Color coding-based reverse Hartmann type profile measuring method

Abstract

The invention relates to a color coding-based reverse Hartmann type profile measuring method which comprises the following steps: replacing a diaphragm array by a picture generator based on a light reversibility principle; firstly, by utilizing ideal parameters of a measured piece, simulating and calculating a corresponding relation between pixels on a CCD (Charge Coupled Device) and points on the picture generator by a computer, thereby generating colored pictures having gradients between adjacent pixel points and being one-to-one corresponding to pixels on the CCD by the computer; converting the generated colored pictures according to the corresponding relation, thereby generating the colored pictures to be displayed on the picture generator and displaying the colored pictures after being inputted into the picture generator; secondly, utilizing the measured piece to measure the pixels of the lights which are sent from the points on the picture generator and are emitted into the CCD after being reflected by the measured piece; and searching for the points on the picture generator corresponding to the pixels, thereby acquiring the gradients of lights and reconstructing the profileof the measured piece.

Description

technical field [0001] The invention belongs to the technical field of optical detection, and in particular relates to a reverse Hartmann surface shape measurement method based on color coding. Background technique [0002] The surface shape of optical parts is one of the key parameters affecting the imaging quality of the optical system. During the production process, it is necessary to continuously measure the surface shape to control the change of the surface shape of the part within a reasonable range. After the part is finished or in the assembly process, it is necessary to measure its surface shape more accurately in order to evaluate and control the imaging quality of the entire system. [0003] The surface shape measurement methods of optical parts are mainly divided into interferometric methods and geometric methods. Among them, the Hartmann method in the quantitative measurement geometric method has the advantages of simple system, stable, low cost, and no need to...

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Problems solved by technology

[0004] However, the Hartmann method has the following three problems: First, because the Hartmann method is based on the relatively small change in the surface slope and uses a sparse aperture stop, each light on the detection surface except for the position In addition to the difference, there is no difference in other aspects such as brightness and color. If the surface slope of the tested part changes greatly, the light will cross and alias on the detection surface, resulting in incorrect detection and recognition. Therefore, it must be detected at a certain defocus Surface detection, so that the light rays can be separated from each other and do not cross each other on the detection surface

Second, in order to improve the measurement resolution, the Manhattan method needs to increase the number of aperture arrays, but with the increase of the number of aperture arrays, the area occupied by each sub-beam will decrease, that is, the dynamic range will decrease, then The slope of the measurable surface shape is reduced; so the existing detection methods are difficult to improve the spatial resolution and dynamic range at the same time

Third, the arrangement of the diaphragm array of the existing Hartmann method cannot be changed at will. Every time the arrangement of the diaphragm array is changed or the number of diaphragms is changed, the diaphragm must be remade, which is poor in versatility.

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