JPS63127181A - Apparatus for detecting object - Google Patents

Abstract

PURPOSE:To confirm an object with high accuracy and good response, by operat ing a reference value from the measuring result signal corresponding to the instantaneous value of a video signal taken in at every predetermined sampling point and comparing the measuring result signal with a reference value. CONSTITUTION:A video camera 7 sends out a video signal VD and a synchronous signal SY to an object detection circuit 8. The circuit 8 has the holding apparatus 11 receiving the signal VD and the synchronous signal generating apparatus 12 receiving the signal SY. An A/D converter 26 inputs the input video signal S4 from the apparatus 11 and the sampling clock signal S5 from a timing generating apparatus 25 to subject both signals to A/D conversion to output a measuring result data S6 which is, in turn, applied to a reference value calculation apparatus 27 and a comparing judge apparatus 28. The apparatus 27 performs the operational processing of the data S6 on the basis of a timing control signal S8 to output an upper limit reference signal S14 and a lower limit reference signal S15. The apparatus 28 compares the signals S6, S14, S15 at every sampling point. As a result, an object detection signal S20 showing whether a product is present is obtained to make it possible to confirm the object with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an object detection device, and particularly to an object detection device for detecting whether or not an object exists within a predetermined three-dimensional space.

As an object detection device, the physical properties of the object, i.e. the weight,
Those that detect the presence or absence of objects using dimensions, positions, etc.
There are devices that detect the presence or absence of an object by using the electrical or magnetic properties of the object, that is, changes in the electric or magnetic field, light beams,
Various methods have been used in the past, such as one in which the existence of an object is confirmed by irradiating an object with an electron beam, an ultrasonic beam, or the like, and checking the presence or absence of reflected waves or transmitted waves.

In addition, as a non-contact detection method for objects, the appearance of the object is converted into a video signal by a stereoscopic imaging device, this video signal is displayed on a cathode ray tube, and an optical sensor is pasted on the cathode ray tube. Conventionally, it has been considered to confirm the presence or absence of an object based on the change in brightness at the position of the object.

However, with this method of detecting the brightness on the cathode ray tube, it is necessary to mount an optical sensor on the display surface as necessary to detect the brightness on the display surface, and it is also difficult to compare the brightness on the cathode ray tube. There is a problem that there is a certain limit to miniaturizing the overall configuration because a cathode ray tube that is large in size must be prepared, and in addition, depending on the state of attachment of the optical sensor to the display surface, external light may be applied to the sensor. There is a possibility that noise may be mixed into the brightness detection results.

The present invention has been made in consideration of the above points, and by electrically processing a video signal obtained by an imaging device,
This is an attempt to propose an object detection device that can detect the presence or absence of an object with high precision and good responsiveness without requiring complicated labor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings as an embodiment in which the present invention is applied to detecting whether or not a product injection-molded in an injection molding machine is knocked out of a mold.

In FIG. 1, an injection molded product as an object to be detected by an injection molding machine 1 is molded by injecting molding material through a conduit 4 with a movable mold 2 in pressure contact with a fixed mold 3, and then After the side mold 2 is moved back and away from the fixed mold 3 along the guide 5, it is pushed down into the injection molding machine 1 by an ejecting pin (not shown) provided on the movable mold 2.

However, if the movable mold 2 moves back in this way and the product should fall, but the product does not fall completely and ends up adhering to the movable mold 2 or the fixed mold 3.
In the next injection molding cycle, there is a risk that the molds 2 and 3 will be damaged because the product will be sandwiched between the movable mold 2 and the fixed mold 3.

An object detection device 6 is provided to prevent such a possibility.

The object detection device 6 includes a video camera 7 and an object detection circuit 8. The video camera 7 is disposed near the movable mold 2 on the side of the injection molding machine 1, and captures an image of the scene near the movable mold 2 at the timing when the movable mold 2 has finished opening from the fixed mold 3. The video signal VD is sent to the object detection circuit 8.

The injection molding machine 1 is sequence-controlled by a sequencer (not shown), and therefore, the sequencer sends a timing command signal S1 as necessary at timings such as when the mold starts to open, when it finishes opening, and when the ejector pin is moved to eject. This is generated and applied to the object detection circuit 8.

In the case of this embodiment, the video signal VD that captures the state in which the product is still attached to the movable mold 2 at the timing when the movable mold 2 has finished opening can be taken into the object detection circuit 8, and the A video signal VD captured at the timing when the object is pushed down by the ejector pin can be taken into the object detection circuit 8.

The object detection circuit 8 is connected to a video camera 7 as shown in FIG.
It has a hold device WIL for receiving a standard television video signal VD including horizontal and vertical synchronization signals sent from the sync signal generator WIL, and a synchronization signal generating device 12 for receiving the synchronization signal SY as a trigger signal. The synchronization signal generator 12 is configured to generate a synchronization signal CL for synchronizing the operation in the object detection circuit 8 with the video camera 7 in synchronization with the synchronization signal SY.

The hold device 11 captures luminance signals of monitoring areas at a plurality of predetermined positions on the screen formed by the video signal VD, and in this embodiment, the monitoring area Al
and A2 are expressed by taking the X coordinate in the H direction and the X coordinate in the V direction as shown in FIG.
+), point (Xl 10m, yI), point (X+%)
'I +n) and point (x.

+ m % y + + n), and the monitoring area A2 is surrounded by the points ("z, Vz),
Point (x.

+m, y2), point (X2, y z +n), point (x
It consists of an area surrounded by four points: z10m, y, +n).

The hold device 11 receives the video signal V as shown in FIG.
It has a data acquisition switch circuit 18 consisting of first and second analog switch circuits 18A and 18B (corresponding to 1 and A2 to the first and second monitoring areas) which receive D through a buffer circuit 15. The data acquisition switch circuit 18 is turned on by the acquisition command signal S31 generated by the timing generator 25.

In other words, as shown in FIG. 5, the timing generator 25 generates the first, second, . Among the lines, for a scanning line that crosses the monitoring areas A1 and A2, a capture command signal S31 is generated at a timing corresponding to the monitoring areas A1 and A2.

In the case of the embodiment shown in FIG. 3, the monitoring area Al is the y-th.

th line (Fig. 5 (B)'+)) to (yt +n
)th line (Fig. 5 (B (yt + n)), the switch signal SWI is activated when a time corresponding to the coordinate x in the X-axis direction has elapsed from the start of the horizontal synchronizing signals Hy1 to H (yt + n). is started for a time corresponding to the distance #m in the X-axis direction of the monitoring area A1.

In addition, regarding the monitoring area A2, the Yzth line - (y
z + r1)th line (Figure 5 (B y z) ~ B
The switch signal S to the analog switch circuit 18B is sent to the analog switch circuit 18B when a timing corresponding to the coordinate x2 of the monitoring area A2 has elapsed from the rising point of each horizontal synchronizing signal HYz to H(yz'+n) for the line up to Cyt+n)).
W2 is raised by a distance m in the X-axis direction of area A2.

Thus, in FIG. 3, for a video signal of 1 field, the analog switch circuits 18A and 1 are activated at the timing when the scanning line crosses the monitoring areas A1 and A2, respectively.
By turning on 8B, monitoring areas AI and A2
A video signal having an instantaneous value corresponding to the light energy at each pixel position is sent to detection signals S2A and 32 through analog switch circuits 18A and 18B for each corresponding line.
The detection signals S2A and 82B are input to the analog-to-digital converter 26 as the input video signal S4.
given as.

The analog-to-digital converter 26 converts the data into digital data using the sampling clock signal S5 sent from the timing generator 25, which is then sent to the reference value calculation device 27 and comparison/judgment device 2 as measurement result data S6.
given to 8.

The reference value calculation device 27 calculates, based on the measurement result data S6 currently obtained from the analog-to-digital conversion device 26,
It calculates the judgment reference value data so that it can be judged whether or not there is a product remaining between the movable side mold 2 and the fixed side mold 3 in the injection molding machine 1 based on the data of the past measurement results. For example, the configuration shown in FIG. 6 can be applied.

In FIG. 6, the reference value calculation device 27 receives measurement result data S6 sent from the analog-to-digital conversion device 26.
The arithmetic processing is executed based on the timing control signal S8 given from the timing generator 25. That is, the measurement result data S6 is given to the first stage memory M1 among the multiple stages of memories M1, M2, . . . The measurement result data S6 that comes in each injection molding cycle is sequentially stored in memories Ml, M2...
・It is designed to be stored in Mk.

Here, the memories M1, M2...Mk have a memory capacity capable of storing a group of sampling data corresponding to the sampling points included in the monitoring area AI, and each The sampling data group is sequentially transferred to the subsequent memory.

The sampling data stored in the memories M1 to Mk is provided to an adder ADI for each sampling point, and the addition result data S9 is provided to a divider 32 as an output of the observed data memory 31. In this way, the adder ADI outputs addition result data S9 obtained by performing an addition operation on each sampling data included in the monitoring area A1.

The divider 32 has the number k of addition data in the observation data memory 31.
A constant signal S10 corresponding to the constant signal S10 is given from the constant setter 30, and the average value data Sll, which is simple average data obtained by dividing each sampling addition data constituting the addition result data S9 by the constant signal S10, is given from the divider 32. is obtained.

This average value data Sll is supplied to an upper limit value circuit 33 having a multiplier configuration.
and the lower limit value circuit 34, respectively, and the constant setter 3
Multiplying outputs S14 and S15 obtained by multiplying the constant signals S12 and 513 given from 5 and 36 are sent out as an upper limit reference signal S14 and a lower limit reference signal S15, respectively.

Here, the contents of the constant signal S12 given to the upper limit value circuit 33 are set to RH(R)I > 1), and the contents of the constant setting signal S13 given to the lower limit value circuit 34 are set to RL (RL < 1). It is set.

In this way, the upper limit reference signal 514, which is larger than the average value of the past measurement result data, is sent from the upper limit value circuit 33 for each sampling point, and the lower limit value reference signal 514, which is smaller than the average value of the past measurement data, is sent from the lower limit value circuit 34. Value reference signal 51
5 is sent out for each sampling point.

These reference signals S14 and 515 are used by the comparison/judgment device 28.
The measurement result data S6 sent from the analog-to-digital converter 26 is compared for each sampling point, and when the measurement result data S6 is smaller than the upper limit reference signal S14 and larger than the lower limit reference signal S15, injection molding is performed. An object detection output signal S20 is sent out indicating that the product has fallen normally from the machine 1 and there is no product between the movable mold 2 and the fixed mold 3.

On the other hand, the measurement result data S6 is the upper limit reference signal S1.
If it is larger than 4, it means that the brightness between the movable side mold 2 and the fixed side mold 3 is brighter than when the product is dropped, and this means that there is a product (its outer surface is quite bright). ).

On the other hand, the measurement result data S6 is the lower limit reference signal S1.
If it is smaller than 5, the brightness between the movable side mold 2 and the fixed side mold 3 is darker than when there is no product, in other words, there is a product (in this case, the outer surface of the product is quite dark). It represents something. In this way, it is possible to obtain an object detection signal 520 indicating whether or not the product is present between the movable mold 2 and the fixed mold 3 at the timing when the injection molding machine 1 opens the mold and drops the product using the ejector pin.

The reference value calculation circuit 27B for the monitoring area A2 has the same configuration as the reference value calculation circuit 27A, and thus
Output signal 31 for each sampling point included in 2
4B and 315B are sent to the comparison/judgment device 2-8 as the upper limit reference signal S14 and the lower limit reference signal 315, thereby making it possible to obtain the object detection signal S20 for each sampling point included in the monitoring area A2.

In the above configuration, after the injection molding machine 1 opens the movable mold 2 and pushes out the product with the ejector pin, the timing generator 25 receives the import command signal S1 from the sequencer in response to the timing command signal S1 given to the object detection circuit 8.
31 to the hold device 11.

That is, regarding the monitoring area A1, the analog switch circuit 18A of the hold device 11 is switched to (By+) and (B
(y+ + 1)) ,...(B (y+
+n)), from the vertical synchronization signal V to the monitoring area A
After a time corresponding to the X-direction coordinate x1 of the left end of 1 has elapsed, it is turned on by the switch signal SWI given as the capture command signal S31.

Therefore, the video signal VD is taken into the hold device 11 while the analog switch circuit 18A is on, and is sampled at the sampling frequency in the analog-to-digital converter 26 and sent to the comparison/judgment device 28 and the reference value calculation device 27. be done.

Here, the reference value calculation device 27 stores data representing the instantaneous value of each sampling point in the past by writing the given measurement result data S6 into the first stage memory M1 for each sampling point. , by supplying this as output data from 1 to Kk to the average value calculation means consisting of the adder ADI and the divider 32, based on the average value of the data of each instantaneous value obtained in the past injection molding cycle. The upper limit value and lower limit reference signals 514A and 515A are supplied to the comparison and determination device 28.

Therefore, the comparison and determination device 28 compares and determines the measurement result data S6 provided from the analog-to-digital conversion device 26 for each sampling point using the average value of the detection data obtained in the past injection molding cycle.

Here, when the surface of the product is bright, when the injection molding machine l operates normally and the product is pushed down correctly by the ejector pin, the level of the measurement result data S6 is
Since the level is intermediate between the upper limit reference signal S14 and the lower limit reference signal S15 obtained at 7 (FIG. 6), the comparison/judgment device 28 detects the object detection signal S2 indicating that there is no object.
Sends 0.

On the other hand, if the product is not ejected from the movable mold 2 even though the injection molding machine l operates the ejector pin, the level of the detection signal S6 will be low because the surface of the product is quite bright. It becomes larger than the upper limit reference signal S14 obtained by the reference value calculation device 27. Therefore, at this time, the comparison and determination device 28 sends out an object detection signal S20 indicating that an object is present.

In the above case, the brightness of the product's surface is bright, but conversely, if the product's surface is darker than when there is no product (for example, if the product's surface is black),
The level of the measurement result data S6 becomes extremely low and becomes lower than the lower limit reference signal 515 obtained by the reference value calculation device 27.

In this case as well, the comparison/judgment device 28 sends an object detection signal S20 indicating that the product has not been pushed down from the injection molding machine l.
will be sent.

According to the above configuration, the presence or absence of an object can be determined by signal processing the video signal VD obtained from the video camera. By doing so, it is possible to determine the presence or absence of an object in each of the monitoring areas A1 and A2 in a short time, and as a result, it is possible to realize an object detection device with even better responsiveness. Incidentally, if an abnormality occurs in part of the plurality of monitoring areas A1 and A2 during repeated injection molding cycles, the video signal VD
When a signal corresponding to the monitoring area At or A2 where the abnormality has occurred is captured, an abnormality determination output can be obtained immediately when this abnormal signal is sampled (without waiting for the detection operation for the entire monitoring area). Thus, it is possible to obtain a judgment output with even better responsiveness.

In addition, by using a signal representing the average value based on the detection signals obtained in the past injection molding cycle as the upper limit value and lower limit value reference signals S14 and S15, it is possible to If the imaging conditions change during the process (e.g. deterioration of the light source,
If the level of the video signal VD drifts due to temperature characteristics, etc.), the effect will be reflected in the measurement result data S6.
This can be compensated by simultaneously occurring in the reference signals S14 and S15, and thus the influence of fluctuations in imaging conditions on the determination result can be further reduced.

In the embodiment shown in FIG. 2, the timing generator 25 includes a take-in signal generation circuit 41 having the configuration shown in FIG. 7 in order to generate the take-in command signal S3I to the hold device Tt t l.

In FIG. 7, the acquisition signal generation circuit 41 has a monitoring position designation memory 42 having a RAM configuration, and this indigo position designation memory 42 contains data on scanning positions of the monitoring areas A1 and A2 described above with reference to FIG. 3 in advance. The data is written as a data signal DP from a main controller (not shown) through a write circuit 40.

For example, as shown in FIGS. 8 and 9, the monitoring areas A1 and A2 described above with reference to FIG. Assuming that an area having a length of
++3), the X-direction position data x1 and data acquisition switch circuit designation data (18A) are stored, and the monitoring area A2 is stored with respect to line number data y2 to (yz +3) in the X direction. Same location data x2
and data acquisition switch circuit designation data (18B) are stored.

Each line number data y1~(y+ +3), yz~
(yz+3) is assigned to a predetermined memory area of the monitoring position designation memory 42, and by reading the address of the memory area, the X-direction position data corresponding to the line number data assigned thereto and a data acquisition switch circuit are obtained. The specified data is read.

The count contents of the X counter 43 are applied to the monitoring position designation memory 42 as a read signal through an address converter 44. The X counter 43 counts clock pulses CLH provided from the synchronizing signal generating circuit 12 (FIG. 2) in synchronization with the horizontal synchronizing signal H. In this way, the contents of the X counter 43 sequentially designate the scanning line numbers of the video signal. When the X counter 43 operates, its contents are y1 to (y++3) or y2.
.about.(yz+3), data regarding the corresponding line number data is read into the X-direction position register 45 and the data acquisition switch circuit designation register 46. X
The contents of the direction position register 45 are provided to a comparator 47 and monitored to see if they match the contents of the X counter 48. The X counter 48 is configured to sequentially designate the number of monitoring points in the X direction.
A clock signal CLX having a period similar to that obtained by dividing the horizontal synchronizing signal obtained from the signal (FIG. 2) by a predetermined number is counted.

When the position is detected by the comparator 47 in this way, the position detection output PS is given as a trigger signal to the pulse generation circuit 49 of, for example, a mono-multi-bibreak configuration, whereby a pulse with a predetermined pulse width is sent to the acquisition signal generation circuit of the decoder configuration. 50 as a load signal. The acquisition signal generation circuit 50 converts the data acquisition switch circuit designation data stored in the data acquisition switch circuit designation register 46 into a switch signal SW1 or SW2, which is transmitted to the analog switch circuits 18A and 18B.
It is sent out as a capture command signal S3I for.

According to the configuration shown in FIG. 7, the monitoring position designation memory 42 stores the monitoring area A1 as shown in FIGS. 8, 9, and 10.
and the X-direction position data of the left end of A2 are stored together with the corresponding data acquisition switch circuit designation data,
In this way, when the video signal VD reaches a section corresponding to a scanning line that crosses the left end of the monitoring position Al or A2, the X-direction position data and The data acquisition switch circuit designation data is read out to the X direction position register 45 and the data acquisition switch circuit designation register 46, and at the same time, the X counter 48 is read out for the relevant scanning line.
The counting operation is performed so that the contents of the scan line are sequentially scanned from the left side to the right side.

Eventually, the contents of the X counter 48 will be transferred to the X direction position register 45.
When the content matches the content read out, this means that the video signal corresponding to the left end of the monitoring areas A1 and A2 has arrived. At this time, since the comparator 47 generates the position detection output ps, the acquisition signal generation circuit 5
Switch signals SWI and SW2, in which 0 corresponds to the contents of the data acquisition switch circuit designation register 46, are sent to the analog switch circuits 18A and 18B.

Here, since the pulse width of the pulse generation circuit 49 is selected to have a length corresponding to the length of the monitoring areas Al and A2 in the X direction, the acquisition command signal S3I output from the acquisition signal generation circuit 50 is generated. The time exactly coincides with the time when the monitoring areas Al and A2 are being scanned.

Thus, as described above with respect to FIGS. 8 and 9, switch signals SWI and SW2 will be obtained for the four scan lines across the monitoring areas At and A2, thereby providing monitoring signals from the analog switches, circuits 18A and 18B. The instantaneous values of the video signal VD that fall into the areas A1 and A2 are sequentially taken into the hold device 11.

Incidentally, it is only necessary to store data regarding the start position of the monitoring area as the data in the monitoring position designation memory 42, so even if the number of monitoring areas increases, the storage capacity of the memory 42 does not need to be increased that much. good. Further, when changing the designation of the monitoring position, the area of the monitoring area, etc., it is only necessary to change the data stored in the monitoring position designation memory 42, thus realizing a highly versatile object detection device.

In addition, in the case of FIGS. 8 and 9, the monitoring areas AI and A2
In the case where multiple monitoring areas are set to overlap on the same scanning line, as shown by the broken line in FIG. 7, the address converter 44 By inputting the count contents of the X counter 48 and specifying the X and X-direction positions, the corresponding X-direction position data and data acquisition switch circuit designation data may be specified.

Furthermore, in the comparator 47, not only the contents of the X counter 48 but also the contents of the X counter 43 may be given as a comparison input as necessary.

Further, the number of monitoring areas is not limited to two as in the above embodiment, but can be three or more, or can be one.

Furthermore, in the above description, when monitoring the screen of the video signal VD obtained by the video camera 7, a case has been described in which a monitoring area having a width of multiple scanning lines in the direction (3) is specified. Alternatively, as shown in FIG. 11, monitoring may be performed only for a predetermined length along one scanning line. In this case, in FIG. 10, for example, the X-direction position data and the data acquisition switch circuit designation data for only one scanning line (in the case of FIG. 10, there are multiple lines) are stored as data for the monitoring area designation position. Just try to remember it.

Thus, in the same manner as described above for the monitoring areas A1 and A2, a determination result can be easily obtained using the detection output representing the optical energy of the monitoring areas.

Furthermore, even if the video signal VD is monitored on the screen by specifying a specific point as shown in FIG. 12, the presence or absence of an object can be detected in the same manner as in the above case.

FIG. 13 shows another embodiment of the reference value calculation device 27, and as shown by assigning the same reference numerals to the corresponding parts as in FIG. 6, when calculating the reference value, the case shown in FIG. has an observation data memory 31 and a division circuit 32 for obtaining a reference value at a timing after the movable mold 2 of the injection molding machine 1 is opened and the product is pushed down by the ejecting pin. In addition to this, the case shown in the figure is characterized in that the reference value is calculated at the timing before the product is pushed down by the ejector pin.

In other words, the reference value calculation device 27 in the case of FIG. It has a constant setter 57.

Here, the measurement result data S6 is input to the observation data memory 31 and the pre-observation data memory 55 via a switch circuit 58.
The switch circuit 58 is switched to the front observation data memory 55 side after the injection molding machine 1 finishes opening the movable mold 2. The measurement result data S6 is input to the front observation data memory 55 side through the switch circuit 58, and the measurement result data S is input at the timing after the ejecting operation is performed and the product is pushed down.
6 is input into the observation data memory 31.

Thus, the reference value calculation device 27 stores the observed data before and after the ejecting operation of the ejecting pin in the observation data memory 31 and the pre-observation data memory 55, calculates the simple average value using the dividers 32 and 56, and calculates the simple average value. Add the result to adder 6
0 and a simple average in the divider 61, and then sent to the comparison/judgment device 28 as a reference value signal S25.

In addition, the reference value calculation device 27 includes dividers 32 and 5.
6 is applied to the comparator 62, and the comparator 62 detects a change between the calculated data before the ejection operation of the injection molding machine 1 and the calculated data after the ejected operation, and sends it as a reference value signal S26 to the comparison and determination device 28. do.

In the configuration shown in FIG. 13, the reference value calculation device 27 can store observation data before and after the ejection operation of the injection molding machine 1 in the observation data memory 31 and the pre-observation data memory 55, respectively. Here, the data stored in the pre-observation data memory 55 before the ejection operation means that the data is for a state in which the product injection-molded by the injection molding machine 1 is still on the movable mold 2. Therefore, the data represents the brightness of the outer surface of the product. On the other hand, the data stored in the observation data memo IJ31 after ejection means that the product is pushed down from the injection molding machine, and therefore, if the injection molding machine is operating normally, the observation data memory 3
Data 1 represents the brightness of the injection molding machine 1 when there is no product.

Therefore, the reference value signal S25 obtained by simple averaging in the divider 61 represents the intermediate value between when there is a product in the injection molding machine l and when there is no product in the injection molding machine l, and thus the measurement given to the comparison and judgment device 28. Based on the result data S6, it is possible to clearly determine whether or not there is a product based on the reference value S25 by determining whether the product exceeds the reference value S25.

In this way, the reference value S25 is configured to include a drift in the video signal VD due to a light source, a video camera, etc., to form the reference value, so that the judgment operation of the comparison judgment device 28 is improved. Sometimes these drifts can be canceled out. Therefore, the object detection signal S
22 can prevent the influence of drift from occurring.

In addition, since the comparator 62 compares the measurement data when the product is present and the measurement data when there is no product, it can be determined whether the product is present or not, regardless of whether the surface color of the product is black or white. can be determined with certainty.

Incidentally, if the product is black, the level of observation data when the product is present will be low, whereas if the product falls and disappears, it means that there is no black object, so the level of observation data when the product is not present will be lower. The level will be higher compared to the level of observation data when using. Therefore, if there is a change in the level of the signal arriving at the comparator 62, the injection molding machine 1 can send out the reference value signal S26 that reliably indicates that there is no product due to the ejecting operation of the ejector pin. Conversely, when the product is white, the level of observation data when there is a product is higher than the level of observation data when there is no product. It can be reliably determined that the product is not inside the injection molded aluminum. Also in this case, it is possible to prevent the influence of drift from occurring on the determination results obtained by the comparison and determination device on the second day.

FIG. 14 shows still another embodiment of the reference value calculation device 27. In FIG. 6 and FIG.
It is replaced with the observation data memory 65 shown in the figure.

The observation data memory 65 includes memories M1 and M2, as shown by assigning the same reference numerals to corresponding parts in FIGS. 6 and 13.
・・・・・・The output of Mk is sent to the weight setters W1, W2...
...Wk's weight output W,, W2... Multipliers PLI, PL2, which multiply wk as a coefficient input
- It is configured to provide it to the adder ADI through PLk.

With the configuration shown in Fig. 14, reference data is obtained based on detection data for past injection molding cycles, and by weighting each data according to its importance, the optimal data as the reference value can be obtained. can be obtained.

For example, if the background brightness of the injection molding machine 1 changes over time, newer observation data is considered to be the most effective data, so the weight setting value W1
, wt...Wa W 1 > W 2...
By setting the relationship .

In the embodiment shown in FIG. 2, the detection data taken in by the hold device 11 is converted into a digital value by the analog-to-digital converter 26 and then digitally compared and determined by the comparison and determination device 28. Alternatively, as shown in FIG. 15, the detection signal taken in by the hold device 11 may be directly given to the comparison and determination device 28, so that the comparison and determination device 28 can determine the presence or absence of an object in an analog manner. good. In this case, the detection output S4 taken in from the hold device 11 is converted into a digital signal by the analog-to-digital converter 71 and given to the reference value calculation device 27 as measurement result data, and the result of calculation processing in the reference value calculation device 27 is The obtained reference value signal is converted into an analog signal by the digital-to-analog converter 72 and then provided to the comparison/determination device 28 .

Even in this case, the same effect as described above with respect to FIG. 2 can be obtained.

Alternatively, instead of the configuration shown in FIG. 2, as shown in FIG. 16, a video signal VD is taken in as a hold device 11 via a data take-in switch circuit 18, and then converted into digital data in an analog-to-digital converter 74. After conversion, it may be temporarily stored in the digital memory 75, and the digital data stored in the digital memory 75 may be sent to the reference value calculation device 27 and the comparison/judgment device 28 as the measurement result data S6.

Even in this case, the monitoring area A1 is stored in the digital memory 75.
, A2 can be stored as digital data, the same effect as in the case of FIG. 2 can be obtained.

Further, in the above embodiment, the video camera 7 provides the synchronization signal to the synchronization signal generator 12, but instead of this, the video camera 7 synchronizes with the synchronization signal generated by the synchronization signal generator 12. You can do it like this.

Further, in the above-described embodiment, the present invention was described as an embodiment in which the present invention was applied to detect whether or not a product fell off when a mold in an injection molding machine was opened. S on the conveyor! It can also be widely applied to security devices that detect objects that are placed or sent to a designated space, or that detect intruders entering a predetermined space.

As described above, according to the present invention, the presence or absence of an object within a predetermined area imaged by a video camera is detected by sampling the instantaneous value of the video signal corresponding to the monitoring area, and the detection result is compared with a reference value. By making the determination based on this, it is possible to easily realize an object detection device that is more responsive to changes in the state of the observed object.

In this way, there is no need to once reproduce the screen on a CRT as in the conventional case, so the configuration as a combination of parts can be made smaller, the measurement work does not become complicated, and it is possible to avoid operational errors. It is possible to easily obtain an object detection device that is free from errors caused by light entering the optical sensor to be disposed on the surface of the screen.

[Brief explanation of the drawing]

FIG. 1 is a route perspective view showing an outline of the object detection device according to the present invention, FIG. 2 is a block diagram showing the detailed configuration of the object detection circuit, FIG. 3 is a route map for explaining the monitoring area, and FIG. The figure is a connection diagram showing the detailed configuration of the hold device in Figure 2.
FIG. 5 is a signal waveform diagram representing the acquisition signal given to the hold device ff1l from the timing generator 25 of FIG. 2, and FIG. 6 is a block diagram showing the specific configuration of the reference value calculation device 27 of FIG. Figure 7 shows the timing generator 25 in Figure 2.
8 to 1θ are route maps and diagrams for explaining the configuration of FIG. 7, and FIGS. 11 and 12 show monitoring positions. 13 is a block diagram showing another embodiment of the reference value calculation device 27 in FIG. 2, and FIG. 14 is a route map showing another embodiment of the reference value calculation device 27 in FIG. 2. Block Diagram Showing Embodiment FIGS. 15 and 16 are block diagrams showing still other embodiments of FIG. 2. l... Injection molding machine, 2.3... Movable side, fixed side mold, 7... Video camera, 8...
...Object output circuit, 11...Hold device,
12... Synchronization signal generator, 25...
Timing generator, 26...Analog-digital converter, 27...Reference value calculation device, 28
. . . Comparison/judgment device, 41 . . . Intake signal generation circuit.

Claims (1)

[Scope of Claims] (a) A video camera that images an object to be detected, and (b) a video camera located at a predetermined monitoring position and having a predetermined size among screen information obtained by a video signal sent from the video camera. (c) measuring means for capturing the video signal corresponding to a monitoring area having a certain level at each predetermined sampling point and outputting a measurement result signal having a level corresponding to the instantaneous value of the captured video signal; (d) a signal level of the measurement result signal obtained from the measurement means; (d) a signal level of the measurement result signal obtained from the measurement means; and comparing and determining means for comparing the reference value obtained by the reference value calculation means and transmitting an object detection signal depending on the presence or absence of an object.