JP2909192B2 - Fabric bend detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a texture bend detecting device, and more particularly to a texture bend detecting device for detecting a texture bend amount of a running woven fabric.

[Conventional technology]

Conventionally, the direction of the weft to the warp of the fabric is not a right angle,
As a typical device for detecting a so-called cloth bend in a tilted or curved state, a light source emits light to a running fabric, and light transmitted through the fabric passes through a slit to generate moiré. (See Japanese Patent Application Laid-Open No. 56-73161), which converts an electric signal into an electric signal, and further converts the signal into a signal proportional to the inclination angle of the weft and outputs the converted signal.

In addition, an image of the woven fabric is captured in advance by a camera, and the woven pattern is stored as a standard state at binary signal levels of “0” and “1”. Similarly, the signal is converted into binary signal levels of “0” and “1”, and the binary signal levels “0” and “1” and the binary signal levels “0” and “1” stored as the standard state. Device that measures the grain bend due to the difference between
63-219676).

There is also a device for outputting a weft bend angle using a detector comprising a pair of light emitting and receiving devices incorporating an optical slit that moves across the entire width of the fabric (Japanese Patent Application Laid-Open No. 58-186668).

Also, a weft position measuring device having one or more scanning heads that move across the entire width of the belt-shaped product and adjusting by comparing signals from the scanning heads at both ends (Japanese Patent Laid-Open No. 55-76159) Gazette).

[Problems to be solved by the invention]

In the case of a woven fabric subjected to a backing finish or resin processing in which a resin solution is coated on the back surface or both front and back surfaces of the woven fabric, almost no light is transmitted through the woven fabric and moire cannot be obtained.
The device disclosed in Japanese Patent Publication No. 1 cannot detect a grain bend.

Also, the apparatus of Japanese Patent Application Laid-Open No. 63-219676 can be applied to some extent when the contrast is clear with a simple woven pattern with oblique stripes.However, when the pattern becomes complicated, the difference from the standard state and the amount of grain bend may occur. And the amount of texture bending cannot be detected.

Further, JP-A-58-186668 and JP-A-55-76159
According to the technique described in Japanese Patent Application Laid-Open Publication No. H10-209, it is possible to calculate the direction of the weft in each portion, but it is not possible to calculate the amount of deviation and the amount of deflection at both ends of the fabric necessary for correcting skew and curvature.

The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to detect the amount of fabric bend even for a fabric that does not transmit light due to resin processing or the like, a fabric having a complicated weave pattern, and a fabric having a poor contrast. It is an object of the present invention to obtain a texture bend detecting device capable of performing the following.

[Means for solving the problem]

In order to achieve the above object, a first invention is, as shown in FIG. 1, an imaging device II for imaging a pattern of a fabric to be measured I and outputting an image signal, and an image output from the imaging device II. Fourier transform means III for outputting a pattern direction signal indicating the direction of the pattern by Fourier transforming the signal, storage means IV for storing the pattern direction signal in the normal state of the measured fabric as a reference pattern signal, and Fourier transform means III And a calculating means V for calculating the degree of skew representing the curvature of the fabric based on the pattern direction signal output from the controller and the reference pattern signal stored in the storage means IV.

[Action]

The operation of the first invention will be described with reference to FIG. The imaging device II captures a pattern of the fabric I to be measured and outputs an image signal. The Fourier transform unit III performs a Fourier transform on the image signal and outputs a pattern direction signal indicating the direction of the pattern. Storage means
In IV, a pattern direction signal of the measured fabric I in a normal state is stored in advance as a reference pattern signal. The calculating means V calculates and outputs the degree of skew of the fabric based on the pattern direction signal and the reference pattern signal. This makes it possible to detect the bending of the fabric.

That is, when the texture of the woven fabric is bent, the direction of the woven pattern changes in accordance with the amount. When the woven pattern is imaged by the imaging device and the image is subjected to Fourier transform, a Fourier image having a bright point in an area corresponding to the period and direction of the woven pattern is obtained.
Since the direction of the bright spot on the Fourier image corresponds to the direction of the woven pattern, the cloth bend can be known by calculating the skew degree of the woven fabric by determining the direction of the woven pattern. Therefore, in the first invention, the woven fabric is imaged by the imaging device, the obtained image is input to the Fourier transform means, and the Fourier transform is performed, and the direction of the woven pattern is calculated from the direction of the bright spot on the obtained Fourier image. By doing so, the texture bend is calculated.

〔The invention's effect〕

As described above, according to the first invention, a pattern direction signal is obtained by performing a Fourier transform on an image signal obtained by imaging a pattern of the fabric, and the pattern direction signal is obtained based on the pattern direction signal and the reference pattern signal. Since the degree of skew is calculated, it is possible to detect a texture bend even in a fabric that does not transmit light, a fabric that has a complicated weave pattern, or a fabric that does not have a clear contrast.
The effect is obtained.

[Description of Other Inventions]

In order to achieve the above object, the second invention, as shown in FIG. 2, uses the image bending device of the first invention to connect the image pickup device II continuously or intermittently across the entire width of the fabric I to be measured. A moving device VI for moving the target is added.

The moving device VI of the present invention moves the imaging device II continuously or intermittently across the entire width of the measurement target fabric I. This allows the imaging device II to take an image across the entire width of the fabric, so that it is possible to know the state of the texture bending over the entire width of the fabric. In this way, by moving the imaging device over the entire width of the fabric, the angle of the weft is calculated by calculating the bend at each point, the skew of the weft, the state of the curvature is expressed as a function, and the weft is expressed at both ends of the fabric. The displacement amount and the deflection amount at the center can be calculated.

Further, in the third invention, as shown in FIG.
The air-burge device VII for forming an air curtain on the front surface of the optical lens of the imaging device II is further provided in the texture bend detection device of the invention and the second invention, and has a dustproof function of protecting the imaging device II from dust, dust and the like. It is added.

The air purge device VII of the third invention forms an air curtain on the front surface of the optical lens of the imaging device II. As a result, the imaging device II is protected from dust, dust, etc., so that the imaging state does not deteriorate even during long-term use.

In the fourth invention, as shown in FIG. 4, a light source device VIII for illuminating the measurement target fabric I, and light transmitted through the measurement target fabric I, which is disposed to face the light source device VIII and is detected. An imaging device II, Fourier transform means III for Fourier-transforming the transmitted light signal output from the imaging device II to calculate a pattern direction signal, and storing the pattern direction signal in the normal state of the measured fabric as a reference pattern signal. It comprises a storage means IV and a calculation means V for calculating the skewness of the fabric I to be measured based on the pattern direction signal and the reference pattern signal.

In the cloth bend detecting device of the fourth invention, the light source device VIII
Irradiates the fabric I to be measured. The imaging device II facing the light source device VIII detects the light transmitted through the measured fabric I and outputs a transmitted light signal. Fourier transform means III
The transmitted light signal output from the imaging device II is Fourier-transformed to output a pattern direction signal. The calculating means V calculates the skew degree of the fabric to be measured from the pattern direction signal and the reference pattern signal. Thereby, the bend of the cloth of the woven fabric can be detected from the image by the light transmitted through the woven fabric.

According to a fifth aspect of the present invention, the difference in the pattern direction signal at each point in the width direction of the measured fabric is calculated by the calculating means of the first to fourth aspects, and a shift at both ends of the fabric having a skewed and curved cloth is provided. It detects the amount and the amount of deflection.

According to a sixth aspect of the present invention, there is provided a light source device that illuminates a measured fabric, an imaging device that is disposed to face the light source device, and detects light transmitted through the measured fabric, and a transmitted light signal output from the imaging device. It includes Fourier transform means for calculating the weft direction by performing Fourier transform, and calculating means for calculating the degree of skew of the fabric from the weft direction signal output from the Fourier transform means.

According to a seventh aspect, the arithmetic means of the sixth aspect provides:
The difference in the weft direction signal at each point in the width direction of the fabric to be measured is calculated, and the amount of displacement and the amount of deflection at both ends of the fabric having a skew and a curve are detected.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 5 shows the configuration of this embodiment. This embodiment includes a moving device VI disposed below the measured fabric I in a direction perpendicular to the running direction of the measured fabric, and an imaging device II that images the fabric and outputs an image signal. . This imaging device II
Is attached to the moving device VI and is moved in a direction orthogonal to the traveling direction. The imaging device II is provided with an air barge device VII that protects the imaging device II from dust and dirt. The imaging device II performs a two-dimensional Fourier transform on the image signal,
It is connected to Fourier transform means III which outputs the obtained feature amount as a pattern direction signal. Fourier transform means III
The storage means IV for storing in advance the pattern direction of the measured fabric I in the normal state as a reference direction and outputting a reference pattern direction signal is connected, and the distortion of each part of the woven pattern is determined from the pattern direction signal and the reference pattern signal. It is connected to the skew degree calculating device V to be measured.

As shown in FIG. 6, the moving device VI includes a camera holder 6 on which the imaging device II and the air barge device VII are attached.
a, a belt 6b for moving the camera holder 6a, a motor 6c,
Encoder that outputs pulses according to the rotation of motor 6c
Has 6d. These are mounted on the support 6h. The encoder 6d is connected to a control device 6 including an up / down counter 6e for counting output pulses of the encoder 6d, a comparator 6f, and a motor control circuit 6g.

The camera holder 6a is reciprocated continuously in the width direction of the fabric I by the motor 6c. The counter 6e counts the number of output pulses of the encoder 6d, and counts the number of output pulses of the encoder 6d.
, And outputs a position signal Xc. Assuming that the number of output pulses of the encoder 6d per rotation of the motor is N, the moving distance of the camera holder 6a per rotation of the motor is s, and the count value of the counter 6e is n, the position signal Xc is expressed as follows. .

The comparator 6f compares the position signal Xc with the width d of the fabric so that the position of the holding table 6a does not exceed the width of the fabric. When the holding table 6a moves to the opposite end of the fabric, the position signal Xc becomes equal to the width of the fabric, and the comparator 6f outputs the inverted signal Mr. The motor control circuit 6g rotates the motor 6c in the reverse direction based on the inversion signal Mr, and moves the holder 6a in the reverse direction. If the rotation direction is reversed, the rotation direction of the encoder 6d changes, and the up / down signal ud output by the encoder 6d changes in the down direction. The counter 6e counts down when the up / down signal ud goes in the down direction, so that the count number n decreases by the number of pulses output by the encoder 6d. At this time, the position of the holding table 6a is
It is similarly obtained from equation (1).

When the holding table 6a moves to the edge of the fabric, the position signal Xc becomes 0.
(N = 0), and the comparator 6f outputs the inverted signal Mr.
Based on the inversion signal Mr, the motor 6c rotates in the reverse direction and the holding table 6a
Is moved in the opposite direction. At the same time, the rotation direction of the encoder 6d changes, the up / down signal ud output from the encoder 6d becomes the up direction, and the count number n increases.

By repeating this operation, the holding table 6a is reciprocated in the width direction of the fabric I, so that the entire width of the fabric can be imaged by the imaging device II.

As shown in FIG. 7, the imaging device II attached to the holding table 6a includes a lens 2a with zoom and auto iris and a zoom controller 2b, and a CCD camera 2c with shutter.
Consists of

When the imaging timing signal ts is input from the skew degree calculation circuit V, the CCD camera 2c images the fabric I for a short time with a high-speed shutter and outputs an image signal g. At this time, the image of the textile taken is automatically adjusted to an appropriate brightness by the auto iris of the lens 2a. Also, CCD camera 2c
The shutter speed is selected to be appropriate so that the image is not blurred by the running speed of the fabric. The zoom controller 2b considers the relationship between the woven pattern and the weft density so that the feature amount of the woven pattern is best obtained, and
Adjust the angle of view.

As shown in FIG. 7, the air barge device VII includes a camera case 7a and a camera case housed in the camera case 7a so as to form an air passage between the camera case 7a and the camera case.
7b, a protective glass 7c provided to close the opening of the camera case 7a, an air hose 7d connected to an air passage, and an air supply pump 7e.

The camera cases 7a and 7b and the protective glass 7c protect and protect the camera 2c and the lens 2a from dust. In addition, an air curtain is formed by blowing air from an air passage formed between the cases so that dust, oil, or the like, or lint of fabric is not attached to the camera 2c and the lens 2a at the device installation location. Air is supplied from a supply pump 7e through a hose 7d.

As shown in FIG. 8, the Fourier transform means III includes an image input circuit 3a for taking in the image signal g of the fabric I, an image enhancing circuit 3b for increasing the contrast of the taken image signal g, and an FFT (high-speed FFT) for performing two-dimensional Fourier transform. Fourier transform) circuit 3
c and a pattern direction calculation circuit 3d for calculating the direction of the woven pattern from the Fourier image.

The image of the woven fabric I obtained by the imaging device II is output as an image signal g, subjected to two-dimensional Fourier transform by the Fourier transform means III, and output as a pattern direction signal od representing a feature amount indicating the direction of the woven pattern. .

The operation of the Fourier transform means III will be described in more detail with reference to FIG.

The image signal g (FIG. 9 (a)) of the fabric obtained by the imaging device II is taken into the image input device 3a. The image enhancement circuit 3b enhances the contrast of the image signal g to enhance the woven pattern, and outputs an enhanced image signal cg (FIG. 9 (b)). As shown in FIG. 12, the image enhancement circuit 3b performs density conversion so that the histogram of the number of pixels is the same for all density values. The FFT circuit 3c performs a two-dimensional Fourier transform on the enhanced image signal cg and outputs a Fourier image signal fg (FIG. 9 (c)). The positions of bright points (feature points) on the Fourier image signal fg in FIG. 9 (c) represent periodic features of the image of the fabric. The distance of this point from the origin corresponds to the period of the woven pattern, and its direction corresponds to the direction of the woven pattern. Therefore, the straight line connecting these points indicates the direction of the woven pattern. Pattern direction calculation circuit 3d
Is the direct gradient α (FIG. 9 (d)) connecting the bright points (feature points) on the image from the Fourier image signal fg,
Output as od.

The storage means IV includes the imaging device II and the Fourier transform means II.
When the woven fabric obtained using I is not skewed (normal state), a direct inclination αr connecting bright points (feature points) on the Fourier image is stored as a reference value, and this inclination αr
Is output as the reference pattern signal rd.

As shown in FIG. 10, the skew degree calculation circuit V includes a timing signal generation circuit 5a that generates an imaging timing signal ts that determines the shutter timing of the CCD camera 3c, and a pattern direction signal of each part of the fabric. It comprises a skew degree calculating circuit 5b for calculating the skew degree and a cloth distortion calculating circuit 5c for calculating the cloth distortion of the fabric from the skew degree of each part.

The timing signal generation circuit 5a outputs an imaging timing signal ts every time the camera 3c moves 1/9 of the total width d of the fabric based on the camera position signal Xc output from the counter 6e. Therefore, while the camera 3c moves once across the entire width of the fabric,
The woven pattern is imaged 10 times, and the pattern direction signal for each image
od is output. The skew degree calculating circuit 5b calculates the difference between the pattern direction signal od and the reference pattern signal rd, that is, the slope of the straight line of the slope α based on the straight line of the slope αr, and determines the difference at the point where the weave pattern is imaged. It is calculated as the skew degree θi of I. The texture distortion calculation circuit 5c calculates the texture distortion of the woven fabric by performing the following calculation and outputs the texture angle signal θ. In other words, as shown in FIG. 11, the skew degree calculating circuit 5b calculates the position of each point (Xi) from the image obtained at the site (Xi, i = 0 to 9) corresponding to 10 points in the width direction of the fabric I. The skew degree θi is output. If the weft of the woven fabric is represented by y = −ax ² + bx (2), as shown in the figure, the degree of skew is represented by the slope at the point of x = Xi.
The inclination is represented by y ′ = − 2ax + bx (3), and since the skew degree θi of each point of the fabric is calculated by the skew degree calculation circuit 5b, the following relationship is established.

θi = −2aXi + b (4) Actually, both θi and Xi include a measurement error. Therefore, a and b in the equation (2) are obtained by the least square method from each point Xi of the fabric and the skew degree θi. The cloth distortion calculating circuit 5c performs the above calculation, calculates the direction θ at x of each portion of the weft using the obtained a and b as cloth distortion by the following equation, and uses the value as the cloth angle signal θ. Output.

θ = −2ax + b (5) With the above configuration, it is possible to calculate and output the texture distortion of each portion with respect to the entire width of the fabric. In this embodiment, since a camera with a shutter is further used, even when the fabric is running at high speed, an image without blur is obtained, and the texture distortion can be obtained with high accuracy. Further, since dust, oil and lint are prevented from adhering to the lens and the camera by using an air barge device, a clear image can be obtained even after long-term use, and the grain distortion can be accurately obtained. In addition, since the optimal angle of view of the camera is controlled in accordance with the woven pattern using the zoom lens, the texture distortion can be accurately obtained. Further, since the woven pattern can be clearly imaged even in a dark place or in a black and non-contrast fabric by the auto iris lens and the image enhancement circuit, the texture distortion can be accurately obtained.

In the present embodiment, the direction of the woven pattern is a straight line connecting bright points (feature points) on the Fourier image, but the angle of a straight line connecting the origin and the feature points may be used. The weft is expressed two-dimensionally, and the cloth distortion is obtained from images of 10 points in the width direction. However, when the distortion is simple, it can be calculated from several images.
Further, the function indicating the weft can be represented by a higher-order polynomial, a spline function, or the like, and the texture distortion of each portion can be more accurately obtained from a large number of images.

As the Fourier transform means, either an optical type or an electric type (including software) may be used.

Further, the image enhancement circuit determines the darkest density value Po of the image signal.
From the smallest density value So (<Po) that can be handled by the processing circuit to the largest density value Sn (> Pn). Examples of the conversion formula include the following.

The second embodiment of the present invention is an application of the sixth and seventh inventions.

FIG. 13 shows the configuration of this embodiment. In this embodiment, the light source device VIII provided opposite to the image pickup device II with the cloth to be measured I interposed therebetween and the camera holding table moved below the cloth I in a direction perpendicular to the running direction of the cloth. Mobile device VI
An imaging device II attached to the moving device VI and outputting a transmitted light signal that detects light transmitted through the fabric I, an air purge device VII for protecting the imaging device II from dust, dust, and the like,
The computer IX calculates and outputs the amount of deflection and the amount of deflection of the weft at both ends of the fabric I from the transmitted light signal obtained over the entire width of the fabric I.

Hereinafter, the configuration, operation, and operation of each unit will be described in detail.

The light source device VIII emits light to the fabric I, and transmitted light is detected by the imaging device II.

The configurations and operations of the imaging device II, the control device 6, the moving device VI, and the air barge device VII are the same as those in the first embodiment, and thus description thereof will be omitted.

As shown in FIG. 14, the computer IX incorporates an image input board 9a, a Da board 9b, and a digital input / output board 9c. The computer IX stores a control routine described below and a gradient αr indicating the reference value.

Hereinafter, a control routine of the computer IX will be described with reference to a flowchart shown in FIG.

Initial settings at the start will be described. First, the computer IX sends a reset signal mr from the digital input / output board 9c to the motor control circuit 6g to move the camera holder of the movable table VI to the end point of the fabric (X _{0 in} FIG. 11) (step
S1). Next, the position output Xc output from the counter 6e is fetched using the digital input / output board 9c, and it is confirmed that the movable table VI has moved to the end point (Xc = 0) (step S2).
Then, a start signal st is output so that the camera holder 6a repeatedly moves over the entire width of the fabric I (step S1).
S3). The motor control circuit 6g controls the motor 6c based on the start signal st and repeats the reciprocating movement.

Next, the measurement routine will be described. First, initialization is performed (step S4), the position signal Xc output from the counter 6e is captured (step S5), and the camera holder 6a is mounted on each part (Xi = i / 9d, i = 0 to 9) of the fabric I described above. It is determined whether or not there is (step S6). When the camera holder 6a is located at each part Xi, an imaging timing signal ts is output from the digital input / output board 9c to the imaging device II (step
S7) The light transmitted through the fabric I is imaged. The transmitted light signal tg (image signal output from the CCD camera) output from the imaging device II is converted into a digital signal by the image input board 9a and taken into the computer IX (step S8).
If the camera holding table 6a is not located at each part Xi, the apparatus stands by until the table moves to that position.

Captured transmitted light signal (transmitted light image, pixel size: 5
(12 pixels × 512 pixels) is subjected to contrast enhancement processing (step S9). Further, a two-dimensional Fourier transform is performed to obtain a Fourier image (step S10). Next, a bright point (feature point) on the Fourier image is searched (step S11), and a direct link between these points is obtained (step S12). The inclination of the straight line αr based on the straight line αr is the direction (skew angle) θi of the weft at the portion Xi.
It is.

Generally, in a Fourier image of 512 pixels × 512 pixels, sufficient accuracy cannot be obtained even by using the position data of the pixel of the feature point. Thus, as shown in FIG. 17, the vertical and horizontal pixels near the feature point are used, and their density values are approximated by a quadratic equation, and the position of the feature point (Pxi, Pyi) (i = 1 to n; n is the number of feature points). A straight line connecting the points (Pxi, Pyi) is obtained by the least square method.

When imaging is performed at 10 points from one end to the other end of the woven fabric, and the weft direction θi of each point is calculated,
The computer IX calculates a and b in the equation (2) (step S15), and a cloth angle signal at an arbitrary point x is obtained using the obtained a and b.

As shown in FIG. 16, the deviation amount Δy and the deflection amount Δw of the weft at both ends of the woven fabric I can be obtained by the following expressions from the expression (2) representing the shape of the weft.

Δy = y (d) (7) Therefore, the computer calculates the equations (6) and (7) using the obtained a and b, and outputs the deviation amount Δy and the deflection amount Δw from the DA board 9b (steps S16 and S1).
8).

The above measurement routine is repeated once for each forward and backward trip of the camera holding base until it is determined in step s19 that it is completed, and the displacement Δy and the deflection Δw are continuously output.

With the above-described configuration, it is possible to continuously calculate and output the shift amount and the deflection amount of the weft at both ends of the fabric I. Also,
As in the first embodiment, since a camera with a shutter, an air barge device, and an auto iris zoom lens are used, the amount of deviation and the amount of deflection can be accurately obtained over a long period of time.

In addition, since the positions of the feature points are obtained using the density values of the five neighboring pixels in the vertical and horizontal directions, highly accurate measurement can be performed.

Here, five pixels in the vicinity are used, but an appropriate number of pixels may be selected according to the state of the density value of the pixels in the vicinity of the feature point. Alternatively, it may be obtained from the barycentric position of the density value of the neighboring pixel.

[Brief description of the drawings]

1 is a block diagram of the first invention, FIG. 2 is a block diagram of the second invention, FIG. 3 is a block diagram of the third invention, FIG. 4 is a block diagram of the fourth invention, FIG. FIG. 6, FIG. 7, FIG. 8, FIG. 10, FIG. 10 is a block diagram of the first embodiment, FIG. 9 is an explanatory diagram of the operation of the Fourier transform means, and FIG. Figure,
FIG. 12 is a diagram for explaining the operation of the emphasizing circuit, and FIGS.
FIG. 15 is a flowchart of a computer, FIG. 16 is an explanatory diagram of a deviation amount, a method of calculating a deflection amount,
FIG. 17 is an explanatory diagram of a feature point position calculating method.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hideo Arakawa 41-Yokomichi, Nagakute-machi, Aichi-gun, Aichi-gun, Toyota-Chuo Research Institute, Inc. 41 No. 1 Yokomichi Inside Toyota Central Research Institute, Inc. (72) Inventor Mayuki Hattori 1-1-1, Toyotamachi, Kariya, Aichi Prefecture Inside Toyota Boshoku Corporation (72) Inventor Takao Hasegawa 1-1-1, Toyotamachi, Kariya, Aichi Prefecture (56) References JP-A-63-219676 (JP, A) JP-A-54-74793 (JP, A) JP-A-3-260145 (JP, A) JP-A-3-249264 ( JP, A) JP-A-3-249243 (JP, A) JP-A-2-22459 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01B 11/26 D06H 3/12 B65H 7/18

Claims (5)

(57) [Claims] 1. An image pickup apparatus for picking up an image of a pattern of a fabric to be measured and outputting an image signal, and a Fourier transform for performing a Fourier transform on the image signal output from the image pickup apparatus and outputting a pattern direction signal indicating the direction of the pattern. Means, a storage means for storing a pattern direction signal in a normal state of the measured fabric as a reference pattern signal, and a pattern direction signal output from the Fourier transform means and a reference pattern direction signal stored in the storage means. A calculating means for calculating a degree of skew representing a texture bend of the fabric based on the texture bend detection device. 2. A light source device for illuminating a fabric to be measured, an imaging device arranged to face the light source device and detecting light transmitted through the fabric to be measured, and a transmitted light signal output from the imaging device. Fourier transform means for performing a Fourier transform to output a pattern direction signal indicating the direction of the pattern, storage means for storing a pattern direction signal in a normal state of the measured fabric as a reference pattern signal, and a pattern output from the Fourier transform means Calculating means for calculating a degree of skew indicating a texture bend of the fabric based on the direction signal and the reference pattern direction signal stored in the storage means; 3. The method according to claim 1, wherein the calculating means calculates a difference in a pattern direction signal at each point in the width direction of the fabric to be measured, and detects a shift amount and a deflection amount at both ends of the fabric having a skewed and curved cloth. 3. The texture bend detecting device according to 1 or 2. 4. A light source device for illuminating a fabric to be measured, an imaging device arranged to face the light source device and detecting light transmitted through the fabric to be measured, and a transmitted light signal output from the imaging device. A cloth bend detecting device, comprising: Fourier transform means for performing a Fourier transform to calculate a weft direction; and calculating means for calculating a skew degree of a woven fabric from a weft direction signal output from the Fourier transform means. 5. The calculating means calculates a difference in a weft direction signal at each point in the width direction of the fabric to be measured, and detects a shift amount and a deflection amount at both ends of the fabric having a skew and a curved cloth. 4. The texture bend detecting device according to 4.