JPS62107383A - Contour depiction method - Google Patents

Abstract

PURPOSE:To obtain distinctly all contour pictures by executing an operation for performing an edge extraction processing to a video image which is photographed by fixing a position of a video camera and an object to be photographed, whenever a direction of a light beam irradiated to the object to be photographed is changed. CONSTITUTION:In an edge extracting circuit, in order to perform a digital differentiation, first of all, a digitized original image data 2-1 is stored in memories 10, 11. In case said data in the memories 10, 11 is shown generally by a(j,i) (j) and (i) are varied from '1' to (n), and from '1' to (m), respectively, and the processing is executed extending over the whole picture of a visual field, but first of all, a differentiation in the horizontal direction is executed in conformity with an expression I. A signal 12-1 is binarized by a binarizing circuit 13, and goes to '0', and '1', in case an absolute value of the signal 12-1 is smaller than a prescribed value beta, and in case it is larger, respectively. In the same way, a differential processing in the vertical direction is executed in conformity with an expression II.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a contour drawing method, and more particularly to a contour drawing method for creating a complete contour image of a desired subject from a video image taken by a video camera.

(Prior Art) Conventionally, as a method for extracting only the outline of a subject from a video image taken with a video camera, Japanese Patent Application Laid-Open No. 57-929
There are some disclosed in Japanese Patent Application Laid-open No. 86, Japanese Patent Application Laid-Open No. 58-222383, and Japanese Patent Application Laid-Open No. 60-7584.

These methods include dividing a video image horizontally and vertically, and applying processing such as delay to the signals obtained by the division to remove the interior of the subject and the background, thereby obtaining only the outline of the subject.

(Problems to be Solved by the Invention) However, the conventional method described above does not take into account the shape of the subject, lighting conditions, etc., and the outline of the subject becomes unclear. It was extremely difficult to create outline drawings such as perspective views.

The present invention is intended to solve these problems, and is a contour drawing method that makes it possible to create contour line drawings such as perspective views by clearly obtaining the entire contour image of a subject from a video image taken with a video camera. The purpose is to provide

(Means for Solving the Problems) In order to solve the above problems, the present invention fixes the positions of the subject and the video camera, changes the direction of the light shining on the subject, and each time the direction of the light changes. Edge extraction processing is applied to video images obtained from a video camera.

(Function) The present invention applies edge extraction processing to a video image signal obtained by shining light onto a subject from a plurality of directions, and extracts a desired contour based on the video image signal subjected to edge extraction processing for each direction of light. Detects images and temporarily stores them in multiple memories. Then, the desired contour images for each direction of light stored in each memory are edited and synthesized to create a complete image of the subject.

Therefore, the present invention can solve the above problems.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, 1 divides the field of view into n parts in the horizontal direction.

A video camera 2 outputs an analog signal 1-1 of each part divided into m parts in the vertical direction and a synchronization signal 1-2 representing the position of each part; 2 is a video camera for digitally image-processing the analog signal 1-1; Digital signal 2-1 which is pre-processing
3 is an edge extraction circuit which will be described in detail later, and 4 is an A-D converter circuit for converting the analog signal 1-1 into 2. A signal processing control circuit that controls the signal 3-1 after the edge extraction process via the edge extraction circuit 3 until it is stored in the editing memory 5 described later, 5 temporarily stores the signal 3-1 after the edge extraction process 6 is an editing control circuit that has a function of partially deleting and merging the contents of the editing memory 5 as necessary; 7 is an editing memory that displays the contents of the editing memory 5 on the screen according to instructions from the editing control circuit 6; A commonly used display device that has a display function; 8 is a subject;
Reference numeral 9 denotes a light source whose direction of light applied to the subject 8 can be changed.

Next, the operation of this embodiment will be explained. Here, FIG. 2 is a diagram showing how a video image is divided into pixels, and FIG. 3 is a diagram showing the relationship between the signal waveforms of each signal in FIG. 1 and the digital values obtained by digitally converting them.

First, a subject 8 is photographed with a video camera 1, and the video image photographed with the video camera 1 is divided into n divisions in the horizontal direction and m divisions in the vertical direction, as shown in FIG. 1 (signal shown in Figure 3(b))
and a synchronization signal 1-2 (signal shown in FIG. 3(a)) representing the position of each divided portion. and,
In the A-D conversion circuit 2, the analog signal 1-
In this embodiment, the analog signal 1-1 is divided into 16 equal parts, that is, into 4-bit digital signals. Therefore, the analog signal 1-1 of each divided portion is converted into the digital value shown in FIG. 3(C) and supplied to the edge extraction circuit 3 as a digital signal 2-1.

The digital signal 2-1 is then subjected to edge extraction processing by the edge extraction circuit 3 and stored in the editing memory 5.

Here, FIG. 4 is a block diagram showing the configuration of the edge extraction circuit in FIG. 1. In Figure 4, to, It
1 is the digital signal 2-1 from the A-D conversion circuit 2 in FIG. 1, a memory that stores digital values as shown in FIG. 3(C), and 12 is the difference between the data stored in the memory 10.11. 13 is a binarization circuit that outputs "0" if the absolute value of the result of subtraction by the subtracter 11 is smaller than a predetermined value, and outputs "1" if it is larger; 14 is a binarization circuit 13 is an image memory for storing binarized data; 15 is a memory 10, 11; a subtracter 1;
2 and the binarization circuit 13, and organically executes edge extraction processing. Here, memory 10
．． 11 is a (1, i), a (
1,2) , +m+.

It has storage areas such as a(j, i), . In this embodiment, as described above, the contents of the data expressed in 4 bits are the values ado to ad3 in FIG. 3(c). Furthermore, the image memory 14 has almost the same configuration as the memories 1.0 and l1, and each part has E (+, i) and 'E (1
,2) ,...

E(j, i)s'' and E(m, n), and the content of the data is expressed by 1 bit.

Furthermore, the subtracter 12 inputs data in the memories io and it from 0 to
Since the value up to 15 is taken, the result of the subtraction is in the range of -15 to +15. The edge extraction circuit having the above configuration performs the following digital differentiation operation.

First, digitized original image data (digital signal 2-1) is stored in memory 10.11. The data in memories 10, 11 are generally a(j, i
), then the following arithmetic processing is performed over the entire field of view by changing j and i from 1 to n and from l to m, respectively.

First, the horizontal differentiation is d(j, 1) = a(j, 1) - a(j, i+cz)
= (1) (However, when i+α≧n, i+α is
Approximate it as α is an integer greater than or equal to 1, and the clay with the most common edges is selected. ) becomes. In other words, this corresponds to the difference between the density of the pixel before shifting the original image by α pixels to the right and the density of the shifted pixel. Therefore, d(j,
The value of i) is from -15 to +15 as described above.

Then, this signal 12-1 is converted to 2 by the binarization circuit 13.
As mentioned above, if the absolute value of the signal 12-1 is smaller than the predetermined value β, it is converted into a value “0”, and if it is larger, it is converted into a value “1”.
“ is output. In other words, it is expressed by the following formula.

(However, β is a threshold value, and the value at which edges appear most often is selected.) The data E(j, i) thus binarized is stored in the memory 14. With the above, the horizontal differentiation is completed.

Further, the vertical differentiation is performed in the same manner as the horizontal differentiation. That is, the vertical differentiation is d(j, 1) = a(j, i) - a(j+a, i)
=-(3) (However, when j+α≧m, change j+α to j
Approximate it as α is an integer greater than or equal to 1, and the value that produces the lowest edge value is chosen. ) becomes. The subsequent binarization processing is the same as that for the horizontal direction, and will therefore be omitted.

In this way, by logically processing each pixel of the horizontal differential and each pixel of the vertical differential, a contour image covering the entire screen can be obtained.

Although the operation of the logical OR calculation processing has not been described above, it goes without saying that these operations can be realized by ordinary methods used in this field.

Although the method for obtaining a contour image from a video image has been described above, it is difficult to obtain a desired contour image for the entire screen using only this method, depending on the shape of the subject and the lighting conditions. In other words, the above method applies when the light source 9 in Fig. 1 illuminates the subject 8 from only one direction, so as shown in Fig. 2, the outline of the part of the subject that will be in the shadow with respect to the light source is It becomes unclear.

As shown in FIG. ) and shines light on the subject 8. Then, (a) of FIG. 6 is a diagram showing the method of obtaining a desired contour image according to this embodiment.
, (b), and the contour images obtained from each are shown in (C) and (d) in Figure 6. As can be seen from each figure, each is only a portion of the desired contour image. Therefore, by synthesizing and editing the contour images shown in FIGS. 6(c) and 6(d), a desired contour image as shown in FIG. 6(e) can be obtained.

However, although the editing memory 5 in FIG. 1 has the same configuration as the binarized image memory 14 in FIG. 4, at least two sets are required for editing work. Note that the image memory 14 may also be used as is for the - group.

It goes without saying that each bit of this editing memory has a one-to-one correspondence with each pixel on the screen of the display device.

Therefore, while looking at the screen, it is possible to extract and edit desired portions of multiple contour images by using techniques used in normal display devices, such as specifying areas such as keys and cursor display, light ben, etc. .

Although this embodiment has been described as an example in which everything is configured with hardware, it is of course possible to manually input the A-D converted signal directly to a personal computer, etc., and perform operations including editing. .

(Effects of the Invention) As explained above, according to the present invention, edge extraction processing can be performed on a video image shot with the video camera and subject fixed in position each time the direction of light shining on the subject is changed. It is possible to provide a contour drawing method that can clearly obtain the entire circumference side of a pair of objects by editing the contour images of the object obtained in each direction.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing how a video image is divided into pixels, and FIG. 3 is a diagram showing the signal waveforms of each signal in FIG. 4 is a block diagram showing the configuration of the edge extraction circuit of this embodiment, FIG. 5 is a diagram showing the configuration of the memory of this embodiment, and FIG. 6 is a diagram showing the configuration of the edge extraction circuit of this embodiment. It is a figure which shows the method of obtaining a contour image. DESCRIPTION OF SYMBOLS 1... Video camera, 2... A-D conversion circuit, 3... Edge extraction circuit, 4... Signal processing control circuit, 5... Editing memory, 6... Editing control circuit, 7...Display device, 8...Subject, 9.
-Light source, 10,11j4-...Memory,
12... Subtractor, 13... Binarization circuit, 15-... Control circuit.

Claims (1)

[Scope of Claims] Edge extraction processing is performed on a video image signal obtained by shining light onto a subject from a plurality of directions, and a desired contour is extracted based on the video image signal that has been subjected to the edge extraction processing for each direction of light. A contour drawing method characterized in that the contour images are detected and temporarily stored in a plurality of memories, and the desired contour images for each direction of light stored in each memory are edited and combined to create a complete contour image of the object. .