SYSTEM FOR ASSESSING THE VISUAL APPEARANCE OF A REFLECTIVE SURFACE

Abstract

The invention refers to a system for assessing the visual appearance of a reflective surface. The system comprises a visual capturing device, adapted to capture at least one image focusing the reflective surface and at least one complementary image focusing a reflection of a test image reflected from the reflective surface. The system further comprises a data processing unit, capable of assessing visual appearance of the reflective surface by deriving objective quality parameters from the one image and the complementary image and by comparing the objective quality parameters with data of a database. The invention further refers to a method of assessing the visual appearance of a reflective surface using the system.

Claims

1. System for assessing the visual appearance of a reflective surface, comprising at least: a) a visual output device, adapted to display at least one test image onto the reflective surface; b) a visual capturing device, comprising an adjustable focal point position; wherein the adjustable focal point position is tunable to the reflective surface as one capturing position and to a complementary capturing position that allows for clear capturing of the test image as a reflection from the reflective surface; and wherein the visual capturing device is adapted to capture at least one image in the one capturing position and to capture at least one complementary image in the complementary capturing position; c) a data processing unit, comprising a database and an evaluation algorithm; wherein the database is equipped with data representing correlation between visual appearance of reflective reference surfaces and objective quality parameters; and wherein the evaluation algorithm is adapted to derive the objective quality parameters of the reflective surface from the one image and from the complementary image and to compare the objective quality parameters with the data of the database to assess visual appearance of the reflective surface.

2. System according to claim 1, wherein the data of the database ( ) comprise logical conjunction of: statistically confirmed results of target group interrogation regarding visual appearance of reflective reference surfaces; and objective quality parameters.

3. System according to claim 1, wherein the data processing unit comprises a control algorithm adapted to automatically control the steps of: a) displaying the at least one test image; b) tuning the adjustable focal point position to the one capturing position; c) capturing at least one image in the one capturing position; d) tuning the adjustable focal point position to the complementary capturing position; e) capturing at least one complementary image in the complementary capturing position; f) deriving objective quality parameters of the reflective surface from the one image and from the complementary image; g) comparing the objective quality parameters with the data of the database to assess visual appearance of the reflective surface; and h) outputting a result representative for visual appearance of the reflective surface.

4. System according to claim 3, wherein the control algorithm is adapted to: repeat the steps a) to g) using different test images; and combining results of all iterations of step g); and outputting a result representative for visual appearance of the reflective surface.

5. System according to claim 1, comprising a contact section adapted to position the system on the reflective surface.

6. System according to claim 1, wherein the visual capturing device comprises a mechanism, adapted to automatically tune the adjustable focal point position.

7. System according to claim 1, wherein the visual capturing device is adapted to allow for capturing of the one image in the one capturing position and the complementary image in the complementary capturing position so that an area of the reflective surface covered by the one image and the complementary image measures 20 mm by 10 mm to 30 mm by 20 mm.

8. System according to one claim 1, wherein the visual capturing device is adapted to tune the adjustable focal point position with an accuracy of at least +/0.3 mm.

9. System according to claim 1, wherein the adjustable focal point position is tunable in less than 500 ms.

10. System according to claim 1, wherein the visual capturing device comprises an image sensor comprising a pixel size of less than 50 m.

11. System according to claim 1, wherein the system is a hand-held unit.

12. System according to claim 11, wherein dimensions of the system measure not more than 200 mm by 150 mm by 60 mm and/or a weight of the system measures not more than 1.5 kg and/or the system comprises an energy source.

13. System according to claim 1, wherein the system comprises at least one of the following elements: a display as a feature of the visual output device; a camera as a feature of the visual capturing device; a microprocessor as a feature of the data processing unit; a graphical user interface; means of wireless communication.

14. Method of assessing the visual appearance of a reflective surface of a vehicle, wherein a system according to claim 1.

15. Method according to claim 14, comprising at least the step of: a) positioning of a contact section of the system on the reflective surface of the vehicle; b) displaying of at least one test image onto the reflective surface by a visual output device of the system; c) tuning of an adjustable focal point position of a visual capturing device of the system to the reflective surface as one capturing position; d) capturing of at least one image in the one capturing position by the visual capturing device; e) tuning of the adjustable focal point position to a complementary capturing position that allows for clear capturing of the test image as a reflection from the reflective surface; f) capturing of at least one complementary image in the complementary capturing position; g) deriving of objective quality parameters of the reflective surface from the one image and from the complementary image by an evaluation algorithm of a data processing unit; and h) comparing of the objective quality parameters with data of a database of the a data processing unit representing correlation between visual appearance of reflective reference surfaces and the objective quality parameters by the evaluation algorithm to assess visual appearance of the reflective surface.

Description

[0092] The invention is further described by the following embodiments in combination with the Figures referring to the respective embodiment.

[0093] The Figures illustrate the following:

[0094] FIG. 1 shows an overview of objective quality parameters acting as influencing factors on the visual appearance of an item (state of the art);

[0095] FIG. 2A shows a preferred embodiment of a system for assessing the visual appearance of a reflective surface according to the invention;

[0096] FIGS. 2B and 2C each show a preferred embodiment of a method of assessing the visual appearance of a reflective surface of a vehicle, wherein a system according to the invention is used; and

[0097] FIG. 3 shows preferred embodiment of a system for assessing the visual appearance of a reflective surface according to the invention.

[0098] FIG. 1 illustrates an overview of objective quality parameters acting as influencing factors on the visual appearance of an item according to state of the art. Visual appearance 10 is influenced by a color 12 as a first one of the objective quality parameters 88 and by a gloss 14 of the item. The gloss 14 of the item is influenced by a number of influencing factors that are observable by observing a surface of the item itself, which means focusing the surface of the item 16. These influencing factors are included in a waviness 18 of the surface of the item and are observable at different orders of magnitude of the wavelength. The major orders of magnitude are commonly referred to as longwave spectrum 20 and shortwave spectrum 22. The longwave spectrum 20 reveals a second one of the objective quality parameters 88 commonly referred to in the art as orange peel 24. The shortwave spectrum 22 reveals a third one of the objective quality parameters 88 commonly referred to in the art as a microwaviness 26. The gloss 14 of the item is further influenced by influencing factors that are detectable by observing an image that is reflected by the surface of the item. This means focusing a reflection of the image 28. Here, the DOI 30 of the image can be determined. It incorporates three more objective quality parameters 88 which are commonly referred to in the art as specular gloss 32, haze 34 and clarity 36 of the reflected image.

[0099] FIG. 2 illustrates a preferred embodiment of a system for assessing the visual appearance of a reflective surface according to the invention along with a preferred embodiment of a method of assessing the visual appearance of a reflective surface of a vehicle, wherein a system according to the invention is used.

[0100] For reasons of clarity, the content of FIG. 2 is allocated to FIGS. 2A, 2B and 2C.

[0101] FIG. 2A primarily emphasizes aspects of the design of the system, FIGS. 2B and 2C primarily emphasize aspects of the method. However, FIG. 2A, needs to be considered as a unit with FIGS. 2B and 2C illustrating alternatives regarding test images 64 displayed onto the reflective surface 50, represented by an alternative single test image 66 that is illustrated in FIGS. 2B and 2C.

[0102] In the preferred embodiment of the system 38 shown in FIG. 2A a visual output device 42 is shown. The visual output device 42 comprises a display 44. The visual output device 42 is adapted to display a variety of different test images 64. The display 44 is a high brightness LCD screen in this embodiment. As further shown in FIG. 2A, the visual output device 42 is adapted to display the test images 64 onto the reflective surface 50. Displaying the at least one test image 66 onto the reflective surface 50 by the visual output device 42 matches step b) of the method of the invention. Just as an example, the one test image 66, displayed onto the reflective surface in step b) of the method of the invention, is illustrated in FIGS. 2B and 2C with FIG. 2B showing the one test image 66 as a number of squares while FIG. 2C alternatively shows the one test image 66 as a number of lines.

[0103] The system 38 shown in FIG. 2A further comprises a visual capturing device 52. The visual capturing device 52 has an adjustable focal point position 54. The adjustable focal point position 54 is adjustable in a range from a point P.sub.0 to P.sub.2. P.sub.0 marks a point closest to the visual capturing device 52, the adjustable focal point position 54 can be tuned to. P.sub.0 can be defined at any position in an interior of the system 38. P.sub.0 is predominantly determined by functional boundaries of the following features: a mechanism 56 of the system 38, adapted to automatically tune the adjustable focal point position 54, and by specifications of a lens system 58, adapted to capture images. Point P.sub.1 marks a point where the adjustable focal point position 54 hits the reflective surface 50, or in other words where it hits a plain representing the reflective surface 50. P.sub.2 lies in a distance D measured from P.sub.1 to P.sub.2 D is equal to a distance from the display 44 of the visual output device 42 to P.sub.1. The distance from the display 44 of the visual output device 42 to P.sub.1 can be chosen by the person skilled in the art according to technical specifications of the system 38, taking into account that a sufficiently large area 74 on the reflective surface 50 needs to be assessable by the system 38.

[0104] The adjustable focal point position 54 tuned to P.sub.1 represents one capturing position 60 of the visual capturing device 52. The adjustable focal point position 54 tuned to P.sub.2 represents a complementary capturing position 62.

[0105] Each one of the test images 64 displayed onto the reflective surface 50, according to step b) of the method of the invention, is mirrored as a reflection 68 in the direction of the visual capturing device 52. Only for reasons of clarity the arrows in FIG. 2A indicating the reflections 68 and the adjustable focal point position 54 are illustrated displaced from one another.

[0106] The visual capturing device 52 is adapted to tune the adjustable focal point position 54 to the one capturing position 60 and to capture at least one image 70 in the one capturing position 60. This represents steps c) and d) of the method of the invention. Further, the visual capturing device 52 is adapted to tune the adjustable focal point position 54 to the complementary capturing position 62 and to capture at least one complementary image 72 in the complementary capturing position 62. This represents step e) and f) of the method of the invention. The one image 70 and the complementary image 72 captured, show the area 74 of the reflective surface 50 and the reflection 68. This is accomplished for each one of the test images 64 reaching the visual capturing device 52 as a reflection 68. As an example, one image 70 and one complementary image 72 as captured in steps d) and f) of the method of the invention are illustrated in FIGS. 2B and 2C. The image 70 and complementary image 72 in each one of the FIGS. 2B and 2C correlate to the respective one test image 66. Here, the reflective surface 50 in step d) in FIG. 2C is also shown in greater detail than the reflective surface 50 in step d) in FIG. 2B.

[0107] The system 38 shown in FIG. 2A comprises a data processing unit 76 an evaluation algorithm 80. The evaluation algorithm 80 is adapted to derive objective quality parameters 88 of the reflective surface 50 from the one image 70, which are color 12, orange peel 24 and microwaviness 26 of the reflective surface 50. The evaluation algorithm 80 is further adapted to derive objective quality parameters 88 of the reflective surface 50 from the complementary image 72, which are color 12, specular gloss 32, haze 34 and clarity 36 of the reflection 68 of the at least one test image 66 reflected by the reflective surface. This represents step g) of the method of the invention. This step g) is illustrated in FIG. 2B. Just as an example, the evaluation algorithm 80 derives the orange peel 24 of the reflective surface 50 from the one image 70 and derives the clarity 36 of the reflection 68 of the test image 66 from the complementary image 72. The evaluation algorithm 80 quantifies characteristics of these objective quality parameters 88 on a scale from 0 to 10. In this example, the orange peel 24 is characterized by a value of 4 and the clarity 36 is characterized by a value of 3. Analogically, the evaluation algorithm 80 does so for the color 12, the microwaviness 26, the specular gloss 32 and the haze 34 as additional objective quality 88 parameters.

[0108] The data processing unit 76 of the system 38 shown in FIG. 2A comprises a database 78. The database 78 is equipped with data 82 representing correlation between visual appearance of reflective reference surfaces and the objective quality parameters 88. As shown in FIG. 2B, the characteristics of the objective quality parameters 88 from step g) of the method of the invention are compared with the data 82 by the evaluation algorithm 80 in step h) of the method of the invention. Just as an example, the characteristics of the objective quality parameters 88 are logically interlinked in step g) and the specific combination is matched with a corresponding visual appearance of a reflective reference surface in step h). In the given example, this leads to a value of 2 on a scale for the visual appearance included in the data 82. For example a value of 2 could represent an average visual appearance from a proficient customer's point of view. A value of 1 could represent a good visual appearance and a value of 3 could represent a bad visual appearance.

[0109] A result is then given out by the system, for example by a graphical user interface 86. The result could be that the reflective surface 50 features an average/normal visual appearance from a proficient customer's point of view.

[0110] FIG. 3 illustrates another preferred embodiment of a system for assessing the visual appearance of a reflective surface according to the invention. The system is based on the system 38 in FIG. 2A. Therefore, the same reference signs are applicable.

[0111] In this embodiment the system 38 is designed as a hand-held unit 40. The hand-held unit 40 comprises a case-like design. The hand-held unit 40 features all important aspects of the system 38 of the invention: the visual output device 42, comprising an internal display 44, the visual capturing device 52, which is an machine camera in this embodiment and the data processing unit 76. The data processing unit is an industrial micro computer in this embodiment and comprises the database 78, the evaluation algorithm 80 and a control algorithm 90. The control algorithm 90 is adapted to control all functionalities of the hand-held unit 40 which means functionalities of the system 38. The hand-held unit 40 comprises a graphical user interface 86 with an input and output function. Further, there is a measurement window 46.

[0112] Through the measurement window 46 light is able to enter or to leave an interior of the hand-held unit 40. The hand-held unit 40 comprises a contact section 48. The contact section 48 allows for positioning the hand-held unit 40, which means the system 38, on a reflective surface 50 as indicated in FIG. 2A. Preferably the hand-held unit 40 comprises means of wireless communication to allow for detection of workpieces featuring the reflective surface 50.

LIST OF REFERENCE NUMBERS

[0113] 10 visual appearance [0114] 12 color [0115] 14 gloss [0116] 16 focusing the surface of the item [0117] 18 waviness [0118] 20 longwave spectrum [0119] 22 shortwave spectrum [0120] 24 orange peel [0121] 26 microwaviness [0122] 28 focusing a reflection of the image [0123] 30 DOI [0124] 32 specular gloss [0125] 34 haze [0126] 36 clarity [0127] 38 system [0128] 40 hand-held unit [0129] 42 visual output device [0130] 44 display [0131] 46 measurement window [0132] 48 contact section [0133] 50 reflective surface [0134] 52 visual capturing device [0135] 54 adjustable focal point position [0136] 56 mechanism [0137] 58 lens system [0138] 60 one capturing position [0139] 62 complementary capturing position [0140] 64 test images [0141] 66 test image [0142] 68 reflection [0143] 70 one image [0144] 72 complementary image [0145] 74 area [0146] 76 data processing unit [0147] 78 database [0148] 80 evaluation algorithm [0149] 82 data [0150] 86 graphical user interface [0151] 88 objective quality parameters [0152] 90 control algorithm [0153] D distance [0154] P.sub.0 point [0155] P.sub.1 point [0156] P.sub.2 point