JPH0757095A - Number of reference picture element setting method in image processor for length measurement - Google Patents

Abstract

PURPOSE:To exactly set the number of reference picture element even when the one end of a reference mark for setting a number of reference picture element is located at the middle of the point of the scale photographed on a screen. CONSTITUTION:A scale 3 existing on the same measuring surface S as an object W to be measured is photographed and the point D is displayed on a screen 2. After one end 1a of a reference mark 1 is made in coincidence with a point D0 of the scale 3, the other end side of the reference mark 1 is stretched along the longitudinal direction of the scale 3 and the other end 1b is also made in coincidence with an arbitrary point D3 in the scale 3. In this state, the number of picture element between the both ends 1a and 1b of the reference mark 1 is detected, the length between the points D0 and D3 that the both ends 1a and 1b indicate is read on the screen 2 and this length is inputted as a reference length L0. Based on a number G0 of picture element and the reference length L0, the number of picture element per unit length is calculated, and this number is set as a number M0 of reference picture element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference pixel number setting method for an image processing apparatus for length measurement which measures the distance between arbitrary two points of an object to be measured imaged on a screen.

[0002]

2. Description of the Related Art An image processing apparatus for length measurement sets in advance the number of pixels per unit length as a reference number of pixels, and compares the number of pixels between two points to be measured with the reference number of pixels. Is used to calculate the actual distance. When setting this reference pixel number, conventionally, as shown in FIG. 1, a reference mark 1 having a length of a preset number of pixels (for example, 100 pixels) is displayed on the screen 2 and the object to be measured is also set. An image of the scale 3 with a scale D placed on the same measurement surface S as W is imaged, and one end of the reference mark 1 is attached to an arbitrary scale D of the scale 3.
_In a state of being adjusted to ₀ , the operator visually reads the length of the reference mark 1 by referring to the scale D of the scale 3 (for example, 2.35 mm), and based on the value, the reference pixel number M ₀ is M _0. = 100 / 2.35 = 42.5532 (pixels / mm). Therefore, once this reference pixel number M ₀ is set, two arbitrary points P ₁ , P on the object to be measured W are set.
_{When 2} is imaged on the screen and the number of pixels between the two points is G, the actual distance L is obtained by L = G / M ₀ (mm),
The actual distance between any two points P ₁ and P ₂ can be easily calculated by image processing.

[0003]

However, both ends of the reference mark 1 do not necessarily match the scale D of the scale 3, and when the one end 1a is aligned with the scale D ₀ , the other end 1b is obtained.
When the mark is located between the scales D ₁ and D ₂ , the operator has to read the length by intuition, so that a reading error is included depending on the skill and subjectivity of the operator. Therefore, the reference pixel number M ₀ calculated as the number of pixels per unit length originally includes an error, and the length is measured based on the reference pixel number M ₀ including this error. However, there is a problem that the measurement result also includes a large error.

Each time the distance to the measurement surface is changed, a known length is measured on the measurement surface, a correction coefficient is obtained from the measured length and the actual length, and the correction coefficient is calculated. Although a method of measuring the length based on the above has been proposed (see Japanese Patent Laid-Open No. 60-263804), in this case as well, the original reference pixel number is set by the same means as the conventional one. No matter how much the correction coefficient is applied, the error in the measurement result does not become small. Therefore, it is a technical object of the present invention to enable anyone to set the reference pixel number accurately even when one end of the reference mark is located in the middle of the scale of the scale.

[0005]

In order to solve this problem, according to the present invention, an object to be measured is imaged on a screen in which each pixel is arranged in a matrix, and the object to be measured specified on the screen is displayed. Before measuring the actual distance by detecting the number of pixels between points and comparing the number of detected pixels with the number of pixels per unit length set as the reference number of pixels, the reference number of pixels is preset. A method of setting a reference number of pixels for a length measurement image processing device, comprising: [a] the length measurement image processing device displays a reference mark on a screen and a reference mark displayed on the screen. An operation means for expanding and contracting in the longitudinal direction and a pixel number detecting means for detecting the number of pixels between both ends of the reference mark are provided.
[B] A scale on the same measurement surface as the object to be measured is imaged and its scale is displayed on the screen, [c] One end of the reference mark is matched with the scale of the scale, and then the scale is measured. Stretch the other end of the mark along the length direction of the scale to match the other end with any scale of the scale,
[D] In this state, the number of pixels between both ends of the reference mark is detected by the pixel number detecting means, the length between the scales indicated by the both ends is read on the screen, and this is input as the reference length. [E] The number of pixels per unit length is calculated based on the number of pixels detected by the pixel number detection means and the reference length, and this is set as the reference pixel number.

[0006]

According to the present invention, with one end of the reference mark displayed on the screen aligned with an arbitrary scale formed on the scale, the other end of the mark is guided along the length direction of the scale. The other end can also be matched with the scale by expanding and contracting, so that the scale indicated by both ends of the reference mark can be accurately read, and the reading can be made by positioning the end of the reference mark between the scale and the scale. No error will occur. Then, the number of pixels per unit length can be easily calculated from the number of pixels between both ends of the detected reference mark and the length of the scale pointed by both ends of the reference mark, and this is set as the number of reference pixels. It

That is, since both ends of the reference mark can be matched with the scale scale by expanding and contracting the reference mark, there is no room for error based on the skill and subjectivity of the operator when reading the scale, and no one can operate it. However, the reference pixel number can be set accurately and the distance can be measured based on the reference pixel number, so that the error in the measurement result can be minimized.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on the embodiments shown in the drawings. FIG. 1 is an explanatory view showing a screen when setting the number of reference pixels by the method of the present invention, FIG. 2 is a flow sheet showing an image processing device for length measurement, FIGS. 3 to 5 are flowcharts showing the processing procedure thereof, FIG. 7 and 8 are explanatory diagrams showing another example of setting the reference pixel number.

In the figure, reference numeral 4 is an image of the object to be measured W on a screen 2 arranged in a matrix so that each pixel can be identified by XY coordinates, and two arbitrary points of the object to be measured W are displayed on the screen. 2) By specifying on 2, the number of pixels G between the two points is compared with the number of pixels per unit length set as the reference number of pixels M ₀ , and the actual distance L is measured. An image processing device, which includes a storage device 5, a computing device 6, and an input / output port 7
Equipped with a microcomputer.

Data and programs necessary for measuring the distance are stored in the storage device 5, and the arithmetic unit 6 executes arithmetic processing according to the programs. Then, at the input side of the input / output port 7, C for photographing the object to be measured W is taken.
A CD camera 8, a mouse 9 for moving the reference mark 1 displayed on the screen 2 and expanding / contracting the length thereof, and a keyboard 10 for inputting various data and commands are connected, and the screen 2 is provided on the output side. Display device 1 having
1 is connected. Further, on the same measurement surface S as the object to be measured W, the scale 3 on which the scale D is formed is placed parallel to the X axis of the screen, and when this is photographed by the CCD camera 8, the screen 2 shows A horizontal scale 3 and a reference mark 1 are displayed as shown in FIG.

Next, the processing procedure in the arithmetic unit 6 is shown in FIG.
~ It will be described with reference to the flowchart shown in FIG. First,
When the switch is turned on, the processing of the program shown in FIG. 2 is started, the CCD camera 8 is turned on in step (1) to take an image of the object to be measured W, and then the process proceeds to step (2) to set the reference pixel number setting key. It is determined whether or not (not shown) is pressed, and when the setting key is pressed, step (3)
If the setting key is not pressed, the process proceeds to step (4).

In step (4), a length measuring key (not shown)
It is determined whether or not is pressed, and when the length measurement key is pressed, the process proceeds to step (5) to set the length measurement mode,
If the length measuring key is not pressed, the process returns to step (2).
Then, in the step (3), the subroutine shown in FIG. 4 is executed, and in the step (5), the subroutine shown in FIG. 5 is executed.

FIG. 4 is a subroutine executed when the reference pixel number setting mode is set in step (3). First, in step (6), the measurement object is placed on the same measurement surface S as the object to be measured W. The scale 3 thus created is picked up by the CCD camera 8 which is turned on in step (1) and displayed on the display device 11, and the process moves to step (7) to display the reference mark 1 on the screen 2.

Next, in step (8), the left end 1a of the reference mark 1 is moved using, for example, the mouse 9 so that the left end 1a of the reference mark 1 exactly overlaps the arbitrary scale D ₀ of the scale 3. Press (not shown). Then, the process proceeds to step (9), and the reference mark 1
The mark 1 is expanded and contracted using the mouse 9 so that the right end 1b of the mark 1 is exactly overlapped with the other scale D _3, and the click button is pressed when the mark 1 is overlapped.

Next, in step (10), the number of pixels G ₀ between both ends 1a and 1b of the reference mark 1 is detected.
This is calculated from the coordinates of the positions of both ends 1a and 1b of the reference mark 1. Then, in step (11), the length between the scales D ₀ and D ₃ indicated by both ends 1a and 1b of the reference mark 1 is read from the scale on the screen 2, and the value is set as the reference length L ₀ from the keyboard 10. input.

Next, in step (12), the number of pixels per unit length is calculated based on the number of pixels G ₀ and the reference length L ₀ , and this is set as the number of reference pixels M ₀ .
At this time, the reference pixel number M ₀ is calculated by M ₀ = G ₀ / L ₀ . In the above description, steps (1) and (6) are means for displaying the reference mark 1, steps (8) and (9) are means for expanding and contracting the reference mark 1, and step (10) is a pixel number detecting means. Is a specific example of.

FIG. 5 is a subroutine executed when the measurement mode is set in step (4), in which the object to be measured W is displayed in step (13), and steps (14) and (15) are displayed. ) At arbitrary two points P ₁ , P on the object to be measured W
_Second coordinate _{(X 1, Y 1) (} X 2, Y 2) detects, based on the coordinates in step (16) the distance G of the screen 2 between the two points P _1, P ₂ by the following formula calculated, G = ^{_{[(X 1 -X 2) 2 +}} (Y 1 -Y 2) 2 ] ^1/2 point P ₁ on the basis of the step (17) in the reference number of pixels M _0, actually between P ₂ of The distance L of is calculated by the following equation and displayed. L = G / M ₀

Next, a method of setting the reference pixel number of the image processing device for length measurement will be described. First, before starting the measurement, as shown in FIG. 1, the CCD camera 8 captures an image of the scale 3 placed on the same measurement surface S as the object to be measured W and displays it on the screen 2 of the display device 11. Then, the reference length L ₀ is input from the keyboard 10 and stored in a predetermined storage area of the storage device 5.

Next, the reference mark 1 displayed on the screen 2 is moved by the mouse 15, and when the left end 1a of the reference mark 1 exactly matches the scale D _{0 of the} scale 3, the click button is pressed to detect the coordinates of the left end 1a. Then, this time, the right end side of the reference mark 1 is expanded and contracted so that the right end 1b is exactly aligned with the scale D ₃ of the scale ₃ , and the click button is pressed to detect the coordinates of the right end 1b. At this time, if a well-defined scale is selected as the scales D ₀ and D ₃ , the scales can be read very easily without causing misreading.

Then, both ends 1 of the detected reference mark 1 are detected.
The number of pixels G ₀ between both ends is calculated from the coordinates of a and 1b, and the scale D indicated by both ends 1a and 1b of the reference mark 1 is calculated.
_When the length (for example, 3 mm) between ₀ and D ₃ is read and the value is input from the keyboard 10 as the reference length L ₀ , the number of pixels G _{0, the} number of pixels per unit length based on the reference length L ₀ The number is calculated and set as the reference pixel number M ₀ .

In this case, for example, in the case where the left end 1a of the reference mark 1 is aligned with the scale D ₀ , the right end 1b is located between the scales D ₁ and D ₂ of the scale 3. Also, by expanding and contracting the reference mark 1, both ends 1a and 1b of the reference mark 1 can be matched exactly with the scales D ₀ and D ₃ , so that the length of the reference mark 1 can be read according to the scale. Since there is no room for an error based on the skill level or subjectivity of No. 1 and the reference pixel number can be accurately set by anyone, it is possible to minimize the error in the measurement result.

FIG. 6 shows another embodiment. In this example, an index Q, which is a mark X for designating a position, is displayed on the screen 2, and two arbitrary scales D ₀ and D _{3 of the} imaged scale 3 are displayed. Is specified by the index Q, the number of pixels between the scales D ₀ and D ₃ indicated by the index Q is detected, and the scale D
_0, enter the reference length L ₀ to read the length between D _3, calculates the number of pixels per unit length on the basis of the the detected pixel number G ₀ reference length L _0, this The reference pixel number M ₀ is set.

FIG. 7 is an explanatory view showing still another embodiment. In this embodiment, as the scale of the scale 3, one having two reference points A and B separated by a distance L ₀ is used. . Then, the XY coordinates A of the reference points A and B on the screen 2
(Xa, Ya), B (Xb, Yb) are detected by the index Q represented by the intersection of the horizontal line H and the vertical line V, and the reference point A,
The number of pixels G ₀ between B is G ₀ = [(Xa-Xb) ² + (Y
a-Yb) ² ] ^1/2 . In this way, the distance G ₀ between the reference points A and B can be calculated by the number of pixels without placing the scale 3 parallel to the X axis, and the reference pixel can be calculated from the number of pixels G ₀ and the reference length L _0. Number M ₀
Can be accurately calculated.

[0024]

As described above, according to the present invention, with one end of the reference mark aligned with the scale of the scale,
Since the mark can be expanded and contracted and the other end can be matched with the scale, the scale indicated by the reference mark can be accurately read, and there is no room for error based on the skill and subjectivity of the operator when reading the scale. , The reference pixel number can be set accurately by anyone, and the distance can be measured based on this reference pixel number, which is extremely excellent in that the error in the measurement result can be minimized. effective.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a screen when setting a reference pixel number by the method of the present invention.

FIG. 2 is a flow sheet showing an image processing device for length measurement.

FIG. 3 is a flowchart showing an example of a processing procedure.

FIG. 4 is a flowchart showing an example of a processing procedure.

FIG. 5 is a flowchart showing an example of a processing procedure.

FIG. 6 is a diagram showing another example of a screen when setting the reference pixel number.

FIG. 7 is a diagram showing another example of a screen when setting the reference pixel number.

[Explanation of symbols]

1 ... Reference mark 2 ... Screen 3 ... Scale D, D _{0 to} D ₃
... Scale Q ... Indicator A, B ... Reference point

Claims (2)

[Claims] 1. A pixel between two points of an object to be measured (W) designated on the screen (2) by imaging an object to be measured (W) on a screen (2) in which each pixel is arranged in a matrix. detecting the number, the detected number of pixels and the reference number of pixels (M ₀₎ before measuring the actual distance by comparing the number of pixels per unit length is set as the reference number of pixels (M ₀ ) Is set in advance, the reference pixel number setting method for the image-measuring device for length-measuring, wherein [a] the image-processing device for length-measuring has a display means for displaying the reference mark (1) on the screen (2). An operation means for expanding and contracting the reference mark (1) displayed on the screen (2) in the longitudinal direction, and a pixel number detecting means for detecting the number of pixels between both ends (1a, 1b) of the reference mark (1). [B] The scale (3) on the same measurement surface (S) as the object to be measured (W) is imaged, and the scale (D) is described above. Is displayed on the face (2), [c] After the end of the reference mark (1) (1a) were consistent on the scale (D ₀₎ of the scale (3), the other end of the reference mark (1) By expanding and contracting along the length direction of the scale (3) so that the other end (1b) also matches the arbitrary scale (D ₃ ) of the scale ( ₃ ), and [d] in this state, the reference mark (1) Both ends of (1a, 1b)
The number of pixels between them is detected by the pixel number detecting means, and the length between the scales (D ₀ , D ₃ ) indicated by both ends (1a, 1b) is read on the screen (2) and this is used as the reference length. (L ₀ )
[E] The number of pixels per unit length is calculated based on the number of pixels (G ₀ ) detected by the number-of-pixels detecting means and the reference length (L ₀ ), and this is calculated as the reference number of pixels ( M ₀ ) is set as the reference pixel number setting method of the image processing device for length measurement. 2. A pixel between two points of an object to be measured (W) designated on the screen (2) by imaging an object to be measured (W) on a screen (2) in which each pixel is arranged in a matrix. detecting the number, the detected number of pixels and the reference number of pixels (M ₀₎ before measuring the actual distance by comparing the number of pixels per unit length is set as the reference number of pixels (M ₀ ) Is set in advance, the reference pixel number setting method of the image-measuring device for length measurement, [a] the image-processing device for length measurement displays an index (Q) designating a position on the screen (2). A display means, an operation means for moving the index (Q) to an arbitrary position, and a pixel number detection means for detecting the number of pixels between two points designated by the index (Q). The scale (3) existing on the same measurement surface (S) as the object (W) is imaged and its scale (D) is displayed on the screen (2). So, [c] two graduations of the scale _{(3) (D 0, D} 3)
Is designated by the index (Q), [d] In this state, the number of pixels between the two points indicated by the index (Q) is detected by the pixel number detecting means, and the scale (D ₀ , D ₃ ) is also detected. The length of the interval is read on the screen (2) and is input as the reference length (L ₀ ). [E] The number of pixels (G ₀ ) detected by the pixel number detecting means and the reference length (L ₀ ). ₀ ), the number of pixels per unit length is calculated, and the number of pixels is set as the reference number of pixels (M ₀ ).