JPH0322209Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inspection device for inspecting a wound package using a solid-state image pickup device such as a CCD sensor, and in particular, the present invention relates to an inspection device for inspecting a wound package using a solid-state imaging device such as a CCD sensor. This invention relates to a focus control device for a package inspection camera that can automatically focus on a solid-state image sensor.

[Conventional technology]

In recent years, solid-state imaging devices such as CCD (charge-coupled device) sensors have been used for various purposes. A winding package inspection device using this solid-state image sensor will be explained with reference to FIG.

In FIG. 3, a wound package P is transported on a transport conveyor 1 and enters an inspection box 2. In FIG.
A light source 3 is provided within the inspection box 2, and the light source 3 irradiates the inspection portion of the package P from the light source 3.
This reflected light R is reflected by a mirror 4, passes through a lens 5, and is received by a solid-state image sensor 6 such as a CCD image sensor.

Conventionally, in order to focus on this solid-state image sensor 6, a reflecting mirror 7 is placed in front of the solid-state image sensor 6 to form an image on a focusing glass 8, and while looking through a viewing window 9, the lens 5 is moved in the optical axis direction. I move it to focus.

After focusing on the focusing glass 8 in this manner, the reflecting mirror 7 is removed from in front of the solid-state image sensor 6 and the thread layer is imaged on the solid-state image sensor 6.

After focusing, the voltage waveform output from the solid-state image sensor 6 is analyzed to inspect the wound yarn package, including whether the winding shape is good or bad.

[Problem that the invention attempts to solve]

However, the above-mentioned focusing is done manually by visual inspection, and even once focused, the wound yarn package P carried into the inspection box 2 is not necessarily in the same position each time it is carried in, so it is necessary to always focus. There is a problem in that the inspection work becomes complicated.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a focus control device for a package inspection camera that can automatically focus on a solid-state image sensor.

[Means for solving problems]

In order to achieve the above object, the present invention is a package for controlling the focus by moving the lens in order to irradiate the surface of the thread layer with a light source and to form an image of the reflected light on the solid-state image sensor through the lens. In a focus control device for an inspection camera, a lens moving means moves the lens in the optical axis direction to adjust the focus, and detects a peak voltage in the voltage waveform from the solid-state image sensor at one moving position of the lens. A detector that stores the peak voltage detected by the detector, a storage circuit that stores the peak voltage detected by the detector, and a peak voltage at the peak position from the storage circuit are compared, and the lens movement voltage and other movement means of the lens are adjusted accordingly. A comparison circuit is provided to move the lens and adjust the lens position to a position where the peak voltage from the solid-state image pickup device is maximized.

[Effect]

According to the above configuration, when the solid-state image sensor is accurately focused, the peak voltage in the voltage waveform that is its output becomes maximum. In other words, when the focus is out of focus, the light that reaches the pixel position of the solid-state image sensor corresponding to the peak voltage is dispersed, resulting in a lower output voltage, but when the focus is adjusted, the dispersion disappears and the output voltage decreases. Maximum. Therefore, it is necessary to detect the peak voltage with a peak detector, store it in a storage circuit, and output it to the lens moving means so that the peak voltage is always high in the comparator circuit when moving the lens. The maximum peak voltage can be detected, and focus can be adjusted automatically based on this.

〔Example〕

A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

First, the arrangement of the package inspection box, light source, lens, and solid-state imaging device is basically as explained in FIG. 3.

FIG. 1 shows a block diagram of a focus control device for a package inspection camera according to the present invention. First, the lens 5 is moved in the optical axis direction by a lens moving means 12 consisting of a motor 10 and an encoder 11, and the lens 5 is moved in the optical axis direction. Reflected light R from the yarn layer surface (not shown) of
is imaged on a solid-state image sensor 6 such as a CCD sensor.

The solid-state image sensor 6 generates (photoelectric conversion) a charge proportional to the amount of light received for each pixel, and sequentially transfers the charge as a voltage signal. The voltage output from the solid-state image sensor 6 is amplified by the amplifier 13 and then input to the peak detector 14, where the peak voltage in the voltage waveform is detected and stored in the storage circuit 15. .

This stored peak voltage and peak detector 14
The peak voltage newly detected in the comparator circuit 16
is input. The comparison circuit 16 compares the previous peak voltage from the storage circuit 15 and the new peak voltage from the peak detector 14, and issues direction commands 17, 18 to the lens moving means 11 based on the comparison information.
By outputting , the lens position is adjusted and focused to obtain the maximum peak voltage.

This focusing operation will be explained in more detail.

First, it is assumed that the lens moving means 12 moves the lens 5, for example, in the + direction.

In this case, the solid-state image sensor 6 outputs the voltage waveform at each position of the lens 5 to the peak detector 14 via the amplifier 13. The peak detector 14 is
For example, as shown by the dotted line in FIG. 2, the peak voltage P ₀ in the waveform W ₀ is detected from the initial voltage waveform W ₀ and is output to the storage circuit 15 . Next, when the position of the lens 5 moves slightly in the + direction from the initial position, the peak detector 14 similarly detects the peak voltage P ₁ and outputs it to the storage circuit 15 and the comparison circuit 16. If the comparison circuit 16 is higher than the peak voltage P ₀ initially stored in the storage circuit 15, it outputs a command 17 to the lens moving means 12 to move the lens 5 in the + direction. do. In this way, lens 5
When moving in the + direction, the memory circuit 15 always memorizes the peak voltage that becomes higher, and this is the maximum peak voltage in the voltage waveform Wmax when the focus is on.
After memorizing Pmax, the peak voltage will decrease. Therefore, the comparison circuit 16 outputs the command 17 in the + direction to the command 18 in the - direction.
The lens moving means 12 constantly stores the lens position using the encoder 11, and as described above, when the comparator circuit 18 outputs the command 18 in the negative direction,
Focusing is performed by returning the lens 5 in the - direction to the lens position where the maximum peak voltage Pmax is shown.

Furthermore, when the lens 5 starts moving, if the new peak voltage P ₁ is lower than the initial peak voltage P ₀ , the comparator circuit 16 outputs a command 18 in the - direction to move the lens 5 in the - direction. The lens moving means 1 is moved to detect the maximum peak voltage Pmax in the same manner as described above, and the lens moving means 1 is moved to the lens position where the maximum peak voltage Pmax is obtained.
2 performs position adjustment.

The speed at which the peak voltage is detected from the voltage waveform from the solid-state image sensor 6 and compared is sufficiently faster than the moving speed of the lens 5, so that the lens moving means 12
Focusing can be performed while continuously moving the lens 5.

[Effect of idea]

As is clear from the above explanation, the present invention provides the following excellent effects.

(1) Automatic focusing can be achieved by moving the lens, detecting the peak voltage from the voltage waveform of the solid-state image sensor, and stopping the lens at the position where the peak voltage is maximum.

(2) Since focusing is performed using the output of the solid-state image sensor, it is possible to focus faster and more accurately than when a person manually focuses.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing a voltage waveform of a solid-state image pickup device in the present invention, and FIG. 3 is a sectional view showing a conventional winding package inspection device. In the figure, 5 is a lens, 6 is a solid-state image sensor, 11 is a lens moving means, 14 is a peak detector, 15 is a storage circuit, and 16 is a comparison circuit.

Claims (1)

[Scope of utility model registration request] In order to irradiate the surface of the thread layer with a light source and image the reflected light on a solid-state image sensor through a lens,
In a focus control device for a package inspection camera for controlling the focus by moving the lens,
a lens moving means for adjusting the focus by moving the lens in the optical axis direction; a detector for detecting a peak voltage in the voltage waveform from the solid-state image sensor at one movement position of the lens; A memory circuit stores the detected peak voltage, and the peak voltage from the memory circuit is compared with the peak voltage at other movement positions of the lens, and the lens is moved by the lens moving means accordingly, and the solid-state image sensor is moved. 1. A focus control device for a package inspection camera, comprising a comparison circuit for adjusting the lens position to a position where the peak voltage from the lens is maximized.