JPH0593609A - Pitch measuring apparatus - Google Patents

Abstract

PURPOSE:To facilitate the removal of image-shaped noises, which are smaller than the minimum shading pitch size of a material under inspection without imposing a load on the processing capability of the hardware or software of an image processing part. CONSTITUTION:A light source part 1, which generated coherent light, and whose beam shape is shaped so that the beam can be cast on a material under inspection having the variable-density pattern, is provided. An optical-system lens part 3, which has the same intensity-distribution evaluation as the minimum variable-density pitch of the material under inspection 2 and forms the image of the material under inspection in an image part 4, is provided. Furthermore, the image input part 4 containing the photoelectric converter, an image processing part 5, which processes the electric signal outputted from the image input part 4, and an output part 6, which outputs the result of the image processing in the image processing part 5, are provided. Thus, the variable- density pitch of the material under inspection is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention facilitates noise removal in image processing as a pre-processing before obtaining calculation for pitch measurement when acquiring image information of an object to be inspected and measuring the density pitch thereof. The present invention relates to a pitch measuring device.

[0002]

2. Description of the Related Art Conventionally, when a pitch measuring device using image processing is used to measure the pitch of an object to be inspected having a light and shade pattern, an image input is performed for removing a noise component contained in image information from the object to be inspected. The electric signal from the unit is input to a filter configured by hardware or software, and only the image information is passed through the filter to perform preprocessing,
Then, after performing various calculations, it is common to output the final pitch measurement value to the output unit.

[0003]

In the pitch measuring device according to the above-mentioned conventional technique, the noise component of the electric signal is removed from the image information after the electric signal conversion by hardware or software by averaging, compression, expansion or the like. It takes time to perform image pre-processing before the calculation for pitch measurement. For this reason, it is difficult to measure the pitch in real time on the production line in mass production of the inspection object having the shade pattern. Further, it takes a lot of man-hours to develop the hardware or software required for the image pre-processing, which is one of the factors that increase the number of device development days.

An object of the present invention is to solve the above problems and to reduce the load on the image preprocessing of the pitch measuring apparatus using the image processing.

[0005]

A pitch measuring apparatus of the present invention comprises a light source section in which a beam shape is shaped so that coherent light of He-Ne, LD or the like can be generated and irradiated to an object to be inspected, and a photoelectric converter. An image input section including the image input section, an optical system lens section for forming an image of an object to be inspected on the image input section, an image processing section for processing an electric signal output from the image input section, and the image processing In a pitch measuring device for measuring the density pitch of an object to be inspected, which comprises an output section for outputting the image processing result of the image part, the optical system lens part has an intensity distribution of an image of the same level as the minimum density pitch dimension of the object to be inspected LineSp
read Function below, L. S. F. Called. ) Has an evaluation, noise on the image smaller than the minimum density pitch of the object to be inspected, without imposing a burden on the processing capability of the hardware or software of the image processing unit,
It is characterized by being easily removed.

[0006]

The pitch measuring apparatus of the present invention constructed as described above operates as follows. The light source unit used in the present invention is He-N.
Generates coherent light such as e and LD. The light beam from the light source unit illuminates the inspection object. The image of the object to be inspected passes through the optical system lens section of the present invention and is input to an image input section such as a CCD. The noise on the image that is smaller than the minimum density pitch size of the inspection object at this time is due to the L. S. F. The light and shade pitch information of the object to be inspected, which is attenuated by the evaluation, arrives at the image input unit without being substantially attenuated by the optical system lens unit of the present invention. Therefore, the load on the image pre-processing of the pitch measuring device using the image processing can be reduced. The image information input to the image processing unit is processed by the image processing unit and output to the display recording device or another device by the output unit.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the pitch measuring apparatus of the present invention. In this figure, the light source unit 1 is a He-Ne, L
The beam shape is shaped so as to generate coherent light such as D and irradiate the object to be inspected, and the transmitted light or the reflected illumination is used according to the state of the object to be inspected. Inspection object 2
Has a pitch of light and shade and is for measuring the pitch. The optical system lens unit 3 forms an image from the inspection object 2 on the image input unit and attenuates minute noises on the image due to scratches, dust, etc. existing on the inspection object 2 but not causing a quality problem. For this reason, the L.D.D. S. F. Adjustable to have a rating. For example, it can be configured by a Kepler type afocal lens group, a telecentric lens group, an optical diaphragm, and the like.

The image input section 4 converts the image data from the inspection object 2 into an electric signal and outputs it to the image processing section 5. The image processing unit 5 performs, if necessary, image pre-processing such as averaging processing and compression / expansion on the image signal of the inspection object 2 converted into an electric signal, and calculates measurement data. Therefore, the image preprocessing by the electric signal can be simplified and speeded up as compared with the conventional pitch measuring device using the image processing. Output unit 6
Outputs the image processing result to a CRT, a printer or another device.

FIG. 2 is an external view of a portion from the light source unit 1 to the image input unit 4 of the pitch measuring apparatus of the present invention. In the apparatus shown in FIG. 2, the light from the light source unit 1 illuminates the inspection object 2, and the pitch image of the inspection object 2 is input to the image input unit 4 through the optical system lens unit 3.

FIG. 3 is a diagram showing an output waveform from the image input unit 4, which is obtained by converting the image information of the inspection object 2 into an electric signal in the pitch measuring apparatus according to the present invention. FIG. 4 is a diagram showing a waveform obtained by converting image information from an object to be inspected into an electric signal in a conventional pitch measuring device. As is clear from this result, the image information by the pitch measuring device of the present invention is, compared with the image information by the device of the conventional example,
It can be seen that the waveform becomes smooth and the peaks due to noise on the small image due to dust, scratches, etc. are largely removed.

As described above in detail, in the pitch measuring apparatus of the present invention, the image information of the object to be inspected is measured in the optical system lens portion by the L.D. S.
F. In the evaluation, image information smaller than the minimum gradation pitch is attenuated, so that the load of the image preprocessing by the electric signal can be reduced, and the processing can be simplified and speeded up. This enables real-time pitch measurement on the inspection object manufacturing line and is effective for mass production. Further, since it is no longer necessary to pass through hardware or software filters for pitch measurement, and it took a long time to develop hardware or software in the related art, the number of device development days can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a pitch measuring device according to the present invention.

FIG. 2 is an external view of a portion from a light source unit to an image input unit of the pitch measuring device according to the present invention.

FIG. 3 is an output waveform diagram from an image input unit, which is obtained by converting image information of an object to be inspected into an electric signal in the pitch measuring device according to the present invention.

FIG. 4 is an output waveform diagram from an image input unit, which is obtained by converting image information from an object to be inspected into an electric signal in a conventional pitch measuring device.

[Explanation of symbols]

 1 Light Source 2 Inspected Object 3 Optical System Lens 4 Image Input 5 Image Processing 6 Output

Claims (1)

[Claims] 1. A light source section whose beam shape is shaped so as to generate coherent light and irradiate an inspected object having a light and shade pattern, an optical system lens section for forming an image of the inspected object, and an imaged object From an image input unit for inputting an image of an inspection object and performing photoelectric conversion, an image processing unit for processing an electric signal output from the image input unit, and an output unit for outputting an image processing result in the image processing unit. In the pitch measuring device for measuring the density pitch of the inspected object, the optical system lens section has the same image intensity distribution evaluation as the minimum density pitch dimension of the inspected object, and the minimum density pitch dimension of the inspected object. A pitch measuring device characterized by easily removing noise on an image which is smaller than that of the above-mentioned, without imposing a burden on the processing capability of the image processing section.