JPH0633361Y2 - Image reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image reading apparatus for detecting a reference position of an image recognition object.

[Prior Art and its Problems] Recently, a method of recognizing an object from image information obtained from a TV camera has been widely used for the purpose of positioning parts and robots.

Therefore, conventionally, as a method of detecting the reference position of the target object in this way, after preprocessing the composite video signal from the TV camera capturing the recognition target object by an amplifier and a filter, the threshold level is detected. There is a method in which binary image data is generated by using, and binary image data is generated, such image data is written in a frame memory, and then necessary data processing is performed by a general-purpose or dedicated processor.

However, in such a method, since the entire image of the recognition target object is input to the frame memory and image processing for position detection is performed, the amount of processed data becomes enormous and the detection result cannot be obtained. Takes a long time,
There is a drawback that it cannot be used as a real-time detection result.

Therefore, in order to reduce the amount of data to be processed, a method of setting a window and processing only the data in the range of this window is considered, but in the case of a fixed window, if the recognition target is out of the window However, there is a drawback that stable position detection cannot be performed, such as the fact that it cannot be recognized.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object thereof is to provide an image reading device capable of accurately detecting a reference position of an image recognition target in real time.

[Summary of the Invention] The present invention provides a sampling clock counting unit that counts a sampling clock and is cleared by a horizontal synchronizing signal, a horizontal synchronizing signal counting unit that counts a horizontal synchronizing signal and is cleared by a vertical synchronizing signal, and an image signal. A black level counting means for counting the sampling clock during the black level and clearing at the white level is provided, and the count value of the black level counting means is compared with the reference value. When the value becomes large, the contents of the sampling clock counting means and the horizontal synchronizing signal counting means are stored in the horizontal position and vertical position storage means, and the reference value is subtracted from the value stored in the horizontal position storage means to be recognized. The reference position of the image recognition target object is detected by obtaining the horizontal position of the object.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of the embodiment. In the figure, reference numeral 1 is a master CPU, and an object to be recognized (not shown) from a projector 13 via a projector controller 12 under the control of this CPU 1.
Is irradiated with light. From this state, the composite video signal including the recognition target captured by the TV camera 14 is given to the A / D converter 16 via the amplifier 15.

Then, the signal digitized by the A / D converter 16 is
It is displayed on the monitor 18 via the CG memory 17.

On the other hand, the image data obtained through the A / D converter 16 is controlled by the image processor 19 and written in the image memory 20, and the image position detecting unit 21 detects the horizontal and vertical directions of the recognition object. The position is detected, and thereafter, the horizontal position correction unit 22 further corrects the horizontal position,
The reference position of the recognition object is detected.

Since the reference position of the recognition object is processed in real time as described below, the image memory is not necessary for detecting the reference position. However, in the present embodiment, the image memory is provided so that the image information can be used when executing other processing.

Next, FIG. 2 shows a circuit configuration of the image position detecting section 21. In this case, the sampling clock CLK is given to the counter 23, and the output of the counter 23 is given to the horizontal position latch 24. In addition, the horizontal sync signal HD is
The output of this counter 25 is given to the vertical position latch 26
Given to.

On the other hand, the sampling clock CLK and the black level image signal corresponding to the recognition object or the print stain are AND gate 27
Of the AND gate 27, and the output of the AND gate 27 is given to the counter 28. The output of the counter 28 is given to one input terminal of the comparator 29. This comparator
To the other input terminal of 29, a digital signal of several pulses (m) for ignoring dust and print stain is given as comparison data.

The output of the comparator 29 is given to one input terminal of the AND gate 30. The output of the toggle F / F 31 is applied to the other input terminal of the AND gate 30 via the inverter 32. The output of the AND gate 30 is given to the pulse generating circuit 33. The pulse generating circuit 33 outputs a latch pulse, and this output is given to the horizontal position latch 24 and the vertical position latch 26, and the counter 23 at this point
The count contents of 25 and 25 are respectively latched, and these are used as horizontal position output and vertical position output. Also, the output from the pulse generation circuit 33 is a toggle F.
/ Give to F31. This toggle F / F31 is designed to be cleared once when the sensor output or the output of the manual switch is given as the image capture start signal ST, and outputs the RDY signal when the output of the pulse generating circuit 33 is given. .

The signal S1 and the counter 28
Signal S2 is given to the CLEAR terminal of
1 and S2 are binary signals obtained from video waveform signals. Here, the signal S1 is normal binary image data. Further, the signal S2 is obtained by setting the threshold level at a position several mV higher than the pedestal level of the composite video signal, so as to distinguish the actual video part (high level) from the other part (low level). It has become. Further, the vertical synchronizing signal VD is applied to the CLEAR terminal of the counter 25.

Next, the operation of the embodiment thus configured will be described.

Now, when the composite video signal capturing the recognition target object is output by the TV camera 14, it is given to the A / D converter 16 via the amplifier 15, and is digitized here to the monitor 18 via the CG memory 17. Is displayed. On the other hand, the output from the A / D converter 16 is written in the image memory 20 as image data, and the position of the recognition object is detected by the image position detector 21. Here, when a screen including the print stain A and the recognition object B as shown in FIG. 4 is given, the horizontal scanning 1H by the first horizontal synchronizing signal HD is as shown in FIG. Since the black level image signal is not supplied without including the print stain and the recognition target B, the output is not generated from the AND gate 27 even if the sampling clock CLK shown in FIG. 28 count operation is not performed. The sampling clock CLK is counted by the counter 23. Furthermore, horizontal scanning 1H
The horizontal synchronizing signal HD of is counted by the counter 25.

When the first horizontal scan 1H is completed, the next horizontal sync signal HD moves to the horizontal scan 2H. In this case, first, as shown in FIG. 3 (c), the contents of the counter 13 are cleared by the fall of the S2 signal. After that, a black level image signal corresponding to the print stain A is input as shown in FIG. This signal is applied to one input terminal of the AND gate 27, and at the same time, the sampling clock CLK is applied to the other input terminal.
This allows the sampling clock from AND gate 27.
An output corresponding to CLK is generated, and this is given to the counter 28 and counted. (At the time when this counting is started, the counter 28 is cleared in advance by the signal S1 corresponding to the print stain A.) Then, the count value of this counter 28 is given to the comparator 29, where dust and dirt are collected. It is compared with the comparison data CD consisting of a digital signal of several pulses for ignoring print stains. In this case, the count value of the counter 28 corresponds to the print stain A, and the comparison data CD
Since it is smaller, no output is generated from the comparator 29. In this state, the counter 23 continues counting the sampling clock CLK, and the counter 25 is incremented by +1 by the horizontal synchronizing signal HD of the horizontal scanning 2H.

Next, as shown in FIG. 3A, when the black level image signal corresponding to the recognition target B is input following the print stain A, this signal is given to one input terminal of the AND gate 27, At the same time, the sampling clock CLK is applied to the other input terminal. As a result, an output corresponding to the sampling clock CLK is generated from the AND gate 27, and this is given to the counter 28 and counted. (At the time when this counting is started, the counter 28 is cleared in advance by the signal S1 corresponding to the recognition object B.) Then, the count value of this counter 28 is given to the comparator 29, where the dust is collected. It is compared with comparison data CD consisting of digital signals for several pulses for ignoring print stains. In this case, the count value of the counter 28 is a sufficient value corresponding to the width dimension of the recognition object B, so that it becomes coincident with the comparison data CD, and an output is generated from the comparator 29, which is given to the AND gate 30. To be In this case, if the screen capture start signal ST is given to the toggle F / F31 in advance, the toggle F / F31 is cleared, and the AND gate 30 is provided with the "1" output via the inverter 32, The output of the AND gate 30 is given to the pulse generation circuit 33, and the latch pulse is output.

Then, this latch pulse is given to the horizontal position latch 24 and the horizontal position latch 26, and the counter at this time is counted.
The contents of 23 and 25 are respectively latched. As a result, the contents of the horizontal position latch 24 are obtained as the vertical position output, and the contents of the horizontal position latch 26 are obtained as the vertical position output.

By the way, the position in the horizontal direction of the recognition target object B thus detected includes the width dimension of the recognition target object B and is not accurate. Therefore, the horizontal position correction unit 22 subtracts the pulse number (m) of the comparison data CD from the count value of the counter 23, and this is used as a normal horizontal position output. Regarding the position in the vertical direction, the interlace method outputs twice the count number (1 bit shift), and the non-interlace method outputs the count number as it is.

Thereafter, when the vertical synchronizing signal VD shown in FIGS. 3 (f) and (g) is output, the contents of the counter 25 are also cleared.

Therefore, in this way, by detecting the horizontal position and the vertical position directly from the video waveform that captures the recognition target, for example, in the case of the interlace method, the time required to detect the position is 16.7 ms or less If there is an object to be recognized, the position can be detected as quickly as 8.3 ms, and real-time processing can be realized. Moreover, no matter where the recognition target object is located on the screen, the position of the recognition target object can be detected, so that it is more accurate and stable than the one that uses a conventional window and has a limited recognition range. Position detection can also be realized.

By the way, such an image reading apparatus can detect the position of the mark in real time even when the mark 32 attached to the roll-shaped tape 31 as shown in FIG. Because you can
It is possible to easily comply with the above, and as shown in FIG. 6, the marks 34 and 35 attached to the two corners of the table 33 are used to detect the distance H1 between these marks 34 and 35, and this distance H1 When the table 33 is correctly set to the distance H0 and the rotation angle of the table 33 is adjusted, the table 33 is moved to x0 and y0 in this state and set to the normal reference position. Also available for.

The present invention is not limited to the above-mentioned embodiment, and can be implemented by appropriately modifying it without changing the gist.

[Advantages of the Invention] According to the present invention, a sampling clock counting means that counts a sampling clock and is cleared by a horizontal synchronization signal, a horizontal synchronization signal counting means that counts a horizontal synchronization signal and is cleared by a vertical synchronization signal, and an image. A black level counting means for counting the sampling clock while the signal is at the black level and clearing at the white level is provided, and the count value of the black level counting means is compared with the reference value. When the value becomes larger, the contents of the sampling clock counting means and the horizontal synchronizing signal counting means are stored in the horizontal position and vertical position storage means, and the reference value is subtracted from the value stored in the horizontal position storage means. Since the horizontal position of the recognition target is obtained and the reference position of the image recognition target is detected, the reference position of the image recognition target is determined. The position can be detected accurately in real time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the invention of FIG. 2, FIG. 2 is a circuit configuration diagram of an image position detecting section used in the same embodiment, and FIG. 3 is for explaining the operation of the embodiment. Of FIG. 4, FIG. 4 is a diagram showing an example of a television screen including an object to be recognized, and FIGS. 5 and 6 are diagrams for explaining an application example of the apparatus of the embodiment. 14 …… TV camera, 18 …… monitor, 20 …… image memory, 21
…… Image position detector, 22 …… Horizontal position corrector, 23, 25,
28 …… Counter, 24 …… Horizontal position latch, 26 …… Vertical position latch, 27, 30 …… AND gate, 29 …… Comparator, 33
...... Pulse generator.

Claims (1)

[Scope of utility model registration request] 1. A sampling clock counting means that counts a sampling clock and is cleared by a horizontal synchronizing signal, and a black level counting means that counts the sampling clock while an image signal is at a black level and is cleared by a white level. , Comparing the count value of this black level counting means with the reference value,
Comparing means for generating an output signal when the count value of the black level counting means becomes larger; and a horizontal means for storing the contents of the sampling clock counting means when the output signal is generated from the comparing means. Position storage means, horizontal synchronization signal counting means for counting the horizontal synchronization signals and cleared by a vertical synchronization signal, and content of the horizontal synchronization signal counting means when the output signal is generated from the comparison means. An image reading apparatus comprising: a vertical position storage unit, and a unit that subtracts the reference value from a value stored in the horizontal position storage unit to obtain a horizontal position of an object to be recognized.