JPH0387603A - Image measuring device - Google Patents

Abstract

PURPOSE:To reduce the cost, and also, to quicken the processing time by varying a size of a picture element in accordance with density of an image signal photographed by a television camera. CONSTITUTION:Input digital image data (ui) of every picture element is inputted to a conversion table 10, and data (vi) for showing a size of a picture element determined clearly against a density value (brightness) of (ui) is outputted. Subsequently, the conversion data (vi) of every picture element is outputted from the table 10, and inputted to an arithmetic circuit 11. The circuit 11 inputs (vi) at every picture element, and executes an integration SIGMAvi of the input (vi), and integrations SIGMAvixi, SIGMAviyi of multiplication of vi by (x) or (y) coordinate data. When these operations are ended, the centroid coordinate of a measuring object can be derived by an expression. Arithmetic data of these measuring objects is outputted from the circuit 11.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an image measuring device that measures the size and position of an object to be measured using digital image data of the object, and more specifically, The present invention relates to an image measurement device that can improve resolution beyond the limitations of video video signals.

(Prior Art) FIG. 5 is a conceptual diagram of the configuration of an image measuring device to which the present invention is applied. In the figure, 1 is an object to be measured, 2 is a television camera that photographs the object to be measured 1, and 3 is an image in which the size and position of the object to be measured 1 are calculated by inputting the video signal from the television camera 2. This is the processing section. The measured size and position of the measurement object 1 are output as measurement data.

Such a system is used, for example, in the process of assembling and inspecting parts. The video signal obtained from the television camera 2 is defined by broadcasting standards, and is a time-series signal that consists of a plurality of scanning lines representing an object image, which is two-dimensional information.

(Problem to be Solved by the Invention) 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. this house,
The number of scanning lines containing valid pixel information is approximately 480, and it has been difficult to improve resolution and accuracy beyond this restriction. Recently, a high-definition television with 1125 scanning lines called high-definition television has been developed, but the television camera used in this television is very expensive.

Therefore, the present inventors filed a patent application for an image measuring device that eliminates such defects (Japanese Patent Application No. 0176193, hereinafter referred to as the prior invention). FIG. 6 is a block diagram of the structure of the invention. This device converts the video signal of the object to be measured OB photographed by a conventional video camera TC into an A/D converter AD.
After converting the converted image data into digital chill data, the interpolation data calculation unit NC generates image data interpolated from the density values of surrounding pixels at each position between each pixel in the horizontal and vertical directions. As if pushing in,
The appearance is that the resolution of the upper image has been increased.

The interpolation data calculation unit NC is composed of a horizontal interpolator EH and a vertical interpolator EV. The image data for each pixel and the interpolation data created by the interpolation data calculation unit NC are sequentially written into the image memory MU.

Here, the image memory MU is divided into memories M1 and M2 for each even-numbered and odd-numbered scanning line, and data is written therein.

The invention of this prior application has a certain effect in that it improves the poor resolution due to the limitations imposed by the television camera. However, the horizontal interpolator El is composed of a latch that holds data, an adder, a data selector, and a clock multiplier, and the vertical interpolator EV is composed of a 1-line delay and an adder. Therefore, the amount of hardware is large and the cost is high. Further, in this prior invention, since the number of pixels is four times 2×2, the amount of calculation processing increases and the processing takes time.

The present invention has been made in view of these problems, and it is an object of the present invention to provide an image measuring device that is low in cost and has a fast processing time.

(Means for Solving the Problems) The present invention solves the above-mentioned problems in an image measuring device that reads an object to be measured as digital image data and measures the size and position of the object. A conversion table that receives input digital image data, converts it into data of a size corresponding to the density of the input digital image data, and outputs the data; It is characterized by being equipped with an arithmetic circuit that performs integration calculations and determines the center of gravity of the image to be measured.

(Function) The size of the pixel is changed according to the density of the image data for each pixel among the image signals of the object to be measured.

By performing such conversion, it is possible to improve the resolution and accuracy of image data captured even in a conventional imaging method using a television camera.

It is assumed that the photograph was taken. The area where the object to be measured covers all of each pixel has a size of 1, and the area where the object to be measured covers only part of each pixel has a smaller density, so it is converted to a pixel with a size corresponding to that density. do. Its size is 051°0 as shown in the figure.2. It is changed to 0.8 according to the density data of the pixel. As a result, the image is converted into an image that reflects the fine structure of the outline of the object to be measured, so that resolution and accuracy can be improved.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a conceptual diagram showing an embodiment of the present invention. In the figure, reference numeral 10 denotes a conversion table that receives input digital image data for each pixel, converts it into data of a size corresponding to the density of the input digital image data, and outputs the data.
Reference numeral 1 denotes an arithmetic circuit which receives the output of the conversion table 10 and two-dimensional coordinate data X+y, performs an integration operation on these input data, and calculates the center of gravity of the image to be measured. As the conversion table 10, for example, an LUT (lookup table) is used. In other words, the input digital image data U
is received as an address, and data indicating the size of the pixel stored at the address indicated by the input address is output as data V. The operation of the circuit configured as described above will be explained as follows.

Input digital image data ui for each pixel is entered into a conversion table 10, which outputs data vi indicating the size of the pixel that is uniquely determined with respect to the density value (brightness) of uf. Here, the output vi is a function of the input ui, and is expressed by the following equation.

v i-f (u i) (1) (1
) conversion is performed for each pixel. In order to perform such an operation, a look-up table (LUT) made of memory (ROM, RAM, etc.) with addresses connected to U and data connected to V is used.

Conversion data vi for each pixel is output from the conversion table 10 and enters the arithmetic circuit 11. The arithmetic circuit 11 inputs vi for each pixel, and calculates the sum Σv of the multiplication of the input v1 (corresponding to finding the area) Σvi and the x, y coordinate data.
Perform i x l, Σviyi. When these calculations are completed, the coordinates of the center of gravity of the object to be measured, which are expressed by the following equation, can be determined by the following equation.

Σvixf/Σvi (x-axis direction) (2) Σviyi/Σ
vi (y-axis direction) (3) These calculation data of the object to be measured are output from the calculation circuit 11.

FIG. 2 is a block diagram showing an example of the configuration of an area calculator in the calculation circuit 11. Output data V from conversion table 10
l enters one input of adder 20. Initially, the output of the data latch 21 is cleared O1, so the output of the adder 20 becomes vl. This vl is data latch 21
latched to. The next data v2 enters one input of the adder 20 and is latched in the data latch 21.
It is added to l. The addition result V+ +v2 is latched into the data latch 21. By repeating such a sequence, Σvi is latched into the data latch 21. The data latch 21 whose processing has been completed is cleared.

FIG. 3 is a block diagram showing an example of the configuration of the center of gravity calculator in the calculation circuit 11. Output data v from conversion table 10
1 enters the subsequent multiplier 22 and is multiplied by the X coordinate value x1. As a result, vl_Xl is latched into data latch 24. Next, the incoming data V2 and the X coordinate x2 are multiplied by the multiplier 22, and the result v2 x2 enters the adder 23 and is added to the content vl xl of the data latch 24.

Addition result V+ X+ +v2 X2 is data latch 24
latched to. Thereafter, such a sequence is repeated, and Σvixt is latched in the data latch 24.

The data latch 24 whose processing has been completed is cleared. Although only the X direction has been described above, the same applies to the Y direction, and Σviyi is latched in another latch.

In this way, the areas Σvi and Σvixi for each pixel,
Once Σviyi is determined, the center of gravity of the object to be measured can be determined using equations (2) and (3). The circuits shown in FIGS. 2 and 3 described above can also be realized in software using a microcomputer, a digital signal processor (DSP), or the like.

In the above-described embodiments, the center of gravity and the like of one object to be measured are measured, but the present invention can be similarly applied to two or more objects to be measured. In that case, a circuit as shown in FIG. 4 is used as the arithmetic circuit 10.

In the figure, the same parts as in FIG. 2 are designated by the same reference numerals. The input data vi is labeled by the labeling circuit 30 for each object. On the other hand, the area Σvi of the input data vL is determined by an arithmetic circuit composed of an adder 20 and a data latch 21. The determined area Σvi is stored in the RAM 31 designated by the circuit 30 with a label.

If the same operation is performed for all measurement objects, the RAM
31, the area data of all objects will be held.

The circuit in Figure 4 is a cumulative calculation circuit for area.
In the case where the multiplication of the data vi and the coordinates Xy is performed as shown in FIG. 3, calculations can be made in the same way for a plurality of measurement objects.

In the above explanation, an LUT was used as the conversion table, but the present invention is not limited to this, and the conversion table is
AM, and the control CPU may write a different conversion table depending on the measurement conditions each time.

(Effects of the Invention) As described above in detail, according to the present invention, by changing the size of the pixel according to the density of the image signal photographed by the television camera, resolution and precision can be improved. can be improved.

[Brief explanation of drawings]

FIG. 1 is a conceptual configuration diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of the configuration of an area calculator, FIG. 3 is a block diagram showing an example of the configuration of a center of gravity calculator, and FIG. A diagram showing another example of the configuration of the area calculator, FIG. 5 is the configuration Il of the image measuring device.
FIG. 6 is a block diagram of the configuration of the prior invention, and FIG. 7 is an explanatory diagram of the operation of the present invention. 10... Conversion table 11... Arithmetic circuit 20.
...Adder 21...Data latch 22...
・Multiplier 23... Adder 30... Labeled circuit 31... RAM Figure 3 t Figure 5

Claims (1)

[Claims] Reading the object to be measured as digital image data,
In an image measuring device that measures the size and position of the object to be measured, a conversion table receives input digital image data for each pixel, converts it into data of a size corresponding to the density of the input digital image data, and outputs the data. and an arithmetic circuit that receives the output of the conversion table and two-dimensional coordinate data, performs an integration operation on these input data, and determines the center of gravity of the image to be measured.