JP6650839B2 - Polarizing camera and image processing method - Google Patents

Description

  The present invention relates to a polarization camera provided with a polarization filter and an image processing method thereof.

  2. Description of the Related Art Conventionally, a polarization camera that acquires not only image information of an imaging target but also polarization information of the imaging target has been known. An example of this type of polarization camera is a polarization camera 100 shown in FIG. The polarization camera 100 includes an area sensor 110 as an image sensor, a polarization filter 120, and an image processing device (not shown).

  The area sensor 110 includes a plurality of pixels 111 arranged two-dimensionally. The polarizing filter 120 is provided between the area sensor 110 and the object to be imaged, and includes a plurality of minute polarizing plates 121 to 124 that are two-dimensionally arranged. Arrows of the minute polarizing plates 121 to 124 indicate the transmission axis directions of the minute polarizing plates 121 to 124, respectively. The minute polarizing plates 121 to 124 having mutually different transmission axis directions are arranged in 2 rows × 2 columns to constitute the polarizing element array 125.

  The area sensor 110 (see FIG. 22) acquires the image information I to IV of the imaging target as shown in FIG. Image information I is obtained through the minute polarizing plate 121, image information II is obtained through the minute polarizing plate 122, and image information III is obtained through the minute polarizing plate 123. , Image information IV is acquired via the minute polarizing plate 124. Then, the image processing apparatus calculates the polarization information 140 for each of the four (2 rows × 2 columns) image information I to IV acquired via the polarization element array 125. The calculated polarization information 140 is estimated as the polarization information at the center of the positions of the four pieces of image information I to IV based on the calculation. This makes it possible to acquire two-dimensional polarization information of the imaging target.

  Here, Patent Document 1 discloses that a line sensor can be used instead of the area sensor 110 as the image sensor. The line sensor is configured by arranging pixels one-dimensionally (in a straight line).

Patent No. 5,118,311

  However, Patent Literature 1 does not disclose a specific mode of a polarizing filter and an image processing device when a line sensor is used. That is, as a specific mode of the polarizing filter in Patent Document 1, only a mode in which minute polarizing plates are arranged two-dimensionally is disclosed. In a polarization camera including a line sensor, a unique device different from a polarization camera including an area sensor is required for the configuration of a polarizing filter and the configuration of an image processing device.

  Then, an object of the present invention is to provide a polarization camera provided with a line sensor as an image sensor.

The polarizing camera of the present invention includes a line sensor having a plurality of pixels arranged in a straight line, and a plurality of polarizing elements arranged in a straight line between the line sensor and the imaging target, and among the plurality of polarizing elements. A polarizing filter having a polarizing element array constituted by three or more types of polarizing elements having mutually different principal axis directions; and an image processing device, wherein the image processing device is configured such that the line sensor and the polarizing filter are imaging targets. While moving relatively to the object, the line sensor repeatedly acquires the image information of the imaging object through the polarizing filter, and a plurality of pieces of image information acquired through the polarizing element array. is configured to calculate the polarization information of the imaged object for each, from twice the image information acquired in succession, of which the first image information and second Characterized in that it is configured to calculate the polarization information of the rows of the image information.

  According to the polarization camera of the present invention, it is possible to provide a polarization camera including a line sensor as an image sensor.

FIG. 2 is a schematic front view of the polarization camera according to Embodiment 1 of the present invention. It is a plane schematic diagram of the same polarization camera. It is a figure which shows the correspondence of the polarizing element array, image information, and polarization information in the same polarization camera. FIG. 3 is a diagram showing a correspondence relationship among a polarization filter, image information, and polarization information in the same polarization camera. FIG. 3 is a diagram illustrating an image processing method according to the first embodiment of the present invention. It is a figure showing the same image processing method. It is a figure showing the same image processing method. It is a figure showing the same image processing method. FIG. 7 is a schematic plan view of a polarization camera according to Embodiment 2 of the present invention. FIG. 3 is a diagram showing a correspondence relationship among a polarization filter, image information, and polarization information in the same polarization camera. FIG. 9 is a diagram illustrating an image processing method according to Embodiment 2 of the present invention. It is a figure showing the same image processing method. It is a figure showing the same image processing method. FIG. 9 is a schematic front view of a polarization camera according to Embodiment 3 of the present invention. FIG. 3 is a diagram showing one mode of a correspondence relationship among a polarization filter, image information, and polarization information in the same polarization camera. It is a figure which shows the other aspect of the correspondence of the polarization filter, image information, and polarization information in the same polarization camera. FIG. 13 is a diagram illustrating an image processing method according to a third embodiment of the present invention. It is a figure showing the same image processing method. It is a figure showing the same image processing method. FIG. 14 is a schematic front view of a polarization camera according to Embodiment 4 of the present invention. It is a front schematic diagram of the same polarization camera. FIG. 14 is a diagram illustrating an image processing method according to Embodiment 4 of the present invention. It is a figure showing the same image processing method. It is a figure showing the same image processing method. It is a figure showing the same image processing method. FIG. 17 is a diagram showing a correspondence relationship among a polarization filter, image information, and polarization information in the polarization camera according to Embodiment 5 of the present invention. FIG. 16 is a diagram illustrating one mode of a correspondence relationship between a polarization filter, image information, and polarization information in the polarization camera according to Embodiment 6 of the present invention. It is a figure which shows the other aspect of the correspondence of the polarization filter, image information, and polarization information in the same polarization camera. FIG. 21 is a diagram illustrating yet another mode of the correspondence between the polarization filter, the image information, and the polarization information in the polarization camera according to Embodiment 7 of the present invention. FIG. 21 is a diagram illustrating a correspondence relationship among a polarization filter, image information, and polarization information in a polarization camera according to Embodiment 8 of the present invention. FIG. 15 is a diagram illustrating an image processing method according to Embodiment 8 of the present invention. It is a figure showing the same image processing method. FIG. 13 is a plan view showing an example of an arrangement relationship between a polarization filter and a color filter in a polarization camera further including a color filter in the embodiment of the present invention. FIG. 7 is a front view of an example of a polarization camera when a micro wavelength plate and a polarizing plate are used instead of the micro polarizing plate in the embodiment of the present invention. It is a typical perspective view of the conventional polarization camera. FIG. 11 is a diagram illustrating a conventional image processing method.

(Embodiment 1)
(Configuration of polarized camera)
Hereinafter, the configuration of the polarization camera 1 according to the first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the polarization camera 1 according to the present embodiment includes a line sensor 10, a polarization filter 20, and an image processing device 30. FIG. 1 is a schematic front view of the polarization camera 1, and FIG. 2 is a schematic plan view of the polarization camera 1. The polarization camera 1 is mounted above the conveyor or the like, for example, in order to inspect the imaging target W transported in the transport direction D (see FIG. 2) by the conveyor or the like.

  The line sensor 10 has a plurality of pixels 11 arranged in one row × a plurality of columns. Each pixel 11 can measure the intensity of light incident on each pixel. The line sensor 10 acquires one-dimensional image information every time the imaging target W is imaged once. The image information includes position information of the imaging target object W and light intensity information at the position. Then, it is possible to acquire two-dimensional image information by repeatedly performing imaging on the image capturing target W to be conveyed.

  The polarization filter 20 is provided between the imaging object W and the line sensor 10. The polarizing filter 20 has a plurality of minute polarizing plates 21 to 24. The plurality of minute polarizing plates 21 to 24 are provided corresponding to the respective pixels 11, and are arranged in one row × a plurality of columns between each pixel 11 and the imaging target W. Further, the plurality of minute polarizing plates 21 to 24 each have a transmission axis for transmitting light polarized in a specific direction. The minute polarizing plate 21 has a transmission axis inclined by 45 ° with respect to the minute polarizing plates 22 and 23, and has a transmission axis inclined by 90 ° with respect to the minute polarizing plate 24. Arrows of the minute polarizing plates 21 to 24 indicate respective transmission axis directions. These minute polarizing plates 21 to 24 are arranged periodically. One polarizing element array 25 is constituted by four minute polarizing plates 21 to 24 arranged in one row × 4 columns. That is, a plurality of polarizing element arrays 25 are provided along the direction (row direction) in which the minute polarizing plates 21 to 24 are arranged. In FIG. 2, the line sensor and the image processing device are omitted.

  As shown in FIG. 1, the image processing device 30 includes a control unit 31, a calculation unit 32, and a storage unit 33. The image processing device 30 is connected to the line sensor 10. The control unit 31 can control the imaging operation of the line sensor 10 and its timing. That is, the line sensor 10 repeatedly captures an image of the imaging target W that is moving in the transport direction D (see FIG. 2, in FIG. 1, the depth direction in FIG. 1) at a predetermined timing according to a command from the control unit 31.

  The storage unit 33 includes an image information storage unit 33a and a polarization information storage unit 33b. When the line sensor 10 images the imaging target W, the image information obtained by the imaging operation is stored in the image information storage unit 33a of the storage unit 33. The calculation unit 32 is configured to calculate polarization information based on the image information. The calculated polarization information is stored in the polarization information storage unit 33b of the storage unit 33. These operations are performed by the control unit 30 controlling the storage unit 33, the calculation unit 32, and the line sensor 10.

(Image processing method)
Hereinafter, a specific image processing method according to the present embodiment will be described with reference to FIGS. FIG. 3A shows a correspondence relationship between the polarization element array 25 and the image information I to IV and the polarization information 40 acquired via the polarization element array 25, focusing on one polarization element array 25. is there. The image information I to IV are stored in the image information storage unit 33a in FIG. 1, and the polarization information 40 is stored in the polarization information storage unit 33b in FIG. The four pixels corresponding to one polarizing element array 25 acquire image information I to IV, respectively, and store them in the image information storage unit 33a (see FIG. 1). The image information I is image information acquired through the minute polarizing plate 21, the image information II is the image information acquired through the minute polarizing plate 22, and the image information III is acquired through the minute polarizing plate 23. The image information IV and the image information IV respectively represent the image information acquired via the minute polarizing plate 24.

  One piece of polarization information 40 can be calculated from the four pieces of image information I to IV. The calculated polarization information 40 is stored in the polarization information storage unit 33b (see FIG. 1) as the polarization information at the center of the position information of the image information I to IV based on the calculation. Here, the polarization information is, for example, the amplitude of the non-polarization component and the polarization component of the light intensity and the polarization direction of the light. Since a specific calculation method of the polarization information is described in Patent Document 1 and the like, a detailed description is omitted. The center of the position information is the average value of each position information. For example, the center of the position information in the first to fourth columns is the 2.5th column. The center of the position information of the second to fifth rows is the 3.5 column.

  Here, in FIG. 3A, for the sake of explanation, attention is focused on only one polarizing element array 25 that is arranged in the order of the minute polarizing plates 21, 22, 23, and 24 from the left side of the paper. Actually, a polarizing element array adjacent thereto (a polarizing element array composed of minute polarizing plates 22, 23, 24, and 21 arranged in this order from the left side of the drawing) and a polarizing element array further adjacent thereto (a minute polarizing plate array from the left side of the drawing) Polarizing element arrays arranged in the order of the polarizing plates 23, 24, 21, 22) and a further adjacent polarizing element array (the minute polarizing plates 24, 21, 22, 23 are arranged in the order from the left side of the sheet). The polarization information 40 can be obtained in the same manner also for the configured polarization element array). In this manner, as shown in FIG. 3B, it is possible to acquire the polarization information 40 for one row.

  4A to 4D show a state in which the image information I to IV stored in the image information storage unit 33a (see FIG. 1) and the polarization information 40 stored in the polarization information storage unit 33b (see FIG. 1) are superimposed. Are shown for each timing. 4A shows a timing 1 showing the first imaging, FIG. 4B shows a timing 2 showing the second imaging, FIG. 4C shows a timing 3 showing the third imaging, and FIG. 4D shows a timing 4 showing the fourth imaging. .

  At each timing, every time the image information I to IV for one row is acquired, the polarization information 40 for one row in the same row as the acquired image information I to IV is acquired. By repeating this operation at each timing, it is possible to acquire two-dimensional polarization information 40. As described above, according to the present embodiment, it is possible to provide the polarization camera 1 including the line sensor 10 as the image sensor.

(Embodiment 2)
(Configuration of polarized camera)
Next, the configuration of the polarization camera according to Embodiment 2 of the present invention will be described. FIG. 5 is a schematic plan view of the polarization camera 2 according to the present embodiment, in which the line sensor and the image processing device are omitted. The schematic front view of the polarization camera 2 is the same as FIG. Hereinafter, points different from the first embodiment will be mainly described, and description of the same configuration as the first embodiment will be omitted.

  The polarization camera 1 according to the first embodiment has a configuration including a polarization filter 20 having micro-polarization plates 21 to 24 arranged in one row × a plurality of columns as shown in FIGS. As shown in FIG. 5, the polarization camera 2 according to the second embodiment has a configuration including a polarization filter 20a having micro-polarization plates 21 to 24 arranged in 2 rows × a plurality of columns.

  The pixels 11 (see FIG. 1) constituting the line sensor 10 are also arranged in 2 rows × a plurality of columns corresponding to the minute polarizing plates 21 to 24. In addition, as shown in FIG. 5, four types of micro-polarizing plates 21 to 24 having different transmission axis directions are arranged side by side in four rows and two columns to constitute one polarizing element array 25a.

(Image processing method)
Hereinafter, an image processing method according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 6 is a diagram showing the correspondence between the polarization filter 20a, the image information I to IV, and the polarization information 41. The image information I to IV are image information obtained via the minute polarizing plates 21 to 24, respectively. Then, one piece of polarization information 41 is calculated based on the four image processing devices I to IV of 2 rows × 2 columns. The calculated polarization information 41 is stored in the polarization information storage unit as polarization information at the center of the position information of the four pieces of image information I to IV based on the calculation. In this way, it is possible to acquire the polarization information 41 for one row.

  7A to 7C show, for each timing, a state in which the image information I to IV stored in the image information storage unit and the polarization information 41 stored in the polarization information storage unit are superimposed. FIG. 7A shows a state at timing 1 indicating the first imaging. Here, the line sensor acquires the image information I to IV for the two rows of the first row and the second row. Based on the image information I to IV, the polarization information 41 between the first and second rows can be obtained.

  FIG. 7B shows a state at timing 2 indicating the second imaging. Here, the line sensor acquires the image information I to IV for the two rows of the third row and the fourth row. Based on the image information I to IV, the polarization information 41 between the third and fourth rows can be obtained. In addition, in this embodiment, the polarization information 42 between rows of the image information I to IV acquired at timing 1 and the image information I to IV acquired at timing 2 is also acquired. Since the image information I to IV are stored in the image information storage unit, the polarization information 42 can be calculated even if the timing of obtaining the image information on which the calculation is based is shifted.

  FIG. 7C shows the state at timing 3 indicating the third imaging. Here, the line sensor acquires the image information I to IV for the two rows of the fifth row and the sixth row. Based on the image information I to IV, the polarization information 41 between the fifth and sixth rows can be obtained. Further, similarly to the above, the polarization information 42 between rows of the image information I to IV acquired at the timing 2 and the image information I to IV acquired at the timing 3 is also acquired. By repeating this operation at each timing, two-dimensional polarization information 41 and 42 can be obtained.

  According to the present embodiment, it is possible to improve the accuracy of polarization information as compared with the first embodiment. In the polarization camera 1 according to the first embodiment, as shown in FIG. 3A, the polarization element array 25 is configured by micro-polarizing plates 21 to 24 of 1 row × 4 columns. One piece of polarization information 40 is calculated from the acquired four pieces of image information I to IV. Then, the calculated polarization information 40 is estimated as the polarization information at the center of the position information of the four pieces of image information I to IV based on the calculation. Here, of the four pieces of image information I to IV based on the calculation, the image information I and IV having both ends as position information are apart from the estimated position of the polarization information 40. Therefore, the estimated polarization information 40 may deviate from the actual polarization information at that position.

  On the other hand, in the polarization camera 2 according to the second embodiment, as shown in FIG. 6, the polarization element array 25 a is configured by 2 rows × 2 columns of minute polarization elements 21 to 24, and the polarization element array 25 a Is calculated from the four pieces of image information I to IV acquired through the. Then, the calculated polarization information 41 is estimated as the polarization information at the center of the position information of the four pieces of image information I to IV based on the calculation. Here, the four pieces of image information I to IV based on the calculation have a common contact point, and the contact point coincides with the estimated position of the polarization information 41. Here, that the image information I to IV has a contact point means that the rows and columns of the position information of the image information I to IV fall within the range of ± 1. For example, when the position information of the image information I to IV is the first row and first column, the first row and second column, the second row and first column, and the second row and second column, respectively, IVs have common contacts. The contact point is at the 1.5th row and 1.5th column, which coincides with the estimated position of the polarization information 41. That is, the four pieces of image information I to IV are in contact with the estimated positions of the polarization information 41, respectively. Therefore, the estimated polarization information 41 does not significantly differ from the actual polarization information at that position. The same applies to the polarization information 42. Therefore, according to the second embodiment, the accuracy of polarization information can be improved as compared with the first embodiment.

  5 and 6 show a mode in which the minute polarizing plates 21 to 24 are periodically arranged. That is, the minute polarizing plates 21 and 24 are alternately arranged in the row direction of the first row (left-right direction on the paper), and the minute polarizing plates 23 and 22 are alternately arranged in the row direction of the second row. Aspects are depicted. However, the polarization camera 2 according to the present embodiment is not limited to this mode. If it is possible to calculate the polarization information between the lines from the acquired two lines of image information, and to calculate the polarization information between the lines of two consecutively acquired image information, The arrangement of the minute polarizing plates 21 to 24 does not need to be periodic.

(Embodiment 3)
(Configuration of polarized camera)
Next, the configuration of the polarization camera according to Embodiment 3 of the present invention will be described. FIG. 8 is a schematic front view of the polarization camera 3 according to the third embodiment. Hereinafter, points different from the first embodiment will be mainly described, and description of the same configuration as the first embodiment will be omitted.

  The polarization camera 3 according to the third embodiment includes two line sensors and two polarization filters. Further, the polarization camera 3 includes a beam splitter 60. The beam splitter 60 is configured to generate image information input to one line sensor 10b and image information input to the other line sensor 10c. Specifically, the beam splitter 60 optically splits incident light from the imaging target object W to generate transmitted light and reflected light, and causes the transmitted light to enter the line sensor 10b via the polarization filter 20b. At the same time, the reflected light is incident on the line sensor 10c via the polarizing filter 20c. There is a case where polarization information is different between the transmitted light and the reflected light. Here, a case where the transmitted light and the reflected light have the same polarization information will be described.

  As shown in FIG. 8, the polarizing filter 20b is configured by alternately arranging two types of minute polarizing plates 21 and 24 in one row × a plurality of columns. The polarizing filter 20c is configured by alternately arranging two types of minute polarizing plates 22 and 23 in one row and a plurality of columns. In the polarizing element array 25b, the minute polarizing plates 21 and 24 are arranged in one line sensor 10a in one row × two columns, and the minute polarizing plates 22 and 23 are arranged in one line sensor 10b in one row × 2 columns. It is configured side by side.

(Image processing method)
Hereinafter, an image processing method according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 9 is a diagram showing the correspondence between the polarization filters 20b and 20c, the image information I to IV, and the polarization information 43. The image information I to IV are image information obtained via the minute polarizing plates 21 to 24, respectively. In the image processing method shown in FIG. 9, the line sensors 10b and 10c (see FIG. 8) perform an imaging operation at the same timing. Therefore, the line sensors 10b and 10c acquire image information at the same position of the imaging target. However, since the transmission axis directions of the minute polarizing plates 21 and 24 included in the line sensor 10b and the transmission axis directions of the minute polarizing plates 22 and 23 included in the line sensor 10c are different from each other, different image information is obtained.

  Then, four pieces of image information I to IV obtained through one polarizing element array, that is, two small polarizing plates 21 and 24 in the polarizing filter 20b and two small polarizing plates 22 and 23 in the polarizing filter 20c. Is calculated on the basis of the polarization information 43. The calculated polarization information 43 is stored in the polarization information storage unit 33b (see FIG. 8) as the polarization information at the center of the position information of the four pieces of image information I to IV based on the calculation.

  Here, in the present embodiment, the image processing method shown in FIG. 10 may be employed instead of the image processing method shown in FIG. In the image processing method shown in FIG. 10, the timings of the imaging operations of the line sensors 10b and 10c are not simultaneous but shifted. Hereinafter, the image processing method illustrated in FIG. 10 will be described in detail with reference to FIGS. 11A to 11C.

  11A to 11C show, for each timing, a state in which the image information I to IV stored in the image information storage unit and the polarization information 44 stored in the polarization information storage unit are superimposed. FIG. 11A shows a state at the timing 1 indicating the first imaging by the line sensor 10b. Since there are only two types of image information acquired here, image information I and IV, polarization information cannot be calculated.

  FIG. 11B shows a state at timing 2 indicating the second imaging by the line sensor 10b. The imaging operation of the line sensor 10c intervenes between the first imaging operation of the line sensor 10b and the second imaging operation. The imaging operation of the line sensor 10c corresponds to the timing 1.5. The image information acquired by the line sensor 10c is two types of image information II and III.

  Here, the polarization information 44 is calculated based on the image information I and IV acquired by the line sensor 10b at the timing 1 and the image information II and III acquired by the line sensor 10c at the timing 1.5. Similarly, the polarization information 44 is calculated from the image information II and III obtained at the timing 1.5 and the image information I and IV obtained at the timing 2. The calculated polarization information 44 is stored in the polarization information storage unit 33b (see FIG. 8) as the polarization information at the center of the position information of the image information I to IV based on the calculation.

  Then, as shown in FIG. 11C, the imaging operation of the line sensor 10b and the imaging operation of the line sensor 10c are alternately repeated. Thereby, two-dimensional polarization information can be obtained by sequentially obtaining the polarization information 44 between the rows of the image information I and IV obtained by the line sensor 10b and the image information II and III obtained by the line sensor 10c. Becomes possible.

  According to the present embodiment, the four pieces of image information I to IV based on the calculation have a common contact point, and the contact point coincides with the estimated position of the polarization information 44. Therefore, similarly to the second embodiment, the accuracy of the polarization information can be improved as compared with the polarization camera 1 according to the first embodiment.

  Although the transmitted light and the reflected light generated by the beam splitter 60 (see FIG. 8) have the same polarization information, the present embodiment is not limited to this. For example, even if there is a deviation of the polarization angle N ° between the transmitted light and the reflected light, if the calculation unit 32 calculates the polarization information in consideration of the deviation of N °, the appropriate polarization information is obtained. Can be obtained.

  In the present embodiment, the line sensors 10b and 10c and the polarization filters 20b and 20c each have one row × a plurality of columns, but the present invention is not limited to this mode. That is, the polarizing filter and the line sensor may each be two or more rows × a plurality of columns, and two polarizing filters and two line sensors may be provided.

(Embodiment 4)
(Configuration of polarized camera)
Next, the configuration of the polarization camera according to Embodiment 4 of the present invention will be described. 12A and 12B are schematic front views of the polarization camera 4 according to the fourth embodiment. Hereinafter, points different from the first embodiment will be mainly described, and description of the same configuration as the first embodiment will be omitted.

  The polarization camera 4 according to the fourth embodiment includes a slide mechanism (not shown) that slides the polarization filter 20 in a direction perpendicular to the transport direction of the imaging target object W. FIG. 12A shows a state in which the polarization filter 20 has been slid to the left side of the drawing with respect to the line sensor 10. FIG. 12B shows a state in which the polarization filter 20 has been slid to the right side of the drawing with respect to the line sensor 10. The arrangement of the polarization filter 20 in FIG. 12B is shifted by two pixels from the arrangement of the polarization filter 20 in FIG. 12A.

  Here, the slide mechanism may slide the actual position of the polarizing filter 20, but may slide the optical position without sliding the actual position of the polarizing filter 20.

(Image processing method)
Hereinafter, an image processing method according to Embodiment 4 of the present invention will be described with reference to FIGS. 13A to 13D. 13A to 13D show, for each timing, a state where the image information I to IV stored in the image information storage unit and the polarization information 44 stored in the polarization information storage unit are superimposed. FIG. 13A shows a state at the timing 1 indicating the first imaging by the line sensor 10. At this timing 1, the imaging operation is performed in the arrangement shown in FIG. 12A. Thereby, the line sensor 10 acquires four types of image information of image information I to IV. However, no polarization information is calculated at this timing.

  FIG. 13B shows a state at timing 2 indicating the second imaging by the line sensor 10. After the first imaging operation of the line sensor 10, the polarization filter 20 is slid, and the second imaging operation is performed in the arrangement shown in FIG. 12B. Therefore, the arrangement of the image information I to IV acquired at the timing 2 is shifted by two pixels from the arrangement of the image information I to IV acquired at the timing 1. Here, the polarization information 44 between the rows of the image information I to IV acquired at the timing 1 and the image information I to IV acquired at the timing 2 is calculated.

  At timing 3 shown in FIG. 13C, the imaging operation is performed in the arrangement shown in FIG. Then, the polarization information 44 between the rows of the image information is calculated from the image information I to IV acquired at the timing 2 and the image information I to IV acquired at the timing 3. At timing 4 shown in FIG. 13D, the imaging operation is performed in the arrangement shown in FIG. Then, the polarization information 44 between the rows of the image information is calculated from the image information I to IV acquired at the timing 3 and the image information I to IV acquired at the timing 4.

  As described above, the image information is acquired one after another while sliding and swinging the polarization filter 20 at each timing. The calculated polarization information 44 is stored in the polarization information storage unit 33b (see FIG. 1) as the polarization information at the center of the position information of the image information I to IV based on the calculation. Acquiring the polarization information 44 one after another makes it possible to acquire two-dimensional polarization information.

  According to the present embodiment, the four pieces of image information I to IV based on the calculation have a common contact point, and the contact point coincides with the estimated position of the polarization information 44. Therefore, similarly to the second and third embodiments, the accuracy of the polarization information can be improved as compared with the polarization camera 1 according to the first embodiment. 13A to 13D, the polarization information 44 at both ends is calculated from three types of image information (I, II, and III or I, II, and IV). There is no problem because it can be calculated from

  Further, in the present embodiment, as compared with the second embodiment, the line sensor 10 and the polarizing filter 20 can be constituted by the pixels 11 in one row or the minute polarizing plates 21 to 24. Furthermore, compared to the third embodiment, there is no need to provide two line sensors 10 and two polarizing filters 20, and a beam splitter is not required.

  In the present embodiment, the sliding mechanism slides the polarizing filter 20, but the present invention is not limited to this mode. The slide mechanism only needs to slide the polarization filter 20 and the line sensor 10 relatively. For example, the slide mechanism may slide the line sensor 10 without sliding the polarization filter 20.

  Further, the polarizing filter 20 may be configured such that the minute polarizers 21 to 24 protrude in the sliding direction by the amount of sliding (for example, two pixels) with respect to the pixel 11.

  Further, in the present embodiment, the polarization filter 20 is slid by two pixels at each timing, but the present invention is not limited to this mode. For example, the polarization filter 20 may be slid by one pixel. Even in this case, three types of image information I to IV acquired at each timing have a common contact point, and polarization information can be calculated based on the three types of image information.

(Embodiment 5)
Next, the configuration of a polarization camera and an image processing method according to Embodiment 5 of the present invention will be described with reference to FIG. Embodiments 1 to 4 are embodiments in which four types of micro polarizing plates 21 to 24 are used, while Embodiment 5 is an embodiment in which three types of micro polarizing plates 21, 26, and 27 are used. . The micro polarizers 21, 26, and 27 have different transmission axis directions, and the transmission axis directions of the micro polarizers 26 and 27 are each inclined ± 60 ° with respect to the micro polarizer 21.

  The polarizing filter 20d has minute polarizing plates 21, 26, and 27 periodically arranged in one row and a plurality of columns. Then, the three continuous micro polarizing plates 21, 26, 27 are arranged side by side to form one polarizing element array 25d. The image information I to III indicate image information obtained via the minute polarizing plates 21, 26, and 27, respectively. One piece of polarization information 45 is calculated based on the three pieces of image information I to III. The calculated polarization information 45 is stored in the polarization information storage unit as the polarization information at the center of the position information of the image information I to III based on the calculation.

  According to this embodiment, as in the other embodiments, it is possible to provide a polarization camera including a line sensor as an image sensor. The polarization information can be calculated as long as there are at least three types of image information obtained through the micro-polarization plates having different transmission axis directions. Therefore, in the present embodiment, three types of minute polarizing plates are used.

(Embodiment 6)
Next, a configuration of a polarization camera and an image processing method according to Embodiment 6 of the present invention will be described with reference to FIGS. The polarization camera according to the sixth embodiment is common to the polarization camera according to the fifth embodiment in that three types of minute polarizing plates 21, 26, and 27 are used. Further, the polarization camera according to the sixth embodiment is common to the polarization camera according to the second embodiment in having minute polarizing plates arranged in 2 rows × a plurality of columns. On the other hand, in the second embodiment, the polarizing filter 20a has four types of minute polarizing plates 21 to 24, whereas in the sixth embodiment, the polarizing filter 20e (or 20f) has three types of minute polarizing elements 21. , 26, 27. Hereinafter, description of the same configuration as in the second embodiment will be omitted, and different points from the second embodiment will be mainly described.

  In FIG. 15, the first line of the polarizing filter 20e is configured by alternately arranging the minute polarizing plates 21 and the minute polarizing plates 26, and the second line is alternately arranged by the minute polarizing plates 27 and the minute polarizing plates 21. Are arranged side by side. In FIG. 16, the first row of the polarizing filter 20f is configured such that the minute polarizing plates 26 and the minute polarizing plates 27 are alternately arranged, and the second row is constituted only by the minute polarizing plate 21.

The polarizing element array 25e in FIG. 15 is configured such that minute polarizing plates are arranged in 2 rows × 2 columns. This is the same as the configuration of the second embodiment. However, the polarizing element arrays 25e and 25f are composed of three types of minute polarizing plates 21, 26 and 27. Specifically, the polarizing element array 25e includes two minute polarizing plates 21, one minute polarizing plate 26, and one minute polarizing plate 27. Further, the polarizing element array 25f in FIG. 16 includes a minute polarizing plate 21 for two pixels, one minute polarizing plate 26, and one minute polarizing plate 27.
Although four pieces of image information are acquired through the polarizing element arrays 25e and 25f, these four pieces of image information are three types of image information I to III. For example, there are two pieces of image information I, one piece of image information II, and one piece of image information III. One piece of polarization information 46 is calculated based on these four (three types) image information I to III. The calculated polarization information 46 is stored in the polarization information storage area as polarization information at the center of the position information of the image information I to III based on the calculation. Therefore, according to the present embodiment, it is possible to provide a polarization camera including a line sensor as an image sensor.

(Embodiment 7)
Next, the configuration of a polarization camera and an image processing method according to Embodiment 7 of the present invention will be described with reference to FIG. In the seventh embodiment, the polarizing filter 20g has the minute polarizing plates 21, 26, and 27 arranged in two rows and plural columns. This is the same as the configuration of the polarization filters 20e and 20f according to the sixth embodiment. Hereinafter, the description of the same configuration as in the sixth embodiment will be omitted, and the points different from the fifth embodiment will be mainly described.

  As shown in FIG. 17, the polarizing filter 20g according to the seventh embodiment is shifted in the row direction by half the pitch between the minute polarizing plates between the minute polarizing plate in the first row and the minute polarizing plate in the second row. Configuration. Since the pixels of the line sensor are also provided corresponding to the minute polarizing plates, they are shifted by a half pitch between the first row and the second row. The first and second rows of the polarization filter 20g are configured by periodically arranging minute polarizing plates 21, 26, and 27.

  Further, the polarizing element array 25g includes two minute polarizing plates 21 and 26 (or 26 and 27 or 27 and 21) continuous in one row and two minute polarizing plates 21 and 26 (or 26 and 27, or 27 and 21) and a minute polarizing plate 27 (or 21, or 26) positioned in the other row.

  Then, when the polarization information 47 is calculated for each of the three pieces of image information I to III acquired via one polarization element array 25g, the pitch of the pieces of polarization information 47 in the row direction becomes the same as that of the pieces of image information I to III. (The pitch between the minute polarizers 21, 26, and 27). That is, the density of the acquired polarization information 47 is about twice the density of the image information I to III. As described above, according to the present embodiment, it is possible to acquire polarization information with higher definition than in the other embodiments.

(Embodiment 8)
Next, a configuration of a polarization camera and an image processing method according to Embodiment 8 of the present invention will be described with reference to FIGS. In the polarization camera according to the present embodiment, as shown in FIG. 18, the polarization filter 20h has three types of minute polarizing plates 21, 26, and 27 arranged in three rows and plural columns. The three types of minute polarizing plates 21, 26, and 27 are periodically arranged in each row of the polarizing filter 20h. Also, three types of minute polarizing plates 21, 26, and 27 are provided in each row of the polarizing filter 20h.

  The polarizing element array 25h includes four types of micro polarizing plates 21, 26, and 27 arranged in two rows and two columns. One piece of polarization information 48 is calculated based on the four (three kinds) image information I to III acquired via the polarization element array 25h. The calculated polarization information 48 is stored in the polarization information storage unit as polarization information at the center of the position information of the four pieces of image information I to III based on the calculation.

  FIG. 19A shows a state in which the image information I to III and the polarization information 48 are superimposed at timing 1 indicating the first imaging. Here, the line sensor acquires the image information I to III for three lines from the first line to the third line. Based on the image information I to III, the polarization information 48 between the first and second rows and between the second and third rows can be acquired.

  FIG. 19B shows a state at timing 2 indicating the second imaging. Here, the line sensor acquires the image information I to III for three lines from the fourth line to the sixth line. Based on the image information I to III, the polarization information 48 between the fourth and fifth rows and between the fifth and sixth rows can be acquired. Further, in the image processing method according to the present embodiment, the polarization information 49 between the third and fourth rows is also acquired. By repeatedly performing this, the polarization camera in the present embodiment can acquire two-dimensional polarization information.

  Note that the polarizing filter of the polarizing camera according to Embodiments 1 to 8 has a mode in which minute polarizing plates are arranged in 1 row × multiple columns, 2 rows × multiple columns, or 3 rows × multiple columns. It is not limited to this mode. For example, the problem of the present invention can be solved even in a mode in which the polarizing filter has four or more rows × a plurality of columns of minute polarizing plates.

  Further, the polarization camera of the present invention may further include a color filter for acquiring color information. For example, as shown in FIG. 20, the line sensor and the polarizing filter are composed of six rows of pixels or minute polarizing plates 21 to 24, and color filters R, G, and B are superimposed on two rows, respectively. Then, if the image information is acquired every time the object to be conveyed moves by two lines, the polarization information and the color information can be acquired simultaneously. In addition to this configuration, color information and polarization information may be simultaneously obtained using a beam splitter such as a prism. Since a specific description of the calculation of the color information is publicly known, the detailed description is omitted.

  Note that the arrangement of the line sensor, the color filter, and the polarizing filter may be such that a polarizing filter may be provided between the line sensor and the color filter, or a color filter may be provided between the line sensor and the polarizing filter. Is also good.

  By the way, the first to eighth embodiments are modes in which the imaging target is moved, but the present invention is not limited to this mode. For example, a configuration in which the polarization camera is moved instead of moving the imaging target may be employed. If the polarization camera and the imaging target move relatively, two-dimensional image information and polarization information can be acquired.

  Although the minute polarizing plate of the polarizing camera according to Embodiments 1 to 8 is provided in correspondence with each pixel, the present invention is not limited to this mode. That is, the present invention is not limited to a mode in which one pixel is provided for one micro-polarizing plate, but may be, for example, a mode in which four pixels are provided for one micro-polarizing plate.

  Further, the polarization cameras according to Embodiments 1 to 8 are modes including the image processing device 30 having the storage unit 33, but the present invention is not limited to this mode. For example, a mode in which a storage device is separately provided in addition to the polarization camera and the image information and the polarization information are stored in the storage device may be adopted. In this case, the polarization information calculated by the calculation unit 32 of the image processing device 30 is processed as the polarization information at the center of the position information of the image information based on the calculation, and then stored in the storage device.

  Further, the present invention is not limited to the mode in which the minute polarizing plate is used. For example, as shown in 21, the polarizing filter 20 ′ may have a mode having a plurality of minute wavelength plates 51 to 54 and a polarizing plate 28 instead of the minute polarizing plate. The object of the present invention can be solved by configuring a plurality of polarizing element arrays 55 by arranging three or more types of microwave plates 51 to 54 having different optical axis directions from each other. Hereinafter, the details will be described.

  Since the microwave plates 51 to 54 have different optical axis directions, the light transmitted through the microwave plates 51 to 54 has different polarization states. The light transmitted through the four types of minute wavelength plates 51 to 54 enters the pixels 11 through the polarizing plate 28 having an arbitrary transmission axis direction. Since the polarizing plate 28 transmits only a component polarized in a specific direction, a difference is generated in the intensity of light transmitted through the polarizing plate 28. The intensity of this light is acquired by the line sensor 10 as image information. Then, polarization information can be calculated from the acquired image information.

  In the claims, the “polarizing element” is a minute polarizing plate or a combination of a minute wavelength plate and a polarizing plate. The "principal axis direction" is the direction of the transmission axis of the minute polarizing plate or the direction of the optical axis of the minute wavelength plate. The term “linear” includes not only one row and a plurality of columns but also two or more rows and a plurality of columns.

1, 2, 3 Polarizing camera 10 Line sensor 11 Pixel 20 Polarizing filter 21 to 24 Micro-polarizing plate 25 Polarizing element array 30 Image processing device W Imaging target

Claims (7)

A line sensor having a plurality of pixels arranged in a straight line,
A polarizing element array including a plurality of polarizing elements arranged in a straight line between the line sensor and the imaging target, and including at least three types of polarizing elements having different principal axis directions among the plurality of polarizing elements. And a polarizing filter having
An image processing device;
The image processing device,
While the line sensor and the polarizing filter are relatively moving with respect to the imaging target, while the line sensor repeatedly acquires image information of the imaging target through the polarizing filter,
It is configured to calculate the polarization information of the imaging target for each of a plurality of image information obtained via the polarizing element array ,
A polarization camera characterized in that it is configured to calculate polarization information between rows of the first image information and the second image information among two consecutively acquired image information . A line sensor having a plurality of pixels arranged in a straight line,
A polarizing element array including a plurality of polarizing elements arranged in a straight line between the line sensor and the imaging target, and including at least three types of polarizing elements having different principal axis directions among the plurality of polarizing elements. And a polarizing filter having
An image processing device;
The line sensor has at least 2 rows × a plurality of columns of pixels,
The polarizing filter has at least 2 rows × a plurality of columns of polarizing elements,
The image processing device,
While the line sensor and the polarizing filter are relatively moving with respect to the imaging target, while the line sensor repeatedly acquires image information of the imaging target through the polarizing filter,
It is configured to calculate the polarization information of the imaging target for each of a plurality of image information obtained via the polarizing element array ,
From the acquired at least two rows of image information, polarization information between the rows is calculated,
A polarization camera characterized in that it is configured to calculate polarization information between rows of the first image information and the second image information among two consecutively acquired image information . A line sensor having a plurality of pixels arranged in a straight line,
A polarizing element array including a plurality of polarizing elements arranged in a straight line between the line sensor and the imaging target, and including at least three types of polarizing elements having different principal axis directions among the plurality of polarizing elements. And a polarizing filter having
An image processing device;
The line sensor and the polarizing filter are each provided two by two,
The polarizing element array is composed of a total of three or more types of polarizing elements: a polarizing element arranged in one polarizing filter and a polarizing element arranged in the other polarizing filter;
The image processing device,
While the line sensor and the polarizing filter are relatively moving with respect to the imaging target, while the line sensor repeatedly acquires image information of the imaging target through the polarizing filter,
A polarization camera configured to calculate polarization information of an imaging target for each of a plurality of pieces of image information acquired via the polarizing element array. The polarizing element is provided corresponding to each pixel,
A plurality of image information acquired via the polarizing element array has a common contact point to each,
The polarization camera according to any one of claims 1 to 3, wherein the image processing device is configured to process the calculated polarization information as polarization information at the contact point. A line sensor having a plurality of pixels arranged in a straight line, and a polarizing filter having a plurality of polarizing elements arranged in a straight line between the line sensor and the imaging target, are relatively moved with respect to the imaging target. While repeatedly causing the line sensor to acquire the image information of the imaging object through the polarizing filter,
For each of a plurality of pieces of image information obtained through a polarizing element array configured by three or more kinds of polarizing elements having different principal axis directions, calculate the polarization information of the imaging target ,
An image processing method comprising calculating polarization information between rows of the first image information and the second image information among two consecutively acquired image information . A line sensor having a plurality of pixels arranged in a straight line, and a polarizing filter having a plurality of polarizing elements arranged in a straight line between the line sensor and the imaging target, are relatively moved with respect to the imaging target. While repeatedly causing the line sensor to acquire the image information of the imaging object through the polarizing filter,
For each of a plurality of pieces of image information obtained through a polarizing element array configured by three or more kinds of polarizing elements having different principal axis directions, calculate the polarization information of the imaging target ,
A line sensor having at least 2 rows × multiple columns of pixels, and a polarizing filter having at least 2 rows × multiple columns of polarizing elements,
The polarization information between the rows is calculated from the acquired image information of at least two lines, and the image information of the first time and the image information of the second time are calculated from the image information of two times continuously acquired. An image processing method for calculating polarization information between rows . The polarizing element is provided corresponding to each pixel,
A plurality of image information acquired via the polarizing element array has a common contact point to each,
The image processing method according to claim 5, wherein the calculated polarization information is processed as polarization information at the contact point.

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