2.Step 101 starts automatic focusing program 100, follows program 100, carries out following steps successively:

Step 102 camera lens moves a step-length, is promptly regulated the distance of micro optical system 40 and target by micrometric displacement control system 20, and a step-length is set at 1 μ m, gathers a width of cloth micro-image by image-taking system 10, and it is converted to a width of cloth microscopic digital image;

Step 103, input picture, image-taking system 10 is the microscopic digital image input picture disposal system of obtaining 20;

Step 104 is selected focus area in the image of input, promptly handles selected by image processing system 20;

Step 105 is pressed the gray scale difference point-score by 20 pairs of these selection areas of image processing system and is calculated the focusing amount, and memory location amount and focusing amount;

Is step 106 judged in focusing range by image processing system 20? if in focusing range (setting 300 μ m), just repeating step (102,103,104,105) obtains 300 position quantity and corresponding focusing amount;

If full focusing range, then execution in step 108,109,110 and 111 successively;

One group of focusing amount that step 108,20 pairs of image processing systems obtain is calculated extreme value, obtains several extreme points, and these extreme points are represented the blur-free imaging position of some aspect cells respectively;

Step 109, image processing system 20 in these extreme points, maximizing;

Step 110, image processing system 20 send micrometric displacement control system 30 with maximum value signal, and the camera lens of micro optical system 40 is moved to the maximal value position by micrometric displacement control system 30, promptly obtain the blur-free imaging position that cell quantity maximum and details are enriched aspect most, thereby finish focusing; Also can cross telecommand, camera lens is moved to other extreme point place, obtain the blur-free imaging position of other aspect cell by user's request.

At last, execution in step 111, focusing finishes.

Focus area among the present invention can be determined the zone in advance; Also can be according to demand some characteristic area as focus area.

Gray scale difference point-score among the present invention is that each pixel in the focus area is carried out calculus of differences, and as shown in Figure 3, this is the simple but effectively Image Definition of form.To point (i, j) and the left pixel (i, j-1) and the top pixel (i-1 j) does calculus of differences, obtains the variation of this place gray-scale value, in order to prevent positive and negative counteracting in the summation process, is sued for peace in the difference value back that takes absolute value.Functional relation is:

$F\left(i\right)=\underset{(x,y)}{\mathrm{\Σ}}\left\{\right|f_i(x,y)-f_i(x,y-1)|+|f_i(x,y)-f_i(x-1,y)\left|\right\}$

(i＝0，1，…，M)

When image focusing, F (i) gets maximal value.

By focusing experiment to individual layer, bilayer and multi-layer cellular, as Fig. 4～curve map shown in Figure 6, proof the present invention can finish the automatic focusing of the cell target that space multistory is distributed, this shows that automatic focusing method of the present invention can be finished the automatic focusing to suspension cell target in the experimentation of space.

Claims (6)

1, a kind of microscopic automatic focusing device of suitable space application comprises:

One micro optical system (40), it becomes optical link and has microlens and travel mechanism with extraterrestrial target; It is characterized in that also having:

One image-taking system (10), it has a CCD image device (11) that is installed on the imaging surface of this micro optical system (40), obtain the target micro-image, convert micro-image the image digitazation module (12) of analysis of digital microscopy images to one, and an image buffer storage module (13) of depositing analysis of digital microscopy images;

One image processing system (20) connects the dsp interface circuit (21) and the dsp processor (22) of this image buffer storage module (13) after it has successively, to the analysis of digital microscopy images processing of focusing, obtain the blur-free imaging position; And

One micrometric displacement control system (30), it comprises control device (31), stepper motor (32) and the ball screw (33) of the connection that links to each other successively, and connect image processing system (20) and is connected micro optical system (40) by ball screw (33) by control device (31) respectively, according to the distance of image processing system (20) the institute's image position that is specified to adjustment micro optical system (40) and extraterrestrial target.

2, the microscopic automatic focusing device of suitable space application according to claim 1 is characterized in that: the moving step length of described micrometric displacement control system (30) is the 1 μ m/ step.

3, a kind of extraterrestrial target microscopic automatic focusing method of device according to claim 1, it comprises step:

A. first step-length of the microscope of mobile micro optical system, and gather piece image by image-taking system, convert a width of cloth analysis of digital microscopy images again to;

B. to image processing system input digit micro-image, and by image processing system selected focus area in input picture;

C. image processing system is pressed the gray scale difference point-score to this selection area and is calculated the focusing amount, and memory location amount and focusing amount;

D. repeating step a, b, c in focusing range obtain desired location amount and corresponding focusing amount;

E. image processing system calculates extreme value to the one group of focusing amount that obtains, and obtains several extreme points, and these extreme points are represented several layers space of planes target blur-free imaging position respectively;

F. image processing system maximizing from these extreme points; And

G. image processing system send the micrometric displacement control system with maximum value information, the micrometric displacement control system moves to the maximal value position with the camera lens of micro optical system, promptly obtain extraterrestrial target quantity maximum and details and enrich the blur-free imaging position of aspect most, finish focusing, or press customer requirements, move to other extreme point place by telecommand, obtain the blur-free imaging position of other aspect extraterrestrial target.

4, according to the described extraterrestrial target microscopic automatic focusing of claim 3 method, it is characterized in that: microlens described in the step a moves a step-length, equals one micron/step.

5, according to the described extraterrestrial target microscopic automatic focusing of claim 3 method, it is characterized in that: the point-score of gray scale difference described in the step c is that each pixel in the focus area is carried out calculus of differences.

6, according to the described extraterrestrial target microscopic automatic focusing of claim 3 method, it is characterized in that: ask maximizing in extreme value and the arbitrary group of extreme value described in step e and the step f, it uses functional relation:

$F\left(i\right)=\underset{(x,y)}{\mathrm{\Σ}}\left\{\right|f_i(x,y)-f_i(x,y-1)|+|f_i(x,y)-f_i(x-1,y)\left|\right\}$

(i＝0，1，…，M)

When image focusing, F (i) gets maximal value.

Images