JPS5836775B2 - hologram success touch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an incoherent hologram creation device using a Fresnel zone plate.

An incoherent hologram is created by subjecting waves from an object to Fresnel transformation using a Fresnel zone plate and recording this transformation pattern on a dry plate using an appropriate imaging device.

When the wave is light, a camera or the like is used as the imaging device, for example.

For radiation such as X-rays and γ (gamma) rays, it is effective to use an image tube that multiplies the brightness of the radiation pattern and converts it into a visible light pattern.

However, since the input surface of the image tube is curved and has unique imaging aberration characteristics, the pattern on the output surface is not similar to the pattern on the input surface, and as it approaches the periphery, Therefore, the pattern is extended.

Therefore, when an image tube is used, the peripheral part of the input surface of the image tube cannot be used, and the effective usable area becomes small, which is very inconvenient.

The present invention was made in view of the above circumstances, and it is possible to create a hologram that does not cause distortion and improves the quality of reproduced images even for imaging devices such as image tubes that have unique imaging aberration characteristics. The purpose is to provide equipment.

To achieve this objective, the present invention sets the effective annular radius of the Fresnel zone plate to a predetermined value in order to correct the imaging aberration characteristics for an imaging device having unique imaging aberration characteristics. Features.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a layout diagram for creating a hologram of the distribution of a radioisotope administered into a patient's body in internal organs.

In this figure, predetermined radioisotopes are distributed in a subject (internal organ) 11, and radiation is generated according to this distribution.

The subject 11 is both a subject and a source of radiation.

When creating a hologram of an X-ray fluoroscopic image, or when creating a hologram using light, place a subject at the position of the subject 11, hold the subject 11 between them, and place an image tube 13 (described later).
Alternatively, an X-ray generation source or light source may be placed at a position facing the Fresnel zone plate 12).

The radiation from the subject 11 is subjected to Fresnel transformation by the Fresnel zone plate 12 according to the present invention, and then the transformed pattern is multiplied in brightness and converted into a visible light pattern by the image tube 13 as an imaging device.

Generally, the radiation pattern input to the input surface 14 of the image tube 13 is not reduced and projected onto the output surface 15 with a similar relationship, but a pattern with distortion that becomes longer toward the periphery is output.

This is mainly because the input surface 14 of the image tube 130 has a curved surface.

The unique imaging aberration characteristics of the image tube 13 are corrected by the Fresnel zone plate 12 as described below.

The Fresnel solenoid plate used to create an incoherent hologram has the configuration shown in FIG.

FIG. 2 shows the Fresnel zone plate 16, in which a is a central sectional view and b is a front view.

That is, the Fresnel zone plate 16 is formed by a large number of concentric circles with different radii.
. . . From N onward, the blocking ring zones 17 and the passing ring zones 18 are arranged alternately.

The blocking ring zones 17 are indicated by diagonal lines in FIG. 2b, and are odd-numbered ring zones such as the ring zones I, ■, .

The passing ring zone 18 is an even-numbered ring zone such as ring zone 2, . . . .

Of course, this relationship may be reversed and the blocking ring zone 17 and the passing ring zone 18 may be interchanged.

When radiation (X-rays, γ (gamma) rays, etc.) is used as in this embodiment, the passing zone 18 is made of a radiolucent material, and the blocking zone 17 is made of a heavy metal such as lead or tungsten that blocks radiation. It is formed.

When viewing the hologram using visible light, the passing zone 18 is formed of a transparent material, and the blocking zone 17 is formed of an opaque material (such as a black material).

The outer diameters of the annular zones I, I, III, ......, N are respectively l1, l2, l3, ..., In, and the areas are S S S ......, Sn and 1
If you do tsu 29 3 tsu, then 11: 12 2 l3: ...
2 ln=・～/'] 2J"2 :J'; :-
:VW S1=S2=S3=...=Sn.

That is, the outer diameter of the ring zone N is given by ln=-vf1l1, and its band width Wn is Wn=(φ=vd11).

As shown in FIG. 1 or 4, the Fresnel zone plate 12 used in the hologram creation apparatus according to the present invention is used by bending the above-mentioned Fresnel zone plate 16 by a predetermined amount.

FIG. 4 shows the Fresnel zone plate 12, in which a is a central sectional view and b is a front view.

In FIG. 1, the output surface side of the image tube 13 is bent to form a concave surface.

This amount of bending, that is, the Fresnel zone rate 12
The zero curvature can be determined experimentally, for example, as follows.

The graph in Figure 3 shows the numbers 1, 2, 3, . . . , n corresponding to the annular zones r, n, m, . . .
The horizontal axis is the normalized outer diameter of these annular zones, and the vertical axis is the normalized outer diameter of these annular zones.

Normalization is performed by setting l1=1.

A solid curve A shows the relationship between the ring zone number and the outer diameter of the Fresnel zone plate 16 shown in FIG.

A curve B indicated by a broken line normalizes the relationship between the ring zone number and the outer diameter of the pattern output to the output surface 15 when the Fresnel zone plate 16 shown in FIG. 2 is the input surface pattern of the image tube 13. It is shown in digitized form.

Since the image tube 13 has an imaging aberration characteristic that extends around the output surface 150, the outer diameter ln' of the n-th annular zone is larger than the outer diameter ln of the n-th annular zone of the Fresnelson plate 16. This is a large value.

In order to correct such imaging aberration characteristics, conversely, the nth
It is sufficient to use a Fresnelson plate whose ring zone has an outer diameter smaller than ln.

That is, if the outer diameter of the front projected image of the nth ring zone of the curved Fresnel zone plate 12 (this is called the effective ln radius) is Hrn, then rn=ln・1.
Bend the Fresnel zone plate 16 with a curvature such that
All that is required is to make the Fresnel zone plate 12 (see Fig. 4).

Fresnel zone plate 12 bent in this way
If this is used, the imaging aberration of the image tube 13 will be completely corrected.

The Fresnel zone plate for correcting imaging aberrations does not necessarily have to have a curved surface as described above.

FIG. 5 shows a modification of the Fresnel zone plate, in which a is a central sectional view and b is a front view.

The Fresnel zone plate 21 in FIG. 5 is a flat disc with the effective radius rt+r2+r3...
- Ring zones I, It, I formed by concentric circles with rn
II,...,N.

In this case as well, similar to the Fresnel zone plate 12, the imaging aberration of the image tube 13 is sufficiently corrected.

Note that the entire thickness of the Fresnel zone plates shown in Figures 1, 2, 4, and 5 is a blocking ring or a passing ring, but when actually manufacturing a Fresnel zone plate, As shown in FIG.
A blocking annular layer 25 is often formed on the (passing base).

That is, it is more common for the Fresnel zone plate according to the present invention to have a central cross section as shown in FIG.

Further, the visible light pattern projected on the output surface 15 of the image tube 13 is recorded on a dry plate by, for example, a camera.

This dry plate is a hologram.

Then, by illuminating this dry plate with laser light, that is, visible light with good coherence, a three-dimensional image of the subject is reproduced.

Since the hologram according to the present invention is an incoherent hologram, it is of course not possible to obtain a perfect three-dimensional image.

However, since the reproduced image represents the tomographic plane of the subject, a large number of continuous tomographic images can be obtained with one dry plate.

In this example, a continuous number of radioisotope distribution maps are obtained.

As described above regarding one embodiment, according to the present invention,
Since the unique imaging aberration characteristics of the imaging device are corrected,
A hologram control device is realized that does not cause distortion and thus improves the quality of reproduced images.

When using an image tube as described above, the input and output surfaces can be fully utilized and the brightness can be multiplied sufficiently, so a trace amount of radioisotope is sufficient and it is also excellent in terms of safety. It has become something like this.

It goes without saying that the present invention is not limited to the above embodiment.

In the above embodiment, a hologram is created using radiation, but a light source can also be used as the incoherent source.

Further, the Fresnel zone plate may not be used entirely, but only a portion thereof.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which FIG. 1 shows a layout, FIGS. 2, 4, and 5 show Fresnel zone plates, a is a sectional view, b is a front view, and FIG. 6 is a graph showing the relationship between the ring zone number and the outer diameter, and FIG. 6 is a sectional view of the Fresnel zone plate. 11... Subject (radiation source), 12, 16
, 21, 24... Fresnel zone plate, 1
3...Image tube, 14...Input surface, 1
5... Output surface, 17, 19, 22, 25...
...Block ring zone, 18, 20, 23... Passage ring zone, 26... Foundation.

Claims (1)

[Claims] 1. In an incoherent hologram production device in which waves from an object are Fresnel-transformed using a Fresnel zone plate and recorded on a dry plate by an imaging device with this transformation pattern, the annular radius of the Fresnel zone plate is set from the central annular zone. The method is characterized in that the area of each ring zone is made equal to the square root of the counted ring zone number, and the effective radius of each ring zone is corrected according to the imaging aberration characteristics specific to the imaging device. A hologram production device.