TWI868666B - Optical device, optical detection method and optical device design method - Google Patents

Abstract

An optical detection method is adapted to apply on an optical device. The optical device comprise a projection unit which defines a projection range, an image capturing unit which defines a image capturing range, and a processing unit which electrically connects to the project unit and the image capturing unit. The image capturing range and the projection range respectively defines a long axis and a short axis which length is shorter than the long axis. The projection unit projects a beam of light toward an object to be measured along an incident path, and after being reflected by the object to be measured, enters the image capturing unit along a reflection path, and the projection of the incident path or the reflection path on a plane to be measured is parallel to an extension direction of the short axis of the projection range or the image capturing range. It can prevent partially over-exposed light spot from appearing in the effective image capturing range, thereby reducing the invalid observation area and improving measurement performance

Description

Optical device, optical detection method and optical device design method

The present invention relates to an optical device and a detection method, in particular to an optical device, an optical detection method and an optical device design method.

In recent years, the application scope of non-contact optical detection has become increasingly wide, especially in three-dimensional detection devices using triangulation. However, when the surface of the object to be tested is a mirror, within the range of the lens's light collection angle, part of the signal light is reflected by the surface of the object to be tested according to the law of reflection, causing the energy to enter the optical system, resulting in partial overexposure of the camera. Therefore, obvious bright spots with saturated grayscale values can be seen on the image, which in turn affects the detection function. In addition, the industry currently also has a demand for three-dimensional detection devices to measure the object to be tested through a glass partition. Since the surface of the glass partition is flat, part of the light beam will enter the three-dimensional detection device according to the law of reflection, resulting in the aforementioned partial overexposure phenomenon (see Figure 1).

Referring to FIG. 2 and FIG. 4, a conventional three-dimensional detection instrument 1 mainly comprises a projection device 11 for projecting structured light, and an imaging device 12 for receiving structured light reflected from a test piece 13 and having a light receiving half angle of γ1. The angle between the optical axis of the imaging device 12 and the optical axis of the projection device 11 is α1, and the projection of the reflection path of the light beam reflected from the test piece 13 on a test plane is perpendicular to the extension direction of the short axis of an imaging range 15. The short axis of the imaging range 15 is defined as the shorter connecting line of the connecting lines between the centers of two opposite sides of the quadrilateral. The optical path drawn in FIG. 2 is an optical path according to the law of reflection (the incident angle θi is equal to the reflection angle θr), so a light spot that is partially overexposed will be generated when entering the imaging device 12 through the optical path. According to FIG2 , the projection range 14 of the projection device 11 is a quadrilateral, and the imaging range 15 of the imaging device 12 is a quadrilateral, and a schematic diagram of FIG4 is drawn, wherein an effective imaging range 16 is defined as a range extending outward from the projection center of the projection device 11 on the plane to D1, β1 is the angle from the projection device 11 to the boundary of the effective imaging range 16, and D1 is the distance from the local overexposure point to the projection center of the projection device 11 on the plane. In FIG4 , since the position of the local overexposure point is within the boundary of the test piece 13, it will affect the detection result.

Referring to FIG. 3 and FIG. 5 , generally speaking, in order to improve the Z-axis resolution and expand the effective imaging range 16 to at least include the size of the object to be tested 13 (half of its side length is D2), the user generally increases the angle α2 between the projection device 11 and the imaging device 12 to increase β2, thereby expanding the effective imaging range 16 and solving the problem of partial overexposure. However, this method not only increases the volume of the three-dimensional detection instrument 1, but also requires a smaller aperture (i.e., reduces γ1 ) to provide sufficient depth of field, which easily leads to insufficient brightness during detection.

Therefore, one of the purposes of the present invention is to provide an optical device that improves detection efficiency.

Therefore, in some embodiments, the optical device of the present invention is suitable for measuring an object to be measured and includes a projection unit, an imaging unit, and a processing unit.

The projection unit is used to project a light beam to the object to be measured and define a projection range.

The imaging unit is used to receive the light beam reflected from the object to be tested and define an imaging range. The imaging range and the projection range each define a long axis and a short axis whose length is less than the long axis. The projection unit projects the light beam along an incident path toward the object to be tested, and after being reflected by the object to be tested, the light beam enters the imaging unit along a reflection path. The projection of the incident path on the plane to be tested is parallel to the extension direction of the short axis of the projection range, or the projection of the reflection path on a plane to be tested is parallel to the extension direction of the short axis of the imaging range.

The processing unit is electrically connected to the projection unit and the imaging unit. After receiving a trigger signal, the processing unit drives the projection unit to project the light beam and drives the imaging unit to receive the light beam reflected from the object to be measured.

In some embodiments, the processing unit drives the projection unit to project a light beam for a continuous projection period, and drives the imaging unit to receive a reflected light beam for a continuous imaging period.

In some embodiments, the processing unit drives the projection unit to project the light beam for a continuous projection period, and drives the imaging unit to receive the reflected light beam at the beginning of imaging.

In some embodiments, the imaging range and the projection range are quadrilaterals, wherein the center lines of two pairs of sides define the major axis, and the center lines of the other two pairs of sides define the minor axis.

In some embodiments, the projection unit and the imaging unit define an effective imaging range, and the effective imaging range is larger than the imaging range.

In some embodiments, an effective imaging range defined by the projection unit and the imaging unit is related to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit.

，其中，R1為該投射單元與該待測物的距離，R2為該取像單元與該待測物的距離，θ為該投射單元與該取像單元的夾角。 In some embodiments, the length of the effective imaging range defined by the projection unit and the imaging unit is half.

, wherein R1 is the distance between the projection unit and the object to be measured, R2 is the distance between the imaging unit and the object to be measured, and θ is the angle between the projection unit and the imaging unit.

In some embodiments, the projection range is larger than and includes the imaging range, and an effective imaging range defined by the projection unit and the imaging unit is larger than and includes the imaging range.

Therefore, one of the purposes of the present invention is to provide an optical detection method that improves detection efficiency.

Therefore, in some embodiments, the optical detection method of the present invention is suitable for measuring an object to be measured set on a plane to be measured by using an optical device. The optical device includes a projection unit for projecting a light beam to the object to be measured and defining a projection range, and an imaging unit for receiving a light beam reflected from the object to be measured and defining an imaging range. The projection unit and the imaging range each define a long axis and a long axis. The optical detection method comprises the following steps: A measurement step: the projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path on the plane to be measured is parallel to the extension direction of the short axis of the projection range, or the projection of the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range.

In some embodiments, the projection range and the imaging range are quadrilaterals, wherein the center lines of two pairs of sides define the major axis, and the center lines of the other two pairs of sides define the minor axis.

In some embodiments, the projection unit and the imaging unit define an effective imaging range, and the effective imaging range is larger than the imaging range.

In some embodiments, an effective imaging range defined by the projection unit and the imaging unit is related to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit.

，其中，R1為該投射單元與該待測物的距離，R2為該取像單元與該待測物的距離，θ為 該投射單元與該取像單元的夾角。 In some embodiments, the length of the effective imaging range defined by the projection unit and the imaging unit is half.

, wherein R1 is the distance between the projection unit and the object to be measured, R2 is the distance between the imaging unit and the object to be measured, and θ is the angle between the projection unit and the imaging unit.

In some embodiments, the projection range is larger than and includes the imaging range, and an effective imaging range defined by the projection unit and the imaging unit is larger than and includes the imaging range.

Therefore, another purpose of the present invention is to provide a method for designing an optical device to improve the detection efficiency of the optical device.

Therefore, in some embodiments of the optical device design method of the present invention, the optical device includes a projection unit for projecting a light beam to an object to be tested and defining a projection range, and an imaging unit for receiving a light beam reflected from the object to be tested and defining an imaging range, the imaging range defines a long axis and a short axis whose length is less than the long axis, and the optical device design method includes a calculation step, a judgment step, and a measurement step.

The calculation step calculates an effective imaging range according to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit.

The judging step judges whether the imaging range is not greater than the side length of the effective imaging range according to the effective imaging range calculated in the calculating step. If the judging result is yes, proceed to the next step.

In the measurement step, the projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path. The projection of the incident path or the reflection path on a plane to be measured is parallel to the extension direction of the short axis.

In some implementations, a setting step is further included: adjusting at least one of the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit. If the result of the determination step is no, the setting step and the calculation step are performed.

The present invention has the following effects: when the object to be measured is a rectangular parallelepiped or a similar elongated object, the effective imaging range without local overexposure is only related to the direction parallel to the incident path or the reflection path, and perpendicular to the direction of the incident path. The direction of the incident path or the reflected path has nothing to do with it. Therefore, through the designed light path Make the projection of the incident path or the reflection path on the plane to be measured parallel to the extension direction of the short axis. The user only needs to consider that the short side of the object to be measured is within the effective imaging range, and there will be no partial Overexposure phenomenon, therefore, can increase the effective observation area of imaging, thereby improving measurement efficiency.

1: Three-dimensional detection equipment

11: Projection device

12: Imaging device

13: Parts to be tested

14: Projection range

15: Imaging range

16: Effective imaging range

2: Optical device

20: Effective imaging range

21: Projection unit

22: Imaging unit

23: Object to be tested

231: Short side to be tested

232: Long side to be tested

24: Projection range

25: Imaging range

26: Processing unit

101: Setup steps

102: Calculation steps

103: Judgment steps

104: Measurement steps

Other features and effects of the present invention will be clearly presented in the implementation method with reference to the drawings, wherein: FIG1 is a photograph of an overexposure condition during measurement by a known three-dimensional detection instrument; FIG2 and FIG3 are side views of the known three-dimensional detection instrument in different settings; FIG4 is a top view of the effective area and the test piece corresponding to the setting of FIG2; FIG5 is a top view of the effective area and the test piece corresponding to the setting of FIG3; FIG6 is a block diagram of the optical device of the present invention; FIG7 is a schematic diagram of the present invention. A flowchart of an embodiment of the optical device design method of the invention; FIG. 8 is a side view schematic diagram of the optical device; FIG. 9 is a top view schematic diagram corresponding to FIG. 8; FIG. 10 is a top view schematic diagram of another embodiment; FIG. 11 is a light path schematic diagram of the optical device; FIG. 12 to FIG. 14 are relationship diagrams drawn according to an operation formula used in a calculation step in the embodiment; FIG. 15A and FIG. 15B are top view schematic diagrams, respectively illustrating the use of a known detection method and the optical detection method of the invention to detect an I/O component.

Referring to Figures 6, 8 and 9, an embodiment of the optical device design method of the present invention. The optical device 2 includes a projection unit 21 for projecting a light beam to an object to be measured 23 and defining a projection range 24, an imaging unit 22 for receiving a light beam reflected from the object to be measured 23 and defining an imaging range 25, and a processing unit 26 electrically connected to the projection unit 21 and the imaging unit 22.

Referring to FIG8, FIG9 and FIG10, in one of the embodiments of the present embodiment, a projection range 24 of the projection unit 21 on the plane to be measured is a quadrilateral, specifically a rectangle, and an imaging range 25 of the imaging unit 22 on the plane to be measured is a quadrilateral, specifically a trapezoid with two sides parallel. It should be noted that the length of a pair of parallel sides in the aforementioned trapezoid varies according to the projection direction, and the scope of the present invention is not limited thereto. In other embodiments of the present embodiment, if the incident surface of the projection unit 21 is not perpendicular to the projection surface, the projection range 24 is a quadrilateral (no two sides are parallel). Referring to FIG10, in another variation of the present embodiment, the positions of the projection unit 21 and the imaging unit 22 are interchanged. It is also noted that in this embodiment, the projection range 24 includes and covers the imaging range 25, but it should not be limited thereto. It is further noted that the projection range 24 and the imaging range 25 each define a long axis and a short axis whose length is less than the long axis, wherein the center line of two pairs of sides defines the long axis, and the center line of the other two pairs of sides defines the short axis.

An effective imaging range 20 is defined as the range extending outward by Δ from the projection center O of the projection unit 21 on the plane to be measured, in which a local overexposure point that complies with the law of reflection and enters the imaging unit 22 will be formed at a distance O point △.

It should be noted that the light beam may be, but is not limited to, structured light. The projection unit 21 may include one or more projectors (not shown), and the imaging unit 22 may include one or more camera lenses (not shown).

Specifically, in this embodiment, the object to be tested 23 is a high-reflective material with a flat surface, for example, an object to be tested 23 with a mirror surface. In one embodiment of this embodiment, the object to be tested 23 is entirely composed of a high-reflective material. In other embodiments of this embodiment, the surface of the object to be tested 23 is a high-reflective material. However, the material of the object to be tested 23 is not limited to the above.

Referring to Figures 6 and 8, the processing unit 26 drives the projection unit 21 to project the light beam after receiving a trigger signal, and drives the imaging unit 22 to receive the light beam reflected from the object to be measured 23.

In this embodiment, the processing unit 26 is an external computer. In other variations of this embodiment, the processing unit 26 may also be a motherboard with a central processing unit, such as but not limited to the Raspberry Pi developed by the British Raspberry Pi Foundation. The processing unit 26 may be connected to an input device (not shown, such as a keyboard, button, etc.) via a signal to receive the trigger signal. The trigger signal may be a key signal from a computer keyboard, or may be from another automated control device electrically connected to the processing unit 26, but is not limited thereto.

In one embodiment of the present embodiment, the lens of the imaging unit 22 is automatically closed, and the processing unit 26 drives the projection unit 21 to project the light beam during the continuous projection period, and drives the imaging unit 22 to receive the reflected light beam at the beginning of the imaging time. Specifically, considering the stability of the light beam of the projection unit 21, the processing unit 26 first drives the projection unit 21 to turn on, and then drives the imaging unit 22 to turn on and receive the reflected light beam at the beginning of the imaging time after the light beam is stable. When the lens of the imaging unit 22 is automatically closed at the end of the exposure time, the processing unit 26 controls the projection unit 21 to be closed.

In another embodiment of the present embodiment, the opening and closing of the imaging unit 22 is controlled by the processing unit 26, that is, the processing unit 26 drives the projection unit 21 to project the light beam during the continuous projection period, and drives the imaging unit 22 to receive the reflected light beam during the continuous imaging period. Preferably, considering the stability of the light beam of the projection unit 21, the processing unit 26 first drives the projection unit 21 to turn on, and then drives the imaging unit 22 to turn on and receive the reflected light beam during the continuous imaging period after the light beam is stable, and then controls the imaging unit 22 and the projection unit 21 to be closed in sequence.

Referring to Figures 7, 8 and 9, the optical device design method includes a setting step 101, a calculation step 102, a judgment step 103, and a measurement step 104.

<Setup steps>

Adjust at least one of the distance between the projection unit 21 and the object to be measured 23, the distance between the imaging unit 22 and the object to be measured 23, and the angle between the projection unit 21 and the imaging unit 22.

In one implementation of this embodiment, the setting step 101 refers to re-setting the optical device 2.

<Calculation steps>

The calculation step 102: using the distance between the projection unit 21 and the object 23 to be measured, the distance between the imaging unit 22 and the object 23 to be measured, and the angle between the projection unit 21 and the imaging unit 22, the effective imaging range 20 is calculated.

，其中，△為有效取像範圍20之邊長的一半，R ₁為該投射單元21與該待測物23的距離，R ₂為該取像單元22與該待測物23的距離，θ為該投射單元21與該取像單元22的夾角。 Specifically, the calculation step 102 uses the equation 1:

, wherein _△ is half of the _side length of the effective imaging range 20, R1 is the distance between the projection unit 21 and the object 23 to be measured, R2 is the distance between the imaging unit 22 and the object 23 to be measured, and θ is the angle between the projection unit 21 and the imaging unit 22.

Furthermore, half of the side length of the effective imaging range 20 refers to the distance between the boundary of the effective imaging range 20 and the projection center of the projection unit 21 on the plane to be measured.

對稱線段

，以通過C點的垂直線(法線)作為對稱軸。D點為B點以水平線為對稱軸所對稱之位置，E點為

延長線與經過D點之水平線的交界處。此外，

線段長度即為△(有效取像範圍20的邊長的一半)，

線段長度即為R ₁，

線段長度即為R ₂。 It is to be noted that the derivation process of the operation formula 1 is shown in FIG. 11. First of all, it should be noted that point O is the center of the object 23 to be measured, point A is the center of the lens of the projection unit 21, point B is the center of the lens of the imaging unit 22, and point C is the reflection position of the light beam in accordance with the law of reflection, that is,

Symmetrical line segment

, with the vertical line (normal) passing through point C as the symmetry axis. Point D is the position of point B symmetrically with the horizontal line as the symmetry axis, and point E is

The intersection of the extended line and the horizontal line passing through point D. In addition,

The length of the line segment is △ (half the length of the side of the effective imaging range 20).

The length of the line segment is R ₁ ,

The length of the line segment is R ₂ .

，經三角函數切換△×(R ₁+R ₂×cos θ)=R ₁×R ₂ sin θ，故求得運算式1。 Since △CAO and △DAE are similar triangles,

, after trigonometric conversion, △×( R ₁ + R ₂ ×cos θ)= R ₁ × R ₂ sin θ, so equation 1 is obtained.

According to the calculation formula used in the calculation step 102, we obtain the data in the following table, where, in the implementation of this embodiment, R1=300mm, R2=270mm, 300mm, 319.5mm and 360mm, that is, R1:R2 are 1:0.9, 1:1, 1:1.065, 1:1.2 respectively. Where Φ is the angle between the boundary of the projection unit 21 to the effective imaging range 20 and a vertical line passing through the center of the projection unit (i.e. ∠OAC in Figure 11)

From the above table and Figures 12 to 14, we can understand that the relationship between Φ and θ, △ and Φ, and △ and θ are all linear between θ=20°~30°, and the standard deviation ^R2 of each trend line in Figures 11 to 13 is all equal to 1, indicating that the relationship between Φ, θ and △ is easy to accurately predict. Therefore, in one implementation of this embodiment, the linear relationship calculation formula between the three can also be pre-stored in the aforementioned processing unit (not shown). When the user adjusts the angle θ between the projection unit 21 and the imaging unit 22, the aforementioned linear relationship calculation formula can be directly used for calculation. Compared with the aforementioned calculation formula 1, it can save computing resources and improve computing efficiency.

<Judgment step 103>

According to the effective imaging range 20 calculated in the calculation step 102, it is determined whether the imaging range 25 is not greater than the effective imaging range 20. If the determination result is yes, the measurement step 104 described later is performed.

If the result of the determination step 103 is no, then return to the setting step 101 and the calculation step 102.

It is to be noted that, since the effective imaging range 20 can be calculated through the calculation step 102, the effective imaging range 20 can also be designed to be larger than the projection range 24, depending on the needs of the user.

It is further explained that the calculation step 102 and the determination step 103 can be calculated manually or performed using a processing unit (not shown) of the optical device 2. For example, the processing unit receives parameters (R1, R2, θ) from an input component (not shown) and performs calculations according to a pre-stored calculation formula 1.

<Measurement step 104>

The projection unit 21 projects a light beam toward the object to be measured 23 along an incident path, and after being reflected by the object to be measured 23, the light beam enters the imaging unit 22 along a reflection path. The projection of the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range 25.

Referring to FIG. 10 , in another embodiment of the present embodiment, the positions of the projection unit 21 (see FIG. 8 ) and the imaging unit 22 (see FIG. 8 ) are interchanged, so that the projection of the incident path on the plane to be measured is parallel to the extension direction of the short axis of the projection range 24 .

Since △ in equation 1 is only related to R1, R2 and θ, that is, the effective imaging range 20 is only related to the direction parallel to the incident path or the reflection path, and has nothing to do with the direction perpendicular to the incident path or the reflection path. Therefore, when the surface of the object to be measured 23 is a rectangle or other long strip with an aspect ratio not equal to 1, the user only needs to consider placing the short side 231 to be measured of the object to be measured 23 (see FIG. 15B ) within the effective imaging range, so that the short side 231 to be measured of the object to be measured 23 is all located within the effective imaging range 20, which can increase the effective observation area of imaging, thereby improving the measurement efficiency. Preferably, if the effective imaging range 20 is designed to include and cover the projection range 24 or the imaging range 25, the user can perform the inspection as long as he confirms that the size of the object to be inspected 23 is within the projection range 24 or the imaging range 25.

To further explain, under the same size of the object to be tested (i.e., the size of the object to be tested 13 in FIG. 4 is equal to the size of the object to be tested 23 in this embodiment) and the same effective imaging range (the effective range 16 in FIG. 4 is equal to the effective imaging range 20 in this embodiment, i.e., D1 in FIG. 4 is equal to △ in FIG. 9), the measurement steps of this embodiment can make the entire imaging range 25 within the effective imaging range 20, so there will be no local overexposure, thereby solving the measurement problem caused by local overexposure.

In detail, the following situations may occur during use:

1. When the side length of the imaging range 25 calculated in the calculation step 102 is not greater than the side length of the effective imaging range 20 (i.e. the judgment result of the judgment step 103 is yes), the measurement step 104 can be performed. Next, if the short side 231 of the object 23 to be measured is smaller than the side length of the effective imaging range 20, the measurement step 104 can be performed.

2. When the side length of the imaging range 25 calculated in the calculation step 102 is greater than the side length of the effective imaging range 20 (i.e., the judgment result of the determination step 103 is no), the setting step 101 is performed, and the user can adjust at least one of the distance between the projection unit 21 and the object 23 to be measured, the distance between the imaging unit 22 and the object 23 to be measured, and the angle between the projection unit 21 and the imaging unit 22 to expand the effective imaging range 20 so that the short side 231 of the object 23 to be measured is located within the effective imaging range 20. Then, the measurement step 104 can be performed. Next, if the short side 231 of the object 23 to be measured is smaller than the side length of the effective imaging range 20, the measurement step 104 can be performed.

It is worth noting that after the optical device 2 is designed by the aforementioned optical device design method, it can be used by the testing industry to perform an optical testing method, which is applicable to the optical device 2 to measure the object to be tested 23 set on the plane to be tested, and only includes the aforementioned measurement step 104.

To sum up, the optical device, optical detection method and optical device design method of the present invention, because the effective imaging range 20 that does not cause local overexposure is only related to the direction parallel to the incident path or the reflection path, and is related to the direction perpendicular to the incident path. The direction of the path or the reflection path has nothing to do with it. Therefore, by designing the light path, the incident path or the reflection path is The projection of the plane to be measured is parallel to the extension direction of the short axis of the imaging range 25 or the projection range 24. The user only needs to consider that the short side of the object to be measured 23 is within the effective imaging range 20, so there is no When local overexposure occurs, the effective observation area of imaging is increased, thereby improving measurement efficiency. Therefore, the purpose of the present invention can indeed be achieved.

，參閱圖15B，惟如採本發明的光學檢測方法，由於該反射路徑於該待測平面的投影平行於該取像範圍25之短軸的延伸方向，因此訊號雜訊比(SNR)會正相關於

，明顯高於傳統習知的檢測方式。綜上述，透過本發明的光學檢測方法檢測該待測物23時，能有效提高訊號雜訊比(SNR)，降低雜訊的比例。 It is to be noted that, due to the increasing demand for electronic component testing, the optical properties of the electrical contacts are similar to those of mirrors, and the aforementioned local overexposure occurs because the material of the electrical contacts is mostly copper or other highly conductive metals. In addition, we also understand that the imaging noise occurs at the electrical contact boundary parallel to the projection (or imaging) direction. Referring to FIG. 15A and FIG. 15B, the object to be tested 23 is an electronic component and has a plurality of electrical contacts 230 in the form of long strips. In order to make the object to be tested 23 have more electrical contacts 230 to improve its computing performance, the length extension direction of each electrical contact 230 is parallel to the short side 231 of the object to be tested 23. Referring to FIG. 15A , if the conventional detection method is used, the projection of the reflection path on the plane to be detected is perpendicular to the extension direction of the short axis of the imaging range 25, and its signal-to-noise ratio (SNR) is positively correlated to

, see FIG. 15B , however, if the optical detection method of the present invention is adopted, since the projection of the reflection path on the plane to be detected is parallel to the extension direction of the short axis of the imaging range 25, the signal-to-noise ratio (SNR) will be positively correlated to

, which is significantly higher than the conventional detection method. In summary, when the optical detection method of the present invention is used to detect the object 23, the signal-to-noise ratio (SNR) can be effectively improved and the proportion of noise can be reduced.

However, the above is only an example of the implementation of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

2: Optical device 21: Projection unit 22: Image acquisition unit 23: Object to be measured

Claims (16)

An optical device, suitable for measuring an object to be measured, and comprising: A projection unit, used to project a light beam to the object to be measured and define a projection range; An imaging unit, used to receive the light beam reflected from the object to be measured and define an imaging range, the imaging range and the projection range each define a major axis and a minor axis whose length is less than the major axis, the projection unit projects the light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path on the plane to be measured is parallel to the extension direction of the minor axis of the projection range, or the projection of the reflection path on the plane to be measured is parallel to the extension direction of the minor axis of the imaging range; and A processing unit is electrically connected to the projection unit and the imaging unit. After receiving a trigger signal, the processing unit drives the projection unit to project the light beam and drives the imaging unit to receive the light beam reflected from the object to be measured. An optical device as described in claim 1, wherein the processing unit drives the projection unit to project a light beam for a continuous projection period, and drives the imaging unit to receive a reflected light beam for a continuous imaging period. An optical device as described in claim 1, wherein the processing unit drives the projection unit to project the light beam for a continuous projection period, and drives the imaging unit to receive the reflected light beam at the beginning of imaging. An optical device as described in claim 1, wherein the imaging range and the projection range are quadrilaterals, wherein the center lines connecting two pairs of sides define the major axis, and the center lines connecting the other two pairs of sides define the minor axis. An optical device as described in claim 1, wherein the projection unit and the imaging unit define an effective imaging range, and the effective imaging range is larger than the imaging range. An optical device as described in claim 1, wherein an effective imaging range defined by the projection unit and the imaging unit is related to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit. An optical device as claimed in claim 1, wherein a half of the side length of an effective imaging range defined by the projection unit and the imaging unit , wherein R1 is the distance between the projection unit and the object to be measured, and R2 is the distance between the projection unit and the object to be measured, is the angle between the projection unit and the imaging unit. In the optical device as described in claim 1, the projection range is larger than and includes the imaging range, and an effective imaging range defined by the projection unit and the imaging unit is larger than and includes the imaging range. An optical detection method is applicable to measuring an object to be measured set on a plane to be measured by using an optical device. The optical device includes a projection unit for projecting a light beam to the object to be measured and defining a projection range, and an imaging unit for receiving a light beam reflected from the object to be measured and defining an imaging range. The imaging range and the projection range each define a long axis and a short axis whose length is less than the long axis. The optical detection method includes the following steps: A measurement step: the projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path on the plane to be measured is parallel to the extension direction of the short axis of the projection range, or the projection of the reflection path on the plane to be measured is parallel to the extension direction of the short axis of the imaging range. An optical detection method as described in claim 9, wherein the imaging range and the projection range are quadrilaterals, wherein the center lines connecting two pairs of sides define the major axis, and the center lines connecting the other two pairs of sides define the minor axis. An optical detection method as described in claim 9, wherein the projection unit and the imaging unit define an effective imaging range, and the effective imaging range is larger than the imaging range. An optical detection method as described in claim 9, wherein an effective imaging range defined by the projection unit and the imaging unit is related to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit. The optical detection method as described in claim 9, wherein the length of a side of an effective imaging range defined by the projection unit and the imaging unit is half , wherein R1 is the distance between the projection unit and the object to be measured, and R2 is the distance between the imaging unit and the object to be measured. is the angle between the projection unit and the imaging unit. An optical detection method as described in claim 9, wherein the projection range is larger than and includes the imaging range, and an effective imaging range defined by the projection unit and the imaging unit is larger than and includes the imaging range. A method for designing an optical device, the optical device comprising a projection unit for projecting a light beam to an object to be measured and defining a projection range, and an imaging unit for receiving a light beam reflected from the object to be measured and defining an imaging range, the imaging range defining a major axis and a minor axis whose length is less than the major axis, the method for designing an optical device comprising the following steps: A calculation step: calculating an effective imaging range according to the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit; A judgment step: judging whether the imaging range is not larger than the effective imaging range according to the effective imaging range calculated in the calculation step, and if the judgment result is yes, proceeding to the next step; A measurement step: the projection unit projects a light beam toward the object to be measured along an incident path, and after being reflected by the object to be measured, the light beam enters the imaging unit along a reflection path, and the projection of the incident path or the reflection path on a plane to be measured is parallel to the extension direction of the short axis. The optical device design method as described in claim 15 further includes a setting step: adjusting at least one of the distance between the projection unit and the object to be measured, the distance between the imaging unit and the object to be measured, and the angle between the projection unit and the imaging unit. If the result of the judgment step is no, the setting step and the calculation step are performed.