Projection device, projection method and storage medium

Abstract

The reduction of the grayscale range that can be expressed is suppressed, and the change in the visual presentation of the image is reduced even when the brightness that the projection device can project is different. The projection device projects an image onto a screen based on input data containing absolute brightness information, and the projection device includes: a peak brightness value acquisition unit (40) that acquires a peak brightness value, which is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value; a reference brightness value setting unit (42) that sets a reference brightness value in a manner higher than the peak brightness value; a relationship information setting unit (46) that sets relationship information indicating the relationship between the output grayscale value and the light output value based on the reference brightness value and the peak brightness value; an output grayscale value setting unit (48) that sets the output grayscale value based on the input data and the relationship information; and an output control unit (50) that outputs the image based on the output grayscale value generated by the output grayscale value setting unit (48).

Description

Technical Field

[0001] The invention relates to a projection device, a projection method and a storage medium. Background Art

[0002] As input data for displaying an image, there is a projection device that inputs input data containing absolute brightness value information, such as an HDR (High Dynamic Range) signal in a PQ (Perceptual Quantization) method. The projection device generates output data and projects the image in such a way that the projected image becomes an absolute brightness value specified by the input data. However, when an HDR image is projected onto a screen, the actual brightness on the screen varies depending on the size of the screen, and the visual presentation of the image sometimes changes. Therefore, the brightness on the screen is calculated, and based on this, the EOTF (Electro-Optical Transfer Function), that is, the relationship between grayscale and output brightness, is sometimes set. For example, Patent Document 1 discloses a method for changing the grayscale conversion processing for image data based on the calculated brightness. In addition, Patent Document 2 describes the content of changing the EOTF by rewriting the EDID of the HDR image data when multiple projection devices are arranged in an overlapping manner.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-198733;

[0006] Patent document 2: Japanese Patent Application Publication No. 2017-200104. Summary of the invention

[0007] However, for example, in Patent Documents 1 and 2, since the EOTF is determined according to the brightness required by the input data, when the brightness on the screen is low, for example, the area that can be displayed according to the PQ curve becomes smaller, so that the grayscale range that can be expressed becomes smaller, and the image may appear distorted. In addition, when the brightness that the projection device can project is different depending on the setting state of the projection device and the state of the main body, there is also a situation where the visual presentation of the image changes significantly. Therefore, it is required to suppress the situation where the grayscale range that can be expressed becomes smaller, and reduce the change in the visual presentation of the image even when the brightness that the projection device can project is different.

[0008] In view of the above problems, the purpose of this embodiment is to provide a projection device, a projection method and a program, which can suppress the reduction of the grayscale range that can be expressed and reduce the change in the visual presentation of the image even when the brightness that the projection device can project is different.

[0009] A projection device according to one embodiment of the present invention projects an image onto a screen based on input data including absolute brightness information, and includes:

[0010] a peak brightness value acquisition unit, which acquires a peak brightness value, wherein the peak brightness value is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value;

[0011] a reference brightness value setting unit that sets a reference brightness value so as to be higher than the peak brightness value;

[0012] a relationship information setting section that sets relationship information indicating a relationship between an output grayscale value and a light output value that is an intensity of light showing an output image from the projection device based on the reference brightness value and the peak brightness value;

[0013] an output grayscale value setting unit, which sets an output grayscale value based on the input data and the relationship information; and

[0014] The output control unit outputs an image based on the output grayscale value generated by the output grayscale value setting unit.

[0015] A projection method according to one embodiment of the present invention projects an image onto a screen based on input data including absolute brightness information, and includes:

[0016] A step of acquiring a peak brightness value, wherein the peak brightness value is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value;

[0017] a step of setting a reference brightness value in a manner higher than the peak brightness value;

[0018] a step of setting relationship information indicating a relationship between an output grayscale value and a light output value, which is an intensity of light showing an output image from the projection device, based on the reference brightness value and the peak brightness value;

[0019] A step of setting an output grayscale value based on the input data and the relationship information; and

[0020] The step of outputting an image based on the output grayscale value.

[0021] A storage medium according to one aspect of the present embodiment stores a program that causes a computer to execute a projection method for projecting an image onto a screen based on input data including absolute brightness information, and causes the computer to execute the following steps:

[0022] A step of acquiring a peak brightness value, wherein the peak brightness value is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value;

[0023] a step of setting a reference brightness value in a manner higher than the peak brightness value;

[0024] a step of setting relationship information indicating a relationship between an output grayscale value and a light output value showing the intensity of light of an output image from the projection device based on the reference brightness value and the peak brightness value;

[0025] A step of setting an output grayscale value based on the input data and the relationship information; and

[0026] The step of outputting an image based on the output grayscale value.

[0027] According to the present embodiment, it is possible to suppress the reduction in the range of grayscales that can be expressed, and to reduce the change in the visual presentation of the image even when the brightness that can be projected by the projection device is different. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the projection system involved in the first embodiment.

[0029] Figure 2 It is a schematic block diagram of a control device for the projection device according to the present embodiment.

[0030] Figure 3 is a graph showing an example of the relationship between the reference luminance value and the peak luminance value.

[0031] Figure 4A is a graph showing an example of reference relationship information.

[0032] Figure 4B is a graph showing an example of reference relationship information.

[0033] Figure 5 is a graph showing an example of relationship information.

[0034] Figure 6 is a graph showing another example of relationship information.

[0035] Figure 7 This is a flowchart explaining the setting flow of relationship information.

[0036] Figure 8 It 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.

[0037] Fig. 9 It 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

[0038] Hereinafter, this embodiment will be described in detail based on the drawings. In addition, this embodiment is not limited to the embodiment described below.

[0039] (First Embodiment)

[0040] Figure 1 Schematic diagram of the projection system involved in the first embodiment. Figure 1 As shown, the projection system 1 according to the present embodiment includes a projection device 10 and a screen 12 .

[0041] The projection device 10 is a device for displaying an image, and displays an image on the screen 12 by irradiating light toward the screen 12 and projecting light on the screen 12. That is, in the present embodiment, the projection device 10 is a projector for projecting an image. The projection device 10 obtains input data containing absolute brightness value information, sets an output grayscale value of an image capable of outputting an absolute brightness value corresponding to the absolute brightness value represented by the input data, and outputs light (image). That is, the projection device 10 displays an image in an HDR (High Dynamic Range) mode. Further, the projection device 10 is preferably a projection device in a PQ (Perceptual Quantization) mode.

[0042] The projection device 10 includes a light source 20, an optical system 22, and a control device 24. The light source 20 is a light source that generates light irradiated from the projection device 10, and may be of any structure. The optical system 22 is an optical element that receives light output from the light source 20 and emits it to the outside. The optical system 22 includes, for example, a projection lens, an illumination optical system, and a display element, and the illumination optical system guides the light from the light source 20 to the projection lens. The illumination optical system may be of any structure, and may include, for example, a flyeye lens, 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. The description of the control device 24 will be described later.

[0043] The screen 12 is a screen (image display surface) that projects the image (light) from the projection device 10 and displays the projected image. Figure 1In the example of FIG. 1 , light (image) from the projection device 10 is irradiated to the projection surface 12a, which is the front side, and the light is reflected by the projection surface 12a, so that the screen 12 displays the image on the projection surface 12a. However, the screen 12 may also be a transmissive screen that irradiates light to the back side, transmits the light from the back side to the projection surface 12a side, and displays the image on the projection surface 12a. Figure 1 In the example of , the screen 12 is flat, but is not limited to flat, and may be of any shape. For example, the screen 12 may be a cylindrical lens type screen in which one side of the back and the front is concave and the other side is convex.

[0044] (Control device)

[0045] Figure 2 FIG. 1 is a schematic block diagram of a control device for a projection device according to the present embodiment. Figure 2 As shown, the control device 24 is a computer in this embodiment, including a storage unit 30 and a control unit 32. The control device 24 may also have an input unit such as a touch panel as a device for accepting user operations, an output unit such as a display that outputs information, and a communication unit such as an antenna as a communication module. The storage unit 30 is a memory that stores various information such as the calculation content and program of the control unit 32, for example, including at least one of a main storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and an external storage device such as a HDD (Hard Disk Drive). The program for the control unit 32 stored in the storage unit 30 may also be stored in a recording medium that can be read by the control device 24.

[0046] The control unit 32 is a computing device, i.e., a CPU (Central Processing Unit). The control unit 32 obtains input data for causing the projection device 10 to display an image, generates an output grayscale value for the projection device 10 to project (output) the image based on the input data, and outputs light (image) with the output grayscale value. The input data is image data indicating how to cause the projection device 10 to display an image, or can be said to be an input grayscale value. The input data also includes information on an input brightness value, which is an absolute brightness value of the image that the projection device 10 is intended to display. The input data is, for example, an HDR signal, but can also be image data in any form. The output grayscale value is output data for the projection device 10 to actually output an image. In other words, the projection device 10 projects light with the output grayscale value. The control unit 32 sets relationship information indicating the relationship between the output grayscale value and the light output value, sets the output grayscale value based on the input brightness value and the relationship information, and outputs light (image) with the output grayscale value. In addition, the light output value refers to the intensity of light output from the projection device 10 (the intensity of light that displays the output image), and the relationship information can also be said to be EOTF (Electro-Optical Transfer Function). In addition, for example, in the case of a display instead of a projection device, the light output value is equivalent to the absolute brightness value of the output image. The specific structure and processing content of the control unit 32 are described below.

[0047] The control unit 32 includes a peak brightness value acquisition unit 40, a reference brightness value setting unit 42, a reference relationship information setting unit 44, a relationship information setting unit 46, an output grayscale 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 to implement the peak brightness value acquisition unit 40, the reference brightness value setting unit 42, the reference relationship information setting unit 44, the relationship information setting unit 46, the output grayscale value setting unit 48, and the output control unit 50, and performs these processes. In addition, the control unit 32 may perform these processes by one CPU, or may have multiple CPUs and perform the processes by these multiple CPUs. In addition, at least a part of the peak brightness value acquisition unit 40, the reference brightness value setting unit 42, the reference relationship information setting unit 44, the relationship information setting unit 46, the output grayscale value setting unit 48, and the output control unit 50 may be implemented by hardware.

[0048] (Peak brightness value acquisition unit)

[0049] The peak brightness value acquisition unit 40 acquires the peak brightness value on the projection surface 12a of the screen 12. The peak brightness value refers to the brightness value of the image projected on the screen when the projection device 10 is set to a predetermined state and the projection device 10 projects the image on the screen 12 at the maximum output grayscale value. That is, the peak brightness value refers to the maximum value of the absolute brightness value of the light that can be projected on the screen 12 by the projection device 10 set to the predetermined state, which can be said to be the absolute brightness value of the light when the light is projected on the screen 12 at the maximum output grayscale value. The predetermined state refers to the state in which the irradiation condition of the projection device 10 is set to the predetermined condition. The irradiation condition may be, for example, at least one of the maximum light beam amount that the projection device 10 can output, light source output information (brightness of the light source 20, usage time of the light source, etc.), the state of the movable optical filter (information about the wavelength of light transmitted by the optical filter, etc.), the aperture position of the aperture provided in the illumination optical system, the aperture position of the aperture provided in the projection lens, the zoom position of the projection lens, the setting related to image processing, and the transmittance of each optical component.

[0050] In the present embodiment, the peak brightness value acquisition unit 40 acquires the peak brightness value when the projection condition of the projection device 10 becomes the current condition. That is, the peak brightness value acquisition unit 40 acquires as the peak brightness value: when the projection device 10 is set to the current state, the image is projected on the screen 12 at the maximum output grayscale value, and the brightness value of the image projected on the screen. However, it is not limited to this, and the peak brightness value acquisition unit 40 may also acquire as the peak brightness value: when the projection device 10 is set to a state different from the current state, the image is projected on the screen 12 at the maximum output grayscale value, and the brightness value of the image projected on the screen.

[0051] In the present embodiment, the peak brightness value acquisition unit 40 calculates the peak brightness value based on the screen information and the amount of light beam from the projection device 10. The screen information is information related to the screen 12. The screen information includes the size of the projection image projected on the screen 12 and the screen gain. The size of the projection image is information indicating the size of the projection image, and in the present embodiment, it is the diagonal length of the projection image. The screen gain refers to the ratio of the brightness of the image projected on the screen 12 to the brightness of the image projected on the standard white board (complete diffusion plate) when the image is projected on the screen 12 under the same conditions. The screen gain can also be said to be a numerical value indicating the inherent reflection characteristics of the fabric of the screen 12. In the present embodiment, the peak brightness value acquisition unit 40 acquires the screen information through the user's input. That is, the user inputs the screen information to the input unit of the projection device 10, and the peak brightness value acquisition unit 40 acquires the input screen information. In this case, the projection device 10 displays a menu screen, and the user can input the screen information from the menu screen, or input it from the outside through a communication command or the like. However, the peak brightness value acquisition unit 40 is not limited to acquiring the screen information through the user's input. For example, the peak brightness value acquisition unit 40 may acquire the size of the projected image based on the value recognized by the distance measuring sensor, camera, etc., or may recognize the aspect ratio of the projected image based on the format of the input image, thereby acquiring the size of the projected image. Similarly, the peak brightness value acquisition unit 40 may also acquire the screen gain based on the brightness of the projected image detected by the photometric sensor, etc. However, if the screen information is recognized without using the distance measuring sensor, camera, photometric sensor, etc., a simpler structure can be achieved.

[0052] The peak brightness value acquisition unit 40 calculates the amount of light beam from the projection device 10 based on the projection conditions of the projection device 10. That is, the peak brightness value acquisition unit 40 estimates the amount of light beam to be projected based on information associated with the internally recognizable brightness. In the present embodiment, the peak brightness value acquisition unit 40 calculates the amount of light beam from the projection device 10 based on the maximum amount of light beam that the projection device 10 can output and the projection conditions of the projection device 10. For example, when the number of projection conditions used for the light beam amount is N, the peak brightness value acquisition unit 40 calculates the amount of light beam from the projection device 10 based on the following formula (1).

[0053] LM=LM MAX ×(1-D1)×(1-D2)×…×(1-D N )…(1)

[0054] Here, LM is the amount of light beam from the projection device 10, and LM MAX is the maximum light beam quantity that the projection device 10 can output, D1~D N It refers to the brightness reduction rate with respect to the maximum light beam amount that can be output by the projection device 10 under each projection condition.

[0055] LM MAX For example, the peak brightness value acquisition unit 40 may use a specification value recorded in a catalog, a product design value, or an actual measurement value in a factory as LM MAX In this case, LM MAX The value of is stored in advance in the storage unit 30. N It may be a preset value, but it may also be calculated by the peak brightness value acquisition unit 40. For example, the light source output information as a projection condition may include: for example, the brightness setting (e.g., high / medium / low) of the light source 20 selected by the user from the menu screen, and the usage time of the light source 20. Generally speaking, the light amount of the light source decreases with the usage time, so the peak brightness value acquisition unit 40 may, for example, calculate the brightness reduction rate related to the light source output information by a mathematical formula with the usage time as a variable, or may pre-have a table of transmittance according to each usage time, and calculate the brightness reduction rate related to the light source output information by referring to the table. In addition, for example, the peak brightness value acquisition unit 40 may also calculate the brightness reduction rate related to image processing based on the color temperature setting (e.g., 6500K) selected by the user from the menu screen, the applicable image quality mode, the color profile, and the internal processing value not displayed on the menu screen, the factory adjustment value, etc. The factory adjustment value may also include a correction value (RGB gain value, etc.) for correcting individual deviations in the color of the projection light. In addition, for example, since the transmittance of each optical component generally decreases with the usage time, the peak brightness value acquisition unit 40 can calculate the brightness reduction rate related to the transmittance of each optical component by a mathematical formula with the usage time as a variable, or it can pre-have a table of transmittance according to each usage time, and calculate the brightness reduction rate related to the transmittance of each optical component by referring to the table.

[0056] The peak brightness value acquisition unit 40 calculates the peak brightness value based on the screen information and the amount of light beam from the projection device 10. In the present embodiment, the peak brightness value acquisition unit 40 calculates the peak brightness value using the following equation (2).

[0057] LP=LM / AR / π×SG…(2)

[0058] LP(cd / m 2 ) is the peak brightness value, and LM (lm) is the amount of light beam from the projection device 10 as described above. AR (m 2 ) is the area of ​​the image projected on the screen 12, which can be calculated based on the size of the projected image. The size of the image projected on the screen 12 is generally expressed in terms of the length of the diagonal (in inches), so the area of ​​the projection area can be calculated based on the length of the diagonal.2 When calculating, the unit conversion from inches to meters is performed as necessary. In addition, π is the circumference of a circle, and SG is the screen gain.

[0059] The peak brightness value acquisition unit 40 calculates the peak brightness value based on the screen information and the amount of light beam from the projection device 10 as described above, but the calculation method of the peak brightness value is not limited to the above and can be arbitrary. In addition, the peak brightness value acquisition unit 40 may not calculate the peak brightness value, but acquire the measured value of the peak brightness value, for example. In this case, for example, an image is projected onto the screen 12 at the maximum output grayscale value from the projection device 10 set to a predetermined state, and the brightness value on the screen 12 is measured, for example, by a brightness sensor. The peak brightness value acquisition unit 40 acquires the brightness value measured by the brightness sensor as the peak brightness value.

[0060] (Refer to the brightness value setting section)

[0061] The reference brightness value setting unit 42 sets the reference brightness value based on the peak brightness value. The reference brightness value is a brightness value that is referred to when setting relationship information indicating the relationship between the output grayscale value and the light output value. The reference brightness value setting unit 42 sets the reference brightness value to be higher than the peak brightness value.

[0062] In this embodiment, the reference brightness value setting unit 42 sets the reference brightness value using reference brightness information indicating the relationship between the reference brightness value and the peak brightness value. That is, the reference brightness value setting unit 42 extracts the reference brightness value corresponding to the peak brightness value acquired by the peak brightness value acquisition unit 40 from the reference brightness information and sets it as the reference brightness value. The reference brightness information is set such that the lower the peak brightness value, the lower the reference brightness value. That is, for example, when the peak brightness value is 100 (cd / m 2 ) is 300 (cd / m 2 ) when the reference brightness value is low.

[0063] Figure 3 is a graph showing an example of the relationship between the reference brightness value and the peak brightness value. Figure 3 As shown in FIG. 1 , the reference brightness information is described in more detail using a curve A representing the reference brightness information. Figure 3 In the figure, the horizontal axis is the peak brightness value, and the vertical axis is the reference brightness value. The curve A representing the reference brightness information includes a first interval A1 and a second interval A2. The first interval A1 is a period when the peak brightness value is less than the threshold value L TH The second interval A2 is the interval where the peak brightness value is the threshold value L THIn the curve A representing the reference brightness information, the slope in the first interval A1 is gentler than the slope in the second interval A2. In other words, in the curve A representing the reference brightness information, the decrease in the reference brightness value when the peak brightness value in the first interval A1 decreases by a unit amount is less than the decrease in the reference brightness value when the peak brightness value in the second interval A2 decreases by a unit amount. That is, the reference brightness information decreases when the peak brightness value is less than the threshold value L. TH When high brightness cannot be achieved on the screen 12, the slope in the first interval A1 is reduced so that the reference brightness value does not become too low. Thus, when high brightness cannot be achieved on the screen 12, the narrowing of the representable grayscale range can be appropriately suppressed.

[0064] More specifically, the slope of the curve A representing the reference brightness information is linear in the second interval A2. In other words, in the second interval A2, the peak brightness value is proportional to the reference brightness value, and the amount of reference brightness value reduction when the peak brightness value decreases by a unit amount is constant in the entire area of ​​the second interval A2. By setting the second interval A2 to be linear in this way, when the light output of the projection device 10 is high, the reference brightness value is increased in proportion to the peak brightness value, and the brightness of the displayed image can be taken into account. On the other hand, the slope of the curve A representing the reference brightness information is curved in the first interval A1, and more specifically, it becomes a downward convex curve shape. In other words, in the first interval A1, the amount of reference brightness value reduction when the peak brightness value decreases by a unit amount is not constant, and the lower the peak brightness value, the smaller the amount of reference brightness value reduction when the peak brightness value decreases by a unit amount. By setting the first interval A1 to be curved in this way, when the light output of the projection device 10 is small, etc., it is possible to appropriately suppress the narrowing of the grayscale range that can be expressed.

[0065] It should be noted that the relationship between the reference brightness value and the peak brightness value in the reference brightness information is not limited to the above content. For example, the reference brightness value setting unit 42 can also use a mathematical formula with screen brightness as a variable to calculate the reference brightness value.

[0066] In the present embodiment, reference brightness information is set in advance, and the reference brightness value setting unit 42 reads the reference brightness information stored in the storage unit 30 to set the reference brightness value. However, a plurality of reference brightness information may be set. In this case, the reference brightness value setting unit 42 may select the reference brightness information to be used from the plurality of reference brightness information. Although the method of selecting the reference brightness information to be used is arbitrary, for example, the user may select the reference brightness information to be used and input it into the input unit, and the reference brightness value setting unit 42 selects the reference brightness information input by the user as the reference brightness information to be used. Figure 3 In the example, two reference brightness information (threshold LTH The curve A and the threshold L TH’ The curve A') represents the reference brightness information, but the shape of the curve A' and the number of reference brightness information are not limited to Figure 3 The shapes listed in , refer to the number of brightness information.

[0067] In the above description, the threshold value L TH The value of L is a preset fixed value, but the threshold L can also be TH In this case, the reference brightness value setting unit 42 can set the threshold value L TH For example, the reference brightness value setting unit 42 sets the threshold value L based on the input data, that is, based on the characteristics of the image. TH Preferably, the reference brightness value setting unit 42 sets the threshold value L to a value greater than the input brightness value included in the input data. TH The higher the value, the lower the input brightness value, making the threshold L TH The lower the value, the better. Thus, when displaying a bright image, the reference brightness value (clipping point) is increased until the high grayscale level included in the image is reached, and the image can be displayed with good grayscale. In addition, when displaying a darker image, since the image does not contain a high grayscale, the reference brightness value (clipping point) can also be lowered, and accordingly, a bright image close to the input brightness value can be realized. In addition, by using the input brightness value to set the reference brightness information, even if the user does not deliberately set the threshold L TH , and can also project images with appropriate relationship information (EOTF) that matches the content.

[0068] The reference brightness value setting unit 42 sets the threshold value L TH When the input brightness value is set, the MaxCLL (Maximum Content Light Level) included in the input data may be used as the input brightness value, that is, the maximum brightness value of the entire content may be used to set the threshold L. TH By using MaxCLL, it is possible to correspond to the maximum brightness included in the content. In addition, the content refers to a set of image data (input data), for example, from the beginning to the end of a movie. In addition, the reference brightness value setting unit 42 sets the threshold value L TH When the input brightness value is set, the MaxFALL (MaximumFrameAverageLightLevel, the maximum value of the frame average brightness) contained in the input data can be used as the input brightness value, that is, the maximum value of the average brightness value of each frame contained in the content is used to set the threshold L THBy using MaxFALL, it is possible to set a preferred value for the entire content corresponding to the average maximum brightness of each frame. In addition, the reference brightness value setting unit 42 is not limited to using MaxCLL and MaxFALL, and the threshold value L may be set based on the result of image analysis such as a histogram. TH MaxCLL and MaxFALL are single values ​​for each content, but if image analysis is performed, the connection point can be dynamically changed for each frame or scene, and more appropriate relationship information can be set.

[0069] In addition, the reference brightness value setting unit 42 may also set the threshold value L when setting the reference brightness information. TH For example, the reference brightness value setting unit 42 may set the slope or intercept of the curve A representing the reference brightness information, or may set all of these slopes and intercepts.

[0070] (Reference relationship information setting unit)

[0071] Figure 4A and Figure 4B is a graph showing an example of reference relationship information. The reference relationship information setting unit 44 sets reference relationship information showing the relationship between the output grayscale value and the light output value based on the reference brightness value. The reference relationship information refers to the EOTF used as a reference when setting the relationship information (EOTF) actually used in the projection device 10. Figure 4A In the figure, the horizontal axis is the output grayscale value, and the vertical axis is the light output value. Figure 4A As shown, if the curve representing the reference brightness relationship information is set to curve CR and the reference brightness value is set to LR, the reference relationship information setting unit 44 sets the curve CR representing the reference relationship information in such a way that the upper limit value of the light output value becomes the reference brightness value LR. That is, the reference relationship information setting unit 44 sets the EOTF with the reference brightness value LR as the clipping point (saturation point) as the curve CR representing the reference relationship information. In the present embodiment, for the pre-set curve C0, the reference relationship information setting unit 44 sets the curve with the reference brightness value as the clipping point as the curve CR representing the reference relationship information. In the present embodiment, the curve C0 is a so-called PQ curve, for example, with a light output value of 10000 cd / m 2 If the output grayscale value when the light output value is LR in curve C0 is set to OR, the curve CR representing the reference relationship information follows the curve C0 (PQ curve) in the interval where the output grayscale value is below OR, and does not follow the curve C0 (PQ curve) in the interval where the output grayscale value is above OR, but maintains the state where the light output value is LR.

[0072] Figure 4BAn example of curves CR1 and CR2 having different peak brightness values ​​is shown. That is, curve CR2 can be said to be a curve CR showing reference relationship information when the peak brightness is smaller than curve CR1. Here, there is a case where the peak brightness value is different depending on the setting state of the projection device and the state of the subject, and the visual presentation of the image may change significantly. In contrast, in the present embodiment, as shown by curves CR1 and CR2, in the region from low grayscale to medium grayscale, the relationship between the output grayscale value and the light output value is equal, so it is possible to appropriately suppress the situation where the visual presentation of the image changes with the setting state of the projection device and the state of the subject. In addition, curves CR1 and CR2 are curves where the peak brightness value is the threshold value L. TH The curve CR in the second interval A2 (straight line interval) is shown above, but when the peak brightness value is less than the threshold value L TH In the first interval A1, it is also possible to appropriately suppress the difference in the relationship between the output grayscale value and the light output value in the region from low grayscale to medium grayscale from becoming larger.

[0073] (Relationship information setting unit)

[0074] Figure 5 is a graph showing an example of relationship information. The relationship information setting unit 46 sets relationship information (EOTF) indicating the relationship between the output grayscale value and the light output value based on the reference brightness value and the peak brightness value. In the present embodiment, the relationship information setting unit 46 uses the reference relationship information and sets the relationship information in such a way that the upper limit value (clipping point) of the light output value becomes the peak brightness value. Figure 5As shown, if the curve representing the relationship information is set to curve C and the peak brightness value is set to LP, the relationship information setting unit 46 compresses the curve CR representing the reference relationship information so that the upper limit value of the light output value becomes the peak brightness value LP, thereby setting the curve C representing the relationship information. Further, the relationship information setting unit 46 compresses the curve CR representing the reference relationship information so that the upper limit value of the light output value becomes the peak brightness value LP and the light output value decreases by the same ratio at all points, thereby setting the curve C representing the relationship information. If the output grayscale value when the light output value is LP is set to O1 in the curve C representing the relationship information, the light output value increases as the output grayscale value increases in the interval where the output grayscale value is less than O1, and the light output value remains unchanged at LP in the interval where the output grayscale value is greater than O1. That is, the curve C representing the relationship information changes the light output value as the output grayscale value changes in the interval where the output grayscale value is less than O1, so that the grayscale change can be expressed. In addition, the slope of the curve C representing the relationship information in the interval where the output grayscale value is less than O1 is gentler than the slope of the curve CR. In other words, in the interval where the output grayscale value is less than O1, the increase in the optical output value when the output grayscale value increases by a unit amount in the relationship information is less than the increase in the optical output value when the output grayscale value increases by a unit amount in the reference relationship information. In addition, the output grayscale value O1 is greater than the output grayscale value O0 when the optical output value is LP in the PQ curve, and in the present embodiment, is the same value as the output grayscale value OR which is the clipping point of the curve CR.

[0075] Figure 6 is a graph showing another example of relationship information. Figure 5 The curve C is a curve obtained by hard clipping the curve CR representing the reference relationship information so that the clipping point becomes the peak brightness value LP. Figure 6 As shown, curve C may also be a curve that performs soft clipping instead of hard clipping. Curve C after soft clipping becomes the same curve as the case of hard clipping in the interval up to the output grayscale value of O2, and O2 is smaller than O1. On the other hand, curve C after soft clipping has a smaller slope in the interval from O2 to O3 than in the interval from the output grayscale value to O2, and O3 is larger than O1. Moreover, the light output value of curve C after soft clipping becomes LP at the output grayscale value O3, and the light output value remains LP thereafter. Curve C after soft clipping may be a straight line, a downward convex curve, or an upward convex curve in the interval from O2 to O3.

[0076] (Output grayscale value setting section)

[0077] The output grayscale value setting unit 48 sets the output grayscale value based on the input data and the relationship information. The output grayscale value setting unit 48 obtains the input data and reads the input brightness value included in the input data. Then, the output grayscale value setting unit 48 sets the light output value as the brightness value to be output based on the input brightness value. For example, when the input brightness value is less than the peak brightness value LP, the output grayscale value setting unit 48 may consider that the input brightness value can be achieved and set the same value as the input brightness value as the light output value. When the input brightness value is higher than the peak brightness value LP, the input brightness value is considered to be unachievable and the peak brightness value LP is set as the light output value. The output grayscale value setting unit 48 inputs the light output value to the relationship information set by the relationship information setting unit 46 and sets the output grayscale value. That is, the output grayscale value setting unit 48 extracts the output grayscale value corresponding to the set light output value from the relationship information and sets it as the output grayscale value.

[0078] (Output control unit)

[0079] The output control unit 50 controls each unit of the projection device 10 to output light (image) from the projection device 10 to the screen 12. The output control unit 50 projects light onto the projection device 10 at the output gradation value set by the output gradation value setting unit 48.

[0080] (Effect)

[0081] Here, for example, the PQ curve is a curve that is set according to the brightness required by the input data. However, when the output grayscale value is determined according to the PQ curve, for example, when the peak brightness value on the screen is low, the area that can be displayed according to the PQ curve becomes smaller, and thus the grayscale range that can be expressed becomes smaller, and the image may appear distorted. In contrast, the control device 24 involved in the present embodiment sets the reference brightness value in a manner higher than the peak brightness value, sets reference relationship information with the reference brightness value as the clipping point, compresses the reference relationship information to set the relationship information, and uses the relationship information to set the output grayscale value. That is, the control device 24 involved in the present embodiment sets the relationship information with the peak brightness value as the clipping point based on the reference brightness value higher than the peak brightness value. Therefore, when the relationship information is used, for example, compared with clipping the PQ curve using the peak brightness value, the grayscale range that can be expressed can be expanded. For example, in Figure 5In the example, the output grayscale value O1 when the curve C representing the relationship information is clipped with the peak brightness value LP is higher than the output grayscale value O0 when the PQ curve is clipped with the peak brightness value LP, and the grayscale range that can be expressed by the curve C representing the relationship information is wider. In this way, according to the control device 24 involved in this embodiment, the situation that the grayscale range that can be expressed is reduced can be suppressed. Furthermore, the control device 24 involved in this embodiment sets the optimal reference brightness value by reflecting the setting state of the projection device and the state of the main body, which can suppress the situation that the grayscale range that can be expressed is narrowed, and brightness can also be taken into account. In addition, according to the control device 24 involved in this embodiment, even if the brightness that can be projected is different depending on the setting state of the projection device and the state of the main body, the change in the visual presentation method of the image can be appropriately suppressed.

[0082] (Relationship information setting process)

[0083] Next, the flow of setting the relationship information of the control device 24 will be described based on the flowchart. Figure 7 is a flowchart that explains the process of setting relationship information. Figure 7 As shown, the control device 24 acquires screen information through the peak brightness value acquisition unit 40 (step S10), calculates the light beam amount (step S12), and calculates the peak brightness value based on the screen information and the light beam amount (step S14). In the present embodiment, the control device 24 calculates the peak brightness value using the above-mentioned formula (2). Next, the control device 24 sets the reference brightness value based on the peak brightness value through the reference brightness value setting unit 42 (step S16), and sets the reference relationship information based on the reference brightness value through the reference relationship information setting unit 44 (step S18). In the present embodiment, the control device 24 sets the reference brightness value in a manner higher than the peak brightness value, clips the PQ curve with the reference brightness value, and sets the reference relationship information. Next, the control device 24 sets the relationship information based on the peak brightness value and the reference relationship information through the relationship information setting unit 46 (step S20). In the present embodiment, the control device 24 compresses the curve CR representing the reference relationship information in such a manner that the upper limit value of the light output value becomes the peak brightness value LP, and sets the relationship information. The control device 24 uses the relationship information set in step S20 , that is, sets the relationship information as EOTF, sets the output grayscale value, and projects the image.

[0084] Furthermore, after setting the relationship information once, the control device 24 may apply the relationship information to all input data to output an image. However, the control device 24 may also update the relationship information. An example of processing when updating the relationship information is described below.

[0085] The control device 24 may update the relationship information when the projection conditions of the projection device 10 are changed, for example. In this case, the control device 24 recalculates the peak brightness value based on the changed projection conditions, for example. The control device 24 adds a curve A ( Figure 3 The control device 24 uses the recalculated reference brightness value to execute the processing after step S18 and update the relationship information. In addition, the control device 24 is not limited to recalculating the reference brightness value using the reference brightness information before the projection condition is changed, and the reference brightness information itself can be reset to calculate the reference brightness value.

[0086] The control device 24 may also update the relationship information when the content is updated. In this case, after acquiring different content, the control device 24 resets the reference brightness information ( Figure 3 For example, the control device 24 obtains the MaxCLL and MaxFALL of the content, and resets the threshold L based on the MaxCLL and MaxFALL. TH , and updates the reference brightness information. Then, the control device 24 inputs the peak brightness value to the updated reference brightness information and recalculates the reference brightness value. The control device 24 uses the recalculated reference brightness value to perform the processing after step S18 and updates the relationship information.

[0087] The control device 24 may also update the relationship information for each input data, that is, for each frame or each scene. In this case, the control device 24 sets the reference brightness information ( Figure 3 For example, the control device 24 obtains the maximum value of the input brightness value of each frame, and sets the threshold value L based on the maximum value of the input brightness value. TH , setting the reference brightness information for each frame. Then, the control device 24 inputs the peak brightness value to the reference brightness information, and calculates the reference brightness value for each frame. The control device 24 uses the reference brightness value to perform the processing after step S18, and sets the relationship information for each frame.

[0088] As described above, the projection device 10 according to the present embodiment projects an image onto the screen 12 based on input data including absolute brightness information, and includes a peak brightness value acquisition unit 40, a reference brightness value setting unit 42, a relationship information setting unit 46, an output grayscale value setting unit 48, and an output control unit 50. The peak brightness value acquisition unit 40 acquires a peak brightness value, which is a brightness value on the screen when the projection device 10 is set to a prescribed state and the projection device 10 projects an image onto the screen 12 at a maximum output grayscale value. The reference brightness value setting unit 42 sets a reference brightness value higher than the peak brightness value. The relationship information setting unit 46 sets relationship information indicating a relationship between an output grayscale value and a light output value, which is an absolute brightness of an output image from the projection device 10, based on the reference brightness value and the peak brightness value. The output grayscale value setting unit 48 sets the output grayscale value based on the input data and the relationship information. The projection device 10 according to the present embodiment sets the relationship information based on a reference brightness value higher than the peak brightness value. Therefore, the projection device 10 involved in the present embodiment can suppress the situation that the grayscale range that the relationship information can express becomes less. Further, the control device 24 involved in the present embodiment sets the best reference brightness value by reflecting the setting state of the projection device and the state of the main body, which can suppress the situation that the grayscale range that can be expressed becomes narrower, and can also take into account brightness. In addition, according to the control device 24 involved in the present embodiment, even if the brightness that can be projected is different according to the setting state of the projection device and the state of the main body, the change of the image visual presentation method can be appropriately suppressed.

[0089] In addition, the projection device 10 further includes a reference relationship information setting unit 44, which sets reference relationship information representing the relationship between the output grayscale value and the light output value in a manner that the upper limit value of the light output value becomes the reference brightness value. The relationship information setting unit 46 uses the reference relationship information and sets the relationship information in a manner that the upper limit value of the light output value becomes the peak brightness value. The projection device 10 involved in this embodiment uses the reference relationship information that uses the reference brightness value as the clipping point to set the relationship information, and the reference brightness value is higher than the peak brightness value. Therefore, the projection device 10 involved in this embodiment can suppress the situation where the grayscale range that the relationship information can express becomes smaller.

[0090] In addition, the reference brightness value setting unit 42 sets the reference brightness value based on the relationship between the peak brightness value and the reference brightness value (reference brightness information) which is set such that the lower the peak brightness value, the lower the reference brightness value. The reference brightness information is set such that when the peak brightness value is less than the threshold value L TH When the reduction is less than the peak brightness value, it is the threshold value L THThe projection device 10 according to the present embodiment can appropriately suppress the narrowing of the grayscale range that can be expressed by setting the reference brightness information in this way, for example, when high brightness cannot be achieved on the screen 12.

[0091] (Second Embodiment)

[0092] Next, the second embodiment is described. In the second embodiment, the difference from the first embodiment is that when the aspect ratio of the image output by the projection device 10 is different from the aspect ratio of the effective projection area projecting the effective image on the screen 12, the peak brightness value is calculated based on the aspect ratio of the image and the aspect ratio of the effective projection area. In the second embodiment, the description of the same configuration as the first embodiment is omitted.

[0093] Figure 8 : is a schematic diagram showing an example in which the aspect ratio of an image is different from the aspect ratio of an effective projection area. When an image is projected from the projection device 10 onto the screen 12, there is a case in which the aspect ratio of the image P output from the projection device 10 is different from the aspect ratio of the effective projection area AR0 on which the effective image is projected on the screen 12. In other words, the projection device 10 sometimes projects an image with an aspect ratio different from the designed aspect ratio. For example, the projection device 10 designed to output an image with a horizontal to vertical aspect ratio of 16:9 projects an image with a horizontal to vertical aspect ratio of 2.35:1 (widescreen size). In such a case, as Figure 8 As shown, the projection device 10 outputs an image P including an effective image area Pa and an invalid image area Pb. The effective image area Pa can be said to be an area set to output an image to be displayed, and the effective projection area AR0 can be said to be an area on the screen 12 where the effective image area Pa is projected. The invalid image area Pb is an area set above and below the effective image area Pa, and outputs a black image, for example. Such an image P is sometimes called a letterbox.

[0094] When the image P called a letterbox is output in this way, the effective projection area AR0 on the screen 12 becomes an area where the aspect ratio of the projected effective image area Pa is 2.35:1. On the other hand, in the input data, it becomes data with an aspect ratio of 16:9 including the effective image area Pa and the invalid image area Pb, and the light from the light source 20 is also output as light that is not reflected as an effective image (light blocked by the display element) in the invalid image area Pb. In such a case, if the peak brightness value is calculated using the aspect ratio of the effective projection area AR0, the peak brightness value may actually be calculated to be higher than the amount by which the invalid image area Pb is removed. Therefore, when the aspect ratio of the image P output from the projection device 10 is different from the aspect ratio of the effective projection area AR0 on the screen 12, the control device 24 involved in the present embodiment calculates the peak brightness value based on the aspect ratio of the image P and the aspect ratio of the effective projection area AR0. The following is a specific explanation.

[0095] Based on the aspect ratio of the image P and the aspect ratio of the effective projection area AR0, the control device 24 calculates the diagonal length of the projection image (the size of the projection image) included in the screen information. For example, the control device 24 calculates L, which is the diagonal length of the projection image, using the following formula (3): 装置 The control device 24 uses the calculated L 装置 , the area AR of the projected image on the screen 12 is calculated as shown in the above equation (2). By calculating the area AR of the projected image and the peak brightness value in this way, the control device 24 can calculate the peak brightness value more accurately.

[0096] L 装置 =(AR 屏幕 / AR 装置 )×(AR 装置 2 +1) 0.5 / (AR 屏幕 2 +1) 0.5 ×L 屏幕 …(3)

[0097] Here, L 屏幕 is the diagonal length of the effective projection area AR0 of the screen 12, AR 屏幕 is the aspect ratio of the effective projection area AR0 of the screen 12, AR 装置 is the aspect ratio of the image P output from the projection device 10. 装置 Information (L 屏幕 , AR 屏幕 , AR 装置 The L may be measured by various sensors or input by the user. In addition, the control device 24 may also calculate L by identifying the presence or absence of the invalid image area Pb and its size through image analysis.装置 , using L 装置 The area AR of the projection image shown in the above equation (2) is calculated.

[0098] In addition, in the above description, although the case where the aspect ratio of the image P output from the projection device 10 is 16:9 and the aspect ratio of the effective projection area AR0 is 2.35:1 is used as an example, when the aspect ratio of the image P output from the projection device 10 and the effective projection area AR0 is different from 16:9 and 2.35:1, the peak brightness value is also calculated based on the aspect ratio of the image P and the aspect ratio of the effective projection area AR0.

[0099] In addition, for example, the projection device 10 is sometimes equipped with an anamorphic lens that optically magnifies the image in the horizontal direction (long side direction). For example, in order to project an effective image with an aspect ratio of 2.35:1 onto the screen 12 using a projection device 10 designed to output an image with an aspect ratio of 16:9, it is sometimes equipped with an anamorphic lens that magnifies the image by 1.33 times in the horizontal direction. In this case, a V stretch function that electrically magnifies the image by 1.33 times in the vertical direction (the short side direction of the image) is used. By magnifying the image in the vertical direction, the invalid image area Pb disappears. In this way, the image is displayed on the screen 12 with the correct aspect ratio through the optical lateral magnification of the anamorphic lens and the electrical vertical magnification based on the V stretch function, and the invalid image area Pb disappears, which can prevent the loss of brightness. In such a case, since the aspect ratio of the image P is the same as the aspect ratio of the effective projection area AR0, there is no need to calculate L 装置 However, in the case where the projection device 10 is not designed to output an image with an aspect ratio of 16:9, even if the image is displayed on the screen 12 with the correct aspect ratio, there is an invalid image area Pb, and L can be calculated based on the size of the invalid image area Pb. 装置 .

[0100] Fig. 9 1 is a schematic diagram showing an example in which the aspect ratio of the image is different from the aspect ratio of the effective projection area. Fig. 9 As shown in FIG. 1 , it is necessary to set invalid image areas Pb on the left and right of the effective image area Pa. For example, when using an anamorphic lens that magnifies 1.33 times in the horizontal direction, it is electrically reduced by 1.33 times in the horizontal direction. In this case, the left and right areas where the image disappears due to the reduction become invalid image areas Pb. In such a case, the control device 24 also calculates L based on the aspect ratio of the image P and the aspect ratio of the effective projection area AR0. 装置 For example, the control device 24 uses the following formula (4) to calculate the diagonal length of the projected image.

[0101] L 装置 =(M 变形 ×AR 屏幕 / AR 装置 )×(AR 装置 2 +1) 0.5 / {(M 变形 ×AR 屏幕 ) 2 +1} 0.5 ×L 屏幕 …(4)

[0102] Here, M 变形 is the elongation of the deformable lens. M 变形 Whether the anamorphic lens is used may be input by a user or the like, or the projection device 10 may automatically recognize whether the anamorphic lens is attached or detached. In this way, when the anamorphic lens is used, the control device 24 may calculate L based on the optical elongation of the anamorphic lens and the electrical elongation of the V stretching function. 装置 , using L 装置 The area AR of the projected image represented by the above equation (2) is calculated.

[0103] (Third Embodiment)

[0104] Next, the third embodiment is described. In the third embodiment, the difference from the first embodiment is that the reference brightness value setting unit 42 obtains the temperature information of the display element possessed by the projection device, and sets the reference brightness value based on the temperature information. In the third embodiment, the description is omitted for the same structure as the first embodiment. In addition, the third embodiment can also be applied to the second embodiment.

[0105] In the case where the display element has a temperature characteristic such as liquid crystal, the gamma characteristic indicating the grayscale response characteristic sometimes changes according to the temperature. Considering the change of the gamma characteristic caused by the temperature change of the display device, the control device 24 involved in the third embodiment obtains the temperature information of the display element and sets the reference brightness value based on the temperature information. That is, in the third embodiment, the reference brightness value is calculated based on the peak brightness value using the same method as the first embodiment, and the calculated peak brightness value is corrected using the temperature information of the display element as the reference brightness value actually used.

[0106] The method of acquiring the temperature information of the display element is arbitrary, but the control device 24 calculates the temperature T as the temperature of the display element based on the following equation (5), for example: 装置 , and is obtained as the temperature information of the display element.

[0107] T 装置 =T 周围 +Q×Q DA …(5)

[0108] Here, T 周围 is the ambient temperature of the projection device 10, Q is the heat generated by the projection device 10, and Q DA is the thermal resistance between the display element and the ambient temperature. 周围 For example, it can be detected by a temperature sensor, etc., or it can be a pre-set value. In addition, the calorific value Q is calculated based on the intensity of the light irradiated to the display element. The intensity of the light irradiated to the display element can be calculated based on the parameters (projection conditions) used when estimating the amount of projected light beam. For example, the intensity of the light irradiated to the display element can be calculated using the light source brightness setting, optical filter, illumination optical system aperture, transmittance of the optical components of the illumination optical system, etc. The calorific value Q can also be added with the calorific value related to driving the display element. In addition, the thermal resistance Q DA Can be preset.

[0109] When the display element is a liquid crystal, when the temperature of the display element rises, the display brightness of the image of the intermediate gray scale usually increases. 装置 Correction is performed so that the reference brightness value is raised as the temperature rises. This eliminates the change in image brightness of the intermediate grayscale level caused by temperature and makes it closer to the image brightness when there is no temperature change.

[0110] (Fourth Embodiment)

[0111] Next, the fourth embodiment is described. In the fourth embodiment, the control device 24 adjusts the aperture of the illumination optical system of the projection device so that the F value of the illumination optical system does not exceed the F value of the projection lens. In addition, the control device 24 of the fourth embodiment adjusts the aperture of the projection lens so that the F value of the projection lens does not exceed the current value. In the fourth embodiment, the description of the same structure as the first embodiment is omitted. In addition, the fourth embodiment can also be applied to the second embodiment and the third embodiment.

[0112] Here, when the zoom position of the projection lens, the aperture of the illumination optical system, and the aperture of the projection lens are moved, the F value changes, and the brightness and contrast of the image change. The change in the brightness of the image is dominated by the part with the largest F value among the various parts of the projection device 10. For example, when the F value of the projection lens is the largest according to the zoom position of the projection lens, the influence of the change of the aperture of the illumination optical system and the aperture of the projection lens on the brightness of the image is limited, but if the aperture of the illumination optical system is reduced and the F value of the aperture of the illumination optical system is larger than the F value of the projection lens, the decrease in brightness becomes larger. Here, the zoom position of the projection lens is determined by the setting conditions. Therefore, in order to suppress the change in brightness, it is preferable to adjust the aperture of the illumination optical system within the range where the F value of the illumination optical system does not exceed the F value of the projection lens. In this case, for example, the control device 24 sets the adjustable range of the aperture of the illumination optical system to the range where the F value of the illumination optical system does not exceed the F value of the projection lens. In addition, when the user adjusts the aperture of the illumination optical system, the control device 24 notifies the user of the adjustable range of the aperture of the illumination optical system, and prompts the user to adjust the aperture within the adjustable range. Similarly, it is preferred that the control device 24 adjusts the aperture of the projection lens within a range where the F value of the projection lens does not exceed the current F value of the projection lens. In this case, the control device 24 sets the adjustable range of the aperture of the projection lens to a range where the F value of the projection lens does not exceed the current F value of the projection lens. Furthermore, when the user adjusts the aperture of the projection lens, the control device 24 notifies the user of the adjustable range of the aperture of the projection lens, and prompts the user to adjust the aperture within the adjustable range. Thus, it is expected that the contrast can be improved by the aperture action of the illumination optical system and the aperture of the projection lens, and on the other hand, a bright image can be realized by limiting the reduction of the light amount.

[0113] Although the present embodiment has been described above, the embodiment is not limited to the contents of these embodiments. In addition, the aforementioned constituent elements include elements that can be easily thought of by a person skilled in the art, substantially the same elements, and elements of the so-called equivalent scope. Furthermore, the aforementioned constituent elements can be appropriately combined, and the structures of each embodiment can also be combined. Furthermore, various omissions, substitutions, or changes of constituent elements can be made within the scope of the gist of the above-mentioned embodiment.

[0114] Industrial Applicability

[0115] The projection device, projection method, and program of the present embodiment can be used for image display, for example.

[0116] Explanation of symbols

[0117] 10 Projection device

[0118] 12 Screen

[0119] 24 Control Devices

[0120] 40 Peak brightness value acquisition unit

[0121] 42 Reference brightness value setting section

[0122] 44 Reference relationship information setting unit

[0123] 46 Relationship information setting unit

[0124] 48 Output grayscale value setting section

[0125] 50 Output control unit

Claims

1. A projection device, the projection device projecting an image onto a screen based on input data containing absolute brightness information, and comprising: a peak brightness value acquisition unit, which acquires a peak brightness value, wherein the peak brightness value is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value; a reference brightness value setting section that sets the reference brightness value to be higher than the peak brightness value based on a relationship between the peak brightness value and the reference brightness value, the reference brightness value being set such that the lower the peak brightness value, the lower the reference brightness value; a relationship information setting section that sets relationship information indicating a relationship between an output grayscale value and a light output value that is an intensity of light showing an output image from the projection device based on the reference brightness value and the peak brightness value; an output grayscale value setting unit, which sets an output grayscale value based on the input data and the relationship information; and an output control unit that outputs an image based on the output grayscale value generated by the output grayscale value setting unit, The relationship between the peak brightness value and the reference brightness value is set such that the reduction when the peak brightness value is less than a threshold value is less than the reduction when the peak brightness value is greater than the threshold value, and the reduction amount is the reduction amount of the reference brightness value when the peak brightness value decreases by a unit amount.

2. The projection device according to claim 1, wherein: It also includes a reference relationship information setting unit, The reference relationship information setting unit sets reference relationship information so that the upper limit value of the light output value reaches the reference brightness value, wherein the reference relationship information is used to indicate the relationship between the output grayscale value and the light output value. The relationship information setting unit uses the reference relationship information and sets the relationship information so that the upper limit value of the light output value reaches the peak brightness value.

3. The projection device according to claim 1 or 2, wherein: When the aspect ratio of the image output by the projection device is different from the aspect ratio of the effective projection area projecting the effective image on the screen, the peak brightness value acquisition unit calculates the peak brightness value based on the aspect ratio of the image and the aspect ratio of the effective projection area.

4. The projection device according to claim 1 or 2, wherein: The reference brightness value setting unit acquires temperature information of a display element included in the projection device, and sets the reference brightness value based on the temperature information.

5. A projection method, the projection method projecting an image onto a screen based on input data containing absolute brightness information, and comprising the following steps: Acquire a peak brightness value, where the peak brightness value is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value; setting the reference brightness value to be higher than the peak brightness value based on a relationship between the peak brightness value and the reference brightness value, the reference brightness value being set such that the lower the peak brightness value, the lower the reference brightness value; setting, based on the reference brightness value and the peak brightness value, relationship information indicating a relationship between an output grayscale value and a light output value, the light output value being the intensity of light displaying an output image from the projection device; setting an output grayscale value based on the input data and the relationship information; as well as outputting an image based on the output grayscale values, The relationship between the peak brightness value and the reference brightness value is set such that the reduction when the peak brightness value is less than a threshold value is less than the reduction when the peak brightness value is greater than the threshold value, and the reduction amount is the reduction amount of the reference brightness value when the peak brightness value decreases by a unit amount.

6. A computer-readable storage medium storing a program, wherein the program causes a computer to execute a projection method for projecting an image onto a screen based on input data containing absolute brightness information, wherein the program causes the computer to execute the following steps: Acquire a peak brightness value, where the peak brightness value is a brightness value on the screen when the projection device is set to a specified state and the projection device projects an image onto the screen at a maximum output grayscale value; setting the reference brightness value to be higher than the peak brightness value based on a relationship between the peak brightness value and the reference brightness value, the reference brightness value being set such that the lower the peak brightness value, the lower the reference brightness value; setting, based on the reference brightness value and the peak brightness value, relationship information indicating a relationship between an output grayscale value and a light output value showing an intensity of light of an output image from the projection device; setting an output grayscale value based on the input data and the relationship information; as well as outputting an image based on the output grayscale values, The relationship between the peak brightness value and the reference brightness value is set such that the reduction when the peak brightness value is less than a threshold value is less than the reduction when the peak brightness value is greater than the threshold value, and the reduction amount is the reduction amount of the reference brightness value when the peak brightness value decreases by a unit amount.

Images