CN104897369A - Lens diopter Moire measuring device and measuring method - Google Patents

Abstract

The invention discloses a lens diopter Moire measuring device and a measuring method based on the device. The measuring device comprises a light source, a beam expanding lens, a diopter compensating lens, a first optical grating, a second optical grating, a strip receiving unit, a strip collecting unit and a strip analyzing unit. The measuring method comprises steps of measuring device adjustment, image acquisition and image processing. In the measuring device, a semiconductor laser with a larger divergence angle outputs the light source in a manner of optical coupling, thereby improving quality of optical beams. The measuring device is simple in structure, lower in cost, firmer and simpler to operate and maintain, and requires less on working environment. In the measuring method, the lens diopter compensating mechanism is added in front of a to-be-measured lens, so while the identification precision of Moire strips is ensured, diopter measuring range of the measuring device is extended.

Description

Lens refractive power mole measuring device and measuring method

Technical field

The invention belongs to consumer applying electronic field, be specifically related to a kind of lens refractive power mole measuring device and measuring method.

Background technology

The noncontact optic measurement technique that More's (Moir é) effect and Taibo (Talbot) effect combine as one by Moire measuring method, there is full filed and non-contacting advantage, and industry and civil area many in obtain application.

The measurement of traditional monochromatic light, two light and three light microscopic sheets is all both at home and abroad generally use two kinds of lensmeters (are also called dioptometer, look into sheet instrument, eyeglass estimate instrument etc.): focusing imaging type lensmeter and automatic lensometer.This quasi-instrument can only be analyzed of an eyeglass zonule, measures the optical properties such as the diopter of the eyeglass representated by this regional center.Monochromatic light, two light and three light microscopic sheets have identical diopter (not considering that aberration and picture move) due to them in the scope of definition, adopt above-mentioned two class diopter instruments (lensmeter) to be just easy to detect.

Be different from traditional monochromatic light, two light and three light microscopic sheets, the surface distributed of progressive multi-focus lens numerous focus, and diopter is all not identical within the scope of whole bore, and, its face shape is also different from common aspheric surface, is a kind of nonaxisymmetrical surface of revolution.Therefore, for this type of eyeglass, point or the bus of only measuring minority are far from being enough for the whole eyeglass of evaluation.For progressive multi-focus lens, domestic done research work is less, has many countries once to do a large amount of scientific researches abroad in this regard, but up to now, examination criteria still ununified in the world and measuring method.

Summary of the invention

The object of the invention is the above-mentioned defect existed when measuring lens refractive power to solve existing Moire measuring method, proposing a kind of lens refractive power mole measuring device.

The technical solution used in the present invention is: a kind of lens refractive power mole measuring device, comprises light source 1, extender lens 2, diopter compensation eyeglass 3, first grating 5, second grating 6, striped receiving element 7, Fringe Acquisition unit 8 and fringe analysis unit 9;

Described light source 1 will produce collimated light beam after extender lens 2, tested eyeglass is placed on diopter and compensates between eyeglass 3 and the first grating 5, first grating 5 and the second grating 6 keep fixing Distance geometry angle, Fringe Acquisition unit 7 takes at striped the Moire fringe that unit 7 produces after taking the first grating 5 and the second grating 6 overlap, after adding diopter compensation eyeglass 3 and tested eyeglass, Moire fringe deflects, Fringe Acquisition unit 8 is connected with fringe analysis unit 9, export Moire fringe image to fringe analysis unit to process, calculate lens refractive power distribution plan, described tested eyeglass left side and diopter compensate that eyeglass 3 right side overlaps, tested eyeglass right side overlaps with the first grating 5 left side.

In order to solve the problem, the invention allows for a kind of lens refractive power Moire measuring method, concrete steps are as follows:

The first step: measurement mechanism adjusts: fix the screen periods of the first grating 5 and the second grating 6, grating angle and talbot distance;

Second step: image acquisition: 1. tested eyeglass is placed on measuring position noted earlier, and observe the Moire fringe image in fringe analysis unit 9; Observe Moire fringe clearly if 2. fail, then change diopter successively from small to large according to diopter and compensate eyeglass 3 until Fringe Acquisition unit 8 can capture moiré topography clearly;

3rd step: image procossing: the Moire fringe image of fringe analysis unit 9 to input processes, and calculates the diopter distribution plan obtaining tested eyeglass.

The above-mentioned image procossing detailed process described in the 3rd step is:

(31) image enhaucament, binaryzation, refinement are carried out to Moire fringe image, obtain the Moire fringe of single pixel wide degree;

(32) for the Moire fringe of single pixel wide degree that single vision lenses uses fitting a straight line step (31) to obtain, the Moire fringe homogenous segmentations of the single pixel wide degree that step (31) is obtained by many light microscopics sheet with curve; The striped deflection slope at each point place on Moire fringe can be obtained after striped matching;

(33) the three-dimensional distributed data at random of lens refractive power value is calculated according to striped deflection slope and the relation of lens refractive power;

(34) surface fitting is carried out to the three-dimensional distributed data at random of the lens refractive power value that step (33) obtains, obtain the diopter distribution plan of eyeglass.

Beneficial effect of the present invention: the semiconductor laser coupling fiber output light source adopting the angle of divergence larger in device of the present invention, improves measuring beam quality.Structure is comparatively simple, and price is lower, firmer, and operating environment requirements is lower, and operation and maintenance is all simpler.Method of the present invention adds lens refractive power compensation mechanism in tested eyeglass front, improves the diopter measurement scope of measurement mechanism while ensure that Moire fringe accuracy of identification.

Accompanying drawing explanation

Fig. 1 is the structural representation of lens refractive power measurement mechanism of the present invention;

Fig. 2 is the stop position schematic diagram of lens refractive power measurement mechanism of the present invention;

Fig. 3 is the schematic diagram of lens refractive power measuring method of the present invention.

Embodiment

Details are as follows by reference to the accompanying drawings for the specific embodiment of the present invention:

As shown in Figure 1, lens refractive power mole measuring device of the present invention comprises light source 1, extender lens 2, diopter compensation eyeglass 3, first grating 5, second grating 6, striped receiving element 7, Fringe Acquisition unit 8 and fringe analysis unit 9, light source 1 is that semiconductor laser is obtained by coupling fiber output, using this monochromatic visible light source as eyeglass lens measurement light source; Extender lens 2 is two gummed achromat, and pointolite is positioned over extender lens focus place, and pointolite produces collimated light beam after extender lens; Described compensation eyeglass 3 is the plano-convex lens of single focal length; Tested eyeglass is positioned over and compensates between eyeglass and the first grating 5, and tested eyeglass left side and diopter compensate, and eyeglass 3 right side overlaps, tested eyeglass right side overlaps with the first grating 5 left side; First grating 5 and the second grating 6 keep fixing Distance geometry angle, here, as a preferred version, second grating 6 is positioned at the first talbot distance place, one, grating 5 downstream, and relative to the first grating 5 at xy plane internal rotation gyration θ, described θ angle (comprises 0 ° and 5 °) between 0 ° and 5 °, and the second grating 6 overlappingly with the Taibo picture of the first grating 5 can produce Moire fringe; Striped receiving element 7 is made for environmental protection organic material, and high-transmission rate, can make Moire fringe reside at screen surface; Described Fringe Acquisition unit 8 can take the Moire fringe image that projection screen is formed; Fringe Acquisition unit 8 is connected with fringe analysis unit 9, exports Moire fringe image to fringe analysis unit and processes, calculate lens refractive power distribution plan.

Here, light source 1 is the light source of optical system; Extender lens 2, as optical repeater system, produces and the collimated light beam measuring the equal bore of eyeglass; Diopter compensates eyeglass 3 as measurement range bucking-out system, can improve diopter measurement scope; First grating 5 can produce periodic Taibo picture under incident light irradiates at talbot distance place; Second grating 6 can be and the identical grating of the first grating, overlappingly with the first grating 5 can produce Moire fringe.

Striped receiving unit 7 is striped receiving element, and light beam produces shadow pattern by receiving on Unit 7 at striped after the first grating 5 and second grating 6; Fringe Acquisition unit 8 is for gathering Moire fringe image and transferring to fringe analysis unit; Fringe analysis unit 9 is for the treatment of the various stripe pattern collected and parse stripe information, obtains lens refractive power distribution plan.

Here, the first grating 5 can be identical with the screen periods p of the second grating 6, and p size is between 0.1mm to 0.5mm, comprises 0.1mm and 0.5mm.

Here, pointolite 1 wavelength X is visible wavelength.

Here, it is a slice eyeglass chosen in the single vision lenses of one group of accurate calibration that diopter compensates eyeglass 3, and this lens set comprises 8 eyeglasses, and diopter is followed successively by-7D ,-5D ,-3D ,-1D, 1D, 3D, 5D and 7D.

As shown in Figures 2 and 3, based on said apparatus, lens refractive power Moire measuring method of the present invention, step is as follows:

The first step: measurement mechanism adjusts: determine the screen periods p of the first grating 5 and the second grating 6, grating angle theta and talbot distance z _k.

First grating 5 and the second grating 6 intersect fixed angle and vertically to place with distance, and the Taibo picture of the first grating 5 and the second grating 6 overlap on striped receiving element 7 and form Moire fringe.Fringe Acquisition unit 8 is positioned at projection screen rear, and Fringe Acquisition unit 8 can record the Moire fringe image that projection screen is formed.

Second step: image acquisition:

If the first grating (5) is p with the screen periods of the second grating (6) ₁=p ₂=p, angle theta, talbot distance is Z _kand k is the threshold coefficient preset.

Place tested eyeglass, place diopter and compensate eyeglass 3, when penetrating the first grating 5 with single color plane illumination, the first grating 5 is at talbot distance Z _kplace's imaging, namely coplanar with the second grating 6, on striped receiving element 7, form light and dark Moire fringe after the Taibo picture of the first grating 5 is overlapping with the second grating 6 and fringe period is w, inclination angle is if the focal length of tested eyeglass is f, the focal length that diopter compensates eyeglass 3 is f ^', the combined focal length that tested eyeglass and diopter compensate eyeglass 3 is F, namely has:

$w=\frac{p_1{p}_2}{{(p_1^2+p_2^2-2p_1{p}_2\cos \mathrm{\θ})}^{1/2}}$ Formula (1)

$\cos \mathrm{\φ}=\frac{p_1\sin \mathrm{\θ}}{{(p_1^2+p_2^2-2p_1{p}_2\cos \mathrm{\θ})}^{1/2}}$ Formula (2)

At distance Z _kplace, the Taibo of G1 Ronchi grating (5) as the cycle is: p ' ₁=[(F-Z _k)/F] p ₁.

From the ultimate principle of Moire deflectometry, in conjunction with the concept of lens refractive power, combine with grating shading shade principle according to Tabo effect and can derive the Moire fringe inclination angle after distortion and the dioptric relation of combined lens, namely have:

$D(x,y)=\frac{\mathrm{\λ}}{{\mathrm{kp}}^2}\[\sin \mathrm{\θ}\tan {\mathrm{\φ}}_k(x,y)+\cos \mathrm{\θ}-1\]$ Formula (3)

Can be obtained by the principle of two combination computation of optical components system:

$f=\frac{\mathrm{\Δ}}{f\′D}$ Formula (4)

Wherein, Δ is the optical interval that tested eyeglass and diopter compensate between eyeglass 3.

The relation at lens refractive power and Moire fringe inclination angle can be measured by formula (3) and (4), namely have:

$d(x,y)=\frac{f^{\′}\mathrm{\λ}}{{\mathrm{kp}}^2\mathrm{\Δ}}\[\sin \mathrm{\θ}\tan {\mathrm{\φ}}_k(x,y)+\cos \mathrm{\θ}-1\]$ Formula (5)

3rd step: image procossing: the Moire fringe image of fringe analysis unit 9 to input processes, and calculate the diopter distribution plan obtaining tested eyeglass, detailed process is as follows:

(31) image enhaucament, binaryzation, refinement are carried out to Moire fringe image, obtain the Moire fringe of single pixel wide degree;

(32) for the Moire fringe of single pixel wide degree that single vision lenses uses fitting a straight line step (31) to obtain, the Moire fringe homogenous segmentations of the single pixel wide degree that step (31) is obtained by many light microscopics sheet with curve; The striped deflection slope at each point place on Moire fringe can be obtained after striped matching.

(33) deflect the relation of slope and lens refractive power according to striped, namely calculated the dioptric optical value of each point on striped by formula (5), and then the three-dimensional obtaining lens refractive power value distributed data at random;

(34) surface fitting is carried out to the three-dimensional distributed data at random of the lens refractive power value that step (33) obtains, obtain the diopter distribution plan of eyeglass.

Here, the three-dimensional of cubic spline interpolation to lens refractive power value distributed data at random specifically can be used to carry out surface fitting.

Those of ordinary skill in the art will appreciate that, embodiment described here is to help reader understanding's principle of the present invention, should be understood to that protection scope of the present invention is not limited to so special statement and embodiment.Those of ordinary skill in the art can make various other various concrete distortion and combination of not departing from essence of the present invention according to these technology enlightenment disclosed by the invention, and these distortion and combination are still in protection scope of the present invention.

Claims (3)

1. a lens refractive power mole measuring device, it is characterized in that, comprise light source (1), extender lens (2), diopter compensation eyeglass (3), the first grating (5), the second grating (6), striped receiving element (7), Fringe Acquisition unit (8) and fringe analysis unit (9);

Described light source (1) will produce collimated light beam after extender lens (2), tested eyeglass is placed on diopter and compensates between eyeglass (3) and the first grating (5), first grating (5) and the second grating (6) keep fixing Distance geometry angle, Fringe Acquisition unit (7) takes over the upper Moire fringe produced of unit (7) at striped after taking the first grating (5) and the second grating (6) overlap, after adding diopter compensation eyeglass (3) and tested eyeglass, Moire fringe deflects, Fringe Acquisition unit (8) is connected with fringe analysis unit (9), export Moire fringe image to fringe analysis unit to process, calculate lens refractive power distribution plan, described tested eyeglass left side and diopter compensate that eyeglass (3) right side overlaps, tested eyeglass right side overlaps with the first grating (5) left side.

2., based on a lens refractive power Moire measuring method for measurement mechanism according to claim 1, it is characterized in that, concrete steps are as follows:

The first step: measurement mechanism adjusts: fix the screen periods of the first grating (5) and the second grating (6), grating angle and talbot distance;

Second step: image acquisition: 1. tested eyeglass is placed on measuring position noted earlier, and observe the Moire fringe image in fringe analysis unit (9); Observe Moire fringe clearly if 2. fail, then change diopter successively from small to large according to diopter and compensate eyeglass 3 until Fringe Acquisition unit (8) can capture moiré topography clearly;

3rd step: image procossing: the Moire fringe image of fringe analysis unit (9) to input processes, and calculates the diopter distribution plan obtaining tested eyeglass.

3. lens refractive power Moire measuring method according to claim 2, is characterized in that, the image procossing detailed process described in the 3rd step is:

(31) image enhaucament, binaryzation, refinement are carried out to Moire fringe image, obtain the Moire fringe of single pixel wide degree;

(32) for the Moire fringe of single pixel wide degree that single vision lenses uses fitting a straight line step (31) to obtain, the Moire fringe homogenous segmentations of the single pixel wide degree that step (31) is obtained by many light microscopics sheet with curve; The striped deflection slope at each point place on Moire fringe can be obtained after striped matching;

(33) the three-dimensional distributed data at random of lens refractive power value is calculated according to striped deflection slope and the relation of lens refractive power;

(34) surface fitting is carried out to the three-dimensional distributed data at random of the lens refractive power value that step (33) obtains, obtain the diopter distribution plan of eyeglass.