JP2974528B2 - Camera film feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film feeder for a camera which optically detects film perforation and detects, for example, one frame of film feed.

[0002]

2. Description of the Related Art As a device for detecting a film feed amount of a camera, an optical sensor such as a photoreflector comprising a light emitting / receiving element is provided in the camera. Light, the reflected light is received by a light receiving element, and reflected on the film surface.
There has already been proposed a method in which non-reflection in perforation is used to detect perforation.

The signal photoelectrically converted by the light receiving element is an analog signal. A signal obtained by converting the analog signal into a digital signal at a predetermined interval is compared with a threshold value (a value for determining that a perforation edge has come). The pulse corresponding to the perforation is output depending on whether or not it exceeds the threshold.

Although it is ideal that the waveform of the analog signal is a sine wave, when the film feeding speed is reduced, the entire waveform tends to look flat.

[0005]

It is ideal that the waveform of the analog signal photoelectrically converted by the light receiving element is a sine wave. However, when the film feeding speed becomes low, the entire waveform becomes flat. Tend to look good.

[0006] For this reason, the AD-converted value becomes linear, and even if there is a slight noise, it can be compared with the threshold value.

SUMMARY OF THE INVENTION An object of the present invention is to provide a camera film feeding apparatus capable of solving such a conventional problem and accurately detecting perforation even when the film feeding speed is reduced. I do.

[0008]

A first structure of a camera film feeder for realizing the object of the present invention is as follows.
An optical sensor for optically detecting the perforations of the film fed by the film feeding means, said detection information from the light sensor to digital conversion every time set in the timer means, and said digital converted converted value in the film feed device for a camera having a perforation counting means for counting the perforations by comparing the threshold value, the perforation counting means determines that the film feeding speed is low, before
Characterized in that the longer the setting time of the serial timer means. Camera film feeder that achieves the object of the present invention
In the second configuration, a film fed by a film feeding means is provided.
Optical sensor for optically detecting film perforations
And the detection information from the optical sensor to timer means.
The digital conversion is performed at set time intervals.
The perforation is compared by comparing the transformed value with the threshold.
Having perforation counting means for counting
In the film feeder for a camera, the perforator
The film feeding speed is low.
Is determined, the first converted value and the second converted value
Comparing an average value of the converted values with a threshold value
You. Camera film feeder that achieves the object of the present invention
In the third configuration, a film fed by a film feeding means is provided.
Optical sensor for optically detecting film perforations
And the detection information from the optical sensor to timer means.
The digital conversion is performed at set time intervals.
The perforation is compared by comparing the transformed value with the threshold.
Having perforation counting means for counting
In the film feeder for a camera, the perforator
The film feeding speed is low.
, The threshold level is detected from the optical sensor.
To a level that is less susceptible to the noise contained in the output information.
It is characterized by the following.

In the film feeding apparatus for a camera having the above-described structure, when the film feeding speed is low, the time from when the analog signal photoelectrically converted by the optical sensor is converted into a digital signal to when the analog signal is next converted is converted. Since the interval (hereinafter, abbreviated as the AD conversion interval) is lengthened, the amount of change (voltage difference) of the analog signal during the interval increases, and even if noise occurs in the light receiving signal, the influence of the noise decreases.

[0010]

FIG. 4 is a block diagram showing a first embodiment of a film feeding apparatus for a camera according to the present invention.

1 is a microcomputer for controlling the operation of the camera (hereinafter abbreviated as microcomputer), 2 is a motor driver for driving a film feeding motor 3, and 4 is a light emitting element 4
a, a photoreflector composed of a light receiving element 4b and the like, 5
Is a constant current circuit for the photoreflector 4, and 6 is a film feed low speed mode switch (MSW).

By setting the output terminal L2 to a high level (hereinafter abbreviated as "H"), the microcomputer 1 operates the well-known constant current circuit 5 to turn on the light emitting element 4a. The reflected light from the film surface on which the light projecting element 4a is projected is received by the light receiving element 4b. If the light projecting surface is perforated, the reflected light is small, and if not, the reflected light is large. The light receiving element 4b allows a current to flow in proportion to the amount of reflected light, and the current × R1 is applied to the input terminal L3.
(Resistance value) is generated.

By setting the output terminal L4 of the microcomputer 1 to a low level (hereinafter abbreviated as "L") and setting the output terminal L5 to "H", the motor driver 2 sends the motor 3 from the output terminals L6 and L7 to feed the film. To output a drive control signal. When both the output terminals L4 and L5 of the microcomputer 1 are set to “H”, the motor driver 2 outputs the output terminals L6 and L6.
A signal for stopping the motor 3 is output from L7.

The microcomputer 1 also determines whether or not the film feeding speed is low. There are three cases where the microcomputer 1 can determine that the film feeding speed is low.

When the power supply voltage is low: When the film feeding mode is low: When the feeding speed is low.

In the above case, for example, the terminal L1
A / D conversion is performed on the divided voltage of the power supply voltage, and a drop in the power supply voltage is detected by checking the value.
Predict that the feed speed will be low.

In the above case, for example, the MSW switch 6
Is turned on, the input terminal L8 of the microcomputer 1 becomes "L", and it is detected that the film feeding speed is designated to the low speed mode. Here, when the low speed mode is designated, the terminal L
5, "H", the terminal L4 is duty-driven, the speed of the motor 3 is reduced, and the film feeding speed is reduced.

In the above case, the film feeding time for one frame is always stored, and before feeding, the previous feeding time is checked to determine whether or not the feeding speed is low.

The microcomputer 1 includes a photo reflector 4
Converts the analog signal from the light receiving element 4b into a digital signal
D conversion is performed, and the converted value is compared with a threshold. The level of the threshold is set at the time of auto loading.

The photoreflector 4 always operates during feeding, and sends the data to the microcomputer 1, and the microcomputer 1 performs the A / D conversion according to the A / D conversion interval to detect the perforation. In addition, a large number of detection operations are performed between perforations.

Therefore, if the conversion output time becomes longer,
The detected data amount (voltage) increases accordingly.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

When the microcomputer 1 starts a film feeding operation, it is determined in step 1 whether or not the film feeding speed is low. If the film feeding speed is low, an interval for converting an analog signal from the light receiving element 4b into a digital signal is determined. Is a constant Y when the AD conversion interval variable (ADTIME) is
(Y> X), the process proceeds to step 2, and the constant current circuit 5
Is driven to drive the photoreflector 4 and step 3
Then, the motor 3 is driven to feed the film, and the process proceeds to step 4.

In step 4, the current time (TIME) is input to the time variable T 1, and the process proceeds to step 5.

In step 5, 0 is input to a counter (PF_CNT) for counting the boundary of the perforation of the film (the boundary between the hole and the non-hole), and it is determined whether or not the perforation is detected. Is input to EG_FLG used as a discriminator for discriminating that this is the reverse of the current time (EG_FLG =
0 or 1), and the process proceeds to step 6.

Step 6 includes steps 7 to 12
In the perforation count processing operation in, the perforation count processing operation is repeatedly performed until the count at the perforation boundary becomes 16 or more. When the count at the perforation boundary becomes 16 or more, it is determined that one frame has been fed. The driving of the motor 3 is stopped (step 13), and the operation of the photo reflector 4 is stopped (step 14).

The perforation count processing operation in steps 7 to 12 is as follows. First, in step 7, while the time from the start of film feeding to the current time is smaller than the A / D conversion interval input in step 1, the following steps are performed. 8 and an infinite loop is formed. For example, if the film feeding speed is low, the ADTI
ME is input with Y, and the conversion time is longer (Y> X) than in the case of the normal feeding speed.

When the conversion time has elapsed, the current time (TIME) is input to the time variable T1 (step 8), and the process proceeds to step 9 in preparation for the next count operation.

In step 9, the voltage value photoelectrically converted by the light receiving element 4b of the photo reflector 4 is converted into a digital signal. Therefore, if the film feeding speed is low, the amount of change in the voltage is increased accordingly, and the influence of noise is reduced.

In step 10, in step 9, A
The D-converted AD conversion value is compared with a threshold value (LEVEL). If the AD conversion value is higher than the threshold value, the process proceeds to step 11;

When the reflected light from the film surface is received, the amount of reflected light is large and the value of the A / D conversion becomes high. On the contrary, when the reflected light from the perforation is received, the reflected light is large. Since the amount of light is small, the value obtained by AD conversion also becomes low. In this embodiment, a threshold level is set at the time of automatic loading of a film.

In step 11, it is determined whether or not EG_FLG is 0. If 0, EG_FLG is set to 1 and PF_FLG is set to 1;
CNT is counted by one.

In step 12, EG_FLG is set to 1
EG_FLG is set to 0 if P is 1, and P
F_CNT is counted by one.

That is, EG_FLG = 0 indicates that the film surface is to be detected, and EG_FLG = 1 indicates that the perforation is to be detected. It is expected that the detection state will switch from the surface to the perforation, and from the perforation to the film surface. If the expected result is obtained, it is ensured that the movement from the film surface to the perforation and the movement from the perforation to the film surface ( That is, it is said that the perforations are detected, and the counter PF_CNT at the boundary of the perforation is counted up by one. And the count number of PF_CNT is 16, that is, 8
When the number of perforations has been counted, it is determined that exactly one frame of the film has been fed, and the perforation counting operation ends.

In steps 11 and 12, EG
If _FLG is not what is expected, the process returns to step 7 and repeats the same operation.

FIG. 2 is a flowchart showing a second embodiment of the present invention. In this embodiment, when the film feeding speed is low, each AD conversion value is not compared with the threshold value each time, and the previous AD conversion value is not compared. A value obtained by averaging the converted value and the current AD converted value is compared with a threshold value.

In step 1, if the film feeding speed is low, the speed flag SPEED_LOW =
As in the first embodiment, the photoreflector 4 is turned on (step 2), the film feed driving of the motor 3 is performed (step 3), and the current time is input (step 4). In step 5, PF_CNT = 0. EG_FLG = 0,
Previous perforation AD conversion value PF_OLDAD
= 0, and the routine proceeds to step 6.

In step 6, the value of PF_CNT is 16
Until the above, the perforation count processing operation from step 7 to step 15 is executed. And
When the value of PF_CNT becomes 16 or more, the motor 3 is stopped (step 16), and the photoreflector 4 is turned off.

In step 7, 1 is input to a new / old conversion value flag N for determining the new / old AD conversion value, and it is assumed that the AD conversion value is new.

Step 8 waits for a fixed AD conversion time to elapse, and then proceeds to the processing from step 9 to step 15. After inputting the current time (step 9), AD conversion is performed (step 10). ).

In step 11, if the speed flag is 1, the film feeding speed is low, and the process proceeds to step 12.

In step 12, the AD conversion value is
If it is a D-converted value (N = 1), the value is converted to the old converted value (PF
_OLDAD), the flag N = 2, and the old A
This indicates that the D-converted value exists, and returns to step 8. If the old conversion value is present, the sum of the old A / D conversion value and the new A / D conversion value is divided by 2, and the averaged value is compared with the threshold value in step 13 (PF_A
D), the flag N is set to 1, and the next AD conversion data is set as a new AD conversion value.

In steps 13 to 15, the same processing as in steps 10 to 12 of the first embodiment is performed, and the perforation is counted.

That is, while the AD-converted individual values are conventionally compared with a threshold value, in this embodiment, for example, the averaged value of the first and second AD-converted values and the third and fourth AD-converted values is obtained. Is compared with the threshold value, even if there is a slight noise when the film feeding speed is low, the noise is averaged, and the possibility of erroneous detection of perforation is reduced.

Of course, if the film feeding speed is not low, the process proceeds from step 11 to step 13 without performing the process in step 12, and the same perforation counting process as in the prior art is performed.

FIG. 3 is a flowchart showing a third embodiment of the present invention.

In this embodiment, when the film feeding speed is low, the threshold value (LVL) for comparing the AD conversion value is made variable, and when the perforation is detected, the level is lowered (LVL = LEVEL-α). When the detection is made, the level is raised (LVL = LEVEL + α) to reduce the influence of noise.

In the film feeding process according to the present embodiment, the film feeding speed is determined in step 1, and if the speed is low, the speed flag SPEED_LOW is set to 1; Steps 2 to 4 perform the same processing as steps 2 to 4 in FIG.
In the above, 0 is input to PF_CNT and EG_FLG, and the variable threshold LVL is set to a normal level (LVEL).
Set to.

Then, in step 6, step 7
When the perforation boundary count becomes 16 or more by the perforation count processing operation of Step 12 to Step 12, the motor 3 is stopped (Step 13) and the photo reflector is turned off (Step 14).

In steps 7 to 9, the photoelectric conversion information detected by the photoreflector 4 is AD-converted at regular intervals, and in step 10 the AD conversion value (P
F_AD) and a variable threshold (LVL) are compared.

If the AD conversion value is higher than the variable threshold value, EG_FLG is determined in step 11 and
If EG_FLG = 0 and the film feeding speed is low (SPEED_LOW = 1), the level of the variable threshold for the next comparison is reduced (LVL = LEVEL-α).
At the same time, EG_FLG is set to 1 and PF_CNT is counted up by one.

If the AD conversion value is lower than the variable threshold value, EG_FLG is determined in step 12, and if EG_FLG = 1 and the film feeding speed is low (SPEED_LOW = 1), Raise the level of the variable threshold for the next comparison (LVL = LEVEL)
+ Α), EG_FLG is set to 0, and PF_CNT is counted up by one.

That is, assuming that the threshold level is always constant as in the prior art, the noise generated in the AD conversion value may exceed the threshold value. In the case of an A / D conversion value of perforation, the threshold value is increased to avoid the influence of noise.

[0054]

As described above, according to the present invention,
When the film feeding speed is low, the signal waveform during one perforation detected by the optical sensor becomes a nearly flat sine wave, but the process of A / D converting the signal from the optical sensor is lengthened or averaged. By adjusting the A / D conversion value in the above, even if there is noise in the signal from the optical sensor, it is not affected by the noise, and the perforation can be accurately detected.

When the film feeding speed is low, A
By changing the level of the threshold for detecting the boundary of perforation to a level that is not easily affected by noise included in the signal from the optical sensor without adjusting the D conversion value, perforation can be accurately detected. .

[Brief description of the drawings]

FIG. 1 is a flowchart showing the operation of a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the second embodiment.

FIG. 3 is a flowchart showing the operation of the third embodiment.

4 shows a block diagram of the onset Ming first embodiment.

[Explanation of symbols]

 1: microcomputer (microcomputer) 2: motor driver 3: motor 4: photoreflector 5: constant current circuit

Claims (3)

(57) [Claims] 1. A an optical sensor for optically detecting the perforations of the film fed by the film feeding means to digital conversion of the detection information from the optical sensor each time set to the timer means, the digital conversion Ca and a perforation counting means for counting the perforations by comparing the transform value and the threshold value
In the film feeding device camera, the perforation counting means determines that the film feeding speed is low, the timer means set time to increase feed film camera feed, wherein device. Wherein an optical sensor for detecting a perforation of the film fed by the film feeding means optically, and digital conversion of the detection information from the optical sensor each time set to the timer means, the digital conversion Ca and a perforation counting means for counting the perforations by comparing the transform value and the threshold value
In the film feeding device camera, the perforation counting means determines that the film feeding speed is low, the threshold average value of the second conversion value is then converted to a first conversion value A film feeder for a camera, characterized by comparison. An optical sensor for optically detecting the perforations of the film fed by wherein the film feeding means to digital conversion of the detection information from the optical sensor each time set to the timer means, the digital conversion Ca and a perforation counting means for counting the perforations by comparing the transform value and the threshold value
In the film feeding device camera, the perforation counting means, the speed film feed is determined to be slow, to change the susceptible level the influence of noise included in the detection information from the light sensor the level of the threshold A film feeding device for a camera .