JPH02253105A - Image measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an image measuring device that measures the position and shape of an object to be measured using an image signal obtained from a television camera. The present invention relates to an image measurement device that can improve resolution and accuracy beyond the limitations of using video signals from a television camera.

(Prior Art) Fig. 7 is a conceptual diagram of the configuration of an image measuring device to which the present invention is applied. An image processing unit that receives the video signal Vs from the camera TC performs predetermined image processing, measures the position and shape of the object to be measured, and outputs the measurement data.

This measurement data is sent and used, for example, to a system that assembles and inspects parts.

The video signal obtained from the television camera TC is defined by broadcasting standards, and consists of a plurality of scanning lines for an object image, which is two-dimensional information, and is a time-series signal.

<Problems to be Solved by the Invention> As described above, when performing image measurement using a television camera that outputs video signals defined by broadcasting standards, the resolution is determined by the number of scanning lines (number of pixels). A video signal for normal broadcasting has 525 scanning lines, of which approximately 480 contain valid pixel information.
It has been difficult to improve resolution and accuracy beyond this restriction. Recently, high-definition televisions with 1.1.25 scanning lines, called high-definition televisions, have appeared, but the television cameras used in these televisions are extremely expensive.

The present invention has been made in view of these circumstances, and provides an image measuring device that can perform inexpensive, high-resolution image measurements using a television camera that outputs normal video signals defined by current broadcasting standards. The purpose is to

<Means for Solving the Problems> The present invention for solving the above-mentioned problems consists of a video camera that captures an object to be measured, and an A/C system that uses a video signal specified by the broadcasting standard output from the video camera as a pixel signal. Pixel signals from a D converter and this A/D converter are input, and interpolation data is created by calculating the average density of the pixel itself and pixels adjacent to the pixel in the vertical and/or horizontal directions. and an interpolation data calculation section.

<Operation> By A/D converting the video signal, several bits of brightness (density value) data are obtained for each pixel, and the interpolation calculation unit calculates and calculates the density value around the pixel, The number of pixels is apparently increased using the obtained interpolation data.

This makes it possible to determine the north side of the position and shape with high accuracy.

<Example> Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, TC is a video camera that captures the object to be measured OB, and AD is an A/D converter that uses a video signal Vs defined by the broadcasting standard output from the video camera TC as a pixel signal.

NC is a pixel signal from the A/D converter AD (for example, 640
This is an interpolation data calculation unit that inputs a VD (consisting of 480 pixels) and calculates the average density of the pixel itself and pixels adjacent to the pixel in the vertical and/or horizontal directions to create interpolation data. Directional interpolator EH and vertical interpolator E
It is composed of V.

MU is an image memory in which pixel data and interpolation data created by the interpolation data calculation unit NC are sequentially written.Here, two image memories M1.MU are used to output even and odd scanning line signals. ．． M2 is used.

The operation of the apparatus configured as described above will be explained as follows.

First, the concept of operation in the interpolation data calculation section in the present invention will be explained.

Since the image from the A/D converter AD is considered to be a two-dimensional density distribution, this is expressed as ψ(x, y).

An image divided into pixels is a sample set at discrete points of ψ (x, y), that is, ψ (l ・ΔX, J ・Δy), where i, j: integers ΔX, Δy: considering the sample interval. good.

FIG. 2 is a conceptual diagram showing a two-dimensional density distribution of sampled pixels. In this figure, the circled part represents the position of a sample pixel, and the number surrounded by the circle represents the density of that pixel.

If the number of pixels is doubled in both the X direction and the y direction, this corresponds to finding the density value at the intermediate position (indicated by a + mark) of each sampled pixel.

When ψ(x, y) is expanded around (i·ΔX, j·Δy), it can be roughly expressed by the following equation.

ψ (x, y) - ψ (1・ΔX, j ・△y) y=j ・Δy 10 (δX2 δy2) However, x−i・Δχ10δX y−j ・Δy+δy, so δx=0 or Each combination of Δx/2 δy-o or Δy/2 (excluding the combination of δX-δy=O)
The value of equation (1) may be calculated for .

The interpolation data calculation section performs calculations for interpolating images according to equation (1).

In the following explanation, the image ψ(x, y) is defined as a two-dimensional array F (
1, J).

The image interpolated twice is also represented by F (I, J).

However, l<I<Imax, 1<J<Jmax, I,
Both J are integers. In this case, the image before interpolation is F (I, J), which is equivalent to knowing the odd values of both I and J.

In FIG. 3, if the symbol rAJ surrounded by a double frame is the image before interpolation, it is sufficient to calculate the values of three pixels α, β1 and γ.

1〉Calculation of the value of α Because it is, ψ (A) + ψ (B) Therefore, ψ(α) −F (1 (even number), J) becomes.

2〉Calculation of the value of β It can be found in the same way as <1>. ψ (β) − F (1, J (even number)) 3. Calculating the value of γ becomes.

As this value, (ψ(A)+ψ(D) l/2) may be used, but the following equation can be better approximated.

=F (1 (even number), J (even number)) becomes.

The interpolation data calculation unit NC can obtain the density value at each interpolation position by performing the interpolation calculation in <1> and then the interpolation calculations in <2> and <3>.

FIG. 4 shows the horizontal interpolator E in the interpolation data calculation section NC.
FIG. 5 is a block diagram showing an example of H, and a time chart showing its operation.

The latch circuit 11 receives data from the A/D converter AD as shown in FIG.
) is latched and stored at the clock timing shown in (b). The adder 12 adds the input data, VD, and the image data before the clock from the latch circuit 11, and outputs Σ(i) shown in the following equation as shown in (C).

Σ(i) −(1/2)f VD(i)+VD(+-1
)1 multiplexer 13 alternately selects and outputs the addition result Σ(i) from the adder 2 and the data V D (+-1) from the latch circuit 1-1, as shown in (d). do. The multiplier 14 doubles the clock to obtain clock 2. The pixel signal in the horizontal direction can be doubled by the output data VEH from the multiplexer 13 and the clock 2.

FIG. 6 shows the vertical interpolator E in the interpolation data calculation unit NC.
FIG. 2 is a block diagram showing an example of V.

The adder 22 receives the image data V from the horizontal interpolator EH.
, , and this image data is added to the image data of the previous scanning line applied via the 1-line delay device 2],
Obtain image data VBIIV that is the average (interpolation) of two scanning lines.

Here, by setting the data vgnv from the delay device 21- to the even line and the data VEHV from the adder 22 to the odd line, the image data is vertically interpolated.

The image data of each even-numbered line and odd-numbered line from this vertical interpolator EV are stored in the memory M1. of the image memory MU.
．． It is written to M2 at the same time.

After writing of image data for one screen is completed, if data is read out alternately or in parallel from these memories M1 and M2, a high resolution image can be obtained and highly accurate image measurement can be performed.

Note that although the above description has been made with a horizontal interpolator provided, this is not necessarily necessary. Furthermore, the interpolation data calculation unit may have a configuration other than that shown here.

<Effects of the Invention> As explained in detail above, according to the present invention, it is possible to perform low-cost, high-resolution image measurement while using a television camera that outputs 1η of normal video signals specified by current broadcasting standards. It is possible to provide an image W1 measuring device.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention, and FIG.
The figure is a conceptual diagram showing the two-dimensional density distribution of sampled pixels, Figure 3 is an explanatory diagram to explain the principle of interpolation operation, and Figure 4 is an example of a horizontal interpolator in the interpolation data calculation section. 5 is a time chart showing its operation, FIG. 6 is a block diagram showing an example of a vertical interpolator in the interpolation data calculation section, and FIG. 7 is an image measurement target of the present invention. FIG. 2 is a conceptual diagram of the configuration of the device. OB...Measurement object TC...Video camera A
D...A/D converter NC...Interpolated data calculation unit EH...Horizontal interpolator EV...Vertical interpolator M
U...Image memory] 4 Angle 2 Fig.■÷■・■1■10↑◎+■・■ヰO− [phase] ->X Fig. 3 Rorozuki country Iida angle ζ4 Fig. angle etc. 6 Fig. 2] 5th 4th (CI) HD] (b) Clock - Ding - L Ding] 2 [1 Ding] - "-Fig.

Claims (1)

[Claims] A video camera that captures an object to be measured, an A/D converter that uses a video signal specified by a broadcasting standard output from this video camera as a pixel signal, and An image measurement device that receives a pixel signal and includes an interpolation data calculation unit that calculates the average density of the pixel itself and pixels adjacent to the pixel in the vertical and/or horizontal directions to generate interpolation data.