JPS63235838A - Photoelastic image processing - Google Patents

Abstract

PURPOSE:To enable extraction and separation of an isochromatic line zero-order fringe and an isoclinic line easily and instantly, by arranging a spectroscope, a Fresnel rhomb quarter wavelength plate, a TV camera, a CPU and the like. CONSTITUTION:Continuous monochroic light with multiple wavelengths emitted from a spectroscope 1 reaches a TV camera 7, a CPU 8 and a monitor 9 via a polarizer 2, a Fresnel rhomb 3, a sample 4 a Fresnel rhomb quarter wavelength plate 5 and an analyzer 6. Here, the CPU 8 performs an overlap processing of an image to store an image of a zero-order fringe 11, with isochromatic lines vanishing excluding a zero-order fringe 11, into a memory 10 therewithin 8 and outputs the image to the device 9. On the other hand, the among isochromatic lines, zero-order fringe 11 alone is left. This enables extraction and separation of an isochromatic line zero-order fringe and an isoclinic line easily and instantly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention utilizes the photoelastic effect to measure the internal stress % of an object, particularly the residual stress in a state where no external force is applied to a plastic molded product. The present invention relates to a photoelastic image processing method.

[Conventional technology]

As a conventional technology for photoelastic devices, Japanese Patent Application Laid-Open No. 48-5168
As described in No. 4, a series of photographic films of isoclinic lines and a reversal photographic film of isochromic lines were multiple-printed to obtain only isoclinal lines. However, although the above method has the advantage of being able to synthesize a series of isoclinic maps set at appropriate intervals, it is time-consuming and requires preparing two types of films in advance each time a sample is changed. However, no consideration was given to high efficiency.

Another method has been considered in which a minute charge amplitude is applied to the sample and the isochromic lines are moved back and forth to disappear, and only the isoclinals are extracted. did not take into consideration the possibility that an external force would cause the original isoclinal vertical position to move.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into account the simplicity and the possibility that the position of isoclines may change when extracting and separating accurate isoclinals efficiently, and the internal residual stress of plasticif molded products etc. The disadvantage of measurement was that it lacked accuracy and speed.

An object of the present invention is to easily create zero-order isochromic lines and isoclinic lines for photoelastic fringe observation of a sample without applying external force to the sample to be observed and under a predetermined constant load. And it can be extracted and separated instantly.

[Means for solving problems]

The above objectives include a spectrometer that can emit monochromatic light of each wavelength in any wavelength range as a light source, a Fresnel ROM that does not require replacement in a wide wavelength range as a quarter-wave plate, and a television camera that can capture photoelastic fringes. In an optical system in which a five-photoelastic device is configured by a CPU, etc. that can perform arithmetic image processing on images obtained from a television camera, a monitor device, and a television camera, the zero-order isochromic line is dark regardless of the wavelength. Utilizing the principle that there are no dark lines in the field of view, and that isoclinal lines also become dark lines regardless of the wavelength, this is achieved by using multiple wavelengths and superimposing their images.

[Effect]

A spectrometer capable of controlling wavelength changes operates to continuously send monochromatic light of multiple wavelengths to a measuring device system including a sample. When extracting the zero-order line, it passes through the polarizer, Fresnel ROM, sample, Fresnel ROM, analyzer, and then reaches the television camera and monitor device. Also, when extracting isoclinals including the zero-order line, The light passes through a polarizer, sample, and analyzer before reaching the television camera monitor device. Here, because the wavelength of the light source changes continuously, the isochromatic lines except the zero-order line and isoclinal line move, and the positions where the zero-order line and isoclinal line do not exist show changes in brightness and darkness. . The CPU, which calculates the image of the change in brightness, superimposes the light as 1 and the dark as 0, that is, performs an addition process, so that only the zero-order line and the isoclinal line remain as 01, that is, the dark line. By superimposing the black-and-white inverted zero-order line image obtained by the above method and the isoclinal lines including the zero-order lines again, only the isoclinal lines can be extracted and separated.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1(a) is an optical system diagram showing an example of zero-order line detection in the photoelastic image processing method according to the present invention, and FIG. 1(b)
FIG. 2(a) is a diagram showing an example of the output obtained by the above embodiment.
is an optical system diagram showing an example of detecting isoclinic lines including zero-order lines in the photoelastic image processing method, FIG. 2(b) is a diagram showing an example of output obtained by the above example, and FIG. Figure 1 above (
This is an output side view obtained by overlapping the output side view shown in FIG. 2(b) with the output side view shown in FIG. In FIG. 1(a), monochromatic light of continuous multiple wavelengths emitted from a spectrometer 1 is transmitted through a polarizer 2 and a Fresnel ROM 3.
, a sample 4, a Fresnel ROM quarter-wave plate 5, an analyzer 6, and then a television camera 7, a CPU 8, and a monitor device path 9. Here, the CPU 8 stores an image of the zero-order line in which isochromatic lines other than the zero-order line have disappeared in the storage device 10 in the CPU 5 by performing image superimposition processing, and displays the image on the monitor device 9. Output the image. FIG. 1(b) is a diagram showing the above output example, in which only the zeroth order line 11 of the isochromatic lines remains.

Figure 2 (a
) is spectrometer 1', polarizer 2', sample 4', analyzer 6'
, a television camera 7', a CPU 8', a monitor device 49', and a storage device 10'. Using the same principle as shown above, isochromatic lines other than zero-order lines disappear from photoelastic fringes in which isochromatic lines and isoclinal lines are mixed, and
As shown in the output side diagram shown in FIG. 2(b), isoclinic lines 12 including zero-order lines are extracted and separated.

When the zero-order line 11 shown in FIG. 1(b) is inverted in black and white and the isoclinal line 12 including the zero-order line shown in FIG. 2(b) is superimposed, the result is as shown in FIG. 3. A figure in which only isoclinic lines 13 are extracted and separated can be obtained.

〔Effect of the invention〕

As described above, the photoelastic image processing method according to the present invention uses a spectrometer capable of controlling arbitrary wavelength changes as a light source, a polarizer,
A Fresnel-ROM quarter-wave plate that enables circularly polarized light in a wide range of wavelengths as a quarter-wave plate, an analyzer, a television camera that captures images, a television monitor,
and a CPU that performs calculations on the image, in which isochromic line images obtained using measurement light of multiple wavelengths are captured by the television camera, and isochromic line images of each wavelength are captured. By performing superimposed image processing, a photoelastic detection image is obtained, and isoclinals without a mixture of zero-order isochromic stripes and isochromic lines can be easily and easily created without changing the internal stress state of the sample. It can be separated and extracted quickly, so it is quick and
This also has the effect of enabling highly accurate stress analysis.

[Brief explanation of the drawing]

FIG. 1(a) is an optical system diagram showing an example of zero-order line detection in the photoelastic image processing method according to the present invention, and FIG. 1(b)
is a diagram showing the output 911 obtained by the above embodiment, FIG. 2 (
Fig. 2(b) is a diagram showing an example of the output obtained by the above embodiment; The figure is the first one above.
This is an output side view obtained by overlapping the output side view shown in FIG. 2(b) with the output side view shown in FIG. 2(b) subjected to black and white inversion processing. 1.1... Spectrometer 2.2... Polarizer 5... Fresnel ROM quarter wave plate 6.6'... Analyzer 7.7... Television camera 8.8... - CPU 9 , 9 , . . . Television monitor 11... Zero-order fringe 12... Isoclinic line image 13 containing zero-order fringe... Isoclinic line image. /-1'-・,

Claims (1)

[Claims] 1. A Fresnel-ROM quarter-wavelength light source that uses a spectrometer that can control the wavelength to be changed arbitrarily, and that uses a polarizer and a quarter-wave plate to generate circularly polarized light in a wide range of wavelengths. In a photoelastic image processing method that includes a plate, an analyzer, a television camera that captures images, a television monitor, and a CPU that performs calculations on the image, etc. obtained using measurement light of multiple wavelengths. Capture the color line image with the above television camera,
A photoelastic image processing method characterized by performing image processing to superimpose isochromic line images of each wavelength to obtain a photoelastic detection image. 2. The photoelastic image processing method as set forth in claim 1, wherein the photoelastic detection image is a zero-order stripe of isochromatic lines. 3. The photoelastic detection image is an isoclinal image obtained by superimposing the zero-order fringe in black and white on an isoclinal image including the zero-order fringe. The photoelastic image processing method described in Section.