Control device, control method, and control program

Abstract

To reduce a change in the appearance of an image even when the luminance that a projection device can project varies while suppressing a reduction in the range of expressible gradations.SOLUTION: A projection device projects an image onto a screen on the basis of input data including information on absolute luminance, and includes a peak luminance value acquisition unit 40 that acquires a peak luminance value, which is the luminance value on the screen when the projection device is set to a predetermined state and projects an image onto the screen with the maximum output gradation value, a reference luminance value setting unit 42 that sets a reference luminance value to be higher than the peak luminance value, a relationship information setting unit 46 that sets relationship information indicating the relationship between the output gradation value and the light output value on the basis of the reference luminance value and the peak luminance value, an output gradation value setting unit 48 that sets the output gradation value on the basis of the input data and the relationship information, and an output control unit 50 that outputs an image on the basis of the output gradation value generated by the output gradation value setting unit 48.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device, a control method, and a control program. [Background technology]

[0002] For example, PQ (Perceptual Quantum) is used as input data for displaying an image. HDR (High Dynamic Range) signals using the 3D image processing technology There are projection devices that accept input data containing information on absolute luminance values, such as Generate output data so that the projected image has the absolute brightness value specified by the input data. However, when projecting HDR images onto a screen, the screen The actual brightness on the screen changes depending on the size of the screen, which changes the way the image appears. Therefore, the luminance on the screen is calculated and the EOTF (E Photo-Optical Transfer Function), i.e., In some cases, the relationship between the tone and the output brightness is set. For example, in Patent Document 1, A method for changing the tone conversion process for image data based on the above is also disclosed. Patent Document 2 describes a method for projecting HDR image data in an EDI environment when multiple projectors are stacked. It states that the EOTF can be changed by rewriting D. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-198733 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-200104 Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, in Patent Documents 1 and 2, the EOTF is determined according to the brightness required by the input data. This allows the image to be displayed according to the PQ curve, for example when the brightness on the screen is low. As the area covered by the image decreases, the range of tones that can be expressed decreases, and the image may appear blurred. Also, the brightness that the projector can project varies depending on the installation state of the projector and the state of the main body. If the brightness is different, the appearance of the image may change significantly. While suppressing the reduction of the range of tones, even when the brightness that the projection device can project is different There is a demand for minimizing changes in the appearance of images.

[0005] In view of the above-mentioned problems, the present invention aims to provide a method for projecting a color image while suppressing a reduction in the range of gradations that can be expressed. It is possible to minimize changes in the appearance of the image even when the brightness that the projection device can project varies. The present invention aims to provide a projection device, a projection method, and a program. [Means for solving the problem]

[0006] A projection device according to one aspect of the present invention is configured to project a screen based on input data including information on absolute luminance. A projection device for projecting an image onto a screen, the projection device being set to a predetermined state; and , when the projection device projects an image onto the screen with the maximum output gradation value, a peak luminance value acquiring unit for acquiring a peak luminance value which is a luminance value on the screen; a reference luminance value setting unit that sets a reference luminance value so that the reference luminance value is higher than a reference luminance value; and displaying an output image from the projection device based on the output gradation value and the peak luminance value. a relationship information setting unit that sets relationship information indicating a relationship between the light output value, which is the intensity of light, and the an output gradation value setting unit that sets an output gradation value based on input data and the relationship information; an output control unit that outputs an image based on the output gradation value generated by the output gradation value setting unit. nothing.

[0007] A projection method according to one aspect of the present invention includes: A projection method for projecting an image onto a screen, the method comprising: setting a projection device in a predetermined state; When the projection device projects an image onto the screen with a maximum output gradation value, obtaining a peak luminance value, which is a luminance value on the screen; a step of setting a reference luminance value so that the reference luminance value is high; and Based on the output gradation value and the light output, which is the intensity of light for displaying an output image from the projection device, a step of setting relationship information indicating a relationship between the input data and the relationship information; a step of setting an output gradation value based on the output gradation value; and a step of outputting an image based on the output gradation value. and

[0008] A program according to one aspect of the present invention is a program for scanning based on input data including information on absolute luminance. A program for causing a computer to execute a projection method for projecting an image cleanly, The projection device is set to a predetermined state, and the projection device projects the maximum output gray scale onto the screen. When an image is projected at this value, the peak brightness value on the screen is obtained. and setting a reference luminance value so that the reference luminance value is higher than the peak luminance value. and based on the reference luminance value and the peak luminance value, an output gradation value and a setting relationship information indicating the relationship with the light output value, which is the intensity of light for displaying the output image of the a step of setting an output gradation value based on the input data and the relationship information; and outputting an image based on the output tone value. [Effects of the Invention]

[0009] According to the present invention, the projection device can project images while suppressing a reduction in the range of gradations that can be expressed. Even if the brightness of the image changes, the change in the appearance of the image can be minimized. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a projection system according to the first embodiment. [Figure 2] FIG. 2 is a schematic block diagram of a control device of the projection device according to this embodiment. [Figure 3] FIG. 3 is a graph showing an example of the relationship between the reference luminance value and the peak luminance value. [Figure 4A] FIG. 4A is a graph showing an example of reference relationship information. [Figure 4B] FIG. 4B is a graph showing an example of reference relationship information. [Figure 5] FIG. 5 is a graph showing an example of the relationship information. [Figure 6] FIG. 6 is a graph showing another example of the relationship information. [Figure 7] FIG. 7 is a flowchart illustrating the flow of setting the relationship information. [Figure 8] FIG. 8 is a schematic diagram showing an example in which the aspect ratio of the image and the aspect ratio of the effective projection area are different. [Figure 9] FIG. 9 is a schematic diagram showing an example in which the aspect ratio of the image and the aspect ratio of the effective projection area are different. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments.

[0012] (First embodiment) FIG. 1 is a schematic diagram of a projection system according to a first embodiment. The projection system 1 according to the embodiment includes a projection device 10 and a screen 12.

[0013] The projection device 10 is a device for displaying an image, and projects light onto a screen 12. By projecting light onto the screen 12, an image is displayed on the screen 12. In this embodiment, the projection device 10 is a projector that projects an image. takes input data containing absolute luminance information and converts it to the absolute luminance value indicated by the input data. An output gradation value that can output an image with a corresponding absolute luminance value is set, and light (image) is output. That is, the projection device 10 projects an image in HDR (High Dynamic Range) format. Furthermore, the projection device 10 displays an image based on PQ (Perceptual Quan Preferably, the projection device is a projection device of the luminance (luminance) type.

[0014] The projection device 10 includes a light source 20, an optical system 22, and a control device 24. The light source 20 The optical system 2 is a light source that generates the light emitted from the projection device 10 and may have any structure. Reference numeral 2 denotes an optical element that receives light output from the light source 20 and outputs the light to the outside. 2 is, for example, a projection lens, an illumination optical system that guides light from a light source 20 to the projection lens, and a display The illumination optical system may have any configuration, but may include, for example, a fly-eye lens or The display element may include a prism, etc. The display element may be, for example, a liquid crystal display element. The control device 24 is a device that controls the irradiation of light from the projection device 10. Ming will be discussed later.

[0015] The screen 12 receives the image (light) from the projection device 10 and displays the projected image. In the example of FIG. 1, the screen 12 is a screen (image display surface) on which the projection device 1 Light (image) from the front surface 12a is projected onto the projection surface 12a. By reflecting the light, an image is displayed on the projection surface 12a. For example, light is irradiated onto the rear side, and the light is transmitted from the rear side to the projection surface 12a, and is projected onto the projection surface 12a. In the example of FIG. 1, the screen 12 may be a transparent screen for displaying an image. Although the shape is planar, it is not limited to a planar shape and may be any shape. The clean 12 has a concave shape on one side of the back and front, and a convex shape on the other side. The screen may be a cylindrical screen.

[0016] (Control device) FIG. 2 is a schematic block diagram of a control device of the projection device according to this embodiment. As shown in the figure, the control device 24 is a computer in this embodiment, and includes a memory unit 30 and a control unit 3 The control device 24 is a device that accepts user operations, such as a touch panel. input section, output section such as a display that outputs information, and communication modules such as antennas. The storage unit 30 stores the calculation contents and programs of the control unit 32. RAM (Random Access Memory) is a memory that stores various information. ss Memory) and main memory such as ROM (Read Only Memory) device and external storage device such as HDD (Hard Disk Drive), The program for the control unit 32 stored in the memory unit 30 is read by the control device 24. It may be stored on a readable recording medium.

[0017] The control unit 32 is a computing device, that is, a CPU (Central Processing Unit). The control unit 32 receives input data for displaying an image on the projection device 10. and based on the input data, the projection device 10 outputs an image using an output gray scale. The input data is input to the projection device 10. It is image data that indicates how the image is to be displayed, and can also be said to be the input gradation value. The input data is information on the input luminance value, which is the absolute luminance value of the image to be displayed on the projection device 10. The input data is, for example, an HDR signal, but may be image data in any format. The output gradation value is output data that the projection device 10 uses to actually output an image. In other words, the projection device 10 projects light at the output gradation value. and the optical output value, and based on the input luminance value and the relation information, The gradation value is set and light (image) is output at that output gradation value. The intensity of the light output from the imaging device 10 (the intensity of the light that displays the output image) is indicated. , EOTF (Electro-Optical Transfer Function) It can also be said that the light output value is, for example, corresponds to the absolute luminance value of the output image. This article explains:

[0018] The control unit 32 includes a peak luminance value acquisition unit 40, a reference luminance value setting unit 42, and a reference relationship information setting unit. The image processing system includes a setting unit 44, a related information setting unit 46, an output gradation value setting unit 48, and an output control unit 50. The control unit 32 reads out and executes a program (software) from the storage unit 30. The peak luminance value acquisition unit 40, the reference luminance value setting unit 42, the reference relationship information setting unit 44, and the relationship information The information setting unit 46, the output gradation value setting unit 48, and the output control unit 50 are realized to perform the processing. The control unit 32 may execute these processes by one CPU, or A plurality of CPUs may be provided, and the processes may be executed by the plurality of CPUs. A luminance value acquisition unit 40, a reference luminance value setting unit 42, a reference relationship information setting unit 44, and a relationship information setting unit 4 6, the output tone value setting unit 48, and at least a part of the output control unit 50 are realized by hardware. You may do so.

[0019] (Peak brightness value acquisition section) The peak luminance value acquisition unit 40 acquires the peak luminance value on the projection surface 12a of the screen 12. The peak luminance value is the value obtained when the projection device 10 is set in a predetermined state and the projection device 10 When an image is projected onto the screen 12 at the maximum output gradation value, In other words, the peak brightness value is the brightness value of the projected image when the projection is set to a predetermined state. The maximum absolute brightness value of the light that the projection device 10 can project onto the screen 12, and the maximum output It can be said that this is the absolute luminance value of light when light is projected onto the screen 12 at a gradation value. The predetermined state refers to a state in which the irradiation conditions of the projection device 10 are set to predetermined conditions. The conditions include, for example, the maximum amount of light flux that the projection device 10 can output, and light source output information (the brightness of the light source 20). The state of the movable optical filter (the amount of light passing through the optical filter) information about the length of the projection lens, the aperture position of the illumination optical system, The aperture position of the projection lens, the zoom position of the projection lens, and the image processing The setting may be at least one of the transmittance of each optical component and the transmittance of each optical component.

[0020] In this embodiment, the peak luminance value acquisition unit 40 determines whether the projection conditions of the projection device 10 are the current conditions. That is, the peak luminance value acquisition unit 40 acquires the peak luminance value when the projection When the device 10 is set to its current state, the screen 12 displays an image with the maximum output grayscale value. The luminance value of the image projected on the screen when the However, the peak luminance value acquisition unit 40 may acquire the peak luminance value by When the screen is set to a different state, the image is displayed on screen 12 with the maximum output gradation value. When projected, the brightness value of the image projected onto the screen is taken as the peak brightness value. You may obtain it.

[0021] In this embodiment, the peak luminance value acquisition unit 40 acquires the peak luminance value from the screen information and the projection device 10. The peak luminance value is calculated based on the amount of light flux from the screen. The screen information is information about the image projected on the screen 12. The projected image size is the size of the projected image. In this embodiment, it is the diagonal length of the projected image. is the standard value when an image is projected onto a standard white board (perfect diffuser) and the screen 12 under the same conditions. The ratio of the brightness of the image projected onto the screen 12 to the brightness of the image projected onto a semi-white board. The screen gain indicates the inherent reflection characteristics of the screen 12 fabric. In this embodiment, the peak luminance value acquisition unit 40 acquires the screen brightness value according to the user's input. That is, the user inputs screen information to the input unit of the projection device 10. The peak luminance value acquisition unit 40 acquires the input screen information. The projection device 10 displays a menu screen, and the user selects screen information from the menu screen. It may be inputted by inputting the peak luminance value or by inputting it from the outside by a communication command, etc. The acquisition unit 40 is not limited to acquiring screen information through user input. For example, The peak luminance value acquisition unit 40 acquires the peak luminance value of the projection image from the values ​​recognized by the distance measurement sensor, camera, etc. You can get the size or recognize the aspect ratio of the projected image from the input video format. Similarly, the peak luminance value acquisition unit 40 may acquire the size of the projected image by measuring the brightness of the light. The screen gain may be obtained from the brightness of the projected image detected by a sensor or the like. It is easier to recognize screen information without using distance sensors, cameras, photometry sensors, etc. A simple configuration can be achieved.

[0022] The peak luminance value acquisition unit 40 acquires the peak luminance value of the light from the projection device 10 based on the projection conditions of the projection device 10. That is, the peak luminance value acquisition unit 40 calculates the amount of light flux by linking it to the brightness that can be recognized internally. In this embodiment, the peak luminance value acquisition unit 40 estimates the amount of projected luminous flux from information based on the Based on the maximum amount of light flux that the projection device 10 can output and the projection conditions of the projection device 10, Calculate the amount of luminous flux from 10. For example, if the number of projection conditions used for the amount of luminous flux is N, The peak luminance value acquisition unit 40 calculates the amount of luminous flux from the projection device 10 based on the following formula (1): do.

[0023] LM=LM MAX ×(1-D1)×(1-D2)×···×(1-D N ) ···(1 )

[0024] where LM is the amount of light flux from the projection device 10, and LM MAX The projection device 10 The maximum luminous flux that can be output is D1 to D N is the maximum image that the projection device 10 can output for each projection condition. Refers to the rate of decrease in brightness relative to a large amount of luminous flux.

[0025] LM MAX is a preset value. For example, the peak luminance value acquisition unit 40 may LM uses specifications listed on product tags, product design values, or actual measurements at factories. MA X In this case, LM MAX The value of is stored in advance in the storage unit 30. Also, D1~D N The peak luminance value may be a preset value, but may be calculated by the peak luminance value acquisition unit 40. For example, the light source output information as a projection condition may be, for example, The brightness setting of the light source 20 to be selected (for example, high / medium / low) and the usage time of the light source 20 Generally, the light intensity of a light source decreases over time, so the peak luminance value is The obtaining unit 40 calculates the brightness reduction rate related to the light source output information by, for example, a mathematical formula using the usage time as a variable. You can calculate the transmittance by using the time, or you can keep a table of transmittance by using time and refer to it. In addition, for example, the brightness reduction rate related to the light source output information may be calculated by The acquisition unit 40 acquires the brightness reduction rate related to the image processing based on the color selected by the user from the menu screen. The temperature setting (for example, 6500K), the image quality mode and color profile applied, It may also be calculated from internally processed values ​​or factory adjusted values ​​that are not displayed on the menu screen. The adjustment values ​​include correction values ​​(RGB gain values, etc.) to correct individual variations in the color of the projected light. For example, the transmittance of each optical component generally decreases over time. Therefore, the peak luminance value acquisition unit 40 calculates the transmittance of each optical component using a mathematical formula with the use time as a variable, for example. You can calculate the brightness reduction rate for the light transmittance, or you can have a table of the transmittance for each usage time. By referring to the obtained data, the brightness reduction rate related to the transmittance of each optical component may be calculated. stomach.

[0026] The peak luminance value acquisition unit 40 acquires the peak luminance value from the screen information and the amount of luminous flux from the projection device 10. In this embodiment, the peak luminance value acquisition unit 40 calculates the peak luminance value using the following formula (2): Then, the peak luminance value is calculated.

[0027] LP=LM / AR / π×SG (2)

[0028] LP(cd / m 2 ) is the peak luminance value, and LM(lm) is the projector brightness as described above. AR(m 2 ) is the area of ​​the projected image on the screen 12, The size of the projected image on the screen 12 can be calculated from the size of the projected image. Since it is expressed as the length of the corner line (in inches), the area of ​​the projected region can be calculated from the length of the diagonal line. The unit of the area of ​​the projection area is m 2If necessary, calculate as inches Converts units from radians to meters. Also, π is the ratio of the circumference of a circle to its diameter, and SG is the screen gain. be.

[0029] As described above, the peak luminance value acquisition unit 40 acquires the peak luminance value based on the screen information and the luminous flux from the projection device 10. The peak luminance value is calculated from the amount of the peak luminance. However, the calculation method of the peak luminance value is not limited to the above and can be any method. Alternatively, the peak luminance value acquiring section 40 may acquire, for example, the peak luminance value without calculating the peak luminance value. In this case, for example, a measurement value of the brightness of the projector set to a predetermined state may be acquired. An image is projected onto the screen 12 from the projection device 10 at the maximum output gradation value. The brightness value on the screen 12 is measured by, for example, a brightness sensor. The brightness value measured by the brightness sensor is acquired as the peak brightness value.

[0030] (Reference brightness value setting unit) The reference luminance value setting unit 42 sets the reference luminance value based on the peak luminance value. The luminance value to be referenced when setting the relation information indicating the relationship between the output gradation value and the optical output value is The reference luminance value setting unit 42 sets the reference luminance value so that it is higher than the peak luminance value. do.

[0031] In this embodiment, the reference luminance value setting unit 42 sets a value indicating the relationship between the reference luminance value and the peak luminance value. The reference luminance value setting unit 42 sets a reference luminance value using the reference luminance information. A reference value corresponding to the peak luminance value acquired by the peak luminance value acquisition unit 40 in the luminance information The luminance value is extracted and set as the reference luminance value. In the reference luminance information, the peak luminance value is The lower the peak luminance value, the lower the reference luminance value. is 100 (cd / m 2 ), the reference luminance value when the peak luminance value is 300 (cd / m 2 ) is lower than the reference luminance value.

[0032] FIG. 3 is a graph showing an example of the relationship between the reference luminance value and the peak luminance value. The reference luminance information will be explained in more detail using curve A, which shows the reference luminance information. In Figure 3, the horizontal axis represents the peak luminance value and the vertical axis represents the reference luminance value. Curve A shows that the peak luminance value is below the threshold L TH A first section A1 is a section where the peak luminance is less than The value is the threshold L TH The curve A indicating the reference luminance information is , the slope in the first section A1 is gentler than the slope in the second section A2. In other words, the curve A showing the reference luminance information is a peak luminance value in the first section A1. The amount of decrease in the reference luminance value when the peak luminance value is lower by a unit amount in the second section A2 is The amount of reduction in the reference luminance value is smaller than when the reference luminance value is low. The line brightness value is the threshold L TH If the brightness is less than 1000 s, and high brightness cannot be achieved on the screen 12, The slope in the first section A1 is made small so that the reference luminance value does not become too low. This allows the range of tones that can be expressed to be limited when high brightness cannot be achieved on the screen 12. Narrowing can be appropriately suppressed.

[0033] More specifically, the curve A representing the reference luminance information has a straight slope in the second section A2. In other words, in the second section A2, the peak luminance value and the reference luminance value are relatively For example, when the peak luminance value is lower by a unit amount, the decrease in the reference luminance value is In this way, by making the second section A2 linear, the projection device 1 When the optical output of 0 is high, the reference luminance value is increased in proportion to the peak luminance value. The brightness of the displayed image can be balanced with the tonal range. On the other hand, curve A, which shows the reference luminance information, In the first section A1, the slope is curved, and more specifically, the shape of the curve is convex downward. In other words, in the first section A1, when the peak luminance value is low by a unit amount, The decrease in the reference luminance value is not constant, and the peak luminance value is lower by a unit amount. The amount of decrease is smaller as the peak luminance value is lower. By using this configuration, when the light output of the projection device 10 is small, the range of gradations that can be expressed becomes narrow. This can appropriately prevent this from happening.

[0034] The relationship between the reference luminance value and the peak luminance value in the reference luminance information is as described above. For example, the reference luminance value setting unit 42 may use a mathematical expression with the screen luminance as a variable. The reference luminance value may be calculated using the above.

[0035] In this embodiment, the reference luminance information is set in advance, and the reference luminance value setting unit 42 stores the reference luminance information in a memory. The reference luminance information stored in the reference luminance value calculation unit 30 is read out and the reference luminance value is set. In this case, the reference luminance value setting unit 42 sets a plurality of reference luminance information. The reference luminance information to be used may be selected from the luminance information. The method is arbitrary, but for example, the user selects the reference luminance information to be used and inputs it to the input unit. The reference luminance value setting unit 42 sets the reference luminance information input by the user as the reference luminance value to be used. In the example of FIG. 3, the relationship between the reference luminance value and the peak luminance value is different. Two reference luminance information (threshold L TH Curve A and threshold L TH 'Curve A') is However, the shape of the curves A and A' indicating the reference luminance information and the number of pieces of reference luminance information are It is not limited to those shown in FIG.

[0036] In the above explanation, the threshold value L TH The value of was a fixed value set in advance, but the threshold L TH In this case, the reference luminance value setting unit 42 may set the threshold value L TH Set For example, the reference luminance value setting unit 42 may set the reference luminance information by Based on the image characteristics, a threshold L TH The reference luminance value setting unit 42 sets The higher the input luminance value contained in the input data, the lower the threshold L TH Higher and lower input luminance values The threshold L TH It is preferable to lower the value. This allows for brighter images to be displayed. By increasing the reference brightness value (clip point), the gradation can be adjusted up to the high gradation levels contained in the image. In addition, when displaying dark images, the image does not contain high gradations. Therefore, the reference luminance value (clip point) can be lowered, and the input luminance value can be adjusted accordingly. In this way, a bright image can be realized. By setting the threshold L TH Even if you do not set It is possible to project images with appropriate related information (EOTF).

[0037] The reference luminance value setting unit 42 sets a threshold value L THWhen setting the input brightness value, MaxCLL (Maximum Content Light Level) included in the data l), i.e., the maximum luminance of the entire content, is used to calculate the threshold L TH Set By using MaxCLL, it can handle the maximum brightness included in the content. It should be noted that content is a single piece of content, such as the entire movie from start to finish. The reference luminance value setting unit 42 sets the threshold value L TH Set up When specifying the input brightness value, MaxFALL (Maximum um Frame Average Light Level), i.e., The maximum value of the average brightness value for each frame included in the content is used to determine the threshold L TH Set By using MaxFALL, the average maximum luminance for each frame can be adjusted. The reference luminance value setting unit 4 can set the reference luminance value to a desirable value for the entire content. 2 is not limited to using MaxCLL or MaxFALL, but also uses image analysis such as histograms. According to the results of the analysis, the threshold L TH You can also set MaxCLL and MaxFALL. is a single value for each content, but if video analysis is performed, it can be dynamically connected for each frame or scene. The points can be changed and more appropriate relationship information can be set.

[0038] Furthermore, when setting the reference luminance information, the reference luminance value setting unit 42 sets the threshold value L TH Other than For example, the reference luminance value setting unit 42 may set a curve A indicating the reference luminance information. The slope and intercept of the curve may be set, or all of these may be set.

[0039] (Reference relationship information setting section) 4A and 4B are graphs showing examples of reference relationship information. 4 sets reference relationship information indicating the relationship between the output gradation value and the optical output value based on the reference luminance value. The reference relationship information is used to set the relationship information (EOTF) actually used in the projection device 10. In Figure 4A, the horizontal axis represents the output gradation value, The vertical axis represents the optical output value. As shown in FIG. 4A, the curve representing the reference luminance related information is designated as curve C. When the reference luminance value is R and the reference luminance value is LR, the reference relationship information setting unit 44 determines whether the upper limit of the optical output value is the reference value. The curve CR indicating the reference relationship information is set so that the illuminance value LR is obtained. The relationship information setting unit 44 calculates the EOTF with the reference luminance value LR as the clip point (saturation point). , and set it as a curve CR indicating the reference relationship information. 44 is a curve that uses the reference luminance value as a clip point for a preset curve C0. The curve C0 is set as a curve CR indicating the reference relationship information. This is the so-called PQ curve, and for example, the gamma where the light output value is at its maximum of 10,000 cd / m2. In curve C0, when the light output value is LR, the output gradation value is OR. The curve CR indicating the reference relationship information is the curve C0 (PQ In the range where the output gradation value is OR or higher, it does not follow the curve C0 (PQ curve). The light output value remains LR.

[0040] FIG. 4B shows an example of curves CR1 and CR2 with different peak luminance values. That is, the curve CR2 has a higher reference relationship information when the peak luminance is smaller than that of the curve CR1. The peak luminance value varies depending on the installation condition of the projector and the condition of the main body. This may vary depending on the state of the screen, which may cause a significant change in the way the image appears. In this embodiment, as shown by the curves CR1 and CR2, in the low to medium gradation range, the output Since the relationship between the gradation value and the light output value is the same, it can be adjusted depending on the installation state of the projection device and the state of the main body. The curves CR1 and CR2 are used to properly suppress changes in the appearance of the image. The line brightness value is the threshold L TH This is the curve CR in the second section A2 (straight section) above. The peak brightness value is the threshold L TH Even in the first section A1, which is less than 1 / 2, in the low to medium gradation range, Therefore, it is possible to appropriately prevent the difference in the relationship between the output gradation value and the light output value from becoming large.

[0041] (Relationship information setting section) 5 is a graph showing an example of the relationship information. The relationship information setting unit 46 sets the reference luminance value and the peak value. Based on the image brightness value, relationship information (EOTF) that indicates the relationship between the output grayscale value and the light output value is set. In this embodiment, the relationship information setting unit 46 uses the reference relationship information and determines the optical output The relevant information is set so that the upper limit (clip point) of the value becomes the peak brightness value. As shown in 5, if the curve showing the relationship information is curve C and the peak luminance value is LP, then The relationship information setting unit 46 sets the curve CR indicating the reference relationship information so that the upper limit value of the optical output value is the peak brightness. The curve C is then compressed to a value LP that indicates the relationship. The relationship information setting unit 46 sets the curve CR indicating the reference relationship information so that the upper limit of the optical output value is the peak luminance. The optical output value LP is obtained by compressing the optical output value so that it is reduced by the same percentage at all points. A curve C showing the relationship information is set. When the optical output value is LP on the curve C showing the relationship information, If the output gradation value in this case is O1, curve C, which shows the relationship information, is the area where the output gradation value is O1 or less. Between these, the light output value increases as the output gradation value increases, and the output gradation value is greater than O1. In this section, the optical output value is maintained at LP. In other words, the curve C showing the relationship information is In the section where the output gradation value is O1 or less, the light output value changes according to the output gradation value. Also, in the section of curve C showing the relationship information where the output gradation value is O1 or less, In other words, when the output gradation value is O1 or less, the slope of the curve is gentler than the slope of the curve CR. In the lower section, the increase in the light output value when the output gradation value in the related information increases by a unit amount The amount is smaller than the increase in the optical output value when the output gradation value in the reference relationship information increases by a unit amount. The output gradation value O1 is the output value when the light output value becomes LP on the PQ curve. In this embodiment, the output gradation value O0 is greater than the output gradation value O1, which is the clip point of the curve CR. This is the same value as the gradation value OR.

[0042] 6 is a graph showing another example of the relationship information. The curve C in FIG. 5 shows the reference relationship information. The curve CR is hard clipped so that the clip point is the peak luminance value LP. However, as shown in Figure 6, curve C is not hard clipped but soft clipped. The soft-clipped curve C is used when the output tone value is smaller than O1. In the section up to O2, the curve is the same as when hard clipped. ,The soft-clipped curve C is the output grayscale value from O2 to O3, which is larger than O1. In this section, the gradient of the output gradation value is smaller than that in the section up to O2. The clipped curve C has an output gradation value of O3 at which the light output value becomes LP, and thereafter the light output value becomes The soft-clipped curve C keeps the output tone value from O2 to O3. In the section, the shape may be a straight line, a curved line that is convex downward, or a curved line that is convex upward. The curved line may be a line having a curved line.

[0043] (Output tone value setting section) The output gradation value setting unit 48 sets the output gradation value based on the input data and the related information. The output gradation value setting unit 48 acquires input data and sets the input luminance value included in the input data as Then, the output gradation value setting unit 48 determines the luminance value to be output based on the input luminance value. For example, the output gradation value setting unit 48 sets the light output value such that the input luminance value is equal to or greater than the peak luminance value. If the input luminance value is equal to or less than the value LP, the input luminance value is considered to be realizable. If the input luminance value is higher than the peak luminance value LP, the input If the luminance value is deemed unattainable, the peak luminance value LP may be set as the light output value. The output gradation value setting unit 48 inputs the optical output value into the related information set by the related information setting unit 46. That is, the output gradation value setting unit 48 sets the output gradation value in the relation information. The output gradation value corresponding to the obtained light output value is extracted and set as the output gradation value.

[0044] (Output control section) The output control unit 50 controls each unit of the projection device 10 to project the image from the projection device 10 onto the screen 12. The output control unit 50 outputs light (image) to the output gradation value setting unit 48. The projection device 10 projects light at the adjusted value.

[0045] (effect) Here, for example, the PQ curve is set according to the brightness required by the input data. However, if the output gradation value is determined according to the PQ curve, for example, the peak on the screen When the brightness value is low, the area that can be displayed according to the PQ curve is reduced, resulting in poorer expression. The range of gradation that can be achieved is reduced, and the image may appear blurred. The control device 24 according to the embodiment sets the reference luminance value to be higher than the peak luminance value, Reference relationship information is set with the reference luminance value as the clip point, and the reference relationship information is compressed to The relationship information is set, and the output gradation value is set using the relationship information. The control device 24 clips the peak luminance value based on a reference luminance value that is higher than the peak luminance value. Therefore, when using relationship information, for example, This allows for a wider range of tones to be expressed than clipping the Q curve at the peak luminance value. For example, in Figure 5, when the PQ curve is clipped at the peak luminance value LP, the output gradation value O0 is Also, when the curve C showing the relationship information is clipped at the peak luminance value LP, the output gradation value O1 is The curve C, which shows the relationship information, has a higher value, and the curve B shows the range of gradation that can be expressed. In this way, the control device 24 according to this embodiment can express a limited range of gradations. Furthermore, the control device 24 according to this embodiment can prevent the projection device from being damaged. By setting the optimum reference brightness value based on the installation condition and the state of the main body, the range of gradations that can be expressed can be improved. It is possible to suppress the narrowing of the range while maintaining brightness. According to the device 24, the brightness that can be projected may vary depending on the installation state of the projection device and the state of the main body. Even in this case, the change in the appearance of the image can be appropriately suppressed.

[0046] (Relationship information setting flow) Next, the flow of setting the related information by the control device 24 will be explained based on a flowchart. FIG. 7 is a flowchart illustrating the setting flow of the relationship information. The control device 24 acquires screen information by the peak luminance value acquisition unit 40 (step S10), calculate the amount of luminous flux (step S12), and based on the screen information and the amount of luminous flux, In this embodiment, the control device 24 calculates the peak luminance value (step S14). The control device 24 calculates the peak luminance value using the formula (2). Next, the control device 24 sets the reference luminance value setting unit 42, a reference luminance value is set based on the peak luminance value (step S16), and the reference relationship The information setting unit 44 sets the reference relationship information based on the reference luminance value (step S18 In this embodiment, the control device 24 sets the reference luminance value to be higher than the peak luminance value. Then, the PQ curve is clipped at the reference brightness value to set the reference relationship information. The device 24 uses the relationship information setting unit 46 to set the relationship information based on the peak luminance value and the reference relationship information. In this embodiment, the control device 24 sets the reference relationship information (step S20). The curve CR is compressed so that the upper limit of the light output value becomes the peak brightness value LP. The control device 24 uses the relationship information set in step S20, i.e., the relationship The output gradation value is set using the correlation information as the EOTF, and an image is projected.

[0047] Once the relevant information is set, the control device 24 stores the relevant information in all input data. However, the control device 24 may update the related information. An example of a process for updating relationship information will be described below.

[0048] The control device 24 updates the related information when, for example, the projection conditions of the projection device 10 are changed. In this case, for example, the control device 24 may adjust the peak brightness based on the changed projection conditions. The control device 24 calculates the brightness value again. The recalculated peak luminance is added to Scope A (the relationship between the peak luminance value and the reference luminance value shown in Figure 3). The control device 24 inputs the reference luminance value and recalculates the reference luminance value. Using the value, the processes from step S18 onwards are executed to update the related information. The device 24 recalculates the reference luminance value using the reference luminance information before the projection conditions are changed. However, the reference luminance information itself may also be reset to calculate the reference luminance value.

[0049] The control device 24 may update the related information when the content is updated. In this case, when the control device 24 acquires different content, it performs the following operation based on the information of the content. Then, the reference luminance information (the relationship between the peak luminance value and the reference luminance value shown in FIG. 3) is reset. For example, the control device 24 obtains the MaxCLL and MaxFALL of the content and Threshold L based on xCLL and MaxFALL TH Reset and update the reference luminance information Then, the control device 24 inputs the peak luminance value into the updated reference luminance information. The control device 24 uses the recalculated reference brightness value to perform the step The processes from S18 onwards are executed to update the related information.

[0050] The control device 24 updates the related information for each input data, i.e., for each frame or scene. In this case, the control device 24 may obtain reference luminance information (peak luminance information shown in FIG. 3) for each frame. For example, the control device 24 may set the relationship between the input luminance value and the reference luminance value for each frame. The maximum input brightness value is obtained and the threshold L is calculated based on the maximum input brightness value. TH Set The control device 24 sets reference luminance information for each frame. The control device 24 inputs the reference luminance value and calculates the reference luminance value for each frame. Then, the processes from step S18 onwards are executed to set the related information for each frame.

[0051] As described above, the projection device 10 according to this embodiment receives input data including information on absolute luminance. The image is projected onto the screen 12 based on the data, and the peak luminance value acquisition unit 40 a reference luminance value setting unit 42, a related information setting unit 46, an output gradation value setting unit 48, and an output control unit The peak luminance value acquisition unit 40 acquires the peak luminance value when the projection device 10 is set to a predetermined state. In addition, when the projection device 10 projects an image onto the screen 12 with the maximum output gradation value, The reference luminance value setting unit 42 obtains the peak luminance value, which is the luminance value on the screen. The relation information setting unit 46 sets the reference luminance value so that the reference luminance value is higher than the reference luminance value. Based on the intensity value and the peak luminance value, the output gradation value and the absolute luminance of the output image from the projection device 10 are calculated. The output gradation value setting unit 48 sets relationship information indicating the relationship between the input data and the optical output value. The projection device 10 according to this embodiment sets the output gradation value based on the pixel data and the related information. The relationship information is set based on a reference luminance value that is higher than the target luminance value. In the projection device 10 according to the embodiment, the related information can prevent the range of gradations that can be expressed from becoming narrower. Furthermore, the control device 24 according to this embodiment can detect the installation state of the projection device and the state of the main body. By setting the optimum reference luminance value to reflect the state of the image, the range of gradation that can be expressed may be narrowed. Furthermore, the control device 24 according to this embodiment can achieve brightness while suppressing the noise. Even if the brightness of the image you can project varies depending on the installation status of the projector or the condition of the projector itself, This can appropriately suppress changes in the way people think.

[0052] Furthermore, the projection device 10 adjusts the output gradation value and the light output value so that the upper limit of the light output value becomes the reference luminance value. It further includes a reference relationship information setting unit 44 that sets reference relationship information that indicates the relationship with the output value. The relationship information setting unit 46 uses the reference relationship information to determine whether the upper limit of the optical output value is equal to the peak luminance value. The projection device 10 according to this embodiment sets the relationship information so that the brightness is greater than the peak brightness value. The relationship information is set using reference relationship information in which the highest reference luminance value is used as a clip point. Therefore, the projection device 10 according to this embodiment can express the related information only in a limited range of gradations. It can prevent it from disappearing.

[0053] The reference luminance value setting unit 42 also sets the reference luminance value so that the lower the peak luminance value, the lower the reference luminance value. The reference luminance value is calculated based on the relationship between the peak luminance value and the reference luminance value (reference luminance information) set as follows: The reference luminance information is set so that the peak luminance value is less than the threshold value L TH In the case of less than The amount of decrease in the reference luminance value when the peak luminance value is lower by a unit amount is TH In the above cases When the peak luminance value is lower by a unit amount, the decrease in the reference luminance value is smaller than the decrease in the reference luminance value when the peak luminance value is lower by a unit amount. The projection device 10 according to this embodiment sets the reference luminance information in this way. Therefore, for example, when high brightness cannot be achieved on the screen 12, the range of gradations that can be expressed is limited. It is possible to appropriately suppress the narrowing of

[0054] (Second embodiment) Next, a second embodiment will be described. In the second embodiment, the projection device 10 outputs The aspect ratio of the image to be projected and the effective projection area on the screen 12 If the aspect ratio is different, the aspect ratio of the image and the aspect ratio of the effective projection area will be The second embodiment differs from the first embodiment in that the peak luminance value is calculated based on the Explanation of the parts that are common to the first embodiment will be omitted.

[0055] FIG. 8 shows an example in which the aspect ratio of the image differs from the aspect ratio of the effective projection area. When an image is projected from the projection device 10 onto the screen 12, the projection device 1 The aspect ratio of the image P output from the screen 12 is In other words, the aspect ratio of the projection device 10 may be different from that of the effective projection area AR0. , an image with an aspect ratio different from the designed aspect ratio may be projected. For example, A projection device 10 designed to output an image with a horizontal to vertical aspect ratio of 16:9 is It may project an image with an aspect ratio of 2.35:1 (Cinemascope size). In such a case, the projection device 10 divides the effective image area Pa and the ineffective image area Pa as shown in FIG. The image P including the effective image area Pb is output. The effective image area Pa is the area in which the image to be displayed is output. The effective projection area AR0 is the area set so that the effective image on the screen 12 is projected. The invalid image area Pb is the area above and below the valid image area Pa. This is the set area, and for example, a black image is output. It is sometimes called x.

[0056] When outputting an image P called a letterbox, the effective area on the screen 12 is The projection area AR0 is the area where the effective image area Pa is projected and has an aspect ratio of 2.35:1. On the other hand, the input data has a 16: The aspect ratio of the light source 20 is 9, and the light from the light source 20 is reflected even in the invalid image area Pb. It is output as light that is not reflected as an effective image (light that is blocked by the display element). In this case, if the peak brightness value is calculated using the aspect ratio of the effective projection area AR0, However, since the invalid image area Pb is excluded, the peak luminance value may be calculated higher than the actual value. Therefore, the control device 24 according to this embodiment controls the image output from the projection device 10. The aspect ratio of the image P is different from the aspect ratio of the effective projection area AR0 on the screen 12. In this case, the peak is determined based on the aspect ratio of the image P and the aspect ratio of the effective projection area AR0. The brightness value is calculated as follows.

[0057] The control device 24 determines the aspect ratio of the image P based on the aspect ratio of the effective projection area AR0. Calculate the diagonal length of the projected image (size of the projected image) included in the screen information. Example For example, the control device 24 calculates the diagonal length L of the projected image using the following equation (3): devic e The control device 24 calculates the calculated L device Using the above formula (2), The control device 24 calculates the area AR of the projected image on the screen 12. By calculating the area AR of the projected image and calculating the peak brightness value, the peak brightness can be calculated more accurately. The degree value can be calculated.

[0058] L device =(AR screen / AR device )×(AR device 2 + 1) 0.5 / (AR screen 2 +1) 0.5 ×L screen ···(3)

[0059] where L screen is the diagonal length of the effective projection area AR0 of the screen 12, AR screen is the aspect ratio of the effective projection area AR0 of the screen 12, and AR device is the aspect ratio of the image P output from the projection device 10. de vice Information to calculate (L screen , A.R. screen , A.R. device The above-mentioned parameters may be measured by various sensors or may be input by the user. In addition, the control device 24 recognizes the presence and size of the invalid image area Pb through video analysis. L device Calculate L device Using the above equation (2), The area AR may be calculated.

[0060] In the above description, it is assumed that the aspect ratio of the image P output from the projection device 10 is 16:9. The aspect ratio of the effective projection area AR0 is 2.35:1. However, the aspect ratio of the image P output from the projection device 10 and the effective projection area AR0 is 1. Similarly, if the aspect ratio of image P is different from 6:9 or 2.35:1, the effective projection area Based on the aspect ratio of the area AR0, the peak luminance value is calculated.

[0061] Furthermore, for example, the projection device 10 may be an anamorphic projection device that optically expands an image in the horizontal (longitudinal) direction. For example, a 16:9 aspect ratio image may be output. A projection device 10 designed to project an effective image with an aspect ratio of 2.35:1 was used. To project onto a clean 12, an anamorphic lens was used, which magnifies the image horizontally by 1.33 times. In this case, the image is electrically displayed in one direction vertically (the short side of the image). The V-stretch function enlarges the image vertically by 33 times. In this way, the optical lateral expansion of the anamorphic lens is The V-stretch function electronically stretches the image vertically to fit the correct image on the screen. The image is displayed in the correct aspect ratio, and the invalid image area Pb is eliminated, reducing the loss of brightness. In such a case, the aspect ratio of the image P and the effective projection area AR 0 aspect ratio is the same, so L device However, the calculation of If the imaging device 10 is not designed to output an image with an aspect ratio of 16:9, However, even if the image is displayed on the screen 12 with the correct aspect ratio, the invalid image area Pb If it exists, L is set according to the size of the invalid image area Pb. device You can calculate .

[0062] FIG. 9 shows an example in which the aspect ratio of the image differs from the aspect ratio of the effective projection area. Furthermore, using a projection device 10 equipped with an anamorphic lens, When an effective image having an aspect ratio of 16:9 is projected onto the screen 12, the following is performed: For example, it is necessary to provide invalid image areas Pb on the left and right of the valid image area Pa. If you are using an anamorphic lens that expands the image by 1.33x, the horizontal The image is reduced by 1.33 times. In this case, the areas on the left and right where the image disappears due to the reduction are called invalid image areas. In this case, the control device 24 determines the aspect ratio of the image P and the effective projection area. Based on the aspect ratio of the area AR0, L device For example, the control device 24 calculates The diagonal length of the projected image is calculated using the following equation (4).

[0063] L device =(M anamorphic ×AR screen / AR device ) ×(AR device 2 +1) 0.5 / {(M anamorphic ×AR screen ) 2 +1} 0.5 ×L screen ···(4)

[0064] where M anamorphic is the elongation factor of the anamorphic lens. ana morphic The user may input whether or not an anamorphic lens is used. The projection device 10 may automatically recognize the attachment or detachment of the anamorphic lens. The device 24 may be configured to adjust the exposure time for the anamorphic lens, if one is used. Based on the optical stretch rate due to the V-stretch function and the electrical stretch rate due to the V-stretch function, dev ice Calculate L device Using this, the area of ​​the projected image AR shown in the above equation (2) is may be calculated.

[0065] (Third embodiment) Next, a third embodiment will be described. In the third embodiment, a reference luminance value setting unit 4 2 acquires temperature information of a display element of the projection device, and calculates a reference brightness value based on the temperature information. The third embodiment differs from the first embodiment in that the configuration is different from the first embodiment. The explanation of common points will be omitted. The third embodiment can also be applied to the second embodiment. be.

[0066] When the display element has temperature characteristics such as liquid crystal, the gamma characteristic, which indicates the response characteristics of the gray scale, changes depending on the temperature. The control device 24 according to the third embodiment may be configured to detect the temperature change of the display device. Taking into account the change in gamma characteristics due to the temperature change, the temperature information of the display element is acquired and the In other words, in the third embodiment, the same method as in the first embodiment is used. The reference luminance value is calculated from the peak luminance value by the method, and the calculated peak luminance value is compared with the temperature information of the display element. The reference luminance value is corrected using the information and used in practice.

[0067] The method for acquiring the temperature information of the display element may be arbitrary. For example, the control device 24 may acquire the temperature information of the display element by using the following formula (5): Based on this, the temperature T device and calculate the temperature information of the display element. and obtain it.

[0068] T device =T ambient +Q×Q DA ···(5)

[0069] where T ambientis the ambient temperature of the projection device 10, and Q is the heat generated by the projection device 10. is the quantity, Q DA is the thermal resistance between the display element and the ambient temperature. ambient teeth, For example, it may be detected by a temperature sensor or may be a preset value. The amount of heat generated Q is calculated from the intensity of the light irradiated onto the display element. The light intensity is calculated from the parameters (projection conditions) used to estimate the amount of projected light flux. For example, the intensity of the light irradiated onto the display element can be controlled by the light source brightness setting, optical filter It can be calculated using the filter, the aperture of the illumination optical system, the transmittance of the optical components of the illumination optical system, etc. The amount of heat generated by driving the display element may be added to the amount of heat generated by Q. DA teeth , may be preset.

[0070] When the display element is a liquid crystal, if the temperature of the display element rises, the intermediate gray level will generally The display brightness of the image of the temperature T device High The lower the temperature, the higher the reference luminance value is corrected. This cancels out the change in brightness of the image, bringing it closer to the brightness of the image when there is no temperature change. can.

[0071] (Fourth embodiment) Next, a fourth embodiment will be described. In the fourth embodiment, the control device 24 The aperture of the illumination optical system of the projection device must be adjusted so that the F-number of the illumination optical system does not exceed the F-number of the projection lens. Furthermore, the control device 24 of the fourth embodiment adjusts the F-number of the projection lens when the F-number exceeds the current value. In the fourth embodiment, the aperture of the projection lens is adjusted so that the The fourth embodiment is the same as the second embodiment and the fourth embodiment. This is also applicable to the third embodiment.

[0072] Here, the zoom position of the projection lens, the aperture of the illumination optical system, and the aperture of the projection lens When you move the lens, the F-number changes, and the brightness and contrast of the image also change. The change is dominated by the part of the projection device 10 that has the largest F-number. When the F-number of the projection lens is at its maximum due to the zoom position of the projection lens, the illumination optics The effect of changes in the system aperture and projection lens aperture on image brightness is limited. However, if the illumination optical system aperture is narrowed, the F-number of the illumination optical system aperture will be If the F-number is larger than the lens's F-number, the brightness will decrease significantly. The zoom position of the projection lens is determined by the installation conditions. The aperture of the illumination optical system should be set within a range where the F-number of the illumination optical system does not exceed the F-number of the projection lens. In this case, for example, the control device 24 adjusts the aperture of the illumination optical system. The adjustable range of the illumination optical system should be set so that the F-number does not exceed the F-number of the projection lens. When the user adjusts the aperture of the illumination optical system, the control device 24 , the adjustable range of the aperture of the illumination optical system is notified, and the user can adjust the aperture. Similarly, the control device 24 adjusts the aperture of the projection lens. It is preferable to adjust the F-number of the projection lens so that it does not exceed the current F-number of the projection lens. In this case, for example, the control device 24 may adjust the adjustable range of the aperture of the projection lens as follows: Set the F-number of the projection lens so that it does not exceed the current F-number of the projection lens. Therefore, when the user adjusts the aperture of the projection lens, the control device 24 adjusts the aperture of the projection lens. The adjustable range of the lens aperture is notified to allow the user to adjust the aperture. This will allow you to adjust the aperture of the illumination optical system and the projection lens. While contrast can be improved by the change in the brightness, the reduction in light intensity can be limited to produce a brighter image. This can be achieved.

[0073] Although the embodiments of the present invention have been described above, the present invention is not limited to the contents of these embodiments. In addition, the above-mentioned components include those that a person skilled in the art can easily imagine, and Furthermore, the above-mentioned components are included in the scope of equivalents. They can be combined as desired, and the configurations of the respective embodiments can also be combined. Furthermore, various omissions, substitutions or modifications of the components may be made without departing from the spirit of the above-described embodiments. Changes can be made. [Explanation of symbols]

[0074] 10 Projection device 12 screens 24 Control device 40 Peak luminance value acquisition unit 42 Reference luminance value setting unit 44 Reference relationship information setting section 46 Relationship information setting section 48 Output tone value setting section 50 Output control section

Claims

1. a luminance value acquisition unit that acquires a peak luminance value calculated based on a maximum luminous flux amount that the projection device can output to a screen, a brightness reduction rate of an optical component with respect to the maximum luminous flux amount, and information about the screen; a reference luminance value setting unit that sets a reference luminance value so that the reference luminance value is higher than the peak luminance value; a relationship information setting unit that, when setting relationship information in which an upper limit of the light output value is the peak luminance value using reference relationship information indicating a relationship between an output gradation value and a light output value which is the intensity of light for displaying an output image from the projection device, sets the unit increment of the relationship information to be smaller than the unit increment of the reference relationship information in a section in which the light output value in the reference relationship information is equal to or smaller than the reference luminance value, where the increase in the light output value when the output gradation value is increased by a unit amount is defined as a unit increment; an output gradation value setting unit that sets an output gradation value based on input data for displaying an image on the projection device and the relationship information; an output control unit that outputs an image using the output gradation value set by the output gradation value setting unit; a control device for controlling the irradiation of light from the projection device,

2. a brightness value acquisition step of acquiring a peak brightness value calculated based on a maximum amount of luminous flux that the projection device can output to a screen, a brightness reduction rate of an optical component with respect to the maximum amount of luminous flux, and information about the screen; a reference luminance value setting step of setting a reference luminance value so as to be higher than the peak luminance value; a relationship information setting step of setting relationship information in which the upper limit of the light output value is the peak luminance value using reference relationship information indicating the relationship between the output gradation value and a light output value which is the intensity of light for displaying an output image from the projection device, and in which, when an increase in the light output value when the output gradation value is increased by a unit amount is defined as a unit increment, setting the unit increment of the relationship information to be smaller than the unit increment of the reference relationship information in a section in which the light output value in the reference relationship information is equal to or smaller than the reference luminance value; an output gradation value setting step of setting an output gradation value based on input data for displaying an image on the projection device and the relationship information; an output control step of outputting an image using the output gradation value set in the output gradation value setting step; a control method for controlling the emission of light from the projection device, the method comprising:

Images