CN110864649A - Method for determining compensation value and determining flatness of optical module - Google Patents

Abstract

The invention discloses a method for determining a compensation value. The method comprises the following steps: providing an optical module to be tested and setting a calibration plate; enabling the optical module to be measured positioned in the placement area to be arranged over against the central calibration point, enabling the optical module to be measured to emit light rays, enabling the light rays to be emitted to the central calibration point to obtain a distance value between the central calibration point and the optical module to be measured, and enabling the distance value between the central calibration point and the optical module to be measured to serve as a reference value; enabling the light rays to be emitted to a plurality of edge calibration points to obtain a plurality of actual distance values between the edge calibration points and the optical module to be tested; taking the center index point as a coordinate origin, and performing surface fitting on a plurality of edge index points and a plurality of actual distance values according to a reference value to obtain a fitting equation; the fitting equation is configured to determine compensation values for a plurality of the edge calibration points. The invention adopts a fitting method to determine the compensation value, and improves the accuracy of the flatness in the optical module.

Description

A method for determining compensation value and determining flatness of optical module

technical field

The invention relates to the field of optics, in particular to a method for determining a compensation value and determining the flatness of an optical module.

Background technique

The flatness of the optical module is an inherent characteristic of the optical module, and the flatness algorithm stored in the optical module is usually used to verify the flatness of the optical module.

In the prior art, the determination of the compensation value in the flatness algorithm is usually determined by the offset compensation method; different distance values are obtained according to the distances from the optical module to different calibration points, and then the distance difference value is obtained; wherein the distance difference value is the compensation value, However, this method can only obtain the compensation values of some specific calibration points. Therefore, in the process of verifying the flatness of the optical module, the image obtained by the optical module is not accurate, and the flatness of the optical module is also inaccurate.

In order to solve the above technical problems, the present invention provides a method for determining a compensation value and verifying the flatness of an optical module.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method for determining a compensation value and determining the flatness of an optical module.

According to a first aspect of the present invention, there is provided a method for determining a compensation value, the method comprising the following steps:

providing a placement area configured to place the optical module to be tested;

Setting up a calibration plate, the calibration plate has calibration points, the calibration points include a center calibration point, and a plurality of edge calibration points, and the center calibration point is located at the geometric center of the calibration plate;

The optical module to be measured located in the placement area is set facing the center calibration point, so that the optical module to be measured emits light, and the light hits the center calibration point to obtain the center calibration point and the center calibration point. the distance value between the optical modules to be measured, and the distance value is used as a reference value;

Make the light radiate to a plurality of the edge calibration points to obtain a plurality of actual distance values between the edge calibration points and the optical module to be measured;

The center calibration point is used as the origin of coordinates, and according to the reference value, a plurality of the edge calibration points and a plurality of actual distance values are subjected to surface fitting to obtain a fitting equation;

The fitting equation is configured to determine compensation values for a plurality of the edge calibration points.

Optionally, the surface of the calibration plate is flat.

Optionally, a plurality of the edge mark points are located around the center mark point.

Optionally, the fitting equation is a surface equation.

Optionally, the parameters in the fitting equation are determined according to the least squares method.

According to another aspect of the present invention, there is provided a method for determining the flatness of an optical module using the method described above, the method comprising the following steps:

causing the fitting equation to be set in the processor of the optical module;

setting the optical module on which the fitting equation has been set relative to the subject;

The subject has the center calibration point and a plurality of the edge calibration points; a plurality of the edge calibration points are obtained by making a difference between the actual distance value corresponding to the plurality of the edge calibration points and the reference value. compensation value;

The optical module for which the fitting equation has been set emits light to the subject, and the first image obtained by the optical module is compensated according to a plurality of the compensation values to obtain a second image;

The second image is configured to indicate the flatness of the optical module for which the fitting equation has been set.

Optionally, the second image is configured as an image actually displayed by the optical module, and the second image is a plane.

Optionally, the first image is stretched according to a plurality of the compensation values to obtain the second image.

Optionally, the coordinate values respectively corresponding to the center calibration point and the plurality of edge calibration points are known variables in the fitting equation.

Optionally, a flatness algorithm is set in the processor of the optical module, and the fitting equation is set in the flatness algorithm.

Beneficial effects of the present invention: The present invention provides a method for determining the compensation value and determining the flatness of the optical module. The present invention obtains the fitting equation by using the surface fitting method to obtain the equation for determining the compensation value, and then obtains different equations according to the fitting equation. Different compensation values at the calibration point are used to compensate the image obtained by the optical module to obtain a compensated image. The invention makes the compensation values at different calibration points more accurate, and at the same time improves the precision of the flatness in the optical module.

Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

FIG. 1 is a schematic diagram of a method for determining a compensation value in the prior art.

FIG. 2 is a schematic diagram of the method for determining the compensation value of the present invention.

3 is a schematic diagram of a first image obtained by the optical module of the present invention.

FIG. 4 is a schematic diagram of a second image presented after compensation by the optical module of the present invention.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

In all examples shown and discussed herein, any specific values should be construed as illustrative only and not limiting. Accordingly, other instances of the exemplary embodiment may have different values.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further discussion in subsequent figures.

According to an embodiment of the present invention, as shown in FIG. 2, a method for determining a compensation value is provided, and the method includes the following steps:

providing a placement area configured to place the optical module 102 to be tested;

A calibration plate 101 is provided, the calibration plate 101 has calibration points, the calibration points include a center calibration point 0, and a plurality of edge calibration points, and the center calibration point 0 is located at the geometric center of the calibration plate;

The optical module 102 to be tested located in the placement area is set facing the center calibration point 0, so that the optical module 102 to be tested emits light, and the light hits the center calibration point 0 to obtain the center The distance value between the calibration point 0 and the optical module 102 to be measured, the distance value is used as a reference value;

Make the light radiate to a plurality of the edge calibration points to obtain a plurality of actual distance values between the edge calibration points and the optical module to be measured;

The center calibration point 0 is used as the origin of coordinates, and according to the reference value, a plurality of the edge calibration points and a plurality of actual distance values are subjected to surface fitting to obtain a fitting equation;

The fitting equation is configured to determine compensation values for a plurality of the edge calibration points.

In the prior art, the offset compensation method is usually used to determine the compensation value at the edge calibration point.

Specifically, as shown in FIG. 1 , a schematic diagram of determining the compensation value at the edge calibration point in the prior art, wherein the horizontal axis represents the coordinate value of the calibration point on the calibration board, and the vertical axis represents the distance value corresponding to the calibration point.

Among them, 0 point represents the center calibration point, a represents the distance value corresponding to the center calibration point at 0 point; 1 point and 2 points represent the edge calibration point respectively, b represents the distance value corresponding to the edge calibration point at 1 point, and c represents 2 The distance value corresponding to the edge calibration point at the point. In the prior art, only the compensation value at a specific edge calibration point can be obtained.

Specifically, the distance between the center calibration point and the optical module to be measured is 1 m (that is, a is 1 m), and the distance between the edge calibration point at 1 point and the optical module to be measured is 1.2 m (that is, b is 1.2m), then the compensation value at the edge calibration point at point 1 is 0.2; at this time, it is considered that the point 0 is used as the circle point, and the distance length from 1 point to point 0 is the radius of the circle formed by the calibration point. The compensation value is 0.2;

The distance between the edge calibration point at 2 points and the optical module to be tested is 1.4m (that is, c is 1.4m), then the compensation value of the edge calibration point at 2 points is 0.4; The compensation value of the calibration point on the circle formed by the distance between the 2 points and the 0 point is 0.4; the distance between the 2 points and the 0 point is twice the distance between the 1 point and the 0 point. .

By analogy, the distance between the edge calibration point at 3 points on the horizontal axis and the optical module to be tested is 1.6m, and the compensation value of the edge calibration point at 3 points is 0.6. The distance between 3 points and 0 point is 3 times the distance between 1 point and 0 point.

However, in the prior art, the compensation value of the calibration point is only obtained by measuring the distance values at a certain number of calibration points, and the compensation value at other calibration points is obtained by analogy; however, the compensation value obtained by analogy is not accurate; and The compensation value at other edge calibration points between the 0-point center calibration point and the 1-point edge calibration point cannot be determined in the prior art, so in the prior art, only the compensation value at a specific edge calibration point can be obtained, and the specific edge calibration point can only be obtained. The compensation value at the edge calibration point is an arithmetic progression (in fact, the compensation value obtained in this way is inaccurate). The image is compensated, so that the flatness of the final optical module is not accurate.

The “specific edge calibration point” is defined as taking the center calibration point as the center point, the distance between the edge calibration point closest to the center calibration point and the center calibration point is the reference value, and the distance between two other adjacent edge calibration points is the same as If the reference values are equal, the edge calibration point is a specific edge calibration point. The edge calibration point at point 1 and the edge calibration point at point 2 in Figure 1 are specific edge calibration points, and the edge calibration point between the center calibration point at point 0 and the edge calibration point at point 1 is a non-specific edge calibration point.

In this example, when determining the compensation value at the edge calibration point, the center calibration point is used as the coordinate origin, and according to the reference value, a plurality of the edge calibration points and a plurality of actual distance values are subjected to surface fitting to obtain the approximate a fitting equation; the fitting equation is configured to determine compensation values for a plurality of the edge calibration points. In this example, the compensation value at any edge calibration point can be determined according to the fitting equation. When the fitting equation is applied to the optical module, the flatness of the optical module can be improved.

Specifically, the present invention uses the center calibration point as the coordinate origin to establish a coordinate system, wherein the calibration point is used as the horizontal axis of the coordinate system, and the distance value and actual distance value corresponding to the center coordinate point are used as the vertical axis of the coordinate system.

The center calibration point, the distance value corresponding to the center calibration point, the multiple edge calibration points and the actual distance values measured by the multiple edge calibration points are subjected to surface fitting to obtain a fitting equation.

Optionally, in order to make the fitting equation more accurate, a plurality of actual distance values are usually measured; for example, 20 to 40 actual distance values may be obtained by measuring 20 to 40 edge calibration points.

Optionally, the parameters in the fitting equation are determined according to the least squares method.

For example, if the fitted image obtained by the surface fitting method is roughly parabolic, the fitting equation is determined as:

Use the least squares method to obtain the parameters given in the fitting equation, where the parameters in formula (1) are the values of the three coefficients a, b, and c, and then obtain an accurate fitting equation.

Optionally, a fitted image is obtained according to the distance value and the actual distance value, wherein the fitted image is not limited to an elliptical paraboloid, but can also be a curved surface in other forms. For example, the fitting equation is a curved surface equation, and the curved surface equation includes a cylindrical surface, a hyperbolic cylindrical surface, an elliptical cylindrical surface, and the like.

In one example, as shown in FIG. 2 , the light source illuminating the calibration plate 101 by the optical module to be tested 102 is divergent, that is, when the optical module to be tested emits light, the light radiates to the central calibration point to obtain the When the distance value between the center calibration point and the optical module to be measured is determined, a plurality of actual distance values between a plurality of edge calibration points and the optical module to be measured can also be obtained at the same time. The optical module to be tested is configured to be electrically connected to an external computer, and the external computer can record and display the distance value and a plurality of actual distance values; or the optical module to be tested is configured to be able to compare the distance value and the actual distance value. Several actual distance values are stored in its memory and displayed via its display.

Optionally, a plurality of the edge calibration points are located around the center calibration point, for example, as shown in FIG. 2 , the calibration point at 1 point, the calibration point at 2 o’clock, and the calibration point at 4 o’clock to 10 o’clock Both are edge calibration points.

Optionally, a plurality of the edge calibration points are evenly distributed on the calibration plate in an array manner. As shown in Figure 2, point 0 is represented as the center calibration point, points 1, 2, 4-10 are represented as edge calibration points, wherein the center calibration point is located at the geometric center of the calibration plate 101, and the edge calibration plate is in a rectangular array Or evenly distributed in a circular array.

Optionally, the surface of the calibration plate 101 is flat. Specifically, when the calibration plate 101 and the optical module to be measured 102 are disposed opposite to each other, the surface of the calibration plate 101 facing the optical module to be measured 102 is flat. That is, the surface of the calibration plate 101 is flat and straight, which improves the accuracy of the compensation value at the edge calibration point, thereby improving the accuracy of the flatness of the optical module.

According to another aspect of the present invention, there is provided a method for determining the flatness of an optical module by using the above-mentioned method for determining a compensation value, the method comprising the following steps:

causing the fitting equation to be set in the processor of the optical module;

setting the optical module on which the fitting equation has been set relative to the subject;

The subject has the center calibration point and a plurality of the edge calibration points; a plurality of the edge calibration points are obtained by making a difference between the actual distance value corresponding to the plurality of the edge calibration points and the reference value. compensation value;

The optical module for which the fitting equation has been set emits light to the subject, and the first image obtained by the optical module is compensated according to a plurality of the compensation values to obtain a second image;

The second image is configured to indicate the flatness of the optical module for which the fitting equation has been set.

Specifically, as shown in FIGS. 3 to 4 , when the flatness of the optical module to be measured is determined by using the method for determining the compensation value described above, the fitting equation obtained in the method for determining the compensation value is set in the The processor of the optical module is used for compensating the first image obtained by the optical module.

For example, a flatness algorithm is set in the processor of the optical module, and the fitting equation is set in the flatness algorithm.

When determining the flatness of the optical module to be measured, the optical module on which the fitting equation has been set is set relative to the object to be photographed; for example, the object to be photographed may be a curtain or the like. The optical modules involved in this example are all "optical modules for which the fitting equation has been set".

The object to be photographed and the optical module are arranged opposite to each other. Specifically, a predetermined distance is set between the object to be photographed and the optical module, and the predetermined distance is configured to enable the light emitted by the optical module to irradiate the optical module. the edge of the subject. That is, the optical module can illuminate the panorama of the subject.

The selection of the predetermined distance is related to the size of the subject. In this example, the predetermined distance is 1m, that is, the vertical distance between the geometric center point of the subject and the optical modules is 1m.

The subject has a center calibration point and a plurality of edge calibration points; according to the fitting equation, the actual distance values corresponding to the plurality of edge calibration points and the reference value are made difference values to obtain a plurality of the edge calibration points. compensation value;

The center calibration point in the subject is located at the geometric center of the subject, and a plurality of edge calibration points are located around the center calibration plate.

Specifically, the optical module is made to emit light, the light is incident on the subject, and the first image obtained by the optical module is compensated according to a plurality of the compensation values to obtain a second image;

For example, when the optical module obtains the first image, the flatness algorithm in the processor in the optical module is automatically activated. At this time, the flatness algorithm already includes the fitting equation, and multiple edge calibration points are obtained through the fitting equation. The compensation value at the first image is compensated according to the compensation value.

Specifically, the subject has calibration points, the calibration points include a center calibration point and an edge calibration point, wherein the edge calibration points can cover the surface of the subject as much as possible. For example, the surface of the subject has an edge calibration point 2 and an edge calibration point 4-10. As shown in FIG. 3, the first image obtained by the optical module also has the edge calibration point 2, and the edge calibration point 4-10. Fixed point 4-10. The optical module emits light, and the light strikes the subject to obtain a first image, wherein the first image is not displayed on the display of the optical module.

Among them, according to the edge calibration point 2, and the compensation value at the edge calibration point 4-10, specifically, using the fitting equation, the edge calibration point 2, and the abscissa coordinate value corresponding to the edge calibration point 4-10 are brought into the simulation In the combined equation, the actual distance values corresponding to different edge calibration points are obtained respectively, and the difference between the obtained actual distance value and the distance value corresponding to the center calibration point 0 is obtained, and the compensation values corresponding to different edge calibration points are obtained respectively. The first image obtained by the module is compensated to obtain a second image. As shown in Figure 4, for the second image obtained after compensating the first image,

The coordinate values corresponding to the center calibration point and a plurality of the edge calibration points are known variables in the fitting equation, that is, the coordinate value of any edge calibration point on the subject can be established according to the center calibration point. The coordinate system is obtained.

Specifically, when the optical module to be tested obtains the first image, the flatness algorithm in the processor in the optical module to be tested is automatically activated. At this time, the flatness algorithm already includes the equation for determining the compensation value in the present invention, and by determining The equation of compensation value compensates the first image.

For example, the first image obtained by the optical module is shown in FIG. 3 , wherein the first image has the edge calibration point 2 corresponding to the object, and the edge calibration points 4 - 10 . The coordinate value corresponding to the edge calibration point is brought into the fitting equation, and the actual distance value corresponding to the edge calibration point is obtained. value.

For example, if the compensation value at the center calibration point 0 is 0, the first image does not perform image compensation here; the compensation value at the edge calibration point 2 is 0.1, then the first image is compensated by 0.1 here, that is, here The image is stretched upward by 0.1 at the edge calibration point 4; the compensation value at the edge calibration point 4 is 0.05, then the first image is compensated by 0.05 here, that is, the image is stretched upward by 0.05 here. In this way, the compensation value at any edge calibration point of the first image is calculated, and the image at any edge calibration point on the first image is compensated to obtain a compensated second image; as shown in FIG. 4 , wherein The compensated second image presented by the optical module, the second image is a plane, that is, the second image is flat and straight, and the second image is configured to mark the optical device for which the fitting equation has been set The flatness of the module.

Optionally, in this example, the compensation values at the edge calibration points are all positive values, that is, the compensation method is that the first image is stretched inward by 0.1 at the edge calibration points, where "inward" is perpendicular to the first image. The orientation of the image is stretched inward. When the compensation value at the edge calibration point is a negative value, that is, the compensation method is that the first image is stretched outward at the edge calibration point by 0.1, and "outward" means that the first image is pulled outward in the direction perpendicular to the first image. stretch.

The present invention adopts the surface fitting method to obtain the fitting equation, and the compensation value at any edge calibration point can be obtained according to the fitting equation, so that the compensation value at any calibration point is more accurate; meanwhile, the fitting equation is applied to the optical model. The accuracy of the flatness of the optical module has also been improved in the group.

Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are provided for illustration only and not for the purpose of limiting the scope of the present invention. Those skilled in the art will appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the invention is defined by the appended claims.

Claims (10)

1. a method for determining a compensation value, characterized in that the method comprises the following steps: providing a placement area configured to place the optical module to be tested; Setting up a calibration plate, the calibration plate has calibration points, the calibration points include a center calibration point, and a plurality of edge calibration points, and the center calibration point is located at the geometric center of the calibration plate; The optical module to be measured located in the placement area is set facing the center calibration point, so that the optical module to be measured emits light, and the light hits the center calibration point to obtain the center calibration point and the center calibration point. the distance value between the optical modules to be measured, and the distance value is used as a reference value; Make the light radiate to a plurality of the edge calibration points to obtain a plurality of actual distance values between the edge calibration points and the optical module to be measured; Using the center calibration point as the coordinate origin, and according to the reference value, a plurality of the edge calibration points and a plurality of actual distance values are subjected to surface fitting to obtain a fitting equation; The fitting equation is configured to determine compensation values for a plurality of the edge calibration points. 2. The method according to claim 1, wherein the surface of the calibration plate is a plane. 3 . The method of claim 1 , wherein a plurality of the edge calibration points are located around the center calibration point. 4 . 4. The method according to claim 1, wherein the fitting equation is a surface equation. 5. The method according to claim 1 or 4, wherein the parameters in the fitting equation are determined according to the least squares method. 6. A method for determining the flatness of an optical module using the method described in any one of claims 1-5, wherein the method comprises the following steps: causing the fitting equation to be set in the processor of the optical module; setting the optical module on which the fitting equation has been set relative to the subject; The subject has the center calibration point and a plurality of the edge calibration points; a plurality of the edge calibration points are obtained by making a difference between the actual distance value corresponding to the plurality of the edge calibration points and the reference value. compensation value; Shooting the light emitted by the optical module for which the fitting equation has been set to the subject, and compensating the first image obtained by the optical module according to a plurality of the compensation values to obtain a second image; The second image is configured to indicate the flatness of the optical module for which the fitting equation has been set. 7 . The method according to claim 6 , wherein the second image is configured as an image actually displayed by the optical module, and the second image is a plane. 8 . 8. The method according to claim 6, wherein the second image is obtained by stretching the first image according to a plurality of the compensation values. 9 . The method according to claim 6 , wherein the coordinate values corresponding to the center calibration point and a plurality of the edge calibration points respectively are known variables in the fitting equation. 10 . 10 . The method according to claim 6 , wherein a flatness algorithm is set in the processor of the optical module, and the fitting equation is set in the flatness algorithm. 11 .

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