JPH045505A - Image processor - 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] [Field of Industrial Application] This invention provides an image that can be processed with high resolution by converting an output signal from a CCD line image sensor that images an object to be measured into a binary signal. It relates to a processing device.

[Prior art] An image of an object to be measured is captured using a CCD (Charge Couple CCD).
pledDevice) is projected onto a line image sensor, and the output signal of this CCD line image sensor is extracted as a binary signal. Then, edge information of the object to be measured is obtained from this binary signal.

FIG. 4 is a block diagram showing a schematic configuration of a conventional device for obtaining a binary signal from a CCD line image sensor.

In the apparatus shown in FIG. 4, a CCD line image sensor 1 is driven by a clock pulse from a clock generation circuit 2.
Obtain an analog output signal from.

This output signal is sent to an analog-to-digital (A/D) converter 3.
This converted digital signal is set to the A input terminal of the digital comparator 4. Further, since a signal of a predetermined threshold value is input to the B input terminal of the comparator 4, a binarized signal is obtained from the A>B output terminal.

FIG. 2(a) shows the waveform of one line of image signals on the CCD line image sensor. In the figure, A indicates the object to be measured between the light source (not shown) and the CCD line image sensor 1. This is the part of the shadow image when placed.

Further, FIG. 2(b) is an enlarged waveform diagram of the falling portion A due to the shadow of the object in the signal waveform of FIG. 2(a).

When using a CCD line image sensor in which the size of one pixel of the CCD line image sensor in FIG. If so, the resolution of this device is only about 14 pm.

[Problems to be Solved by the Invention] There is a problem in that the resolution of the CCD line image sensor of the conventional device as described above is limited by the size of one pixel. Therefore, in order to use a CCD line image sensor with higher resolution, first
The output signal of the CD line image sensor is A/
D-convert the data, import this A/D-converted data into a CPU, etc., calculate a least squares function from this imported data, and use the calculated function to obtain a resolution smaller than 1 pixel. was.

On the other hand, if a function is found by fitting data using software, it takes a lot of processing time, and it is difficult to perform real-time processing.

In addition, by increasing the magnification of the optical system in front of the CCD line image sensor, the object can be made larger and
There is also a conventional method of projecting onto a D-line image sensor to obtain high resolution.

However, when the magnification of the optical system is increased, the optical path length increases, making the device larger. In addition, the increased optical path length requires a higher-intensity light source.

The present invention was made to solve these problems, and is an apparatus that does not require an enlarged apparatus, does not require a particularly high-intensity light source, and has a short processing time.
An object of the present invention is to provide an image processing device capable of high-resolution processing.

[Means for Solving the Problems] In order to achieve the above object, an image processing device of the present invention projects an image of an object to be measured onto a CCD line image sensor, and converts the CCD line image sensor into a frequency fAD. /N (where N is a positive integer) to extract an output signal, input the extracted output signal to an analog-to-digital converter via a low-pass filter, and perform this analog-to-digital conversion. converting the analog signal from the low-pass filter into a digital signal by driving the device with a clock pulse of frequency fAD, and forming a binarized signal by comparing the converted digital signal with a predetermined threshold value. It is something to do.

[Operation] According to the present invention, it is possible to appropriately select the frequency fAD of the clock generation circuit and the frequency division ratio N of the frequency divider, thereby easily obtaining an arbitrary resolution.

Furthermore, since processing is performed using a specific circuit rather than software, processing can be performed in real time.

[Embodiment] FIG. 1 is a block diagram showing a schematic configuration of a main part of an embodiment of an image processing apparatus of the present invention.

In FIG. 1, 5 is a low-pass filter (LPF), 6
is a frequency divider, and since the same reference numerals as in FIG. 4 indicate the same or corresponding parts, detailed explanation will be omitted.

3(a) is a waveform diagram of the output signal of the LPF 5, and FIG. 3(b) is a signal waveform diagram obtained by A/D converting the signal in FIG. 3(a) using a clock pulse of frequency fAD.

Next, the operation of the apparatus shown in FIG. 1 will be explained.

The clock generation circuit 2 generates a clock pulse with a frequency fAD, and the clock pulse is divided into 1/N by the frequency divider 6.
(N is a positive integer; in this embodiment, N=14) to create a clock pulse of frequency fAD/14.

The CCD line image sensor 1 is driven by a clock pulse having a frequency fA,/14 divided by the frequency divider 6, and an output signal of the CCD line image sensor 1 is obtained at the data rate of that frequency.

At this time, if there is an object within the field of view of the CCD line image sensor l relative to the light source (not shown) of transmitted light, the output signal will be as shown in FIG. 2(a). When the part A in Figure 2(a) is enlarged, as shown in Figure 2(b), CC
Each pixel of the D-line image sensor 1 produces a stepped output signal.

When a signal having the waveform shown in FIG. 2(b) is inputted to the LPF 5, a signal without steps as shown in FIG. 3(a) is obtained. At this time, it is assumed that the diagonal portion is a straight line.

Next, the output signal of the LPF 5 is A/D converted using a clock pulse having a frequency fAD from the clock generation circuit 2. That is, A/D conversion is performed using a clock pulse having a frequency 14 times that of a clock pulse having a frequency fA,/14 that drives the CCD line image sensor 1. As a result, A/
As shown in Fig. 3(b), the data after D conversion can be A/D converted at the speed of dividing one pixel into 14, and the output of the A/D converter 3 is the l of one pixel. /14. That is, C
The size of one pixel of a CD line image sensor is 14X1.
At 4 pm, it is possible to output the resolution of Igm.

When this data is set to the A input terminal of the digital comparator 4 and a predetermined threshold value is set to the B input terminal, a binarized signal is output to the A>B output terminal of the comparator 4. . The binarized signal thus obtained has a resolution 14 times that of one pixel of the CCD line image sensor l.

[Effects of the Invention] As described above, according to the present invention, all signal processing is performed by constructed circuits, so that processing can be performed in real time compared to a method using software.

Further, by appropriately selecting the frequency fAD and the frequency division ratio N, a signal with arbitrary resolution can be easily obtained.

Furthermore, since there is no need to increase the magnification due to the optical system provided upstream of the CCD line image sensor, the device can be made compact, and as a result, a very high-intensity light source is not required.

[Brief explanation of the drawing]

WS1 is a block diagram showing a schematic configuration of the main parts of an embodiment of the image processing device of the present invention, and FIG. 2(a) is a CC
A waveform diagram of the image signal for one line of the D-line image sensor. Figure 3(b) is an enlarged waveform diagram of the falling part due to the shadow of an object in the signal waveform of Figure 3(a). Figure 3(a) is an enlarged waveform diagram of the falling part due to the shadow of an object. LPF5
Fig. 4 shows the waveform of the output signal from the CCD line image sensor. 1 is a block diagram showing a schematic configuration of a conventional device for obtaining In the figure, CCD line image sensor clock generation circuit A/D converter comparator PF frequency divider agent patent attorney 1) Kitatake Haruy's French arrangement (b)

Claims (1)

[Claims] An image of the object to be measured is projected onto a CCD line image sensor, and the CCD line image sensor is
A_D/N (where N is a positive integer) clock pulse is used to extract an output signal, and this extracted output signal is input to an analog-to-digital converter via a low-pass filter. converter to frequency f_A_D
converting the analog signal from the low-pass filter into a digital signal by driving with a clock pulse of Image processing device.