CN106094193A - Automatic focusing microscopic imaging system for planet surface substance in-place detection - Google Patents

Abstract

The present invention proposes an automatic focusing microscopic imaging system for in-situ detection of planetary surface materials, including an illumination unit, a microscopic imaging unit, an image acquisition unit, a focusing transmission unit, and a host computer unit; the lighting unit and the microscopic imaging unit are located at the same The optical path, the microscopic imaging unit includes the microscope objective lens and the lens barrel; the focusing transmission unit is a gear external engagement transmission device, and its setting direction is perpendicular to the lighting unit, which converts the transmission of the gear into the movement of the microscope barrel; the image acquisition unit In the same optical path as the microscope tube, the image acquisition unit is connected with the focusing transmission unit; the host computer unit evaluates the clarity of the collected images and controls the entire system to be in a quasi-focus state. The invention can judge the sharpness of the collected image of the sample to be tested, quickly find the quasi-focus position by fitting the focusing function, and improve the speed and precision of focusing, and the device adopts a unitized design and has the advantages of small size , strong functions and other advantages.

Description

An auto-focusing microscopic imaging system for detection of material in place on the surface of a planet

technical field

The invention belongs to the field of optical engineering, and in particular relates to an automatic focusing microscopic imaging device, which utilizes an image definition evaluation function to quickly realize the focusing process and obtain a clear microscopic image of a sample to be tested.

Background technique

In the field of deep space exploration, the microscopic imaging system is used as an optical load for in-situ detection. By imaging planetary geological surface soil and rock samples, according to the image size, texture, color and other characteristics, it is possible to recognize the topography from a microscopic point of view, and then judge Soil element composition, mineral composition analysis, etc. For example, the microscopic imager (MI) carried by the "Opportunity" of the United States, the optical microscope (OM) carried by the "Phoenix" Mars lander, the MAHLI camera carried by the "Curiosity" and the "ExoMars" carried by the European Space Agency. The MicroOmega hyperspectral microscope can image and analyze the collected soil samples from a microscopic perspective.

When microscopic imaging loads acquire clear images, the traditional method is to image the samples to be tested at different object distances, and then select clear images from a series of images collected. This method collects more images and takes more time. Long and inefficient.

Contents of the invention

In order to solve the technical problems existing in the background technology, the present invention proposes an automatic focusing microscopic imaging system device, which can judge the sharpness of the collected image of the sample to be tested, and by fitting the focusing function , to quickly find the quasi-focus position, which improves the speed and accuracy of focusing, and the device adopts a unitized design, which has the advantages of small size and strong functions, and conforms to the light and small design principle of aerospace payloads.

The technical solution of the present invention is: an automatic focusing microscopic imaging system for in-situ detection of planetary surface materials, characterized in that: the system includes an illumination unit, a microscopic imaging unit, an image acquisition unit, a focusing transmission unit, and a host computer unit;

The illumination unit and the microscopic imaging unit are located on the same optical path, and the microscopic imaging unit includes a microscope objective lens and a lens barrel. The focus transmission unit is a gear external engagement transmission device, and its setting direction is perpendicular to the lighting unit. This unit converts the transmission of the gear into the movement of the microscope tube.

The image acquisition unit and the microscope barrel are in the same optical path, and the image acquisition unit is connected with the focusing transmission unit;

The upper computer unit evaluates the clarity of the collected images, fits the focusing curve, and sends focusing instructions to control the entire system to be in a quasi-focus state.

The above-mentioned focusing transmission unit includes a driving wheel, a driven wheel, a magnetic bead, a motor and a Hall sensor; the motor drives the driving wheel to drive the driven wheel; the magnetic bead is arranged on the driven wheel, and the magnetic bead and the Hall sensor are used to calibrate the gear transmission. The starting position; the driven wheel connects the microscope tube and the image acquisition unit.

The above-mentioned image acquisition unit is a CCD camera.

The present invention has the following advantages:

1) The present invention adopts an imaging unit with a common light path for illumination and imaging, so that the integration of the whole system is higher.

2) The wavelength of the illumination light source is optional, and light sources with different wavelengths are selected for different samples to analyze the characteristics of the sample more comprehensively and flexibly.

3) The device effectively eliminates the impact of the backstroke difference of the gear transmission mechanism on the positioning accuracy through the calibration function of the Hall sensor.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a work flow diagram of the automatic focusing microscopic imaging system of the present invention;

detailed description

Referring to Fig. 1, the present invention is a kind of auto-focusing microscopic imaging system device of planetary surface material in-situ detection, whole system comprises: illumination unit, microscopic optical imaging unit, image acquisition unit (CCD camera 9), focusing transmission unit ( Drive wheel, driven wheel, magnetic beads, motor, Hall sensor), host computer unit. When the device performs microscopic imaging of the sample under test, the host computer calculates the quasi-focus position by judging the image clarity, and sends corresponding instructions to control the imaging system to reach the designated position, and quickly obtain a clear microscopic image of the measured object .

The illumination part and the micro-optics imaging part of the automatic focusing device share an optical path. The light emitted by the LED lighting source 1 is irradiated on the spectroscopic sheet through the illuminating condenser, and shines on the sample surface of the observed object, and the light reflected by the sample is imaged on the image plane through the imaging mirror group. The focusing mechanism is a gear-to-gear transmission device. The driving wheel 3 is driven by the stepping motor 2 to drive the driven wheel 4. The lens barrel 5 gradually approaches or moves away from the target, that is, the method of changing the object distance to find the quasi-focus position. A magnetic bead 6 is installed on the driven wheel 4, and the magnetic bead 6 and the hall sensor 7 are used to calibrate the starting position of the gear transmission, so as to eliminate the influence of the backstroke difference of the gear transmission mechanism on the positioning accuracy. The stepping motor 2 drives the lens to move forward in equal steps, and collects a frame of image every step, and the host computer 8 calculates the image definition of this position. If the current image definition is greater than the previous frame image, it is considered that the system is gradually approaching the in-focus position. When the image clarity of four consecutive positions decreases, take the position with the maximum clarity and two adjacent positions on the left and right sides and the corresponding image clarity to realize the fitting of the focusing curve, find out the peak position, and send According to the instruction, the imaging system is controlled to reach the peak position to realize the focusing process.

The specific implementation process is as follows:

The upper computer 8 sends a focusing instruction, and the stepping motor 2 rotates in the forward direction. Through the gear transmission mechanism, the lens barrel 5 gradually approaches the sample to be tested. When the Hall sensor 7 senses the magnetic field of the magnetic bead 6 for the first time, the sensor sends a signal to the upper computer. 8. Mark this position as the starting point of the focusing stroke.

At the starting point, the motor drives the driving wheel 3 to rotate with a large step length, and images are collected at equal step lengths, and the host computer 8 judges the image clarity. When the sharpness of four consecutive points drops, it is considered that the quasi-focus position point has been crossed at this time, and the motor stops at this time. The host computer 8 takes the maximum sharpness position and two adjacent positions on the left and right sides and the corresponding image sharpness to realize the fitting of the focusing curve, and the peak position of the focusing curve is regarded as the quasi-focus position.

The motor reverses, and when the Hall sensor 7 senses the magnetic field signal again, it indicates that the starting position has been reached. The motor rotates forward until the focusing mechanism is driven to the fitted quasi-focus position to collect images.

Claims (3)

1. An automatic focusing microscopic imaging system for in-situ detection of planetary surface materials, characterized in that: the system includes an illumination unit, a microscopic imaging unit, an image acquisition unit, a focusing transmission unit, and a host computer unit; The lighting unit and the microscopic imaging unit are located on the same optical path. The microscopic imaging unit includes a microscope objective lens and a lens barrel; , converted into the movement of the microscope tube; The image acquisition unit and the microscope barrel are in the same optical path, and the image acquisition unit is connected with the focusing transmission unit; The upper computer unit evaluates the clarity of the collected images, fits the focusing curve, and sends focusing instructions to control the entire system to be in a quasi-focus state. 2. The automatic focusing microscopic imaging system for in-situ detection of planetary surface materials according to claim 1, characterized in that: the focusing transmission unit includes driving wheels, driven wheels, magnetic beads, motors and Hall sensors; The driving wheel drives the driven wheel for transmission; the magnetic beads are arranged on the driven wheel, and the magnetic beads and the Hall sensor are used to calibrate the starting position of the gear transmission; the driven wheel is connected to the microscope tube and the image acquisition unit. 3 . The autofocus microscopic imaging system for in-situ detection of planetary surface materials according to claim 2 , wherein the image acquisition unit is a CCD camera. 4 .