TW201721120A - Detection target plate, optical detection device and optical detection method - Google Patents

Abstract

The present invention provides a detection target for detecting an image in one linear direction sensed by an image sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having a bend a folded stripe, wherein the bent stripe is symmetrical with respect to a vertical direction of the linear direction and has two symmetric sub-stripes, and when the detecting target is aligned with the linear direction, the two-symmetric sub-stripes and the linear direction The two angles are equal.

Description

Detection target plate, optical detection device and optical detection method

The present invention relates to an optical detection pattern, an optical detection apparatus, and an optical detection method, and more particularly to an optical detection pattern, an optical detection apparatus, and an optical detection method for detecting a modulation transfer function (MTF) of an image sensor.

Conventionally, the resolution of an optical element has been obtained by detecting an MTF of an optical element such as a photographic film, a scanner, a printer, a digital output, or the like. For example, at a specific spatial frequency, the optical lens and the image sensor provided in the optical image capturing device have respective MTF values, and the MTF value of the optical image capturing device is the product of the optical lens MTF value and the image sensor MTF value. At the time of detection, if one of the MTF values is known, another MTF value can be obtained by detecting the optical detecting means.

This method of detecting optical components is further divided into direct detection and indirect detection. The direct detection method is to use a sinusoidal function of a single frequency to image through a focusing mirror, measure the contrast of the image, and directly calculate the MTF value at this spatial frequency. The MTF values of other spatial frequencies are measured by the grating of another sinusoidal function. Such a little bit of measurement depicts the MTF curve.

The indirect detection method utilizes an artificial pattern to image an imaging system for projection light such as a slit or a knife edge, and analyzes the imaging result into MTF values of respective spatial frequencies by Fourier transform, and measures the MTF curve at a time.

When the optical lens is detected together with the image sensor, due to the discrete sampling relationship of the image sensor, under-sampling occurs when the MTF detects. In this case, the sampling frequency can be increased by means of sub-pixel scanning, but this scanning requires time and precise control. In order to measure correctly. Alternatively, the sampling frequency is increased by the edge pattern having the inclined boundary and the detection time is shortened. However, when the detection is performed by the knife edge pattern having the inclined boundary, the detection result is related to the inclination angle, and the inclination angle must be consistent with the design value to obtain the correct angle. Test results.

For this reason, the applicant invented the "detection target, optical detection device and optical detection method" in view of the lack of the prior art to improve the above-mentioned deficiency.

In order to detect the image sensor more quickly, an embodiment of the present invention provides an optical detecting device for detecting one of the linear directions sensed by an image sensor, including: a light source device, providing a uniformity a pattern adjustment device configured to detect a target plate on a light path of the uniform beam, wherein the detection target includes a detection pattern having a bending stripe, the bending stripe being opposite to the linear direction The vertical direction is symmetrical and has two symmetrical sub-stripes; a moving device is configured to move the image sensor; a focusing mirror is located between the moving device and the detecting target, and the detecting target is projected on The image sensor is connected to the image sensor and receives a detection result from the image sensor. According to the detection result, the detection target is adjusted by the pattern adjustment device. The two symmetrical sub-stripes are equal to the two angles of the linear direction.

Another embodiment of the present invention provides an optical detecting method for detecting an image in one of linear directions sensed by an image sensor, the method comprising: providing a detecting target, wherein the detecting target comprises a detection pattern having a bent stripe symmetrical with respect to a vertical direction of the linear direction and having two symmetric sub-stripes; projecting the detection target to the image sensor; The detection result of one of the image sensor outputs is adjusted, and the detection target is adjusted such that the angle between the two symmetrical sub-stripes and the linear direction is equal.

A further embodiment of the present invention provides a detection target for detecting one of the linear directions sensed by an image sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having a bent stripe, wherein the bent stripe is symmetrical with respect to a vertical direction of the linear direction, and has two symmetric sub-stripes, and when the detecting target is aligned with the linear direction, the two-symmetric sub-stripes The linear direction has the same angle.

Yet another embodiment of the present invention provides a detection target for detecting a shadow An image of one of the linear directions sensed by the sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having two symmetric sub-line segments, wherein the symmetric sub-line segments are not connected, and relative to the A vertical direction of the linear direction is symmetrical, and when the detecting target is aligned with the linear direction, the two symmetric sub-segments have the same angle with the linear direction.

A further embodiment of the present invention provides an optical detecting method for detecting an image in a linear direction sensed by an image sensor, comprising: providing a second symmetric sub-line segment, wherein the two symmetric sub-line segments are relative to the linear A vertical direction of the direction is symmetrical, wherein each of the symmetric sub-line segments is not connected; and the positional relationship between the detection target plate and the linear direction is adjusted such that the two symmetric sub-line segments have the same angle with the linear direction.

1‧‧‧Optical inspection device

10‧‧‧Light source device

11‧‧‧ Filter

12 ‧ ‧ integral ball

20‧‧‧Detection target

21‧‧‧Vertical direction

22a, 22b‧‧‧symmetric substripes

30‧‧‧ Focusing mirror

40‧‧‧Image Sensor

41‧‧‧Three-axis mobile device

42‧‧‧Linear direction

50‧‧‧Electronic computer

α, β‧‧‧ angle

The first figure shows a schematic view of an optical detecting device according to an embodiment of the present invention.

The second figure shows a schematic diagram of the steps of adjusting the detection pattern of the detection target plate. In the stage (a), the angle between the symmetrical sub-stripes and the linear direction is not equal before the adjustment of the detection target plate, and after the adjustment of the detection target plate in the (b) stage, The symmetrical sub-stripes are equal to the two angles in the linear direction.

The third diagram shows a graph of the (a) line spread function calculated by the knife edge algorithm, (b) the side spread function, and (c) the modulation transfer function according to an embodiment of the present invention.

The detailed description of the embodiments of the present invention is set forth below, however, in addition to the detailed description, the invention may be That is, the scope of the present invention is not limited by the embodiments which have been proposed, and the scope of the claims of the present invention shall prevail.

Please refer to the first figure. The first figure shows a schematic view of an optical detecting device 1 according to an embodiment of the present invention. The optical detecting device 1 includes a light source device 10, a filter 11, an integrating sphere 12, a detecting target 20, a focusing mirror 30, an image sensor 40, a three-axis moving device 41, and an electronic computer 50. The light source device 10 emits a light beam (visible light or infrared light) to the filter 11, which is filtered by the filter 11 and enters the integrating sphere 12, and after diffusing reflection in the integrating sphere 12, a uniform beam is generated. The uniform beam passes through the detection target 20 and the focusing mirror 30, The detection pattern is projected and focused to the image sensor 40. The image sensor 40 is disposed on the three-axis moving device 41 such that the three-axis moving device 41 can freely move the image sensor 40, thereby detecting portions of the image sensor 40. When the detection pattern of the detection target 20 is projected and focused to the image sensor 40, the image sensor outputs the imaging waveform data to the electronic computer 50. The computer 50 calculates the imaging waveform data as a knife-edge algorithm to generate a modulation transfer function (MTF).

The light source device 10, the optical filter 11, and the integrating sphere 12 according to an embodiment of the present invention are means for generating a uniform light beam, in other words, a light source element (for example, a collimator) capable of generating a uniform light beam belongs to the present invention. A "light source device" or a part thereof of the scope of the invention. The image sensor 40 of the embodiment of the present invention may be a linear image sensor or a planar image sensor. In the embodiment of the present invention, the linear direction image sensed by the linear image sensor is used for detection, but The linear direction image sensed by the planar image sensor is used for detection. The electronic computer 50 according to an embodiment of the present invention further includes a display to display a modulation transfer function graph.

Please refer to the second figure, which shows a schematic diagram of the steps of adjusting the detection pattern of the detection target 20 . In the second figure, the detection target 20 of an embodiment of the present invention senses an image in the linear direction 42 and includes a substrate and a detection pattern. The substrate is a transparent substrate. The detection pattern is formed on the substrate by the opaque coating on the detection pattern. The detection pattern has a bent stripe, wherein the bent stripe is symmetrical with respect to a vertical direction 21 of the linear direction 42 and has two symmetric sub-stripes 22a, 22b, when the detection target 20 is aligned with the linear direction 42. The two symmetrical sub-stripes 22a, 22b are equal to the two angles α, β of the linear direction 42. In other words, the detection target 20 has two symmetrical oblique stripes 22a, 22b in a vertical direction 21 perpendicular to the linear direction 42, and the oblique stripes 22a, 22b and the linear direction 42 have two angles α, β interposed therebetween. As shown in the second (a) figure, when the electronic computer 50 calculates the imaging waveform data output by the image sensor 40, and calculates the modulation conversion function by the knife edge algorithm, the two symmetric sub-stripe 22a, 22b and the linearity can be known. Whether the angles α and β between the directions 42 are equal. When the angles α and β are not equal (usually detecting, when the two angles between the two symmetric sub-stripe 22a, 22b of the target plate 20 and the linear direction 42 are not exactly equal), a pattern adjusting device can be used. The detection target 20 is adjusted such that the two oblique stripes are equal to the two angles α and β of the linear direction. After that, then The most accurate MTF test results can be obtained by calculating and generating the modulation transfer function by the knife-edge algorithm.

Further, the symmetrical sub-stripe 22a, 22b of the detection target 20 is a stripe pattern formed by transmitting light and opaque. The two angles α and β between the symmetrical sub-stripes 22a and 22b and the linear direction 42 are preferably 2214 degrees, more preferably 2 to 10 degrees, but are not limited thereto. In one embodiment of the present invention, the three-axis moving device 41 is taken as an example. However, the image sensor 40 may be moved using a two-axis moving device or a single-axis moving device.

It is to be noted here that the widths of the symmetrical sub-stripes 22a and 22b are not particularly limited, and the light transmitting portions and the opaque portions of the symmetrical sub-stripes 22a and 22b do not necessarily have the same width. In an extreme, even if the width of the opaque portion of the symmetrical sub-stripes 22a, 22b is so small that it is close to a line segment, as long as the image sensor can clearly sense black, white, and black (ie, opaque, The image of light transmission and opacity can be used. Or, in other words, even if the width of the opaque portion of the symmetrical sub-stripes 22a, 22b is as large as only one stripe, it occupies most of the surface of the detecting target 20, as long as the line sensor can be made clear. Black, white, and black images can be measured. Furthermore, although in the second figure, one end of the symmetric sub-stripes 22a is connected to one end of the symmetric sub-stripes 22b to form the bent stripes, the symmetric sub-strips 22a, 22b may not be connected to each other as long as they are symmetrically arranged. It can make the image sensor measure black, white and black images. Therefore, the symmetric sub-stripes 22a, 22b that are not connected to each other may not constitute the bending stripe, and each of the symmetric sub-stripes 22a, 22b may be symmetric with each other to form a two-symmetric sub-line segment, and such changes are sensed. Image and test demand for MTF.

Please refer to the third figure for the process of calculating the modulation transfer function by the knife-edge algorithm. The third diagram shows a graph of the (a) line spread function calculated by the knife edge algorithm, (b) the side spread function, and (c) the modulation transfer function according to an embodiment of the present invention. As shown in the third figure, the electronic computer 50 obtains an edge spread function (ESF) of the linear direction 42 and the symmetric sub-stripe 22a, 22b (boundary) based on the image sensed by the image sensor 40 (refer to In the three figures (a), the ordinate is the gray scale value), and the extension function is differentiated (dESF/dx) to obtain the line spread function (LSF) (refer to the third figure (b)), and then the line The extension function performs Fourier Transform to obtain a spatial frequency response (SFR), which can generate an MTF graph (refer to the third diagram). (c)). In addition, since the sensor in this case is a symmetrical pattern, if the angles α and β are not equal during the detection, two curves appear in the third graphs (a) to (c), respectively. If the angles α and β are equal, Then, in the third graph (a) to (c) above, a coincident curve appears. That is to say, when the MTF graph is generated through the detection, it can be judged by the graph whether the angles α, β need further adjustment.

Example

An optical detecting device for detecting an image in one of linear directions sensed by an image sensor, comprising: a light source device for providing a uniform light beam; and a pattern adjusting device configured to detect a target plate at the uniform light beam An optical path, wherein the detection target comprises a detection pattern having a bending stripe, the bending stripe being symmetrical with respect to a vertical direction of the linear direction, and having two symmetric sub-stripes; a mobile device Configuring to move the image sensor; a focusing mirror between the mobile device and the detecting target, projecting the detecting target to the image sensor; and an electronic computer connected to the image sense The detector receives a detection result from the image sensor, and according to the detection result, the detection target plate is adjusted by the pattern adjustment device so that the angle between the two symmetrical sub-stripes and the linear direction is equal.

2. The optical detecting device of embodiment 1, wherein each of the symmetrical sub-strips is between light and opaque, and the two angles are between 2 and 14 degrees, and the uniform beam is an infrared light and a visible light. The image sensor is one of a line sensor and a plane sensor. The light source device further includes one of an integrating sphere and a collimator. The moving device is a single axis moving device. One of a two-axis moving device and a three-axis moving device, the electronic computer generates a modulation transfer function (MTF) by a knife-edge algorithm to obtain the detection result, and according to the detection result, whether the two angles are consistent, when the When the two angles are not equal, the detection target is adjusted so that the two angles are equal, and the modulation conversion function is recalculated.

3. An optical detection method for detecting one of the linear directions sensed by an image sensor, the method comprising: providing a detection target, wherein the detection target comprises a detection pattern having a bend a folded stripe symmetrical with respect to a vertical direction of the linear direction and having two symmetric sub-stripes; projecting the detection target to the image sensor; and according to one of the image sensor outputs As a result of the detection, the detection target is adjusted such that the angle between the two symmetrical sub-stripes and the linear direction is equal.

4. The optical detection method of embodiment 3, wherein each of the symmetrical sub-strips is between light and opaque, and the two angles are between 2 and 14 degrees. The image sensor is a line sensor and a sensor. One of the flat sensors.

5. The optical detection method of embodiment 3, the method further comprising: generating a modulation transfer function (MTF) by a knife-edge algorithm to obtain the detection result, and determining whether the two angles are equal according to the detection result; When the two angles are not equal, the detection target is adjusted such that the two angles are equal, and the modulation conversion function is recalculated.

A detection target for detecting one of the linear directions sensed by an image sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having a bent stripe, wherein the target The bending stripe is symmetrical with respect to a vertical direction of the linear direction and has two symmetrical sub-stripes. When the detecting target is aligned with the linear direction, the two symmetrical sub-stripe has an angle with the linear direction. equal.

7. The detection target plate according to embodiment 6, wherein the detection target plate is used to generate a modulation transfer function (MTF), each of the symmetrical sub-stripes being light-transmissive and opaque, and the two angles are 2 ~14 degrees.

8. An optical detection method for detecting an image in a linear direction sensed by an image sensor, comprising: providing a bending stripe; and causing the bending stripe to be symmetrical with respect to a vertical direction of the linear direction The bent stripe has two symmetric sub-stripes; and adjusting a positional relationship between the detecting target and the linear direction such that the two symmetric sub-stripe has the same angle as the linear direction.

A detection target for detecting an image in one of linear directions sensed by an image sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having two symmetric sub-line segments, wherein each The symmetrical sub-line segments are not connected, and are symmetric with respect to a vertical direction of the linear direction. When the detecting target plate is aligned with the linear direction, the two symmetrical sub-segment segments have the same angle with the linear direction.

10. An optical detection method for detecting an image in a linear direction sensed by an image sensor, comprising: providing a second symmetric sub-line segment such that the two symmetric sub-line segments are symmetric with respect to a vertical direction of the linear direction a state in which each of the symmetric sub-line segments is not connected; and adjusting a positional relationship between the detection target plate and the linear direction, so that the two symmetric sub-segment segments and the linear direction have two clips The angles are equal.

The present invention has been described above with reference to the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and those skilled in the art can understand the spirit of the present invention without departing from the invention. Within the scope of the spirit, when there are some changes and replacements, the scope of patent protection depends on the scope of the patent application and its equivalent.

20‧‧‧Detection target

21‧‧‧Vertical direction

22a, 22b‧‧‧symmetric substripes

42‧‧‧Linear direction

α, β‧‧‧ angle

Claims (10)

An optical detecting device for detecting one of the linear directions sensed by an image sensor comprises: a light source device providing a uniform light beam; a pattern adjusting device configured to detect a target plate in the uniform light beam An optical path, wherein the detection target comprises a detection pattern having a bending stripe, the bending stripe being symmetrical with respect to a vertical direction of the linear direction, and having two symmetric sub-stripes; a mobile device, configured The image sensor is movable; a focusing mirror is disposed between the moving device and the detecting target, and the detecting target is projected on the image sensor; and an electronic computer is connected to the image sensor Receiving a detection result from the image sensor, and adjusting the detection target by the pattern adjustment device according to the detection result, so that the angle between the two symmetrical sub-stripes and the linear direction is equal. The optical detecting device of claim 1, wherein each of the symmetrical sub-strips is transparent and opaque, and the two angles are 2 to 14 degrees, and the uniform beam is an infrared light and a visible light. In one aspect, the image sensor is one of a line sensor and a plane sensor, and the light source device further comprises one of an integrating sphere and a collimator, the moving device is a single axis moving device, One of a two-axis moving device and a three-axis moving device, the electronic computer generates a modulation transfer function (MTF) by a knife-edge algorithm to obtain the detection result, and according to the detection result, whether the two angles are consistent, when When the two angles are not equal, the detection target is adjusted such that the two angles are equal, and the modulation conversion function is recalculated. An optical detecting method for detecting one of linear directions sensed by an image sensor And the step of providing a detection target, wherein the detection target comprises a detection pattern having a bending stripe, the bending stripe being symmetrical with respect to a vertical direction of the linear direction, and having two a symmetric sub-strip; projecting the detection target to the image sensor; and adjusting the detection target according to a detection result of the image sensor output, so that the angle between the two symmetrical sub-stripes and the linear direction is equal. The optical detection method of claim 3, wherein each of the symmetrical sub-strips is transparent and opaque, and the two angles are 2 to 14 degrees, and the image sensor is a line sensor and One of a planar sensors. The optical detection method according to claim 3, wherein the step further comprises: generating a modulation transfer function (MTF) by a knife-edge algorithm to obtain the detection result, and determining whether the two angles are equal according to the detection result, When the two angles are not equal, the detection target is adjusted such that the two angles are equal, and the modulation conversion function is recalculated. a detection target for detecting one of the linear directions sensed by an image sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having a bent stripe, wherein the bending The stripe is symmetrical with respect to a vertical direction of the linear direction and has two symmetrical sub-stripes. When the detecting target is aligned with the linear direction, the two symmetrical sub-stripe has the same angle as the linear direction. The detection target of claim 6, wherein the detection target is used to generate a The modulation transfer function (MTF), each of the symmetrical sub-strips is between light and opaque, and the two angles are 2 to 14 degrees. An optical detection method for detecting an image in a linear direction sensed by an image sensor, comprising: providing a bending stripe; and causing the bending stripe to be symmetrical with respect to a vertical direction of the linear direction, wherein The bending stripe has two symmetrical sub-stripes; and adjusting a positional relationship between the detecting target and the linear direction such that the two symmetrical sub-stripe has the same angle as the linear direction. a detection target for detecting one of the linear directions sensed by an image sensor, comprising: a substrate; and a detection pattern disposed on the substrate and having two symmetric sub-line segments, wherein each of the symmetry The sub-line segments are not connected, and are symmetric with respect to a vertical direction of the linear direction. When the detecting target plate is aligned with the linear direction, the two symmetric sub-line segments have the same angle with the linear direction. An optical detection method for detecting an image in a linear direction sensed by an image sensor, comprising: providing a second symmetric sub-line segment, wherein the two symmetric sub-line segments are symmetric with respect to a vertical direction of the linear direction, Each of the symmetric sub-line segments is not connected; and the positional relationship between the detection target and the linear direction is adjusted such that the two symmetric sub-line segments have the same angle with the linear direction.