TWI659392B - Coding method and system through gray-code for structured-light 3d scanner - Google Patents

Abstract

The invention provides a method and a system for three-dimensional measurement of color structured light combined with Gray coding, in which a pattern arrangement step arranges patterns of the maximum frequency and the minimum frequency in a plurality of Gray coding patterns. The pattern combining step corresponds to combining the first Gray coded pattern and the second Gray coded pattern to generate a Gray combined pattern. The projection measurement step projects a gray combined pattern onto the object to be measured to form a deformed gray combined pattern, and then captures the pattern to calculate and output a three-dimensional model. In this way, the combination of the pattern with the highest frequency and the lowest frequency and the combination of the pattern with the sub-high frequency and sub-low frequency are used to avoid the problem of fringe blur caused by too high frequency. Can double the time and still have high accuracy.

Description

Three-dimensional measurement method and system of color structured light combined with Gray coding

The invention relates to a three-dimensional measurement method and system for color structured light, and more particularly to a three-dimensional measurement method and system for color structured light combined with Gray coding, which can shorten the measurement time and effectively solve the problem of color crosstalk.

At present, the coding technology commonly used on the market for more common and higher-precision 3D scanning instruments is Gray coding. Gray coding has the advantages of simplicity, high stability, high accuracy, and wide application. This coding technology is time coding. It is necessary to project patterns one by one and capture photos one by one according to time, so the number of coded images projected during the entire process will affect the overall speed.

In addition, in the process of 3D model reconstruction, the Gray coded pattern can be combined with a projector to project a known pattern on the object to be measured, and then photographed with a camera to calculate a three-dimensional model of the object to be measured. Although Gray coding is widely used in the construction of many three-dimensional models, under the requirements of high accuracy and high accuracy, its measurement time is still too long and the computing efficiency is still insufficient. Therefore, relevant industries are seeking their solutions. .

Therefore, an object of the present invention is to provide a three-dimensional measurement method of color structured light combined with Gray coding and a system thereof, which utilize a combination of patterns of the highest frequency and the lowest frequency and a combination of patterns of the second high frequency and the low frequency to avoid excessive frequency The short-axis effect and the blurring of the stripes cause the number of projections to be half of the Gray code, so that the overall measurement time can be doubled, and still have high accuracy, in order to solve the measurement time of conventional technologies. Disadvantages and problems of too long and high frequency fringes that affect decoding accuracy.

According to an embodiment of the present invention, a three-dimensional measurement method of color structured light combined with Gray coding is provided for measuring a three-dimensional model of an object to be measured. The 3D color structured light measurement method combining gray coding includes a step of selecting a projection order, a step of generating a gray coding pattern, a step of arranging patterns, a step of pattern combining, and a step of projecting measurement. The step of selecting a projection order is to select a projection order value . The step of generating gray coding patterns is to generate a plurality of gray coding patterns. The number of gray coding patterns is equal to the value of the projection level. Each gray coding pattern is arranged in a striped pattern. In addition, the step of arranging patterns is to arrange the first gray coding pattern having a first fringe frequency and the second gray coding pattern having a second fringe frequency among the gray coding patterns, and the first fringe frequency is greater than the second fringe frequency. The pattern combining step corresponds to combining the first Gray coding pattern and the second Gray coding pattern to generate a Gray bonding pattern. The Gray bonding pattern has a plurality of colors. Furthermore, the projection measurement step is to project a gray combination pattern onto the object to be tested to form a deformed gray combination pattern, and then extract a colored gray combination pattern on the surface of the object to be measured to calculate and output a three-dimensional model of the object to be measured.

In this way, the three-dimensional measurement method of color structured light combined with gray coding according to the present invention uses gray coding patterns to be paired one by one. The combined gray bonding pattern uses specific colors to replace black and white colors, so it can be used with fewer number of pattern sheets. Hiding more encoding information, which increases encoding speed and shortens encoding time.

Other examples of the foregoing embodiment are as follows: each of the foregoing Gray coding patterns has a fringe frequency. The first fringe frequency is the maximum of these fringe frequencies, and the second fringe frequency is the minimum of these fringe frequencies. In addition, the aforesaid arrangement pattern step can arrange a third Gray coding pattern having a third fringe frequency and a fourth Gray coding pattern having a fourth fringe frequency in the Gray coding pattern. The first fringe frequency is greater than the third fringe frequency, the third fringe frequency is greater than the fourth fringe frequency, and the fourth fringe frequency is greater than the second fringe frequency. In addition, the aforementioned pattern combining step may correspondingly combine the third Gray coding pattern and the fourth Gray coding pattern to generate another Gray combining pattern, and the other Gray combining pattern has a plurality of colors. Furthermore, the aforementioned projection measurement step may project another Gray combination pattern onto the object to be measured to form another deformed Gray combination pattern, and then capture another deformed Gray combination pattern displayed on the surface of the object to be measured, and use the deformation The gray combination pattern is combined with another deformed gray combination pattern to calculate and output a three-dimensional model of the object to be measured. In addition, the aforementioned colors may include black, cyan, and purple. The range covered by black in the gray combination pattern forms a first color region; the range covered by cyan in the gray combination pattern forms a second color region; the range covered by purple in the gray combination pattern forms a third color region. The first color region, the second color region, and the third color region do not overlap each other. In addition, the first Gray code pattern and the second Gray code pattern pass. Lightning patterns can correspond to overlap. The first color region of the gray combination pattern corresponds to the first region of the first gray coding pattern, and the first region of the first gray coding pattern is black. The second color region of the gray combination pattern corresponds to the second region of the first gray coding pattern and the third region of the second gray coding pattern. The second area of the first Gray coded pattern is white and the third area of the second Gray coded pattern is black. The third color region of the gray combination pattern corresponds to the fourth region of the first gray coding pattern and the fifth region of the second gray coding pattern. The fourth region of the first gray coding pattern and the fifth region of the second gray coding pattern are both present. white.

In addition, the aforementioned colors may include black, red, green, and blue. The range covered by black in the gray combination pattern forms the first color region; the range covered by red in the gray combination pattern forms the second color region; the range covered by green in the gray combination pattern forms the third color region; The range forms a fourth color area. The first color region, the second color region, the third color region, and the fourth color region do not overlap each other. Furthermore, the first Gray coding pattern, the second Gray coding pattern, and the Gray combination pattern correspond to overlap. The first color region of the gray combination pattern corresponds to the first region of the first gray coding pattern and the second region of the second gray coding pattern. The first region of the first gray coding pattern and the second region of the second gray coding pattern are both present. black. The second color region of the gray combination pattern corresponds to the third region of the first gray coding pattern and the fourth region of the second gray coding pattern. The third region of the first gray coding pattern is black and the fourth region of the second gray coding pattern. White. The third color region of the gray combination pattern corresponds to the fifth region of the first gray coding pattern and the sixth region of the second gray coding pattern, and the first gray coding The fifth region of the pattern is white and the sixth region of the second Gray coding pattern is black. The fourth color region of the gray combination pattern corresponds to the seventh region of the first gray coding pattern and the eighth region of the second gray coding pattern. The seventh region of the first gray coding pattern and the eighth region of the second gray coding pattern are present. white. In addition, the aforementioned projection order value may be 9 or more. The aforementioned three-dimensional measurement method of color structured light combined with Gray coding may include a complementary operation step which calculates and generates one of the complementary Gray coding patterns corresponding to the first Gray coding pattern, and the complementary Gray coding pattern and the first Gray coding. The colors of the patterns are complementary. The pattern combining step corresponds to combining the complementary Gray coded pattern and the second Gray coded pattern to generate a complementary Gray coded pattern, and then the first Gray code is restored according to a complementary intensity value of the complementary Gray coded pattern and an intensity value of the Gray coded pattern. pattern.

According to another embodiment of the present invention, a three-dimensional color structured light measurement system incorporating gray coding is provided, which includes a projection order selection module, a gray coding pattern generation module, a pattern arrangement module, and a projection measurement module. group. The projection order selection module is used to select the projection order value. The gray code pattern generating module signal is connected to the projection order selection module. This gray code pattern generating module is used to generate a gray code pattern. The signal of the pattern arrangement module is connected to the gray code pattern generation module. The pattern arrangement module is used to arrange the first gray code pattern and the second gray code pattern. Furthermore, the pattern combining module signals are connected to the pattern arranging module, and the pattern combining module correspondingly combines the first Gray coding pattern and the second Gray coding pattern to generate a Gray bonding pattern having a plurality of colors. The projection measurement module signal is connected to the pattern combination module. The projection measurement module is used to project the gray combination pattern on the object to be measured to form a deformed gray combination map. And capture a colored deformed gray combination pattern on the surface of the object to be measured to calculate and output a three-dimensional model of the object.

Thus, the three-dimensional color structured light measurement system incorporating gray coding of the present invention uses the combination of the highest frequency and the lowest frequency pattern and the combination of the sub-high frequency and the sub-low frequency pattern to avoid the problem of fringe blur caused by too high frequency. The number of sheets is half of the Gray code, the overall measurement time can be doubled, and still has high accuracy. In addition, through the specific complementary restoration method and the zero-crossing point finding threshold, the boundary of the stripes can be accurately found even when the graphics have color crosstalk and when using ordinary cameras.

Other examples of the foregoing embodiment are as follows: each of the aforementioned gray coding patterns has a fringe frequency, the first fringe frequency is a maximum value of these fringe frequencies, and the second fringe frequency is a minimum value of the fringe frequencies. The aforementioned pattern arranging module arranges a third Gray coding pattern having a third fringe frequency and a fourth Gray coding pattern having a fourth fringe frequency in the Gray coding pattern. The first fringe frequency is greater than the third fringe frequency, the third fringe frequency is greater than the fourth fringe frequency, and the fourth fringe frequency is greater than the second fringe frequency. Furthermore, the aforementioned pattern combining module may correspondingly combine the third Gray coding pattern and the fourth Gray coding pattern to generate another Gray combining pattern, and the other Gray combining pattern has a plurality of colors. The aforementioned projection measurement module projects another Gray combination pattern onto the object to be measured to form another deformed Gray combination pattern, and then captures another deformed Gray combination pattern of the color presented on the surface of the object to be measured, and uses the deformed Gray combination pattern Combine the pattern with another deformed Gray to calculate and output a three-dimensional model of the object to be measured. The aforementioned colors may include black, cyan, and purple. Gray combines a range covered by black in the pattern to form a first color area; Gray The range covered by cyan in the combination pattern forms a second color region; the range covered by purple in the Gray pattern forms a third color region. The first color region, the second color region, and the third color region do not overlap each other. In addition, the first Gray coding pattern, the second Gray coding pattern, and the Gray combination pattern correspond to overlap. The first color region of the gray combination pattern corresponds to the first region of the first gray coding pattern, and the first region of the first gray coding pattern is black. The second color region of the gray combination pattern corresponds to the second region of the first gray coding pattern and the third region of the second gray coding pattern. The second region of the first gray coding pattern is white and the third of the second gray coding pattern is white. The area is black. The third color region of the gray combination pattern corresponds to the fourth region of the first gray coding pattern and the fifth region of the second gray coding pattern. The fourth region of the first gray coding pattern and the fifth region of the second gray coding pattern are both present. white.

100, 100a‧‧‧Three-dimensional measurement method of color structured light combined with Gray coding

101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 101D, 110D

103a, 104a‧‧‧ Complementary Gray coding pattern

210, 220, 230, 240, 250, 260, 270, 210a, 220a, 230a, 240a, 250a

260a, 270a‧‧‧Complementary Gray combination pattern

300‧‧‧Color structured light combined with Gray coding 3D measurement system

S11, S21‧‧‧‧Selection of projection order

S12, S22‧‧‧Generate Gray code pattern steps

S13, S23‧‧‧‧Arrange pattern steps

S14, S25‧‧‧ pattern combination steps

S15, S26‧‧‧‧Projection measurement steps

S24‧‧‧ Complementary operation steps

N‧‧‧ projection value

C1‧‧‧ first color area

C2‧‧‧second color area

C3‧‧‧ third color area

310‧‧‧Projection Order Selection Module

320‧‧‧Gray coding pattern generation module

330‧‧‧ Pattern Arrangement Module

340‧‧‧Pattern complementary module

350‧‧‧ Pattern Combination Module

360‧‧‧Projection measurement module

R1‧‧‧First Zone

R2‧‧‧Second Zone

R3‧‧‧ third zone

R4‧‧‧Fourth Zone

R5‧‧‧Fifth District

R‧‧‧ Observation area

BP, RP + RIP‧‧‧ dashed line

BIP, GP + GIP‧‧‧Solid line

FIG. 1 is a schematic diagram illustrating a three-dimensional measurement method of color structured light combined with Gray coding according to an embodiment of the present invention.

FIG. 2A is a schematic diagram showing the combination of the first to tenth-order gray coding patterns of FIG. 1 in pairs.

FIG. 2B is a schematic diagram illustrating the seventh-order Gray code pattern to the tenth-order Gray code pattern in FIG. 2A.

FIG. 3 is a schematic diagram showing a Gray combination pattern in which the Gray coding patterns in FIG. 2A are combined in pairs.

FIG. 4 is a first-order to fourth-order Gray edition of another embodiment of the present invention. Schematic illustration of a pair of code patterns.

FIG. 5 is a schematic diagram illustrating a three-dimensional measurement method of color structured light combined with Gray coding according to another embodiment of the present invention.

FIG. 6 is a schematic diagram showing the high-frequency Gray coding pattern in FIG. 4 replaced with a complementary pattern.

FIG. 7 is a schematic diagram showing the Gray combination pattern generated by combining the high-frequency Gray coding pattern of FIG. 2A with a complementary pattern and combining the low-frequency Gray coding pattern.

FIG. 8 is a partial schematic diagram of the Gray combination pattern in the first column of FIG. 3.

FIG. 9 is a schematic diagram showing the intensity variation of the high-frequency fringe blue plate in the observation area of FIG. 8 and its complementary diagram.

Fig. 10 is a schematic diagram showing the changes after the red and green intensities of the low-frequency stripes in the observation area of Fig. 8 and its complementary diagram are added.

FIG. 11 shows the higher-frequency Gray coding pattern obtained by the reduction method in FIG. 8.

FIG. 12 shows the lower-frequency Gray coding pattern obtained by the reduction method in FIG. 8.

FIG. 13 is a schematic diagram showing a three-dimensional measurement system of color structured light combined with Gray coding according to an embodiment of the present invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. For the sake of clarity, many practical details will be described in the following description. Bright. It should be understood, however, that these practical details should not be used to limit the invention. That is, in some embodiments of the present invention, these practical details are unnecessary. In addition, in order to simplify the drawings, some conventional structures and components will be shown in the drawings in a simple and schematic manner; and repeated components may be represented by the same number.

Please refer to FIGS. 1, 2A, 2B, and 3 together. FIG. 1 is a schematic diagram illustrating a three-dimensional measurement method 100 for color structured light combined with Gray coding according to an embodiment of the present invention. FIG. 2A is a schematic diagram showing the combination of the first-order Gray code pattern 101 to the tenth-order Gray code pattern 110 in FIG. 1. FIG. 2B is a schematic diagram illustrating the seventh-order Gray code pattern 107 to the tenth-order Gray code pattern 110 in FIG. 2A. FIG. 3 is a schematic diagram showing the Gray combination patterns 210, 220, 230, 240, and 250 after the Gray code patterns 101 to 110 of FIG. 2A are combined in pairs. As shown in the figure, the gray structure-coded three-dimensional measurement method 100 for color structured light is used to measure a three-dimensional model of an object to be measured. The gray structure-coded three-dimensional measurement method for color structured light 100 includes selecting a projection order step S11, generating Gray coding pattern step S12, arrangement pattern step S13, pattern combining step S14, and projection measurement step S15.

Step S11 of selecting a projection order is to select a projection order value N. The projection order value N is greater than or equal to 9, and the projection order value N in this embodiment is equal to 10.

Step S12 of generating gray code patterns is to generate ten gray code patterns 101 to 110, and the number of gray code patterns 101 to 110 and the projection order value N are both 10. Each Gray code pattern 101 to 110 is in a stripe pattern arranged at intervals. In detail, the gray coding patterns 101 to 110 are arranged in black and white intervals. Striated. The projection order value N corresponding to the gray code patterns 101 to 110 will affect the number of point clouds and the accuracy of the reconstruction. The number of point clouds represents the amount of three-dimensional point cloud data used to reconstruct a three-dimensional model of the object to be measured. In practice, the projection order value N needs to be greater than or equal to 9 to achieve the required reconstruction accuracy requirements. Projection to the Nth order will require N patterns, and if the thinnest stripes in the Nth pattern are X pixels ( pixels), the size of the Nth pattern is X‧2N pixels. If this pattern is enlarged twice, the thinnest stripe will become 2‧X pixels, and the resolution is equivalent to the N-1th sheet before the enlargement, and it is also equivalent to the projection to the N-1th order.

The arranging pattern step S13 is to arrange the gray coding patterns 101 to 110, and the gray coding patterns 101 to 110 respectively represent the first-order gray coding patterns 101 to the tenth-order gray coding patterns 110. In detail, each gray coding pattern 101 to 110 has a fringe frequency, wherein the gray frequency of the gray coding pattern 101 is a minimum value of all gray coding patterns 101 to 110, and the gray frequency of the gray coding pattern 110 is all gray coding patterns. The maximum value of 101 ~ 110 fringe frequency. The fringe frequencies of the Gray code patterns 101 to 110 are in order from small to large. For example, in the two columns on the left of Figure 2A, the fringe frequency of the gray code pattern 110 is greater than the fringe frequency of the gray code pattern 109, the fringe frequency of the gray code pattern 109 is greater than the fringe frequency of the gray code pattern 102, and the gray code pattern 102 The fringe frequency of is greater than the fringe frequency of the Gray coding pattern 101.

The pattern combining step S14 is to combine the Gray coded patterns 101, 102, 103, 104, and 105 with the Gray coded patterns 110, 109, 108, 107, and 106 respectively to generate the Gray coded patterns 210, 220, 230, 240, and 250 respectively. Five Gray combined patterns 210, 220, 230, Both 240 and 250 have three colors. In detail, the pattern combining step S14 corresponds to combining the first-order Gray coding pattern 101 and the tenth-order Gray coding pattern 110 to generate a Gray coupling pattern 210; the second-order Gray coding pattern 102 corresponding to combining the ninth-order Gray coding pattern 109 The gray combination pattern 220 is generated; the third-order gray coding pattern 103 is correspondingly combined with the eighth-order gray coding pattern 108 to generate a gray combination pattern 230; the fourth-order gray coding pattern 104 is corresponding to the seventh-order gray coding pattern 107 to generate gray combination Pattern 240; the fifth-order Gray coding pattern 105 is correspondingly combined with the sixth-order Gray coding pattern 106 to generate a Gray bonding pattern 250. The gray combination patterns 210, 220, 230, 240, and 250 each have three colors and are color graphics. The three colors in this embodiment are black, cyan, and purple, respectively. Each gray combination pattern 210, 220, 230, 240, 250 covers the range covered by black in the first color region C1, the range covered by cyan in the pattern forms the second color region C2, and the range covered by purple in the pattern forms the third color region C3 . The first color region C1, the second color region C2, and the third color region C3 do not overlap each other.

The projection measurement step S15 is to project the gray combined patterns 210, 220, 230, 240, and 250 onto the object to be measured to form five deformed gray combined patterns, and then capture the five deformed gray combined patterns on the surface of the object to be colored. To calculate and output a three-dimensional model of the object to be measured. In this way, the present invention combines the Gray code pattern 101 with the lowest frequency with the Gray code pattern 110 with the highest frequency, and combines the Gray code pattern 102 with the lowest frequency and the Gray code pattern 109 with the highest frequency. Similarly, the other Gray code patterns 103, 108, Gray code patterns 104, 107, and Gray code patterns 105 and 106 correspondingly complete the combination of five sets of high and low frequency patterns to generate shadow gray pattern 210, 220, 230, 240 and 250 are shown in Fig. 2A and Fig. 3. In this way, the present invention uses high and low frequency gray coding patterns 101 to 110 to be combined in pairs, and the combined gray bonding patterns 210, 220, 230, 240, and 250 use specific colors to replace black and white colors, so fewer patterns can be used. The number of pages introduces more encoding information, which greatly increases the encoding speed and shortens the encoding time.

Please refer to FIG. 1 and FIG. 4 together. FIG. 4 is a schematic diagram showing the combination of the first to fourth-order Gray coding patterns 101 to 104 according to another embodiment of the present invention. This embodiment is a combination of the first-order Gray coded pattern 101 and the fourth-order Gray coded pattern 104 to generate a Gray-combined pattern 260, and the second-order Gray coded pattern 102 and the third-order Gray coded pattern 103 to generate Gray combined pattern 270. When the first-order Gray coded pattern 101, the fourth-order Gray coded pattern 104, and the Gray combined pattern 260 overlap, the first color region C1 (black) of the gray combined pattern 260 corresponds to the first region of the fourth-order Gray coded pattern 104. R1, and the first region R1 of the fourth-level Gray coding pattern 104 is black. In addition, the second color region C2 (cyan) of the gray combination pattern 260 corresponds to the second region R2 of the fourth-order Gray coding pattern 104 and the third region R3 of the first-order Gray coding pattern 101. The second region R2 is white and the third region R3 of the first-level Gray coding pattern 101 is black. Furthermore, the third color region C3 (purple) of the Gray combination pattern 260 corresponds to the fourth region R4 of the fourth-order Gray coding pattern 104 and the fifth region R5 of the first-order Gray coding pattern 101, and the fourth-order Gray coding pattern The fourth region R4 of 104 and the fifth region R5 of the first-level Gray coding pattern 101 are both white, and the color distribution is shown in Table 1. Similarly, when the second-order Gray code pattern 102, the third-order Gray code pattern 103, and the Gray combination pattern 270 overlap, the first A color region C1 (black) corresponds to the first region R1 of the third-level Gray coding pattern 103, and the first region R1 of the third-level Gray coding pattern 103 is black. The second color region C2 (cyan) of the gray combination pattern 270 corresponds to the second region R2 of the third-order Gray coding pattern 103 and the third region R3 of the second-order Gray coding pattern 102, The two regions R2 are white and the third region R3 of the second-order Gray coding pattern 102 is black. In addition, the third color region C3 (purple) of the Gray combination pattern 270 corresponds to the fourth region R4 of the third-order Gray coding pattern 103 and the fifth region R5 of the second-order Gray coding pattern 102, and the third-order Gray coding pattern 103 The fourth region R4 and the fifth region R5 of the second-level Gray coding pattern 102 are both white.

It can be seen from FIG. 2A that the projection order value N of the present invention is 10, and if the color coding of the tenth order of gray coding is to be projected, the first order gray coding pattern 101 to the tenth order gray coding pattern 110 are required according to the present invention The combined gray-coded 3D color structured light measurement method 100 combines two of them in groups. In addition, if you only want to project the 9th-order color coding combined with Gray coding, you still need the first-order Gray coding pattern 101 to the tenth-order Gray coding pattern 110. The three-dimensional color structured light measurement method combining gray coding according to the present invention 100 Combine two of them into groups, and then double the five Gray combined patterns 210, 220, 230, 240, 250 obtained by combining to double the stripes, so you can get the ninth order thickness Stripes pattern. Therefore, the present invention makes use of double To make the stripes thicker, we can solve the problem that odd-numbered patterns cannot be paired one by one when the order is odd.

Please refer to FIG. 1 and FIGS. 4 to 7 together. FIG. 5 is a schematic diagram illustrating a three-dimensional measurement method 100a of color structured light combined with Gray coding according to another embodiment of the present invention. Fig. 6 is a schematic diagram showing the high-frequency Gray coding patterns 104 and 103 in Fig. 4 replaced with complementary patterns. Figure 7 shows the gray code generated by combining the high-frequency Gray code patterns 110, 109, 108, 107, and 106 in Figure 2A with complementary patterns and combining the low-frequency Gray code patterns 101, 102, 103, 104, and 105. Schematic diagrams of bonding patterns 210a, 220a, 230a, 240a, 250a. As shown in the figure, the gray structured three-dimensional color measurement method 100a incorporating gray coding includes a selection projection step S21, a gray coding pattern generation step S22, an arrangement pattern step S23, a complementary operation step S24, a pattern combining step S25, and a projection measurement. Step S26.

In the embodiment of FIG. 5, the projection order selection step S21, the gray code pattern generation step S22, the arrangement pattern step S23, the pattern combination step S25, and the projection measurement step S26 are respectively selected from the projection projection order selection step in FIG. 1. S11. The steps of generating a gray code pattern S12, the arrangement pattern step S13, the pattern combining step S14, and the projection measurement step S15 are the same, and will not be described again. In particular, the gray structure-encoded three-dimensional measurement method 100a for color structured light combined with the gray code embodiment shown in FIG. 5 further includes a complementary operation step S24. This complementary operation step S24 is to calculate and generate complementary Gray coding patterns 103a and 104a corresponding to Gray coding patterns 103 and 104. The complementary Gray coding patterns 103a and 104a are complementary to the colors of Gray coding patterns 103 and 104, as shown in FIG. 6 Example. In other words, the complementary Gray coding pattern 104a is a complementary pattern of the Gray coding pattern 104; The gray coding pattern 103a is a complementary pattern of the gray coding pattern 103, and the so-called complementary system represents that the original black becomes white and the white becomes black. The Gray code pattern 101 is combined with the complementary Gray code pattern 104a to generate a complementary Gray code pattern 260a, and the Gray code pattern 102 is combined with the complementary Gray code pattern 103a to generate a complementary Gray code pattern 270a. The reason why the present invention uses the complementary Gray bonding patterns 260a, 270a is that the gray bonding patterns 210, 220, 230, 240, 250 combined with the gray structured color structured light three-dimensional measuring method 100 of the original figure 1 are originally The black and white stripe pattern becomes a colored stripe pattern, and the color stripe code is prone to mix colors at the stripe border, causing color crosstalk. In order to avoid the phenomenon of color crosstalk, although a chip color camera (3-Chip CCD Camera) can be used to correctly distinguish the boundaries between different color stripes, but because the chip color camera is expensive, it does not meet the requirements of low cost application. In order to enable ordinary cameras to accurately find the position of the fringe boundary for correct decoding, the present invention proposes the concept of complementary graphics. Through the generation and combination of complementary Gray coded patterns 104a, 103a and complementary Gray combined patterns 260a, 270a, Avoid colors interfering with each other, and find zero-interlaced points as accurate boundaries.

Please refer to FIGS. 8 to 12 together. FIG. 8 is a partial schematic diagram of the gray combination pattern 210 in the first column in FIG. 3. FIG. 9 is a schematic diagram showing the intensity variation of the high-frequency fringe blue plate in the observation region R in FIG. 8 and its complementary diagram. FIG. 10 is a schematic diagram showing the changes of the intensity of the low-frequency stripe red plate and the green plate of the observation area R in FIG. 8 and its complementary diagram after addition. The dotted line in FIG. 10 is the diagram of FIG. 8 and its complementary diagram. The schematic diagram of the change of the intensity of the low-frequency stripe red plate in the observation area R after addition, and the solid line in FIG. 10 shows the observation area R in FIG. 8 and its complementary figure Schematic diagram of the changes of the low-frequency stripe green version after the intensity is added. FIG. 11 shows a higher-frequency Gray coding pattern 110D obtained by the reduction method in FIG. 8. FIG. 12 shows the lower-frequency Gray coding pattern 101D obtained by the reduction method in FIG. 8. As shown in the figure, the restoration method of the present invention is to find the zero-interlaced points through the original graphics and the complementary graphics to accurately determine the fringe boundary. Figure 8 is a combination of the first-order Gray coding pattern 101 and the tenth-order Gray coding pattern 110. The gray bond pattern 210 is a partial enlarged view of the gray bond pattern 210 in FIG. 3. The Gray combination pattern 210 is an image projected on a white plane, with blue-black streaks on the left and purple-black streaks on the right. The cyan on the left is a combination of green and blue, and the purple on the right is a combination of blue and red. Both the cyan and purple stripes have blue, so to capture the boundary of the high-frequency stripes on the left and right at the same time, you must first take the blue version of the gray combination pattern 210 in Figure 8, where "take the blue version" means The detected image has a blue intensity value. After taking the blue version, an image of the intensity changes of the cyan and purple high-frequency stripes can be obtained. The variation of the intensity of the fringe in the observation area R in FIG. 8 is shown as the dotted line BP in FIG. 9. (Blue Pattern). In addition, taking the blue version of the complementary pattern can also obtain its complementary high-frequency fringe intensity change image, that is, the complementary intensity value of the complementary Gray combination pattern, as shown by the solid line BIP (Blue Inverse Pattern) in Figure 9 . The center of the observation area R is just at the intersection of the blue-black stripes and the purple-black stripes, and this intersection is about 1250 pixels. Next, subtract both the dotted line BP and the solid line BIP. If the subtraction value is greater than zero, let it be 1, that is, white; and if the subtraction value is less than zero, let it be 0, that is, black. After the subtraction operation is complete, The high-frequency Gray code pattern 110D is restored, as shown in FIG. 11. In addition, when capturing the low-frequency fringe boundary, since the left cyan is a combination of green and blue, and the right purple is a combination of red and blue, Therefore, the gray combination pattern 210 in Figure 8 and its complementary pattern are added in red to obtain the low-frequency stripe intensity image with full red on the right and black on the left, such as the dashed line RP + RIP (Red Pattern + Red Inverse Pattern). The above “take the red version” refers to the intensity value of red in the detected image. Furthermore, the gray combination pattern 210 in Figure 8 and its complementary graphics are added in green to obtain low-frequency fringe intensity images that are all black on the right and green on the left, such as the solid line GP + GIP in FIG. 10 (Green Pattern + Green Inverse Pattern). The above “take the green version” refers to the intensity value of green in the detected image. Then, subtract the dotted line RP + RIP and the solid line GP + GIP. If the subtraction value is greater than zero, let it be 1, that is, white; and if the subtraction value is less than zero, let it be 0, that is, black. Subtraction operation After completion, the low-frequency Gray coding pattern 101D can be restored, as shown in FIG. 12. Therefore, the present invention can accurately find the boundaries of the stripes even if the graphics have color crosstalk and the use of ordinary cameras (non-chip color cameras) through a specific complementary restoration method. After being decomposed and reduced to two black and white Gray coded patterns 110D and 101D, they can be regarded as Gray coded and decoded, and then the correct coded value of each position on the image can be found.

Please refer to FIGS. 5, 6 and 13 together. FIG. 13 is a schematic diagram showing a color structured light three-dimensional measurement system 300 combining gray coding according to an embodiment of the present invention. The color structured light three-dimensional measurement system 300 incorporating gray coding includes a projection order selection module 310, a gray coding pattern generating module 320, a pattern arranging module 330, a pattern complementary module 340, a pattern combining module 350, and a projection amount. Test module 360. The projection order selection module 310 is used to select a projection order value N. The gray code pattern generating module 320 is connected to the projection order selection module 310, and the gray code pattern generating module 320 is used to generate a gray code pattern. 101 ~ 110. In addition, the pattern arrangement module 330 is connected to the gray code pattern generation module 320, and the pattern arrangement module 330 is used to arrange the gray code patterns 101 to 110. The pattern complementary module 340 signals connect the pattern arrangement module 330 and the pattern combination module 350, and the pattern complementary module 340 is used to calculate and generate complementary gray coding patterns 103a and 104a corresponding to the gray coding patterns 103 and 104, and complementary gray coding. The patterns 103a, 104a are complementary to the colors of the Gray code patterns 103, 104. In addition, the pattern combining module 350 signals are connected to the pattern arranging module 330. The pattern combining module 350 respectively combines the gray coding patterns 101, 102, 103, 104, and 105 with the gray coding patterns 110, 109, 108, 107, and 106 respectively. The gray combination patterns 210, 220, 230, 240, and 250 are generated. The five gray combination patterns 210, 220, 230, 240, and 250 each have multiple colors. In addition, the projection measurement module 360 signals are connected to the pattern combination module 350, and the projection measurement module 360 is used to project the gray combination patterns 210, 220, 230, 240, and 250 onto the object to be measured to form five deformed gray combinations respectively. Pattern, and then capture the five deformed gray combined patterns on the surface of the object under test to calculate and output a three-dimensional model of the object under test. In this way, the present invention combines two sets of Gray coded patterns 101 to 110, and combines the high-frequency pattern and low-frequency pattern to generate Gray-linked patterns 210, 220, 230, 240, and 250. This method is better than projecting traditional Gray-coded patterns. Save half the measurement time. In addition, the present invention uses the complementary graphic concept of colored stripes to accurately find the fringe boundary, which can solve the problems and disadvantages of traditional manual search threshold or global image search threshold.

It is also worth mentioning that, in addition to using three colors of cyan, purple and black to form colored stripes, the present invention can also use coding patterns of other colors, for example, using a color consisting of four colors of black, red, green, and blue. Color stripes. In detail, the colors of the Gray bond pattern (not shown) include black, red, green, and blue. The range covered by black in the gray combination pattern forms the first color region; the range covered by red in the gray combination pattern forms the second color region; the range covered by green in the gray combination pattern forms the third color region; The range forms a fourth color area. The first color region, the second color region, the third color region, and the fourth color region do not overlap each other. When the low-frequency Gray code pattern, the high-frequency Gray code pattern, and the Gray combination pattern overlap, the first color region (black) of the Gray combination pattern corresponds to the first region of the low-frequency Gray code pattern and the second region of the high-frequency Gray code pattern. The first region of the low-frequency Gray coding pattern and the second region of the high-frequency Gray coding pattern are both black. Furthermore, the second color region (red) of the gray combination pattern corresponds to the third region of the low-frequency Gray coding pattern and the fourth region of the high-frequency Gray coding pattern, and the third region of the low-frequency Gray coding pattern is black, and the high-frequency gray The fourth area of the coding pattern is white. In addition, the third color region (green) of the Gray combination pattern corresponds to the fifth region of the low-frequency Gray coding pattern and the sixth region of the high-frequency Gray coding pattern, and the fifth region of the low-frequency Gray coding pattern is white, and the high-frequency Gray coding The sixth area of the pattern is black. In addition, the fourth color region (green) of the gray combination pattern corresponds to the seventh region of the low-frequency Gray coding pattern and the eighth region of the high-frequency Gray coding pattern, and the seventh region of the low-frequency Gray coding pattern and the first All eight areas are white. Therefore, the present invention can use different color types to cooperate with the same decoding and reduction method, and take out complementary color intensity values to perform a zero-interlaced search threshold, and then perform a binarization to find the correct fringe boundary by the threshold to restore. Back to gray coding pattern.

It can be known from the above embodiments that the present invention has the following advantages: First, the Gray code pattern is used in combination correspondingly, and the combined Gray pattern uses a specific color instead of black and white, so it can be used to collect less More encoding information, which increases encoding speed and shortens encoding time. Second, through the specific complementary reduction method, even if the graphics have color crosstalk and the situation of using ordinary cameras, the boundary of the stripes can still be accurately found by using the threshold value of zero interlacing.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and retouches without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be determined by the scope of the attached patent application.

Claims (16)

A three-dimensional measurement method of color structured light combined with Gray coding for measuring a three-dimensional model of an object to be measured. The three-dimensional measurement method of color structured light combined with Gray coding includes the following steps: a step of selecting a projection order, a A projection level value is selected; a step of generating gray coding patterns is to generate a plurality of gray coding patterns, the number of the gray coding patterns is equal to the projection level value, and each of the gray coding patterns is arranged in a stripe pattern arranged at intervals; a step of arranging patterns, A first Gray coding pattern having a first fringe frequency and a second Gray coding pattern having a second fringe frequency are arranged in the Gray coding patterns, the first fringe frequency is greater than the second fringe frequency; The pattern combining step corresponds to combining the first Gray coded pattern and the second Gray coded pattern to generate a Gray combined pattern, the Gray combined pattern has a plurality of colors; and a projection measurement step, which projects the Gray combined pattern onto the A deformed Gray combination pattern is formed on the object to be tested, and then the surface of the object to be tested is captured to present The deformed gray color combination pattern is used to calculate and output the three-dimensional model of the object to be measured; wherein each gray coded pattern has a fringe frequency, and the first fringe frequency is a maximum value among the fringe frequencies. The two fringe frequencies are the minimum of these fringe frequencies. The gray structure-coded three-dimensional measurement method of color structured light combined with gray coding according to item 1 of the scope of patent application, wherein the step of arranging patterns includes: arranging the third gray coding patterns having a third fringe frequency among the gray coding patterns And a fourth gray coding pattern having a fourth fringe frequency; wherein the first fringe frequency is greater than the third fringe frequency, the third fringe frequency is greater than the fourth fringe frequency, and the fourth fringe frequency is greater than the second Stripe frequency. As described in item 2 of the scope of the patent application, a three-dimensional measurement method of color structured light combined with gray coding, wherein the pattern combining step includes: correspondingly combining the third gray coding pattern and the fourth gray coding pattern to generate another gray coupling. Pattern, the other Gray bond pattern has a plurality of colors. The three-dimensional measurement method of color structured light combined with Gray coding according to item 3 of the scope of patent application, wherein the projection measurement step includes: projecting another Gray combination pattern onto the object to be measured to form another deformed Gray combination Pattern, and then capture the another deformed Gray combination pattern of the color presented on the surface of the object to be measured, and use the deformed Gray combination pattern and the other deformed Gray combination pattern to calculate and output the three-dimensional model of the object to be measured. According to the three-dimensional measurement method of color structured light combined with gray coding as described in item 1 of the scope of the patent application, wherein the colors include black, cyan, and purple, and the range covered by black in the gray combined pattern forms a first color area, the The range covered by cyan in the gray combination pattern forms a second color region, and the range covered by purple in the gray combination pattern forms a third color region. The first color region, the second color region, and the third color region are different from each other. overlapping. The three-dimensional measurement method of color structured light combined with Gray coding according to item 5 of the scope of patent application, wherein the first Gray coding pattern, the second Gray coding pattern, and the Gray bonding pattern are correspondingly overlapped; The first color region corresponds to a first region of the first Gray coded pattern, and the first region of the first Gray coded pattern is black; the second color region of the gray combination pattern corresponds to one of the first Gray coded patterns. A second region and a third region of the second Gray coding pattern, the second region of the first Gray coding pattern is white and the third region of the second Gray coding pattern is black; and The third color region corresponds to a fourth region of the first Gray coded pattern and a fifth region of the second Gray coded pattern. The fourth region of the first Gray coded pattern and the second region of the second Gray coded pattern. The fifth area is all white. The three-dimensional measurement method of color structured light combined with gray coding as described in the first item of the patent application range, wherein the colors include black, red, green, and blue, and the range covered by black in the gray combined pattern forms a first color Area, the range covered by red in the gray combination pattern forms a second color region, the range covered by green in the gray combination pattern forms a third color region, and the range covered by blue in the gray combination pattern forms a fourth color region The first color region, the second color region, the third color region, and the fourth color region do not overlap each other. The three-dimensional measurement method of color structured light combined with gray coding according to item 7 of the scope of the patent application, wherein the first gray coding pattern, the second gray coding pattern, and the gray coupling pattern are correspondingly overlapped; The first color region corresponds to a first region of the first Gray coded pattern and a second region of the second Gray coded pattern. The first region of the first Gray coded pattern and the first region of the second Gray coded pattern. Both regions are black; the second color region of the gray combination pattern corresponds to a third region of the first gray code pattern and a fourth region of the second gray code pattern, and the first region of the first gray code pattern The three regions are black and the fourth region of the second Gray coded pattern is white; the third color region of the gray combination pattern corresponds to one of the first Gray coded pattern and the fifth region and one of the second Gray coded pattern. A sixth area, the fifth area of the first Gray coded pattern is white, and the sixth area of the second gray coded pattern is black; and The fourth color region corresponds to a seventh region of the first Gray coding pattern and an eighth region of the second Gray coding pattern. The seventh region of the first Gray coding pattern and the second gray coding pattern. The eighth area is all white. As described in item 1 of the scope of the patent application, the three-dimensional measurement method of color structured light combined with gray coding, wherein the projection order value is 9 or more. The three-dimensional measurement method of color structured light combined with gray coding as described in item 1 of the scope of the patent application, further includes: a complementary operation step for calculating and generating a complementary gray coding pattern corresponding to one of the first gray coding patterns. The complementary Gray code pattern is complementary to the color of the first Gray code pattern; wherein the pattern combining step corresponds to combining the complementary Gray code pattern and the second Gray code pattern to generate a complementary Gray code pattern, and then according to the complementary Gray code pattern A complementary intensity value of the pattern is calculated with an intensity value of the Gray combination pattern to restore the first Gray coded pattern. A measurement system using the gray structured three-dimensional measurement method of color structured light combined with gray coding as described in the first patent application scope includes: a projection order selection module for selecting the projection order value; a gray coding pattern generation A module, a signal is connected to the projection order selection module, and the Gray code pattern generating module is used to generate the Gray code patterns; a pattern arrangement module, a signal is connected to the Gray code pattern generating module, and the pattern arrangement module It is used for arranging the first Gray coding pattern and the second Gray coding pattern. A pattern combining module is connected to the pattern arranging module. The pattern combining module correspondingly combines the first Gray coding pattern and the second Gray coding pattern. Encoding the pattern to generate the gray bond pattern with a plurality of colors; and a projection measurement module, which is connected to the pattern bonding module by a signal, and the projection measurement module is used to project the gray bond pattern onto the object to be measured and formed The deformed gray combined pattern is captured and the deformed gray combined pattern on the surface of the object to be detected is colored to calculate and output the measured object. The three-dimensional model; wherein each of the gray coding patterns has the fringe frequency, the first fringe frequency is a maximum value of the fringe frequencies, and the second fringe frequency is a minimum value of the fringe frequencies. The measurement system according to the three-dimensional measurement method of color structured light combined with gray coding according to item 11 of the scope of patent application, wherein the pattern arranging module arranges one of the gray coding patterns having a third fringe frequency and a third Gray coding pattern and a fourth Gray coding pattern having a fourth fringe frequency; wherein the first fringe frequency is greater than the third fringe frequency, the third fringe frequency is greater than the fourth fringe frequency, and the fourth fringe frequency is greater than The second fringe frequency. According to the measurement system of the three-dimensional measurement method of color structured light combined with gray coding according to item 12 of the scope of patent application, the pattern combining module correspondingly combines the third gray coding pattern and the fourth gray coding pattern to generate another One Gray bond pattern has a plurality of colors. The measurement system according to the three-dimensional measurement method of color structured light combined with Gray coding according to item 13 of the scope of the patent application, wherein the projection measurement module projects the other Gray combination pattern onto the object to form another Deformed Gray combination pattern, and then capture the another deformed Gray combination pattern of the color presented on the surface of the object to be tested, and use the deformed Gray combination pattern and the other deformed Gray combination pattern to calculate and output the three-dimensional model of the object to be measured . According to the measurement system of the three-dimensional measurement method of color structured light combined with gray coding as described in item 11 of the scope of patent application, wherein the colors include black, cyan, and purple, the range covered by black in the gray combination pattern forms a first A color region, the range covered by cyan in the gray combination pattern forms a second color region, and the range covered by purple in the gray combination pattern forms a third color region, the first color region, the second color region, and the third region The color areas do not overlap each other. The measurement system according to the three-dimensional measurement method of color structured light combined with Gray coding according to item 15 of the scope of patent application, wherein the first Gray coding pattern, the second Gray coding pattern, and the Gray coupling pattern are correspondingly overlapped; the Gray The first color region of the combined pattern corresponds to a first region of the first Gray coded pattern, and the first region of the first Gray coded pattern is black; the second color region of the gray combined pattern corresponds to the first gray. A second region of a coding pattern and a third region of the second gray coding pattern, the second region of the first gray coding pattern is white and the third region of the second gray coding pattern is black; and the The third color region of the gray combination pattern corresponds to a fourth region of the first gray coding pattern and a fifth region of the second gray coding pattern. The fourth region of the first gray coding pattern and the second gray The fifth area of the coding pattern is all white.