TWI539820B - Projection system and brightness adjusting method thereof - Google Patents

Description

Projection system and brightness adjustment method thereof

The present invention relates to a projection system, and more particularly to a projection system having a plurality of projection devices and a brightness adjustment method thereof.

At present, it is quite difficult to manufacture a large-sized display, and the display effect is not bad, and the cost and the price are quite expensive. Therefore, when there are multiple viewers sharing the screen at the same time, the projector is usually used to project the content to be shared onto a large screen or a wall. In order to achieve a better sharing environment, the conventional technology will increase the number of projectors, so that the shared picture and brightness are greatly improved.

1 is a schematic diagram of a conventional projection system. Referring to FIG. 1 , a conventional projection system 100 has a projection device 112 and a projection device 114 . The projection system 100 causes the projection device 112 to overlap with the image projected by the projection device 114 to improve the projection effect of the screen. In more detail, the projection device 112 and the projection device 114 can respectively project the screen 122 and the screen 124 onto the screen 10, wherein the screen 122 is identical to the image in which the screen 124 partially overlaps in the region 130.

However, since the two projection devices 112 and the projection device 114 are different The image is projected at an angle, so that the brightness of the projected picture 122 and the picture 124 is not exactly the same in the area 130. In order to make the brightness of the screen in the overlapping area 130 uniform, the conventional technique adjusts the brightness projected by the projection device 112 and the projection device 114 only by means of human eye observation and manual adjustment, but the manual adjustment method is used. It is quite inconvenient and time consuming.

The invention provides a projection system and a brightness adjustment method thereof, which can automatically adjust a plurality of projection devices in the projection system such that a plurality of projected images have a relatively concentrated and uniform brightness in an overlapping region.

The invention provides a brightness adjustment method for a projection system, wherein the projection system comprises a plurality of projection devices. The projection device projects a plurality of screens onto the screen, and the screens form a joint region and have overlapping regions. The brightness adjustment method includes: capturing the image on the screen to obtain image information; selecting a target area from the image information to obtain a fusion image corresponding to the image in the target area; performing a gene according to brightness information in the target area Algorithmizing and obtaining an optimal set of parameters; and causing the projection device to project in accordance with an optimal set of parameters, wherein the target area is smaller than the joint area and includes at least a portion of the overlap area.

The invention provides a projection system comprising a plurality of projection devices, an image capture device and a control unit. A plurality of projection devices are used to project a plurality of screens onto the screen, and the screens form a joint region and have overlapping regions. The image capturing device is configured to capture the image on the screen to obtain image information. The control unit is coupled to the The projection device and the image capturing device are described. The control unit selects a target area from the image information to obtain a fused image corresponding to the image in the target area, performs a genetic algorithm according to the brightness information in the target area, obtains an optimal parameter set, and causes the projection apparatus to Projection is performed in accordance with an optimal parameter set, wherein the target area is smaller than the union area and includes at least a portion of the overlap area.

Based on the above, in the projection system of the present invention and the brightness adjustment method thereof, the control unit selects a target area from a plurality of pictures projected by the plurality of projection devices, and performs a genetic algorithm according to the brightness distribution in the target area. In order to find the adjustment function or / and the width of the overlapping area suitable for adjusting the projection system. In this way, the fused image projected by the projection device according to the adjustment function can have a relatively uniform brightness, so that the user can more conveniently project a relatively uniform brightness through the projection system.

The above described features and advantages of the invention will be apparent from the following description.

100,200‧‧‧projection system

10, 20‧‧‧ screen

112, 114, 210, 220‧‧‧ projection devices

130, 60, A1, A1, A3, C, T‧‧‧ areas

122, 124, 212, 222, 600, 602, 604, 606‧‧‧ pictures

230‧‧‧Image capture device

240‧‧‧Control unit

H ₁ , H ₂ , H _t ‧‧‧High

W ₁ , W ₂ , W _t , W ₆ ‧ ‧ wide

S302~S310‧‧‧Steps of brightness adjustment of projection system

S502~S514‧‧‧Steps for performing a gene algorithm

1 is a schematic diagram of a conventional projection system.

2A is a schematic diagram of a projection system in accordance with an embodiment of the present invention.

2B is an image schematic view of the projection system of FIG. 2A.

3 is a flow chart of a method for adjusting brightness of a projection system in accordance with an embodiment of the present invention.

4A and 4B are schematic diagrams of the control unit selecting a target area from the image information.

Figure 5 is a flow chart illustrating a method by which a control unit performs a gene algorithm.

6A-6D are schematic diagrams illustrating projection of a fused image by an adjustment function using a plurality of projection devices in accordance with an embodiment of the present invention.

7A to 7C are diagrams illustrating a function pattern obtained by bringing an adjustment function into a different candidate parameter group.

2A is a schematic diagram of a projection system in accordance with an embodiment of the present invention. 2B is an image schematic view of the projection system of FIG. 2A. Referring to FIGS. 2A and 2B , the projection system 200 includes a plurality of projection devices, namely, a first projection device 210 and a second projection device 220 , and an image capturing device 230 and a control unit 240 .

The first projection device 210 and the second projection device 220 are each, for example, an optical projection device or a digital projection device. The first projection device 210 is used to project the first screen 212 onto the screen 20, and the second projection device 220 is used to project the second screen 222 onto the screen 20. It should be noted that the first projection device 210, the second projection device 220, and the first screen 212 and the second screen 222 respectively projected are exemplified, and the embodiment does not limit the projection device and the projected image thereof. quantity. That is, in other embodiments, the projection system 200 can be configured with more projection devices, such that the projection devices can project more frames onto the screen 20.

The image capturing device 230 is, for example, a general camera or a camera. A device used to capture image information. The image capturing device 230 is configured to capture the first image 212 and the second image 222 on the screen 20 to obtain image information, so that the control unit 240 adjusts the projection system 200 according to the image information.

The control unit 240 is coupled to the first projection device 210, the second projection device 220, and the image capturing device 230, for example, by wired or wireless connection, thereby controlling the operation thereof. The control unit 240 can include a memory and a processor, wherein the memory can store image information captured by the image capturing device 230, and the processor calculates the image information. Specifically, the control unit 240 can adjust the projection system according to the image information captured by the image capturing device 230 to make the brightness of the screen projected by the first projection device 210 and the second projection device 220 uniform.

In addition, in an embodiment, the first projection device 210, the second projection device 220, the image capturing device 230, and the control unit 240 may be integrated into the same device, for example, having photography, photography, and projection functions. The invention is not limited to the personal computer, the notebook computer, the smart phone and the tablet computer.

The detailed steps of the brightness adjustment method of the projection system 200 will be described below with reference to FIGS. 2A and 2B. 3 is a flow chart of a method for adjusting brightness of a projection system in accordance with an embodiment of the present invention. Referring to FIG. 2A, FIG. 2B and FIG. 3 simultaneously, in step S302, the first projection device 210 projects the first screen 212 on the screen 20, and the second projection device 220 projects the second screen 222 on the screen 20. Further, the first projection device 210 and the second projection device 220 partially overlap the projected first picture 212 and the second picture 222 (ie, partially overlap in the area C), and the partially overlapping pictures are the same.

In step S304, the image capturing device 230 captures the first screen 212 and the second screen 222 to obtain image information corresponding to the first screen 212 and the second screen 222. Next, in step S306, the control unit 240 selects a target area from the image information, so as to obtain a fused image corresponding to the first picture 212 and the second picture 222 in the target area.

In detail, FIG. 4A and FIG. 4B are schematic diagrams of the control unit 240 selecting a target area from the image information. Referring to FIG. 4A, the area A1 is the image information corresponding to the first screen 212, the area A2 is the image information corresponding to the second picture 222, and the control unit 240 is the combination area A3 formed by the area A1 and the area A2 ( Select the target area T (as indicated by the slanted line). For example, assuming that the height of the union region A3 is H ₁ and the width is W ₁ , wherein the height H _{1 is} less than the width W ₁ , the height H _{t of} the target region T is, for example, the upper end and the lower end of the high H ₁ are respectively subtracted ( H ₁ /8), and the width W _{t of the} target region T is, for example, the left end and the right end of the width W ₁ minus (W ₁ /4), respectively. Alternatively, referring to FIG. 4B, assuming that the height of the joint region A3 is H ₂ and the width is W ₂ , wherein the high H _{2 is} greater than the width W ₂ , the high H _{t of} the target region T is, for example, the upper end and the lower end of the high H ₂ respectively. Subtract (H ₂ /4), and the width W _{t of the} target region T is, for example, the left end and the right end of the width W ₂ minus (W ₂ /8), respectively. The target region T should include at least a portion of the overlapping region C in the overlapping direction (W direction in FIG. 4A; H direction in FIG. 4B). Certainly, the embodiment does not limit the selection of the target area by the above method. In other embodiments, other calculation formulas may be used to select the target area from the combination areas corresponding to the plurality of pictures.

It is worth mentioning that since the target area T of the embodiment is equivalent to the first The reduced area of the merged area A3 of the image information of the second screen 222 and the second screen 222 includes at least a part of the overlapping area, so the fused image of the first picture 212 and the second picture 222 in the target area T may have a smaller The screen area is used to reduce the amount of data processing, and since the noise in the image information other than the target area T can be excluded in this embodiment, in a subsequent step, the control unit 240 can accurately perform the overlapping area portion of the fused image of the target area T. The calculation is performed to obtain a more accurate parameter set, thereby causing the first projection device 210 and the second projection device 220 to project according to the parameter set.

Next, in step S308, the control unit 240 performs a genetic algorithm according to the brightness information in the target area T and obtains an optimal parameter set. In this embodiment, the first projection device 210 and the second projection device 220 use a suitable adjustment function to adjust the projected first picture 212 and the second picture 222, and the purpose of the genetic algorithm is to find This appropriate adjustment function. That is, the control unit 240 generates a plurality of adjustment functions according to the concept of the genetic algorithm, wherein each adjustment function may have a plurality of parameters, and the control unit 240 will combine the parameters in each of the adjustment functions (ie, candidates) The parameter set) is treated as a chromosome and these parameters are respectively mapped to multiple genes in this chromosome. For example, for an adjustment function f(x)=A _n x ^Bn +A _(n-1) x ^B(n-1) +...+A ₀ x ^Bo , the parameter is, for example, A _n ~A ₀ and B _n ~B ₀ , where n is a positive integer, and A _n ~A ₀ and B _n ~B ₀ correspond to multiple genes in one chromosome (see below for details). In this way, when the gene algorithm ends, the control unit 240 obtains a parameter group that is most suitable for the candidate parameter as a plurality of parameters of the adjustment function, thereby obtaining an appropriate adjustment function. The above adjustment function is an example, and the embodiment does not limit the adjustment function. In another embodiment, the control unit 240 performs a genetic algorithm to find the width of the most appropriate overlapping region according to the brightness information in the target region T. In another embodiment, the control unit 240 performs a genetic algorithm to find the most appropriate adjustment function and the width of the overlapping region according to the brightness information in the target region T, that is, the candidate parameter group includes parameters of the adjustment function and overlapping regions. The parameter of the width.

Finally, in step S310, the first projection device 210 and the second projection device 220 use the adjustment function obtained by the gene algorithm to obtain the most suitable candidate parameter group for projection, so that the projected first screen 212 is The luminance distribution of the second picture 222 is uniform and the overlapping area is not conspicuous.

An embodiment is further described below to explain in detail the steps of the above control unit 240 performing a genetic algorithm and obtaining an optimal parameter set.

FIG. 5 is a flow chart illustrating a method by which control unit 240 performs a gene algorithm. Referring to FIG. 5, in step S502, since the initial step of the genetic algorithm randomly generates a predetermined number of chromosomes (for example, 200 or 300 chromosomes), and the chromosome may be referred to as a candidate parameter group, the control unit 240 A plurality of candidate parameter sets corresponding to a plurality of adjustment functions or/and a plurality of overlapping regions are randomly generated in the first computation cycle (i.e., in the initial step of the genetic algorithm). In addition, since each chromosome has a random combination of various genes, each chromosome has the same number of multiple genes corresponding to a plurality of parameters of each candidate parameter group.

In step S504, the control unit 240 uses the candidate parameter groups as one. A plurality of parent candidate parameter sets in a computation cycle, and a plurality of progeny candidate parameter sets are generated by a selection procedure, a mating calculation, and a mutation calculation. In detail, the control unit 240 performs a selection procedure, so as to select a part of the candidate parameter group from the above-mentioned parent candidate parameter group as a basis for subsequently generating the sub-candidate parameter group, wherein the method of selecting the program may be a roulette selection. The Roulette Wheel Selection, the Tournament Selection, or the Rank Based Wheel Selection are not limited thereto. When performing the mating calculation, the control unit 240 exchanges some of the selected two parent candidate parameter sets in the concept of gene segment exchange to generate two new candidate parameter sets, wherein the mating calculation The method can be a common single point, two point, multiple point or uniform mating calculation method, and is not limited thereto. Thereafter, the control unit 240 determines whether the generated new candidate parameter set needs to perform the mutation calculation according to a preset mutation occurrence rate (for example, 0.001<P<0.002, where P is the mutation occurrence rate). And, for the candidate parameter group that needs to perform the mutation calculation, the control unit 240, for example, randomly generates the parameter value to replace some of the parameter parameters in the candidate parameter group. In this way, the new candidate parameter set obtained after the mating calculation and the mutation calculation is the progeny candidate parameter group.

In step S506, the control unit 240 will bring the parameters in all the obtained candidate parameter groups, that is, the parameters in the descendant candidate parameter group and the parameters in the parent candidate parameter group, into the adjustment function or/and the overlapping region, respectively. Width, and causing the first projection device 210 and the second projection device 220 to use the adjustment functions or/and the width of the overlap region to respectively project the first screen 212 and the second screen 222 onto the screen 20, and the control unit 240 calculates Target area T corresponds to different adjustment functions or/and overlap A plurality of standard deviations of the plurality of luminance distributions of the width of the region, and the standard deviation of the luminance distributions is used as the fitness of each of the descendant candidate parameter groups and each of the parent candidate parameter groups.

In detail, the first projection device 210 and the second projection device 220 respectively multiply the original images (ie, the original first screen 212 and the second screen 222) respectively projected by the adjustment function at corresponding pixel positions. The value of the original image to be projected. For example, suppose the adjustment function obtained after bringing in the parameter is f(x):

Where x corresponds to the normalized pixel coordinates of the overlap of the overlap region in the target region T, the first projection device 210 and the second projection device 220 respectively correspond to the overlapped region of the projected original image in the target region. The pixel luminance of the x coordinate is normalized, and the adjustment function f(x) is multiplied, whereby the adjusted luminance is projected on the screen 20.

Then, corresponding to each adjustment function, the image capturing device 230 captures the first picture 212 and the second picture 222 on the screen 20 to obtain image information, and the control unit 240 calculates the target area T according to the above. Image information, calculating the brightness in the target area T. In an embodiment, the control unit 240 converts the RGB (red, green, and blue) color input signals in the image information in the target area T into a YUV (luminance-chroma) color signal, and uses the brightness in the YUV color signal ( Y) Signal to calculate the brightness. Thereby, the control unit 240 can calculate according to the calculated brightness. The standard deviation of the luminance distribution in the target region T, and the standard deviation is used as the fitness for this candidate parameter group.

In step S508, the control unit 240 sorts all the candidate parameter groups, that is, the child candidate parameter group and the parent candidate parameter group, according to the calculated fitness degree. In addition, in step S510, the control unit 240 reserves, in all the candidate parameter groups, a partial candidate parameter group that meets a preset screening condition (for example, the fitness value meets the preset threshold value), as the next operation cycle. Multiple parent candidate parameter sets. In other words, if the fitness is too high (that is, the standard deviation is too large), it means that the first screen 212 and the second screen 222 projected by the first projection device 210 and the second projection device 220 have uneven brightness distribution in the overlapping region. Therefore, the control unit 240 does not reserve the candidate parameter group corresponding to the fitness. Therefore, in order to make the brightness distribution of the screen projected by the projection device 210 and the second projection device 220 uniform, the control unit 240 reserves the candidate parameter group corresponding to the preset threshold value, and performs the gene algorithm according to the algorithm. A computing cycle.

In step S512, the control unit 240 determines whether the genetic algorithm has reached the termination condition. Here, the control unit 240 may determine whether the number of operations of the gene algorithm is up to the iterative operation threshold. In other embodiments, the control unit 240 may also determine whether the number of candidate parameter groups that meet the preset fitness exceeds the threshold number as the basis for the termination condition.

If the control unit 240 determines that the genetic algorithm has not reached the termination condition, the control unit 240 repeats the above steps S502 to S512 until the genetic algorithm reaches the termination condition. And, when the genetic algorithm reaches the termination condition, it is like As shown in step S514, the control unit 240 selects the candidate parameter group having the smallest fitness among all the candidate parameter groups as the optimal parameter group. In other words, the parameters in this optimal parameter set will be brought into the width of the adjustment function or/and the overlap region, and the first projection device 210 and the second projection device 220 will utilize this adjustment function or/and the overlap region. The width of the first screen 212 and the second screen 222 are respectively projected on the screen 20. That is, the first projection device 210 and the second projection device 220, for example, multiply the projected original first picture 212 and the second picture 222 by the adjustment function having the optimal parameter group in the corresponding pixel in the overlapping area. The value of the position, or / and the width of the overlap area, to adjust the brightness of the projected original picture. Moreover, since the brightness distribution of the first picture 212 and the second picture 222 in the target area T has a minimum standard deviation, the brightness of the first picture 212 and the second picture 222 in the overlapping area may be more uniform. As a result, the fused image projected by the first projection device 210 and the second projection device 220 can have a relatively uniform brightness.

6A-6D are schematic diagrams illustrating the first projection device 210 and the second projection device 220 using an adjustment function to project a fused image according to an embodiment of the present invention. 7A to 7C are diagrams illustrating a function pattern obtained by bringing an adjustment function into a different candidate parameter group. Referring to FIG. 6A , the original screen 600 is a merged image of the first screen and the second screen that the first projection device 210 and the second projection device 220 have not projected by using the adjustment function. As can be seen from Fig. 6A, the brightness of the original picture 600 without the adjustment function is not uniform.

When the control unit 240 performs the genetic algorithm, it is assumed that the adjustment function is

Where a and p are parameters in a candidate parameter set, where x corresponds to the normalized pixel position on the overlap region width W ₆ in the target region 60, then the adjustment function takes the parameters with different candidate parameter groups. The obtained pattern is shown in Figures 7A to 7C. 7A is a graph obtained when the candidate parameter group (a, p) is (1, 1), (1, 2), and (1, 3) respectively brought into the adjustment function f(x), and FIG. 7B is a candidate. The parameter group (a, p) is a graph obtained when (0.5, 1), (0.5, 2), and (0.5, 3) are respectively brought into the adjustment function f(x), and FIG. 7C is a candidate parameter group (a, p). ) A graph obtained by introducing the adjustment function f(x) for (1.5, 1), (1.5, 2), and (1.5, 3), respectively. In another embodiment, the interval threshold value (0.5 in the above equation) of the normalized pixel position of the different interval of the adjustment function f(x) may also be used as a parameter in the candidate parameter group for performing the genetic algorithm. Values can range from 0 to 1.

In addition, the first projection device 210 and the second projection device 220 can utilize a different adjustment function to project a plurality of fused images. For example, FIG. 6B and FIG. 6C respectively show the merged pictures 602 and 604 projected by the first projection device 210 and the second projection device 220 by multiplying the original picture 600 by different adjustment functions. In one embodiment, the adjustment function used by the first projection device 210 in the overlap region and the adjustment function used by the second projection device 220 in the overlap region have a sum of 1 at each normalized pixel position x. Thereafter, the image capturing device 230 captures the fused image (eg, the fused frames 602 and 604), and the control unit 240 calculates the target of the luminance distribution in the target region 60. The quasi-difference is used as the fitness of each candidate parameter group in the genetic algorithm. Finally, when the genetic algorithm reaches the termination condition, the control unit 240 brings the optimal parameter set into the adjustment function or/and the width of the overlap region, such that the first projection device 210 and the second projection device 220 project using the adjustment function. A fused picture 606 of uniform brightness is shown, as shown in FIG. 6D. In this way, since the brightness of the first picture and the second picture projected by the first projection device 210 and the second projection device 220 in the projection system 200 are uniform in the overlapping area, the fused picture 606 is projected as a single projection device. The whole picture.

In summary, in the projection system and the brightness adjustment method thereof of the present invention, the control unit selects a target area from a plurality of pictures projected by the plurality of projection devices, and performs a genetic algorithm to find a suitable one for use. The adjustment function of the projection system or/and the width of the overlap region is adjusted, wherein the control unit uses the standard deviation of the luminance distribution in the target region as the fitness in the genetic algorithm. In this way, the fused picture projected by the projection device can have a relatively uniform brightness. In addition, the present invention achieves the effect of projecting a single fused picture by a plurality of projection devices as a picture projected by a single projection device. Thereby, the user can more conveniently project a relatively uniform brightness through the projection system.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

S302~S310‧‧‧Steps of brightness adjustment of projection system

Claims (10)

A brightness adjustment method of a projection system, wherein the projection system comprises a plurality of projection devices, the projection devices project a plurality of pictures onto a screen, the pictures form a joint area and have an overlapping area, and the brightness adjustment method The method includes: capturing the images on the screen to obtain an image information; selecting a target area from the image information to obtain the fused image corresponding to the image in the target area; according to a brightness in the target area The information performs a genetic algorithm and obtains an optimal parameter set; and causes the projection devices to project according to the optimal parameter set, wherein the target area is smaller than the joint area and includes at least a portion of the overlap area. The brightness adjustment method of the projection system of claim 1, wherein the step of performing the genetic algorithm according to the brightness information in the target area and obtaining the optimal parameter set comprises: a. in a calculation cycle Randomly generating a plurality of candidate parameter sets corresponding to a function, wherein each candidate parameter set has a plurality of genes respectively corresponding to each of the candidate parameter sets; b. using the candidate parameter sets as the operation cycle a plurality of parent candidate parameter sets, and generating a plurality of progeny candidate parameter sets by a selection procedure, a mating calculation, and a mutation calculation; c. bringing all of the obtained candidate parameter sets into the function to calculate a plurality of brightness distributions in the target area, and a standard deviation of the brightness distributions as a fitness of each of the candidate parameter groups; d. sorting all of the candidate parameter groups according to the fitness levels; e. All of the candidate parameter sets retain a portion of the candidate parameter sets that meet a predetermined screening condition as a plurality of parent candidate parameter sets for the next computation period; and f. repeat steps (a) through (e) above. And until the execution of the gene algorithm reaches a termination condition, and selects a candidate parameter group having a minimum fitness degree among the currently reserved parent candidate parameter groups as the optimal parameter group. The brightness adjustment method of the projection system according to claim 2, wherein the candidate parameter sets include a parameter of an adjustment function or a width of the overlapping area. The method for adjusting brightness of a projection system according to claim 3, wherein the step of causing the projection devices to project according to the optimal parameter set comprises: respectively, the screens projected by the projection devices, Multiplying the value of the adjustment function having the optimal parameter set at the corresponding pixel position, or/and adjusting the width of the overlapping area according to the optimal parameter set to adjust the projections of the projection devices The brightness of the picture. The brightness adjustment method of the projection system of claim 1, wherein the step of performing the genetic algorithm according to the brightness information in the target area and obtaining the optimal parameter set comprises: An RGB (red, green and blue) color input signal is converted into a YUV (brightness-chroma) color signal, and the brightness (Y) in the YUV color signal Signal to calculate the brightness information. A projection system comprising: a plurality of projection devices for projecting a plurality of screens onto a screen, the screens forming a joint area and having an overlapping area; and an image capturing device for capturing the screen And the control unit is coupled to the image capturing device and the image capturing device, wherein the control unit selects a target area from the image information to obtain the corresponding image. a fused image in the target area, performing a gene algorithm according to a brightness information in the target area and obtaining an optimal parameter set, and causing the projection devices to project according to the optimal parameter set, wherein the target area is smaller than the target area The collection area includes at least a portion of the overlapping area. The projection system of claim 6, wherein the control unit performs a plurality of steps in a computation cycle, wherein the control unit randomly generates a plurality of candidate parameter sets corresponding to a function, wherein each candidate parameter group Having a plurality of genes respectively corresponding to each of the candidate parameter sets, the control unit using the candidate parameter sets as a plurality of parent candidate parameter sets of the operation cycle, and selecting a program, mating calculation and mutation Calculating a plurality of progeny candidate parameter sets, the control unit respectively bringing all of the obtained candidate parameter sets into the function to calculate a plurality of brightness distributions in the target area, and using the standard deviation of the brightness distributions as a fitness of each of the candidate parameter sets, the control unit sorts all of the candidates according to the fitness levels Selecting a parameter group, and the control unit retains, in all of the candidate parameter groups, a part of the candidate parameter groups that meet a predetermined screening condition as a plurality of parent candidate parameter groups of a next operation period, and repeats the execution Each step in the operation cycle until the execution of the genetic algorithm reaches a termination condition, and the control unit selects a candidate parameter group having a minimum fitness degree among the currently reserved candidate parameter sets for the best Parameter group. The projection system of claim 7, wherein the candidate parameter sets comprise a parameter of an adjustment function or a width of the overlapping area. The projection system of claim 8, wherein the projection devices respectively multiply the respective projected images by a value of the adjustment function having the optimal parameter set at a corresponding pixel position. Or / adjusting the width of the overlapping area according to the optimal parameter set to adjust the brightness of the pictures projected by the projection devices. The projection system of claim 6, wherein the control unit converts an RGB color input signal in the image information into a YUV color signal, and calculates the brightness information by using the brightness signal in the YUV color signal.