Capturing method for images with different view-angles and capturing system using the same

A capturing method for a plurality of images with different view-angles and a capturing system using the same are provided. The capturing method for the images with different view-angles includes the following steps. An appearance image of an object is captured by an image capturing unit at a capturing angle. A light reflection area of the appearance image is detected by a detecting unit, and a dimension characteristic of the light reflection area is analyzed by the same. Whether the dimension characteristic of the light reflection area is larger than a first predetermined value is determined. If the dimension characteristic of the light reflection area is larger than the first predetermined value, then the capturing angle is adjusted within a first adjusting range. After the step of adjusting the capturing angle within a first adjusting range is performed, the step of capturing the appearance image is performed again.

BACKGROUND

1. Technical Field

The disclosed embodiments relate in general to a capturing method and a capturing system using the same, and more particularly to a capturing method for a plurality of images with different view-angles and a capturing system using the same.

2. Description of the Related Art

Along with the advance in technology, various electronic devices are provided over the time. For an electronic device, the appearance quality is also highly valued by consumers in addition to the functional performance. Investigation shows that the sale return due to the problem of appearance quality has become a heavy burden to the manufacturers. Thus, before a final product is delivered from the factory, the manufacturers would normally check the important parts and the appearance of the final product.

However, most appearance surfaces of electronic devices are curved or non-uniformed, and would therefore generate reflection or non-uniformity of the light. Due to the capturing angle and the projection of the light source, the light shadow or false appearance formed by electronic devices normally fails to reflect the characteristics of defects. Since the ordinary 2D planar static image detecting device is incapable of detecting the above defects and the 3D appearance detecting device is not yet available, currently, the detection can only be done manually.

To perform 3D surface check on electronic devices, the image must be captured at multiple view-angles. The reflection of the light generated at different view-angles varies accordingly and is difficult to control. Therefore, how to capture an appearance image whose light reflection area is conformed to the requirements at each view-angle has become an imminent task for the industries.

SUMMARY

The disclosure is directed to a capturing method for a plurality of images with different view-angles and a capturing system using the same, which reduce the dimension characteristic of a light reflection area of an appearance image for each view-angle by way of dynamic detection and adjustment.

According to one embodiment, a capturing method for a plurality of images with different view-angles is provided. The capturing method for the images with different view-angles includes the following steps. An appearance image of an object is captured by an image capturing unit at a capturing angle. A light reflection area of the appearance image is detected by a detecting unit, and a dimension characteristic of the light reflection area is analyzed by the same. Whether the dimension characteristic of the light reflection area is larger than a first predetermined value is determined. If the dimension characteristic of the light reflection area is larger than the first predetermined value, then the capturing angle is adjusted within a first adjusting range. After the step of adjusting the capturing angle within a first adjusting range is performed, the step of capturing the appearance image is performed again.

According to another embodiment, a capturing system for capturing a plurality of images with different view-angles is provided. The capturing system includes an image capturing unit, a detecting unit, a determining unit and an adjusting unit. The image capturing unit is used for capturing an appearance image of an object at a capturing angle. The detecting unit is used for detecting a light reflection area of the appearance image, and analyzing a dimension characteristic of the light reflection area. The determining unit is used for determining whether the dimension characteristic of the light reflection area is larger than a first predetermined value. If the dimension characteristic of the light reflection area is larger than the first predetermined value, then the capturing angle is adjusted by the adjusting unit within a first adjusting range. After the adjusting unit adjusts the capturing angle within a first adjusting range, the image capturing unit again captures the appearance image.

The above and other aspects of the disclosure will become better understood with regard to the following detailed description of the non-limiting embodiment(s). The following description is made with reference to the accompanying drawings.

DETAILED DESCRIPTION

Referring toFIG. 1, a schematic diagram of a capturing system100according to an embodiment of the disclosure is shown. The capturing system100includes an image capturing unit110, a detecting unit120, a determining unit130, an adjusting unit140and a storage unit170. The image capturing unit110, used for capturing an image, is realized by such as a camera or a video recorder. The detecting unit120is used for detecting a light reflection area of an image. The determining unit130is used for executing various determining procedures. The detecting unit120and the determining unit130are realized by such as a micro-processing chip set, a firmware circuit, or a storage medium storing a plurality of programming codes. The adjusting unit140is used for adjusting the position, angle and environment light source of the image capturing unit110. The storage unit170, used for storing data, can be realized by such as a hard disc, a memory, a flash drive or a memory card.

In the present embodiment of the disclosure, the image capturing unit110can be equipped with a movable mechanism (eye-in-hand) and a dom-shaped light source, wherein the shape of the light source is not limited to a dom, a ring, a square, a quadrilateral or a strip, and the light source for providing supplementary lighting can also be used. The object900is disposed on a platform P, and the image capturing system100captures a plurality of appearance images I0with a plurality of view-angles above the object900along a X-axial direction and a Y-axial direction of a hemispheric surface S.

A dimension characteristic (such as a ratio of an area measurement, a perimeter, each length of a long axis and a short axis, or a ratio of the long axis to the short axis) of some light reflection areas of the captured appearance images I0may be too large. Therefore, in the present embodiment of the disclosure, adjustment at each view-angle is performed for reducing the dimension characteristic of some light reflection areas of the appearance images I0captured at each view-angle to an acceptable range, so that the image can be subsequently used for defecting defects.

Referring toFIG. 2, a flowchart of a capturing method for the images with different view-angles according to an embodiment of the disclosure is shown. The capturing method for the images with different view-angles of the present embodiment of the disclosure is exemplified with the capturing system100ofFIG. 1. However, anyone who is skilled in the technology of the disclosure will understand that the application of the capturing method for the images with different view-angles of the present embodiment of the disclosure is not limited to the capturing system100ofFIG. 1, and the application of the capturing system100ofFIG. 1is not limited to the capturing method for the images with different view-angles ofFIG. 2either.

In step S110, an appearance image I0of an object900is captured by the image capturing unit110at a capturing angle θ. The capturing angle θ such as corresponds to a view-angle on the X axis of the hemispheric surface S. In steps S120to S160, the capturing angle θ and the brightness of the light source are fine-tuned so that the dimension characteristic of the light reflection area of the appearance image I0captured at the specific view-angle is reduced to an acceptable range.

In step S120, a light reflection area of the appearance image I0is detected by the detecting unit120, and a dimension characteristic of the light reflection area is analyzed by the same. In the present step, the detecting unit120analyzes the appearance image I0to recognize which portion belongs to the light reflection area. There could be several light reflection areas detected at the beginning. After suitable analysis procedure is performed, a light reflection area with a larger dimension characteristic is sifted. The number of sifted light reflection area can be one (for example, the light reflection area with the largest dimension characteristic is sifted) or several (for example, a plurality of light reflection areas whose dimension characteristic is larger than a threshold are selected). The step S120includes a plurality of sub-steps as indicated inFIG. 4. Descriptions related toFIG. 4are given in subsequent paragraphs. In step S120, at least the dimension characteristic of the light reflection area is analyzed. In other embodiments, step S120may further analyze other geometric information such as the center position, the long axis, the short axis, and the bounding rectangle.

In step S130, whether the dimension characteristic of the light reflection area is larger than a second predetermined value is determined by the determining unit130. If the dimension characteristic of the light reflection area is larger than the second predetermined value, then the process proceeds to step S140. If the dimension characteristic of the light reflection area is not larger than the second predetermined value, then the process proceeds to step S150.

In step S140, an environment brightness is adjusted by the adjusting unit140. For example, the brightness of a dom-shaped light source is adjusted, wherein the shape of the light source is not limited to a dom, a ring, a square, a quadrilateral or a strip, and the light source for providing supplementary lighting can also be used. In present step, the dimension characteristic of the light reflection area can be reduced by decreasing the environment brightness.

After step S140is completed, the process returns to step S110, another appearance image I0is captured by the image capturing unit110. That is, steps S110to S140will be repeated until the dimension characteristic of the light reflection area is not larger than the second predetermined value, and only then will the method proceed to step S150.

In step S150, whether the dimension characteristic of the light reflection area is larger than a first predetermined value is determined by the determining unit130. If the dimension characteristic of the light reflection area is larger than the first predetermined value, then the process proceeds to step S160. If the dimension characteristic of the light reflection area is not larger than the first predetermined value, then the process proceeds to step S170. The second predetermined value may be larger than or smaller than the first predetermined value. In the present embodiment of the disclosure, the second predetermined value is smaller than the first predetermined value.

In step S160, the capturing angle θ is adjusted by the adjusting unit140within a first adjusting range. The first adjusting range is such as ½, ⅓ or a particular ratio of the length DX of the light reflection area along the X axis. The design of the first adjusting range has much to do with the radius R of the hemispheric surface S, and the smaller the radius R of the hemispheric surface S is, the smaller the first adjusting range will be. In the present step, the adjustment made on the capturing angle θ is very small, and the image capturing unit110will not be adjusted to other view-angle.

After step S160is completed, the process returns to step S110, another appearance image I0is again captured by the image capturing unit110. That is, steps S110to S130and steps S150to S160will be repeated until the dimension characteristic of the light reflection area is not larger than the first predetermined value, and then the process will proceed to step S170. After the process proceeds to step S170, this indicates that the dimension characteristic of the light reflection area is conformed to an acceptable range.

In step S170, the current appearance image I0is stored to the storage unit170. Since the dimension characteristic of the light reflection area of the appearance image I0is already conformed to an acceptable range, the view-angle can be designated by the appearance image I0.

In step S180, whether there are remaining view-angles at which no appearance image I0is captured is determined by the determining unit130. If yes, then the process proceeds to step S190. If no, the process terminates.

In step S190, the capturing angle is adjusted by the adjusting unit140within a second adjusting range. The second adjusting range is different from the first adjusting range. The second adjusting range can be larger than the first adjusting range. Or, the second adjusting range can be smaller than the first adjusting range. For example, if the length DX of the light reflection area along the X axis is smaller than or a predetermined ratio (such as ⅔) of the length L of the object900along the X axis, then the second adjusting range is larger than the first adjusting range. If the length DX of the light reflection area along the X axis is larger than a predetermined ratio (such as ⅔) of the length L of the object900along the X axis, then the second adjusting range is smaller than the first adjusting range.

After step S190is completed, the process returns to step S110, the appearance image I0along another view-angle is again captured by the image capturing unit110. That is, steps S110to S170are performed again and repeatedly until an appearance image I0representing the view-angle is obtained.

Through the above process, the appearance image I0whose light reflection area is conformed to an acceptable range is stored at each view-angle. Despite the above process is exemplified by a plurality of view-angles on the X axis, a plurality of view-angles on the Y axis or other directional axis are also applicable to the above process. The implementations and descriptions for the two applications are similar, and the similarities are not repeated.

Despite the capturing method for the images with different view-angles of the present embodiment of the disclosure is exemplified by the flowchart ofFIG. 2, the capturing method for the images with different view-angles of the present disclosure is not limited to such exemplification. Referring toFIG. 3, a flowchart of a capturing method for the images with different view-angles according to another embodiment of the disclosure is shown. In another embodiment, step S130and step S140can be omitted, and the process can directly proceed to step S150after step S120is completed. Or, step S130and step S140can be performed after step S150and step S160are completed.

Referring toFIG. 4, a schematic diagram of the step S120ofFIG. 2according to an embodiment of the disclosure is shown. The step S120of the present embodiment of the disclosure includes a plurality of sub-steps S121to S125and S127. Let the capturing system100ofFIG. 1be taken for example. The detecting unit120of the capturing system100of the present embodiment of the disclosure includes a log transform unit121, a Gaussian filtering unit122, an exponential transform unit123, a difference analyzing unit124, a characteristic analyzing unit125and a geometry analyzing unit127. The characteristic analyzing unit125includes a pixel sifting unit1251, an objectifying unit1253, a first region sifting unit1254, a second region sifting unit1255and a third region sifting unit1256.

In step S121, a log transform process is performed on the appearance image I0by the log transform unit121to obtain a log image I1.

In step S122, a Gaussian filtering process is performed on the log image I1by the Gaussian filtering unit122to obtain a filtered image I2.

In step S123, an exponential transform process is performed on a filtered image I2by the exponential transform unit123to obtain an exponential image I3.

In step S124, a difference between the appearance image I0and the exponential image I3is analyzed by the difference analyzing unit124to obtain a residual image I4.

In step S125, the light reflection area is obtained by the characteristic analyzing unit125according to the residual image I4. In step S125, the residual image I4includes a plurality of residual pixels. Through steps S1251, and S1253to S1256, the light reflection area is analyzed according to the residual pixels. InFIG. 4, steps S1254to S1256are performed in sequence. In other embodiments, steps S1254to S1256can be performed according to other arrangements of sequence, or, only one or two of steps S1254to S1256is performed. The number and sequence of steps S1254to S1256are determined according to the needs of the design.

In step S1251, residual pixels are sifted by the pixel sifting unit1251according to each residual pixel value of the residual pixels. For example, the pixel sifting unit1251deletes these residual pixels whose pixel values are smaller than a predetermined threshold, and selects these residual pixels whose pixel values are larger than the threshold. The selected residual pixels are suspected reflective pixels.

In step S1253, the selected residual pixels are objectified by the objectifying unit1253to obtain at least one suspected light reflection area. That is, the objectifying unit1253connects the selected residual pixels to form a plurality of suspected light reflection areas one by one.

In step S1254, the suspected light reflection areas are sifted by the first region sifting unit1254according to the geometric characteristic of the suspected light reflection area. That is, the first region sifting unit1254deletes these suspected light reflection areas whose geometric characteristic is significant (the suspected light reflection areas with significant geometric characteristic could be the original pattern of the object900) but reserves these suspected light reflection areas whose geometric characteristic is insignificant.

In step S1255, the suspected light reflection areas are sifted by the second region sifting unit1255according to the edge characteristic of the suspected light reflection area. That is, the second region sifting unit1255deletes these suspected light reflection areas whose edge fuzzy degree is lower (the suspected light reflection areas with lower edge fuzzy degree could be the original pattern of the object900) but reserves these suspected light reflection areas whose edge fuzzy degree is higher. In the present step, the edge fuzzy degree is analyzed according to the pixel values of the original appearance image I0.

In step S1256, the suspected light reflection areas are sifted by the third region sifting unit1256according to the dimension characteristic of the suspected light reflection area to obtain the light reflection area. That is, these light reflection areas whose dimension characteristic is larger than a specific threshold can be set by the user or selected from the suspected light reflection areas built in the system, and can be defined as the light reflection areas.

In step S127, the dimension characteristic of the light reflection area, such as the center-of-gravity position or the geometric center position, are analyzed by the geometry analyzing unit127. The dimension characteristic obtained from analysis can be used in step S130or step S150.

The above step S120can be implemented by steps S121to125and S127ofFIG. 4or other process. Referring toFIG. 5, a schematic diagram the step S120ofFIG. 2according to another embodiment of the disclosure is shown. In an embodiment, step S120can be implemented through a plurality of sub-steps S521to S523, S525and S527. Let another capturing system500ofFIG. 6be taken for example. A detecting unit520of the capturing system500includes a providing unit521, an aligning unit522, a difference analyzing unit523, a characteristic analyzing unit525and a geometry analyzing unit527. The characteristic analyzing unit525includes a first pixel sifting unit5251, a second pixel sifting unit5252, an objectifying unit5253, a first region sifting unit5254, a second region sifting unit5255and, a third region sifting unit5256.

In step S521, a comparison image15is provided by the providing unit521. The comparison image15is such as the object image previously captured by the image capturing unit110.

In step S522, the comparison image15is adjusted as an alignment image16by the aligning unit522according to the appearance image I0and the comparison image I5, so that the alignment image I6is aligned with the appearance image I0. During the adjustment process, adjustment operations such as shifting, enlargement, reduction and rotation are performed on the comparison image I5, so that the pattern of the alignment image I6corresponds to the pattern of the appearance image I0.

In step S523, a difference between the appearance image I0and the alignment image I6is analyzed by the difference analyzing unit523to obtain a differential image I7.

In step S525, the light reflection area is obtained by the characteristic analyzing unit525according to differential image I7and the appearance image I0. In step S525, the differential image I7includes a plurality of differential pixels. Through steps S5251to5256, the light reflection area is analyzed according to the differential pixels.

In step S5251, differential pixels are sifted by the first pixel sifting unit5251according to each differential pixel value of the differential pixels of the differential image I7. For example, the first pixel sifting unit5251deletes these differential pixels whose pixel values are smaller than a predetermined threshold but reserves these differential pixels whose pixel values are larger than the threshold. The reserved differential pixels are suspected reflective pixels.

In step S5252, the appearance pixels are sifted by the second pixel sifting unit5252according to each pixel value of the appearance pixels of the appearance image I0. For example, the second pixel sifting unit5252deletes these appearance pixels whose pixel values are smaller than a predetermined threshold but selects these appearance pixels whose pixel values are larger than the threshold. The selected appearance pixels are suspected reflective pixels.

In step S5253, the selected differential pixels and appearance pixels are objectified by the objectifying unit5253to obtain at least one suspected light reflection area. That is, the objectifying unit5253connects the selected differential pixels and appearance pixels to form a plurality of suspected light reflection areas one by one.

In step S5254, the suspected light reflection areas are sifted by the first region sifting unit5254according to the geometric characteristic of the suspected light reflection area. That is, the first region sifting unit5254deletes these suspected light reflection areas whose geometric characteristic is significant (the suspected light reflection areas with significant geometric characteristic could be the original pattern of the object900) but reserves these suspected light reflection areas whose geometric characteristic is insignificant.

In step S5255, the suspected light reflection areas are sifted by the second region sifting unit5255according to the edge characteristic of the suspected light reflection area. That is, the second region sifting unit5255deletes these suspected light reflection areas whose edge fuzzy degree is lower (the suspected light reflection areas with lower edge fuzzy degree could be the original pattern of the object900) but reserves these suspected light reflection areas whose edge fuzzy degree is higher. In the present step, the edge fuzzy degree is analyzed according to the pixel values of the original appearance image10.

In step S5256, the suspected light reflection areas are sifted by the third region sifting unit5256according to the dimension characteristic of the suspected light reflection area to obtain the light reflection area. That is, these light reflection areas whose dimension characteristic is larger than a specific threshold can be set by the user or selected from the suspected light reflection areas built in the system, and can be defined as the light reflection areas.

InFIG. 5, steps S5254to S5256are performed in sequence. In other embodiments, steps S5254to S5256can be performed according to other arrangements of sequence, or, only one or two of steps S5254to S5256is performed. The number and sequence of steps S5254to S5256are determined according to the needs of the design.

In step S527, the dimension characteristic of the light reflection area, such as the center-of-gravity position or the geometric center position, are analyzed by the geometry analyzing unit527. The dimension characteristic obtained from analysis can be used in step S130or step S150.

According to the above embodiments of the present disclosure, the dimension characteristic of the light reflection area of the appearance image captured at each view-angle is reduced through dynamic detection and adjustment. When performing surface quality testing, the object image captured according to the above capturing method is less affected by the light reflection area. Furthermore, through proactive detection and adjustment, the influence produced by the light reflection area is effectively reduced, and the object does not require specific light source, so that the hardware cost can thus be reduced accordingly.