JP2005189312A - Perforation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform setting of a threshold of high reliability for the purpose of detecting perforations. <P>SOLUTION: When photographing of all the frames of a film is completed, the film is automatically rewound. When the film is completely rewound into a cartridge, a photodetecting level which is a reference value for the absence of the film is detected by a photosensor. The detected reference value is stored in an EEPROM. The threshold is set based on the reference value and the threshold stored in the EEPROM is updated to the set threshold. When the new cartridge is loaded into a loading chamber of the camera, the changed threshold is read out to a perforation detecting section and is used for detecting of the perforations at the time of rewinding of the film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a perforation detection device incorporated in a camera in order to control film feeding.

  As a device for controlling the film feed amount of a camera, there is a perforation detection device for detecting the number of perforation holes formed in a film by using an optical sensor composed of a light projecting element and a light receiving element. In this perforation detection device, light is projected from a light projecting element to a perforation passage, and the reflected light or transmitted light is detected by a light receiving element. Then, the number of passing perforations is detected by comparing the change in the received light signal according to the amount of received light with a predetermined threshold value.

  Also, in order to detect the number of perforation holes reliably, the maximum and minimum values of the detection signal are obtained during film loading, and the perforation is detected by setting a reference value within the range of the maximum and minimum values. (See Patent Document 1). In addition, the average value of the light reception output by the photoelectric element at the time of film loading is obtained, and the number of perforation holes is counted by comparing the output signal level using this average value as a reference value (see Patent Document 2). Further, the light projecting drive current of the light projecting element is changed so that the light reception output detection level by the light receiving element is optimized (see Patent Document 3). There are also processes for obtaining a reference value before loading a film and loading it, or before sending one frame after shooting.

JP-A-5-88244 Japanese Patent Laid-Open No. 5-107616 JP 7-5533 A

  However, if the threshold value is fixed in advance as described above, perforation cannot be detected when the detection level is lowered due to aging or sensitivity deterioration of a photoelectric element such as a sensor or aging of a reflecting surface. Further, in the reflection type photoelectric element, the reflection output on the film surface takes various values depending on the type of the film, so the threshold for detecting perforation must be an optimum value with a certain degree of accuracy. In Patent Documents 1 and 2, since the reference value is set during film loading, the setting process is complicated. Furthermore, if the maximum value, minimum value, and reference value of the detection signal are set while the film is moving, an accurate value cannot be detected. In Patent Document 3, it is necessary to newly provide a circuit for controlling the driving current for light projection so that the detection level by the light receiving element becomes a certain level or more. In addition, when the processing for obtaining the reference value is performed before the film is loaded and loaded, or before one frame is fed after shooting, the film may be partially covered on the photoelectric element. There is also a problem that the value cannot be measured.

  An object of the present invention is to provide a perforation detection device capable of easily setting a highly reliable threshold for detecting the number of perforation holes.

  The perforation detection apparatus of the present invention stores a light projecting element that projects light onto a perforation passage portion of a film, a light receiving element that receives reflected or transmitted light, and a threshold value that is a criterion for determining the presence or absence of perforation. A perforation detection device that detects the number of passing perforations by comparing a change in a received light signal from the light receiving element and a threshold value, and when the film is completely rewound on the cartridge, the light emitting element and the light receiving element are A setting unit that detects a light reception level as a reference value when there is no film and sets a threshold value based on the detected reference value, and a threshold value that is set by the setting unit as a threshold value stored in the storage unit Updating means for updating to a threshold value when a cartridge is newly loaded. Reading and detects a passage number of perforations.

  In addition, a determination unit that determines whether or not the reference value is included in a predetermined range that is set in advance, and when the determination unit determines that the reference value is not included in the predetermined range, It is preferable that the threshold value is set based on the reference value by the setting means. A determination unit configured to determine whether the reference value is included in a predetermined range set in advance; and when the determination unit determines that the reference value is included in the predetermined range, It is preferable that the threshold value is set based on the reference value by the setting means.

  Further, it comprises a determining means for comparing the reference value with the previous reference value used for setting the threshold value stored in the storage means to determine whether or not it is increased or decreased by a certain value or more. When it is determined by the determination means that the value has increased or decreased by a certain value or more, it is preferable that the threshold value is set based on the reference value and the previous reference value by the setting means. In addition, it comprises a determination means for comparing the reference value and the previous reference value to determine whether or not it has increased or decreased by a certain value or more. Preferably, the setting means sets a threshold based on the reference value and the previous reference value. In addition, it comprises a determination means for comparing the reference value with the previous reference value and determining whether or not the comparison result matches a preset increase or decrease, and the comparison result is set by the determination means. When it is determined that the increase or decrease matches, the threshold value is preferably set by the setting means based on the reference value and the previous reference value. Further, when the comparison result between the reference value and the previous reference value is increased or decreased, weighting is performed in advance, and the setting means is based on the reference value and the previous reference value, and the weighting is performed. It is preferable to set a threshold according to the above.

  According to the present invention, when the film is completely rewound onto the cartridge, the light receiving level is detected as a reference value when there is no film on the light projecting element and the light receiving element, and based on the detected reference value. A setting unit configured to set a threshold value; and an updating unit configured to update the threshold value stored in the storage unit to the threshold value set by the setting unit. When a cartridge is newly loaded, the threshold value is read from the storage unit. Since the number of perforations that have passed is detected, it is possible to simply detect the light receiving level accurately and to set the threshold when there is no film, and to detect perforations due to secular change and sensitivity deterioration of the light emitting element and light receiving element. Defects can be prevented.

  In addition, since a determination means for comparing the detected reference value with a predetermined range set in advance or the previous reference value and the current reference value is provided, it is possible to prevent erroneous threshold setting. Improved reliability when detecting perforations.

  FIG. 1 shows an example of a camera provided with the perforation detection device of the present invention. The photographic camera 2 is provided with a cartridge loading chamber 5 and a film winding chamber 6. A cartridge 7 is loaded in the loading chamber 5, and a spool 10 for winding the film 9 is provided in the film winding chamber 6. An aperture 11 is formed between the loading chamber 5 and the film take-up chamber 6, which determines the exposure range for the film 9 and cooperates with the film plank 13 elastically attached to the back cover 12, so that the film 9 Positioning in the axial direction.

  As shown in FIG. 2, the film feeding motor 15 is accommodated in the spool 10. The motor 15 is connected to the system controller 18 via a motor driver 16, and its rotation and rotation direction are controlled. The rotation of the motor 15 is transmitted to the fork 20 engaged with the spool 10 or the cartridge 7 via the feeding transmission mechanism 19, and the motor 15 is driven forward when the film 9 is wound around the spool 10, and the cartridge 7 When rewinding to, reverse drive.

  On the upper and lower side edges of the film 9, perforations 21 corresponding to each photographing frame defined by the aperture 11 are opened. As shown in the figure, a reflection type photosensor 22 for detecting the perforation 21 is disposed on the passage portion of the perforation 21. The reflection type photosensor 22 includes a light projector using a light emitting diode and a light receiver using a phototransistor. The light projector projects infrared light on a moving region through which the lower perforation 21 of the film 9 passes, and the light receiver receives the film. Infrared light reflected by the surface is received, and a received light signal of an analog signal obtained by photoelectric conversion is output.

  Most of the infrared light projected from the projector of the photosensor 22 is transmitted through the perforation 21, so that the infrared light reflected by the light receiver is reduced. Therefore, the light reception level of the light reception signal output from the phototransistor of the light receiver is low. When infrared light is reflected on the film 9, most of the light is received by the light receiver, so that the light reception level of the light reception signal output from the phototransistor is high. Thereby, as the perforation 21 established in the film 9 progresses, the level of the received light signal periodically fluctuates.

  The perforation detection unit 26 receives the reception signal from the photosensor 22 and detects the perforation 21. The counter 30 sends a signal to the system controller 18 when the detection signal from the perforation detection unit 26 is detected for one frame. The system controller 18 controls each part of the photographic camera 2 and stops the motor 15 in response to a signal from the counter 30. The ROM 22 stores a control program for controlling each part of the camera and setting information, and also stores an initial threshold value used when the film 9 is taken up when the patrone 7 is loaded into the photographic camera 2 for the first time. .

  As shown in FIG. 3A, the detection signal 25 from the photosensor 22 is sent to the perforation detection unit 26, and the perforation 21 is detected. When the cartridge 7 is loaded into the camera 2 for the first time, an initial threshold value preset in the ROM 27 is sent to the perforation detection unit 26. The perforation detection unit 26 converts an analog signal into a pulse signal based on the initial threshold value and the light reception signal 25. The counter 30 counts this pulse signal and detects the number of passing perforations 21. The initial threshold value detects that the received light signal 25 crosses different threshold levels Vnh and Vnl at the time of rising and falling. The counter 30 counts every time the received light signal 25 crosses the threshold level Vnh when rising, and when the number of passing perforations 21 for one frame is detected, a signal is sent to the system controller 18 to wind the film 9 To stop. By providing such hysteresis, erroneous counting is prevented when noise or other disturbance is received.

  As described above, the number of passages of the perforation 21 is counted for each photographing, and when the winding of the film 9 is completed for all the frames, the system controller 18 drives the motor 15 in the reverse direction to drive the film 9 wound on the spool 10. Are all rewound into the patrone 7. When the film 9 is rewound, a pulse signal of the perforation 21 is sent from the perforation detection unit 26 to the system controller 18. The system controller 18 detects whether or not the film 9 has been rewound by continuously detecting pulse signals. The system controller 18 reliably rewinds the film 9 by driving the motor 15 in reverse rotation for a certain time after the pulse signal is no longer detected. In order to reliably rewind the film 9 around the cartridge 7, the motor 15 was driven in reverse for a certain period of time after the perforation 21 was not detected, but a sensor for detecting the presence of the film 9 was provided in the vicinity of the cartridge 7. May be.

  When the reverse drive of the motor 15 is stopped after a certain time has elapsed, the light reception level when the film 9 is not on the photosensor 22 is detected. The system controller 18 records the detected light reception level in the EEPROM 31 as a reference value when there is no film. Further, the system controller 18 is provided with a setting unit 18a. The setting unit 18a sets threshold values Vh and Vl at the time of rising and falling based on the reference value, and records them in the EEPROM 31.

  When the cartridge 7 is newly loaded into the photographic camera 2 and the back cover 12 is closed, the system controller 18 reads the threshold values Vh and Vl from the EEPROM 31 to the perforation detection unit 26. When the winding of the film 9 is started, the perforation 21 is detected based on the light reception signal 35 from the photosensor 22 and the threshold values Vh and Vl, and the counter 30 counts the number of passing perforations 21 and counts the film. The first frame is set in the aperture 11 by controlling the feed. When photographing is performed, the perforation 21 is detected based on the light reception signal 35 from the photosensor 22 and the threshold values Vh and Vl. The counter 30 counts the number of passages and winds up the film 9 for one frame. Do.

  When all the shootings are completed, the film 9 is automatically rewound onto the cartridge 7. When all of the film 9 is rewound onto the cartridge 7, the reference value when there is no film is detected again. This reference value is newly recorded in the EEPROM 31, and a threshold based on the reference value is set by the setting unit 18a. Then, the threshold value stored in the EEPROM 31 is updated to the newly set threshold value and stored by the updating unit 18b provided in the system controller 18.

  The detection of the reference value when there is no film, the setting of the threshold value, and the update to the EEPROM 31 are performed every time the film 9 loaded in the photographic camera 2 is all rewound to the cartridge 7. Note that after all frame shooting was completed and all the films 9 were rewound onto the cartridge 7, the light reception level serving as a reference value when no film was detected was detected. Even when the rewinding operation is performed, after all of the film 9 has been rewound to the cartridge 7, the reference value when there is no film is detected, and the threshold value is set and updated.

  Next, the effect | action of this embodiment is demonstrated using FIG. When the cartridge 7 is loaded for the first time, the perforation 21 is detected based on the preset initial threshold value and the light reception signal of the photosensor 22, and the number of passages of the perforation 21 is counted by the counter 30. Is taken up.

  When all frames have been photographed and all the film 9 has been rewound onto the cartridge 7, the photo sensor 22 detects a light receiving level that is a reference value when there is no film. The detected reference value is stored in the EEPROM 31. Further, a threshold value is set based on the reference value and stored in the EEPROM 31. When a new cartridge 7 is loaded in the loading chamber 5, the threshold value stored in the EEPROM 31 is read out. When the film 9 is wound, the perforation 21 is detected based on the threshold value and the light reception signal. Since the counter 30 counts the number of passing perforations 21 for one frame, the winding of the film 9 is controlled.

  The detection of the reference value and the setting of the threshold value when there is no film are performed every time the film 9 is completely rewound onto the cartridge 7, and the newly set threshold value is updated and stored in the EEPROM 31. Then, when a new cartridge 7 is loaded, the threshold value is read from the EEPROM 31 and used for detecting the perforation 21. Accordingly, since the camera operation after the film 9 has been completely rewound into the cartridge 7 has been completed, the detection of the received light level that is the reference value when there is no film and the threshold value setting process based on the reference value are performed. The reference value detection and the threshold setting process are facilitated, and the perforation 21 can be detected without being affected by the sensitivity deterioration of the photosensor 22.

  In the above embodiment, after all the film 9 has been rewound onto the cartridge 7, the received light level that is the reference value when there is no film is detected, and the threshold value is set and updated based on this reference value. As shown in FIG. 5, after the cartridge is replaced, the system controller 18 is provided with a determination unit 18c for determining whether or not the newly detected reference value when there is no film is included in a predetermined range. The threshold value stored in the EEPROM 31 may be updated according to the determination result of the determination unit 18c.

  As shown in FIG. 6, when photographing of the film 9 loaded in the photographic camera 2 is completed and all the film 9 is rewound to the cartridge 7, a light receiving level serving as a reference value when there is no film is detected. The detected reference value is sent to the determination unit 18c, and a predetermined range set in advance is also sent from the ROM 27 to the determination unit 18c. The determination unit 18c determines whether or not the reference value is included in the predetermined range. When the reference value is not included in the predetermined range, the setting unit 18a sets a threshold value based on the reference value, and the update unit 18b updates the threshold value stored in the EEPROM 31 to the newly set threshold value. The updated threshold value is read by the perforation detection unit 26 when a new cartridge 7 is loaded in the camera 2, and used to detect the perforation 21 when the film 9 is wound up. In addition, when the reference value is included in the predetermined range, the update is not performed because there is no significant change in the threshold value.

  In the above embodiment, the example in which the threshold is changed when it is determined that the reference value is not included in the predetermined range has been described. However, the predetermined range is set to an appropriate range of the reference value, and the reference value is set. Is determined to be included in the predetermined range, the threshold value may be set based on the reference value and the EEPROM 31 may be updated.

  In the above embodiment, the determination unit 18c for determining whether or not the reference value when there is no film is included in the predetermined range is provided in the system controller 18, and the threshold value is changed according to the determination result of the determination unit 18c. However, instead of this, the current reference value detected when the film 9 is completely rewound into the cartridge 7 and the previous reference value used to set the threshold value stored in the EEPROM 31 are used. In comparison, the determination unit 18c shown in FIG. 5 may determine whether or not it has increased or decreased by a certain value or more, and a threshold value may be set and updated based on the determination result.

  In this case, as shown in FIG. 7, when the film 9 is all rewound onto the cartridge 7 after the photographing is completed and the received light level without the film is detected, it is sent to the determination unit 18c as the current reference value. Then, the previous reference value stored in the EEPROM 31 is also sent to the determination unit 18c. The determination unit 18c compares the previous reference value with the current reference value to determine whether or not the value has increased or decreased by a certain value or more. When it is determined that the value has increased or decreased by a certain value or more, a threshold value is newly set based on the current reference value and the previous reference value by the setting unit 18a, and stored in the EEPROM 31 by the updating unit 18b. The threshold value is updated to the newly set threshold value. If the determination unit 18c determines that the value has not increased or decreased by a certain value or more, the threshold value is not set or updated.

  If the determination unit 18c determines that the value has increased or decreased by a certain value or more, the setting unit 18a sets the threshold based on the following formula 1 considering the current reference value and the previous reference value.

Here, the characters shown in Equation 1 are as follows.
Vh: newly set rising threshold
Vl: newly set threshold at falling
Vbh: Threshold value at the time of rising used last time
Vbl: Threshold value at the time of falling used last time
ΔAD: Amount of change between the previous reference value and the current reference value

  Alternatively, when the current reference value increases or decreases by a predetermined value or more with respect to the previous reference value, weighting may be performed in advance, and the threshold value may be set based on the following formula 2.

Here, the characters shown in Equation 2 are as follows.
Vnh: preset threshold value at the time of rising
Vbl: a preset threshold value at the time of falling
Vbh: Threshold value at the time of rising used last time
Vbl: Threshold value at the time of falling used last time
AD: current reference value
ΔAD: Amount of change between the previous reference value and the current reference value

  In this formula 2, when the previous reference value is compared with the current reference value, the weighting when the reference value increases by a certain value or more is set high, and the amount of change in the threshold value is large. Further, the weighting when the value decreases by a certain value or more is set low, and the amount of change in the threshold is small.

  In the above embodiment, the threshold value is changed when it is determined that the previous reference value and the current reference value are increased or decreased by a certain value or more. The threshold value may be set and updated when it is determined that it has not increased or decreased.

  In the above embodiment, the previous reference value and the current reference value are compared and it is determined that the threshold value has been increased or decreased by a certain value or more. When the comparison result comparing the current reference value and the current reference value matches the preset increase or decrease, the determination unit 18c determines whether the comparison result matches the preset increase or decrease. Setting and updating may be performed.

  As shown in FIG. 8, for example, when the previous reference value is compared with the current reference value in advance and the comparison result is set to increase, the current reference value detected after all the films 9 have been rewound. Is sent to the determination unit 18c. The determination unit 18c compares the previous reference value stored in the EEPROM 31 with the current reference value, and detects whether the comparison result has increased or decreased. Then, it is determined whether or not the comparison result matches a preset increase. When the comparison result is increasing, the threshold value is set based on the above formula 1, and the threshold value stored in the EEPROM 31 is updated. If the comparison result is decreasing, the setting and updating of the threshold is prohibited because it does not coincide with the set increase.

  In each of the above embodiments, the light reception level that is a reference value when there is no film is detected, and not only the threshold value is set based on this reference value, but also the threshold value after determining the reference value as a predetermined range or the previous reference value. Since setting and updating are performed, erroneous threshold setting can be prevented.

It is the schematic which shows an example of the camera provided with the perforation apparatus of this invention. It is the schematic which shows the perforation detection apparatus of this invention. It is a timing chart explaining the detection of perforation. It is a flowchart which shows the threshold value setting based on the reference value at the time of no film. It is the schematic which shows having provided the determination part in the perforation detection apparatus. It is a flowchart which shows performing a threshold value change by determining a reference value and a predetermined value. It is a flowchart which shows performing the threshold value change by determining the present reference value and the previous reference value. It is a flowchart which shows changing a threshold value in anticipation of increase / decrease in the variation | change_quantity of the last reference value and this reference value.

Explanation of symbols

7 Patrone 9 Film 18 System controller 18a Setting unit 18b Update unit 18c Determination unit 21 Perforation 22 Photo sensor 26 Perforation detection unit 30 Counter 31 EEPROM

Claims (7)

A light projecting element that projects light onto the perforation passage part of the film; a light receiving element that receives the reflected or transmitted light; In the perforation detection device that detects the number of passing perforations by comparing the change of the received light signal and the threshold value,
When all of the film is rewound onto the cartridge, a light receiving level is detected as a reference value when there is no film on the light projecting element and the light receiving element, and a threshold is set based on the detected reference value. A setting unit; and an updating unit that updates a threshold value stored in the storage unit to a threshold value set by the setting unit. When a cartridge is newly loaded, the threshold value is read from the storage unit and perforation is performed. A perforation detection device characterized by detecting the number of passages.   A determination unit configured to determine whether or not the reference value is included in a predetermined range set in advance; and when the determination unit determines that the reference value is not included in the predetermined range, the setting unit The perforation detection device according to claim 1, wherein a threshold value is set based on the reference value.   A determination unit configured to determine whether or not the reference value is included in a predetermined range set in advance; and when the determination unit determines that the reference value is included in the predetermined range, the setting unit The perforation detection device according to claim 1, wherein a threshold value is set based on the reference value.   Comparing the reference value with the previous reference value used for setting the threshold value stored in the storage means, the determination means comprises a determination means for determining whether or not it is increased or decreased by a certain value or more. 2. The perforation detection according to claim 1, wherein when it is determined that the threshold value has increased or decreased by a certain value, the setting means sets a threshold value based on the reference value and the previous reference value. apparatus.   Comparing the reference value with the previous reference value used for setting the threshold value stored in the storage means, the determination means comprises a determination means for determining whether or not it is increased or decreased by a certain value or more. 2. The perforation detection device according to claim 1, wherein if it is determined that the threshold value has not increased or decreased by a certain value, the setting means sets a threshold value based on the reference value and the previous reference value. .   The reference value is compared with the previous reference value used for setting the threshold value stored in the storage means, and it is determined whether or not the comparison result matches a preset increase or decrease. And determining a threshold value based on the reference value and the previous reference value by the setting means when it is determined that the comparison result matches the set increase or decrease. The perforation detection apparatus according to claim 1.   When the comparison result between the reference value and the previous reference value is increased or decreased, weighting is performed in advance, and when the determination unit determines that the reference value is increased or decreased by a certain value or more, the setting unit 6. The perforation detection apparatus according to claim 4, wherein a threshold is set based on the value and the previous reference value and in accordance with the weighting.

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