CN103105285B - Shadow-rejection based test method and test instrument for optical fiber panel limiting resolution - Google Patents

Abstract

The invention discloses an optical fiber panel limit resolution test instrument based on shadow elimination, comprising: a standard light source (1) and its steady current source (2), a condenser lens (3), an integrating sphere (4) and its moving mechanism, a resolution rate target (5), and CCD data acquisition and microcomputer processing system (8), the resolution target (5) is set on the uniform diffusion outlet of the integrating sphere (4); the invention also discloses a Test method for limit resolution of optical fiber panels with shadow removal. The present invention supplements the blank of the current limit resolution testing technology for optical fiber panels, uses a resolution target to eliminate shadow points to accurately and systematically measure the limit resolution of each part of the optical fiber panel, and can give the resolution distribution of each part of different optical fiber panels , and can also locate the shadow coordinates of the optical fiber panel.

Description

Optical fiber panel limit resolution test method and instrument based on shadow removal

technical field

The invention relates to an optical instrument for measuring the limit resolution of an optical fiber panel and an optical lens, in particular to a resolution test device based on the principle of shadow compensation, which belongs to the field of optics.

Background technique

The optical fiber panel has the characteristics of high light transmission efficiency, small inter-stage coupling loss, clear and real image transmission, and zero thickness. Widely used in various cathode ray tubes, camera tubes, CCD couplings and other instruments and equipment that need to transmit images. The fiber optic panel is a user terminal product that realizes the fiber-to-the-desktop solution, and the internal space design is reasonable. Thus gradually moving towards some home and work areas. The quality of the fiber optic panel is inseparable from the resolution of the panel, so the parameters of its limit resolution also need to be tested. Due to the influence of various uncontrollable factors (such as infrared response, temperature, etc.) out of these shadow spots. At present, there is no in-depth research on the shadow detection method of optical fiber panels in China, and the technology for systematically testing the limit resolution of various parts of optical fiber panels is almost zero. As for the detection of the shadow in the optical fiber panel, there is a method called using the optimal operator Canny operator to realize the detection of the shadow. But this solution has the following problems:

1) The Canny operator uses mathematical simulation to approach practical problems, and its positioning accuracy and width cannot be described intuitively.

2) The call statement of the Canny operator contains the standard deviation of the Gaussian filter parameters, the ratio of the low threshold to the high threshold, and the ratio of the high threshold to the total number of image pixels. Not only can several parameters not be uniquely determined, but there are also certain human factors.

3) There is not only additive noise in the resolution image, but also multiplicative noise, and the Canny operator cannot solve the multiplicative noise.

Contents of the invention

In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides an optical fiber panel limit resolution test instrument based on shadow removal, including: a standard light source and its steady current source, a condenser, an integrating sphere and its moving mechanism, a resolution Rate target, and CCD data acquisition and microcomputer processing system, the resolution target is set on the uniform diffuse outlet of the integrating sphere.

Further, the standard light source is a bromine tungsten lamp, and the steady current source is a DC power supply with high precision.

Further, the condenser is a quartz condenser.

Further, the distance between the standard light source and the condenser lens is shorter than the focal length of the condenser lens.

Further, the integrating sphere is a hollow sphere coated with non-wavelength-selective diffuse reflective white paint inside.

Further, the moving mechanism is a metal sliding table connected with the integrating sphere, and the periphery thereof is marked with scales.

Further, the optical fiber panel to be tested is arranged between the resolution target and the uniform diffusion outlet of the integrating sphere.

Further, it also includes a microscope observation system, the microscope observation system has a CCD interface, and its objective lens is aligned with the optical fiber panel to be tested.

Further, it also includes a Z-axis moving mechanism, which is used to adjust the Z-axis position of the microscope objective lens.

The present invention also provides a method for testing the limit resolution of an optical fiber panel based on shadow removal, comprising the following steps:

Set the optical fiber panel to be tested between the resolution target and the uniform diffuse outlet of the integrating sphere;

The monochromatic light emitted by the standard light source passes through the condenser, and then enters a compensation port of the integrating sphere;

Afterwards, the incident light is diffusely reflected in the integrating sphere and then emitted from another compensation port of the integrating sphere;

Then transmit through the optical fiber panel to be tested and the resolution target to the microscope objective lens.

At any moment, the potential of any point in the resolution target Determined by the two-dimensional Laplace equation and the corresponding boundary conditions:

;

;

;

in is the thickness of the resolution target, is the resolution target surface potential distribution, is the target pressure;

because have Respectively satisfying a linear superposition of two-dimensional Laplace squares with homogeneous boundary conditions can lead to the final expression as:

,

in respectively The derived coefficient of is a hyperbolic sine function, and , C is the contrast of the target, I is the current photocurrent, is the reference current of the target;

When there is a shadow point somewhere, the electric potential is zero, and the coordinates of x and y can be uniquely determined.

The optical fiber panel limit resolution test method and instrument based on shadow elimination of the present invention supplement the current blank of the optical fiber panel limit resolution test technology, and use a resolution target to eliminate shadow points to accurately and systematically measure the limit resolution of each part of the optical fiber panel The ratio can give the resolution distribution of each part of different fiber optic panels, and can also locate the shadow coordinates of the fiber optic panels.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1) Directly judge the limit resolution of different areas of the fiber optic panel through the microscopic visual observation system, which is more intuitive than the traditional method, and the operation is relatively simple;

2) The resolution target eliminates shadows, which solves the problem of inaccurate measurement of the resolution of the fiber optic panel;

3) The measurement of the limit resolution of different parts of the fiber optic panel is given, and the shadow position of the panel can be accurately given.

Description of drawings

Fig. 1 is the structural representation of the optical fiber panel limit resolution testing instrument based on shadow elimination of the present invention;

Fig. 2 is a cross-sectional view of a resolution target.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

As shown in Figure 1, the optical fiber panel limit resolution test instrument based on shadow removal of the present invention includes a standard light source 1 and its steady flow source 2, a condenser lens 3, an integrating sphere 4 and its moving mechanism, a resolution target 5, and a microscope observation system 6 and Z-axis moving mechanism 7, CCD data acquisition and microcomputer processing system 8.

The standard light source 1 and its steady current source 2 are a light source system with a bromine tungsten lamp and a high-precision DC power supply, which stabilizes the intensity and color temperature of the output light of the light source. The standard light source 1 must be isolated from external light sources, so it must be carried out in a dark box at a certain temperature.

The condenser lens 3 is a quartz condenser lens, the purity of which is relatively high, and the refraction angle of light is not easily affected. It is set at a fixed distance from the standard light source 1 , this distance is less than the focal length of the condenser 3 , and the projection of the light source along the optical axis is just on the center of the condenser 3 .

The integrating sphere 4 is a hollow sphere coated with non-wavelength selective (uniform) diffuse reflective white paint inside, and the integrating sphere has two compensation ports, one of which is the output light entrance of the condenser lens 3, and the other is a uniform diffuse ejection port. Integrating sphere 4 is arranged on the moving mechanism, and moving mechanism is the metal sliding platform that is closely connected together with integrating sphere, and its periphery is all marked with scale, makes integrating sphere 4 can move back and forth, left and right in X-Y plane smoothly.

The optical fiber panel 9 to be tested is closely attached to the resolution target 5, wherein the resolution target 5 is a standard resolution target with a uniform resolution strip width and a light-dark contrast of over 90%.

The microscope observation system 6 is an optical microscope with a CCD interface, which can be processed by a microcomputer. The objective lens of the microscope is aimed at the optical fiber panel 9 to be tested. The Z-axis moving mechanism 7 is a peripheral auxiliary device for adjusting the focal length of the microscope.

The CCD data acquisition and microcomputer processing system 8 includes a CCD image acquisition card and a microcomputer platform. The CCD image acquisition card is located at the interface connection of the microscope, and can convert the analog quantity of the observed image into a digital quantity. The microcomputer can comprehensively process the transmitted data, such as shadow positioning, parameter setting, drawing images, printing reports and other operations.

The optical path of the present invention is that the standard light source 1 emits monochromatic light through the condenser lens 3, and then enters a compensation port of the integrating sphere 4, and then the incident light is diffusely reflected in the integrating sphere and then emitted from another compensation port of the integrating sphere, and then transmitted Pass through the optical fiber panel 9 to be tested, then from the resolution target 5 to the microscopic objective lens, and then from the microscopic objective lens to the eyepiece, and finally enter the human eyeball.

The standard light source 1 and the steady flow source 2 provide 2856K standard light with stable intensity and color temperature. After passing through the condenser lens 3, the light source has been converged due to the light-gathering effect of the condenser lens 3. Then adjust the metal panel of the moving mechanism of the integrating sphere 4 XY coordinates, so that the converged light enters the interior of the integrating sphere through a compensation port of the integrating sphere, and the integrating sphere uniformly diffuses the light beam and illuminates the resolution target 5 at the uniformly diffused exit.

As shown in Figure 2, at any moment, the potential of the resolution target 5 has nothing to do with the Z axis, and can be calculated as a two-dimensional problem, so the potential of any point in the target must be determined by the two-dimensional Laplace equation and the corresponding boundary conditions:

;

;

;

in is the thickness of the resolution target 5, is the target surface potential distribution, is the target pressure. because You may have Respectively satisfying a linear superposition of two-dimensional Laplace squares with homogeneous boundary conditions can lead to the final expression as:

,

in respectively The derived coefficient of is a hyperbolic sine function, and , C is the contrast of the target, I is the current photocurrent, is the reference current of the target, in order to maintain a high precision, a resolution target with a contrast ratio greater than 90% is used, and the influence caused by the charge leakage can be ignored at this time. When there is a shadow point there, the electric potential is zero, so this method can uniquely determine the coordinates of x and y. Adjust the Z coordinate of the microscopic objective lens manually or automatically until a clear image can be observed through the microscope eyepiece, the microscopic objective lens will enlarge the partial panel pattern, and the microscopic eyepiece can be directly observed by the human eye. At the same time, the microscope observation system has a CCD interface, and is equipped with a CCD acquisition card to collect the analog data of the image, which is processed and calculated by a microcomputer to output the required results.

The actual situation can be based on the parameter requirements of the resolution of the light panel, and there are two methods:

1) Replace the microscopic magnification eyepieces (10X, 16X, etc.) and achromatic eyepieces (5X, 10X, 40X, etc.), and observe through the microscopic eyepieces to directly judge the resolution of different areas of the fiber optic panel;

2) To give quantitative data images, the CCD interface can be connected with peripheral microcomputer equipment. Through CCD data acquisition, calculation and processing, the output data comprehensive parameter report.

Claims (6)

1. An optical fiber panel limit resolution test instrument based on shadow removal, including: standard light source (1) and its steady current source (2), condenser lens (3), integrating sphere (4) and its moving mechanism, resolution target (5), and CCD data acquisition and microcomputer processing system (8), characterized in that: the resolution target (5) is set on the uniform diffuse outlet of the integrating sphere (4); the optical fiber panel to be tested (9 ) between the resolution target (5) and the uniform diffusion outlet of the integrating sphere (4); the condenser lens (3) is a quartz condenser lens. 2 . The optical fiber panel limit resolution testing instrument based on shadow removal according to claim 1 , wherein the distance between the standard light source ( 1 ) and the condenser lens ( 3 ) is smaller than the focal length of the condenser lens ( 3 ). 3 . 3. The optical fiber panel limit resolution test instrument based on shadow elimination according to claim 1, characterized in that: the integrating sphere (4) is a hollow sphere coated with non-wavelength-selective diffuse reflective white paint inside . 4. The optical fiber panel limit resolution test instrument based on shadow removal according to claim 1, characterized in that: the moving mechanism is a metal sliding table connected with the integrating sphere (4), and its periphery is marked with scale. 5. The optical fiber panel limit resolution test instrument based on shadow removal as claimed in claim 4, characterized in that: it also includes a microscope observation system (6), the microscope observation system (6) has a CCD interface, and its objective lens is aligned with The optical fiber panel to be tested (9). 6. A method for testing the limit resolution of an optical fiber panel based on shadow removal, comprising the steps of: Set the optical fiber panel (9) to be tested between the resolution target (5) and the uniform diffuse outlet of the integrating sphere (4); The monochromatic light emitted by the standard light source (1) passes through the condenser lens (3), and then enters a compensation port of the integrating sphere (4); Afterwards, the incident light is diffusely reflected in the integrating sphere (4) and then emitted from another compensation port of the integrating sphere (4); Then transmit through the optical fiber panel to be tested (9) and the resolution target (5) to the microscope objective lens, At any moment, the potential of any point within the resolution target (5) Determined by the two-dimensional Laplace equation and the corresponding boundary conditions: ; ; ; in is the thickness of the resolution target (5), is the surface potential distribution of the resolution target (5), is the target pressure; because have Respectively satisfying a linear superposition of two-dimensional Laplace squares with homogeneous boundary conditions can lead to the final expression as: , in respectively The derived coefficient of is the hyperbolic sine function; When there is a shadow point somewhere, the electric potential is zero, and the coordinates of x and y can be uniquely determined.