JP3067357B2 - Binary image contour extraction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contour extracting apparatus for displaying a contour by binarizing a digital image.

[0002]

2. Description of the Related Art Conventionally, regarding an image contour extracting apparatus, SHLee; Applied Physics, 1
0, (1976), p. 203 et seq., A method using a quadruple exposure hologram has been proposed. This method utilizes the fact that an image can be differentiated by forming a double-exposure hologram by superimposing two Young interference fringes having slightly different frequencies. If this hologram is further subjected to quadruple exposure, a differential action in the orthogonal direction of the grid lines is included, so that the contour extraction of the image in an arbitrary direction can be performed.

[0003]

However, in a method using a hologram such as double exposure or quadruple exposure, one method is used.
For one input image, a recording medium for transferring the image to a hologram dry plate and performing a developing process was required. Therefore, each time the input image changes, the hologram must be recreated each time, and it takes time and effort to create the hologram, and it is difficult to perform real-time processing.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an apparatus for extracting a contour of a binary image in which the contour of the image can be drawn as a binary image in real time without requiring a recording medium. With the goal.

[0005]

SUMMARY OF THE INVENTION
The value image contour extraction device includes an input screen in which each pixel has a light-emitting element, a stop surface that blocks a part of light emitted from these light-emitting elements, and a filter that converts the intensity of light emitted from the light-emitting elements. A light receiving surface having a light receiving element corresponding to each pixel of the input screen on a one-to-one basis, a threshold circuit corresponding to each of the light receiving elements on a one-to-one basis and calculating a contour of a binary image; An output screen in which a pixel having a light emitting element corresponds to each light receiving element on a one-to-one basis and allows the light emitting element to emit light based on the threshold circuit.

In the above-described filter, for light emitted from one light-emitting element on the input screen, the intensity of light that travels perpendicular to the input screen and enters the corresponding light-receiving element is located above, below, left, and right of the light-receiving element. It is configured to be greater than the sum of the intensities of the light incident on four adjacent light receiving elements.

In FIG. 1, an arbitrary pixel in the input screen 1 is focused on and is referred to as a pixel G. Of the light receiving elements on the light receiving surface 2, the pixel G is perpendicular to the input screen 1 through the pixel G. Those on the straight line are referred to as light receiving elements H. Of the light emitted from the light emitting element of the pixel G, the light traveling to the light receiving element H and light receiving elements other than the light receiving element adjacent to the light receiving element H in the vertical and horizontal directions is
The light is reflected or absorbed by the stop surface.
Therefore, as shown in FIG. 2A, when viewed from the light receiving element H side, the light receiving element H is not only light traveling from the pixel G in the direction perpendicular to the input screen 1 but also adjacent to the pixel G vertically and horizontally. Do 4
Only each light emitted from the light emitting elements of one pixel can be incident. Moreover, the intensity of these five lights is converted by passing through filters arranged between the input screen 1 and the light receiving surface 2, respectively.

Now, the conversion intensity of the filter will be described with reference to FIG. Let _Io be the intensity of light when light perpendicular to the input screen 1 emitted from the light emitting element of the pixel G passes through a filter (not shown) and enters the light receiving element H, and is adjacent to the pixel G vertically and horizontally. Light emitted from the light emitting element of each pixel passes through the filter and passes through the light receiving element H
The intensity of light when entering the respectively _{I a, I b, I c} , I
_d . In this case, the filter, the light intensity I _o and _{I a, I b, I c} , is configured as the following relationship between the I _d is upright. _{I a + I b + I c} + I d <I o

A threshold circuit having the following threshold function is provided between the light receiving element H and the corresponding pixel on the output screen. That is, when placing a _{I e = I o + I a} + I b + I c + I d, the output screen intensity I _H received by the light receiving element H is not less than I _o and smaller than I _e, corresponding to the light receiving element H Pixel emits light by its light emitting element. or,
Whether the light intensity I _H received by the light receiving element H is smaller than I _o ,
Or, if _Ie or more, the light emitting element of the pixel on the output screen corresponding to the light receiving element H does not emit light. FIG. 3 shows a graph of the threshold function realized in this manner, where the light emitting state is 1 and the other state is 0. In this way, in the contour extraction device for a binary image, for example, only when the pixel G and four pixels adjacent to the upper, lower, left, and right thereof emit light, the emission of the pixel of the output screen corresponding to the pixel G is stopped. Can be performed in parallel on all the pixels on the output screen. Thus, the outline of the binary image can be drawn.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 4 is a schematic block diagram of a binary image contour extracting apparatus according to the first embodiment. In the figure, an input screen 4, a two-dimensional diffraction grating 5, an aperture surface 6, a light receiving surface 7, and an output screen 8 are sequentially arranged so as to be linear and parallel to each other. The input screen 4 and the output screen 8
Each pixel is composed of m × n pixels, and the corresponding pixels located at (i rows × j columns) are represented by G (i, j) and S (i, j), respectively. . Each pixel of the input screen 4 and the output screen 8 is provided with a light emitting element. The light receiving surface 7 is also composed of m × n light receiving elements, and the light receiving elements located at (i rows × j columns) corresponding to the pixels G (i, j) and S (i, j) are denoted by H. (I,
j). Therefore, the pixels G (i, j), the light receiving elements H (i, j) and the pixels S (i, j) are arranged on a straight line perpendicular to the input screen 4, as shown in FIG. Will be.

A two-dimensional diffraction grating 5 shown in FIG. 6 is located behind the input screen 4 (on the light receiving surface 7 side) and diffracts light emitted from the light emitting elements on the input screen 4. Since the two-dimensional diffraction grating 5 has a square grid shape, the light emitted from one light-emitting element is diffracted by the diffraction grating and the intensity of ± 1st-order diffraction light is obtained. I _a ,
I _b, I _c, I _d is configured to be equal to each other. Further, assuming that the intensity of the 0th-order diffracted light is I _O and the respective intensities I _a , I _b , I _c , and I _d of the ± 1st-order diffracted light are I ₁ , the two-dimensional diffraction grating 5 has 4I ₁ <I _O It is configured to satisfy 満 足 (1).

An aperture surface 6 located behind the two-dimensional diffraction grating 5 has m × n apertures 6 a formed therein (see FIG. 7). Of the diffracted light diffracted by the two-dimensional diffraction grating 5, Most of the above high-order diffracted lights are shielded, but pass the 0th-order and ± 1st-order diffracted lights. Here, the intensity of the diffracted light becomes significantly weaker as the order is higher. Therefore, the second or third order diffracted light may be kept at the stop surface 6. In order to remove all the second-order or higher-order diffracted light, a light-blocking member (see FIG. 10), which will be described later, is provided in the direction perpendicular to the diffraction grating 5 behind the two-dimensional diffraction grating 5 instead of the stop surface 6. I just need.

A threshold circuit 9 for realizing a simple threshold function is provided between the light receiving element H (i, j) on the light receiving surface 7 and the pixel S (i, j) on the output screen 8. Are electrically connected to each pixel (see FIG. 8). That is, the lower and upper thresholds, which are the boundary intensities for determining the presence or absence of light emission, are p and q, and are set so that p and q satisfy the following equation. 4I ₁ <p ≦ I _O <I _O +3 I ₁ ≦ q <I _O + 4I ₁ ‥‥ (2) Moreover, the light receiving intensity I _H of each light receiving element on the light receiving surface 7 is p ≦ I _H ≦ q ‥‥ (3 If so, the circuit is set so that the light emitting element on the output screen 8 emits light, otherwise it does not emit light. In addition, input screen 4
, The apertures 6 a of the aperture surface 6, the light receiving elements of the light receiving surface 7, and the pixels of the output screen 8 are configured to correspond one-to-one.

Since the present embodiment is configured as described above, the light emitted from the light emitting element of each pixel of the input screen 4 corresponds to the input of an image to each pixel of the input screen 4 from outside.
The light passes through the two-dimensional diffraction grating 5 and is diffracted. Of the diffracted light, most of the second-order or higher-order diffracted light is cut off by the stop surface 6, and the 0th and ± 1st-order diffracted lights pass through the stop hole 6 a toward the light receiving element on the light receiving surface 7. Here, since each pixel of the input screen 4 and each light receiving element of the light receiving surface 7 have a one-to-one correspondence, the light emitted from the light emitting element of an arbitrary pixel G (i, j) is generated at the 0th time. The folded light is incident on the light receiving element H (i, j), and the ± 1st-order diffracted lights are adjacent to the light receiving element H (i, j) in the vertical and horizontal directions, respectively, and the light receiving elements H (i−1, j) and H (i +).
1, j), H (i, j + 1), and H (i, j-1). Therefore, from the standpoint of the light receiving element on the light receiving surface 7, as shown in FIG. 9, the light receiving element H (i,
In j), the 0th-order light emitted from the light emitting element of the pixel G (i, j) of the input screen 4 and the pixels G adjacent vertically, horizontally, and vertically thereto
(I-1, j), G (i + 1, j), G (i, j +
1), +1 emitted from the light emitting element of G (i, j-1)
The next or -1st order diffracted light is incident.

Here, regarding the intensity I _o of the zero-order diffracted light and the intensities I _a , I _b , I _c , and I _{d of} the ± first-order diffracted light, the intensities I _a , I _b , I _c , and I _d ( = I ₁ ) is a two-dimensional diffraction grating 5
Are equal to each other because their lattice shapes are square. Therefore,
The zero-order light and the ± first-order light transmitted through the two-dimensional diffraction grating 5 have characteristics satisfying 4I ₁ <I _{o o} (1).

At this time, the threshold circuit 9 outputs the threshold values p,
q is as described above (2) _{4I 1 <p ≦ I o <} I o + 3I 1 ≦ q <I o + 4I 1 ‥‥ is set so as to satisfy (2), moreover the light receiving elements of the light receiving surface 6 If the light receiving intensity I _H of the light emitting element is p ≦ I _H ≦ q ‥‥ (3), the light emitting element on the output screen 8 emits light; otherwise, it does not emit light. In this manner, the pixel G (i, j) of the input screen 4 and its adjacent pixels G
(I-1, j), G (i + 1, j), G (i, j +
1) Only when all the light emitting elements of G (i, j-1) emit light, the operation of stopping the light emission of the pixel S (i, j) on the output screen 8 is performed for all the pixels. It can be executed in parallel. Thereby, the outline of the binary image can be extracted on the output screen 8.

As described above, according to the present embodiment, since the parallelism of light is used for extracting the outline of a binary image, the outline can be extracted in real time without the need for a synchronization operation or a recording medium. Can be.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the schematic configuration diagram of the contour extraction device shown in FIG. The circuit 9 is the same as in the first embodiment. Behind the input screen 4 (on the light receiving surface 7 side), plate-shaped light shielding members 11 are arranged on the boundary between adjacent pixels and in a direction perpendicular to the input screen 4 so as to form a lattice as a whole. Is formed. The light emitted from the light emitting element of the pixel G (i, j) by the light shielding member 11 causes the light receiving element H (i, j) and the light receiving element H (i−1) adjacent to the light receiving element H (i, j) on the light receiving surface 7 in the vertical and horizontal directions. , J), H (i + 1,
j), H (i, j + 1) and H (i, j-1).

As shown in FIG. 1 between the light shielding member 11 and the light receiving surface 7.
As shown in FIG. 1, a strip-shaped permeable film 12a having a transmittance t
There are permeable membrane filter 12 formed in a lattice shape are arranged vertically and horizontally, the transmittance t _w of the m × n window 12b partitioned by the permeable membrane 12a (corresponding to each pixel) is larger than 4t 1 or less (accordingly, t <0.25).
Therefore, the transmittance at the portion where the strip-shaped transmission film 12a overlaps is t ² <0.0625, and light transmitted through this portion can be almost ignored. However, the configuration may be such that the transmittance of this portion is 0 if it is absolutely necessary.
The intensity of light incident from the light emitting element of the pixel G (i, j) to each light receiving element on the light receiving surface 7 is I _o , the intensity of light entering the light receiving element H (i, j) is I _o , and the light receiving element H ( i-1, j), H
(I + 1, j), H (i, j + 1), H (i, j-1)
The intensity of light entering the respective _{I a, I b, I c} , When I _d, can be placed as _{I 1 = I a = I b} = I c = I d,
Regarding the relationship between I _o and I ₁ , as described above, it is assumed that the permeable membrane filter 12 is configured to satisfy the condition of Equation (1) 4 I ₁ <I _o ‥‥ (1).

Since the present embodiment is configured as described above, the light emitted from the light emitting element of the pixel G (i, j) of the input screen 4 is partially blocked by the light blocking member 11, On the light receiving surface 7, a light receiving element H (i, j) and light receiving elements H (i-1, j), H (i + 1,
j), H (i, j + 1) and H (i, j-1). Then, the light passing through the light shielding member 11 passes through the lattice-shaped transmission film filter 12, and in this case, the intensity of the light entering each light receiving element on the light receiving surface 7 enters the light receiving element H (i, j). The light intensity is I _o ,
Light receiving elements H (i-1, j), H (i + 1, j), H
(I, j + 1), H (i, j-1) 's intensity of light entering the husband _{I a, I b, I c} , since the I _d, satisfies the equation (1), first embodiment The outline of the binary image can be extracted in the same manner as in.

[0021]

As described above, according to the outline extracting apparatus for a binary image according to the present invention, since the parallelism of light is used, a synchronous operation and a recording medium are required as in the conventional quad exposure hologram. Instead, the outline of the binary image can be easily drawn in real time.

[Brief description of the drawings]

FIG. 1 is a diagram showing light incident on each light receiving element on a light receiving surface from one pixel of an input screen for explaining the principle of the present invention.

FIGS. 2A and 2B are diagrams showing light from light emitting elements of each pixel on an input screen, which is incident on one light receiving element on a light receiving surface, respectively.

FIG. 3 is a graph showing a function realized by a threshold circuit according to a relationship between a light receiving intensity of a light receiving element and a light emitting state of an output screen.

FIG. 4 is a diagram showing a schematic configuration of a contour extraction device according to a first embodiment of the present invention.

FIG. 5 is a diagram showing a correspondence relationship between pixels and light receiving elements on an input screen, a light receiving surface, and an output screen.

FIG. 6 is a schematic perspective view of a two-dimensional diffraction grating.

FIG. 7 is a schematic perspective view of a diaphragm surface.

FIG. 8 is a diagram showing a relationship between a light receiving element, pixels on an output screen, and a threshold circuit.

FIG. 9 is a diagram illustrating light input from a light emitting element of each pixel on an input screen to one light receiving element on a light receiving surface.

FIG. 10 is a schematic sectional view showing a schematic configuration of a second embodiment of the present invention.

11 is a main part front view showing the configuration of the permeable membrane filter of FIG. 10;

[Explanation of symbols]

 1, 4 input screen 2, 7 light receiving surface 5 two-dimensional diffraction grating 6 aperture surface 8 output screen 9 threshold circuit 11 light shielding member 12 transmission film filter

Claims (2)

(57) [Claims] An input screen in which each pixel has a light-emitting element; a stop surface for blocking a part of light emitted from the light-emitting element; a filter for converting the intensity of light emitted from the light-emitting element; A light receiving surface having a light receiving element corresponding to each pixel of the input screen on a one-to-one basis, a threshold circuit corresponding to the light receiving element on a one-to-one basis and calculating a contour of a binary image; A contour extraction device for a binary image, comprising: a pixel having a one-to-one correspondence with a light-receiving element, each pixel having a light-emitting element, and an output screen capable of causing the light-emitting element to emit light by the output of the threshold circuit. 2. The filter according to claim 1, wherein, of the light emitted from the light emitting elements on the input screen, the intensity of light traveling perpendicular to the input screen and entering the light receiving element is adjacent to the upper, lower, left and right sides of the light receiving element. 2. The outline extracting apparatus for a binary image according to claim 1, wherein the apparatus is configured to be larger than the sum of the intensities of the light incident on the four light receiving elements.