JP5407254B2 - Projection apparatus, projection method, and program - Google Patents

Description

  The present invention relates to a projection apparatus, a projection method, and a program suitable for a projector apparatus using an LED as a light source, for example.

  When a light source that can be turned on instantaneously, such as a projection device using an LED as a light source and whose light emission amount changes with temperature, the light amount changes within a period of one frame of an image even if the output of the light source is kept constant.

  FIG. 6 is a diagram for explaining a case where an image is projected by a DLP (Digital Light Processing) (registered trademark) projector device using an LED as a light source. As shown in FIG. 6A, an image for each color component is formed and projected by time-division lighting of three color LEDs of R (red), G (green), and B (blue) for one color image frame. In this case, the lighting timing and the amount of emitted light of each color LED are as shown in FIGS. 6 (B) to 6 (D). That is, in each lighting period of R, G, and B, the LEDs of each color reduce the light amount immediately after starting lighting with a high light amount at the beginning of the period, and gradually reduce the amount of decrease to obtain a constant level of light amount. To keep.

  FIG. 6E shows gradation control in the case of using, for example, DMD (Digital Micromirror Device) (registered trademark) as a light modulation element under such characteristics of the amount of emitted light. For example, when the number of quantization bits is 8 and each color of R, G, B is expressed by 256 gradations, the light modulation element uses the PWM (pulse width modulation) to set the reflection time of light to the projection optical path during the period. Gradation is expressed by controlling.

  In this case, in the actual projector apparatus, the continuous reflection time from the beginning of the period is not controlled from the “1” gradation to the “255” gradation based on the basic PWM control. ), The corresponding period is divided according to the length of each bit of the 8-bit gradation data, and the reflection time is controlled at the timing corresponding to “1” in the 8-bit gradation data. It is supposed to be.

  For example, when the gradation data is “123 (011111011)”, “1 (= 2 to the power [0])”, “2 (= 2 to the power [1])” in FIG. "8 (= 2 to the power [3])", "16 (= 2 to the power [4])", "32 (= 2 to the power [5])", "64 (= 2 to the power [6]) The corresponding pixel position of the light modulation element is turned “ON” at each timing corresponding to “”, and the light from the light source is controlled to be reflected to the projection system.

  However, since the light source light has a characteristic that the amount of light is particularly high at the beginning of the lighting period as described above, the gradation value to be lit on the minimum bit “1 (= 2 [0] power)” side of the head position of the period. However, there is a problem that gradation expression brighter than the original is made in the whole period.

  FIG. 7 shows a change in the amount of modulated light corresponding to the input gradation value in consideration of the lighting characteristics of the LED. Originally, the actual gradation value R due to the lighting characteristics of the LED is as shown by a solid line in the figure, whereas the ideal value I is desirable to change the linear linear light quantity as shown by the dotted line in the figure. As a result, the gradation inversion X in which the amount of light decreases despite the increase in the gradation value at a plurality of locations results.

  For example, in FIG. 7, the light intensity is inverted from 127 to 128, and this is because the gradation expression is controlled by 8 bits as described above, so that the gradation value of 127 is the entire lighting period. Since the first half portion is made as (01111111), 128 gradation values are made as (10000000) instead of the latter half portion of the lighting period, so that the light is lit with a high light quantity at the beginning of the period. Due to this, the phenomenon of brightness reversal has occurred.

  As a method for dealing with such a situation, a method of adjusting the time for turning on / off the element's minimal mirror in one frame for correction can be considered, but the length of time and the total light amount are not proportional. There is a problem that the light amount of gradation is deviated from the assumed value.

Therefore, a technique has been considered in which the LED current is changed according to the light amount in the lighting pulse, and the illumination light amount is controlled as constant as possible. (For example, Patent Document 1)
JP 2006-349731 A

  In the technique described in the above patent document, the recording of the light quantity with respect to the current and the temperature, the conversion control of the current value at a fast timing, and the like are required, so that the configuration of the drive circuit and the storage table is complicated.

  Moreover, there is a risk that a vigorous cycle will occur in which a temperature rise will occur by increasing the current and a further increase in current will be required.

  The present invention has been made in view of the above circumstances, and an object thereof is a projection apparatus capable of forming and projecting an optical image that faithfully reproduces the gradation value of an input image. Another object is to provide a projection method and a program.

The invention according to claim 1 is a light source having a non-constant amount of light in a period of one image frame, and a light modulating unit that modulates and emits light from the light source to a predetermined number of gradations using pulse width modulation, The relationship between each gradation value in the predetermined number of gradations and the light amount of each gradation value emitted from the light source and modulated by the light modulation means for each gradation value in the period of one frame of the image And a projecting unit that projects light modulated by the light modulating unit as image light based on the relationship stored in the storing unit, and each floor represented by the light modulating unit. Measuring means for measuring the light quantity of the light source for each tone, and the storage means is a gradation value of 1 which is a pair of gradation values in which the light quantity decreases as the gradation value increases. And the gradation value of 2 The amount of light with an increase be associated to increase, and updates and stores the above relationship.

  According to the present invention, it is possible to form and project an optical image that faithfully reproduces the gradation value of an input image.

  An embodiment in which the present invention is applied to a data projector apparatus will be described below with reference to the drawings.

(Configuration of one embodiment)
FIG. 1 is a block diagram showing a schematic functional configuration of an electronic circuit included in the data projector device 10 according to the embodiment.
An input / output connector unit 11 includes, for example, a pin jack (RCA) type video input terminal, a D-sub15 type RGB input terminal, and a USB (Universal Serial Bus) connector.

  Image signals of various standards input from the input / output connector unit 11 are input to an image conversion unit 13 that is also generally referred to as a scaler via an input / output interface (I / F) 12 and a system bus SB. The image conversion unit 13 unifies the input image signal into an image signal of a predetermined format suitable for projection, and appropriately stores it in the video RAM 14 which is a buffer memory for display, and then sends it to the projection image processing unit 15.

  At this time, data such as symbols indicating various operation states for OSD (On Screen Display) is also superimposed on the image signal by the video RAM 14 as necessary, and the processed image signal is sent to the projection image processing unit 15.

  The projection image processing unit 15 multiplies a frame rate according to a predetermined format, for example, 30 [frames / second], the number of color component divisions, and the number of display gradations in accordance with the transmitted image signal. The micromirror element 16, which is a spatial light modulation element (SOM), is driven to display by high-speed time division driving.

  The micromirror element 16 is turned on / off individually at a high speed by tilting angles of a plurality of micromirrors arranged in an array, for example, XGA (horizontal 1024 × vertical 768 dots). Form an image.

  On the other hand, the LED array 17 is used as a light source of the data projector device 10. The LED array 17 is configured in an array arrangement so that a large number of LEDs that emit light of RGB colors are regularly mixed. Light emission by time division for each of the color components is reflected on the entire inner surface. The light is collected by the affixed pyramid-shaped housing 18, converted into a luminous flux having a uniform luminance distribution by the integrator 19, then totally reflected by the mirror 20 and irradiated onto the micromirror element 16.

  Then, an optical image is formed by the reflected light from the micromirror element 16, and the formed optical image is projected and displayed via a projection lens unit 21 on a screen (not shown) to be projected.

  In the LED array 17, LED groups of corresponding colors are driven and controlled by the R driver 22, the G driver 23, and the B driver 24, respectively, and each primary color of RGB emits light in a time division manner.

  The R driver 22, the G driver 23, and the B driver 24 drive the LED groups of individual color components constituting the LED array 17 with timing and drive current based on a control signal from the projection light processing unit 25.

  The projection light processing unit 25 controls the light emission timing and driving current by the R driver 22, G driver 23, and B driver 24 according to the image data given from the projection image processing unit 15. Further, the projection light processing unit 25 receives a detection signal from the illuminance sensor 26 that detects the luminance of the light image formed by the micromirror element 16.

  The CPU 27 controls all the operations of the above circuits. The CPU 27 performs control operations in the data projector apparatus 10 using a main memory 28 composed of DRAM and a program memory 29 which is an electrically rewritable nonvolatile memory storing an operation program, various fixed data, and the like. Run.

  The CPU 27 executes various projection operations according to key operation signals from the operation unit 30. The operation unit 30 includes a key operation unit provided in the main body of the data projector device 10 and a laser light receiving unit that receives infrared light from a remote controller (not shown) dedicated to the data projector device 10. A key operation signal based on the key operated via the controller is directly output to the CPU 27.

  The CPU 27 is further connected to an audio processing unit 31 and a wireless LAN interface (I / F) 32 via the system bus SB.

  The sound processing unit 31 includes a sound source circuit such as a PCM sound source, converts the sound data given during the projection operation into an analog signal, drives the speaker unit 33 to emit a loud sound, or generates a beep sound or the like as necessary.

  The wireless LAN interface 32 transmits / receives data to / from a plurality of external devices including a personal computer using a 2.4 [GHz] band radio wave in accordance with, for example, the IEEE802.11b / g standard via the wireless LAN antenna 34.

  The projected image processing unit 15 includes a gradation storage unit 15a that stores gradation correction data obtained by gradation correction processing described later. The gradation storage unit 15a stores the input gradation data, the luminance value detected by the illuminance sensor 26, and the output gradation data in association with each other for each of R, G, and B.

  The stored contents of the gradation storage unit 15a can be set as a unique value of the individual data projector apparatus 10 as a product test before shipping the data projector apparatus 10 to the factory, and the user can update and store it at an arbitrary timing after purchasing the product. It shall be possible. Furthermore, the stored contents of the gradation storage unit 15a may be updated and stored as an initial setting when the data projector device 10 is turned on.

(Operation of one embodiment)
Next, the operation of the above embodiment will be described.
FIG. 2 shows the processing content when the content of the gradation correction data stored in the gradation storage unit 15a of the projection image processing unit 15 is updated. The operation shown in FIG. 11 is basically executed by the CPU 27 after the operation program stored in the program memory 29 is read out and stored in the main memory 28.

  At the beginning of the operation, an initial value “1” is set as a variable c for selecting the R driver 22, G driver 23, and B driver 24 as an initial setting (step S101), and a variable gd indicating a gradation value is set. Is set to an initial value “1” (step S102).

  Originally, the minimum value of the gradation value handled by the data projector device 10 is “0”. This gradation value “0” is a projection lens in which all the light from the light source side is shielded by the micromirror element 16. The operation of measuring the gradation value “0” is omitted, assuming that it is not necessary to measure the brightness at the micromirror element 16 as indicating that the light is not reflected to the unit 21 side.

Thus, the red light source is turned on by the R driver 22 with the value “1” of the variable c and the value “1” of the variable gd, and the front surface of the screen is changed to the gradation value “1” by the micromirror element 16. A light image is formed and projected by the projection lens unit 21, and the brightness at the micromirror element 16 at that time is detected by the illuminance sensor 26 and stored in the gradation storage unit 15a of the projection image processing unit 15. (Step S103).
The operation in step S103 is executed in synchronization with the R, G, and B fields (in this case, the R field) constituting one frame of the image.

  Thereafter, after confirming that the value of the variable c is not “3” indicating B (blue) (step S104), the value of the variable c is updated by “+1” (step S105), and again from the above step S103. Return to the process.

  In step S103, the brightness of the light image having the gradation value “1” with the green light source is detected by the G driver 23 based on the value “2” of the variable c and the value “1” of the variable gd. Store in 15a.

  Further, in step S105, the value of the variable c is updated by “+1” and set to “3” through step S104, and again in step S103, the value of the variable c is “3” and the value of the variable gd is “1”. The B driver 23 detects the brightness of the light image having the gradation value “1” with the green light source and stores it in the gradation storage unit 15a.

  If it is determined in the subsequent step S104 that the value of the variable c is “3”, it is assumed that the measurement of the brightness of the light images of the R, G, B colors with the gradation value “1” has been completed. After confirming that the variable gd indicating the gradation value is not the final value “256” (step S106), the initial value “1” is set again in the variable c (step S107), and the variable indicating the gradation value is set. gd is updated by “+1” and set to “2” (step S108), and the process returns to step S103.

  In this way, the brightness at the gradation values “1” to “255” given under the R, G, and B color light sources is sequentially measured by repeatedly executing the processing of steps S103 to S108 as appropriate.

  When the time corresponding to 255 frames of the image has elapsed and the measurement of the brightness at the gradation values “1” to “255” corresponding to the R, G, and B colors is completed, the process passes through the above steps S104 and S106. Then, based on the contents stored in the gradation storage unit 15a, conversion data for rearranging the gradations according to the order of the measured brightness is created (step S109).

  FIG. 3A shows that the brightness R1 at the gradation values “63” and “64” obtained by the above measurement is different from the brightness I1 along the original gradation, and the original gradation value increases. In spite of this, the state where the reversal phenomenon in which the actual brightness is reduced is illustrated.

  FIG. 3B shows the brightness R1 with respect to the gradation value shown in FIG. 3A as a digital value characteristic that changes stepwise in accordance with the actual control contents. The portion indicated by X1 corresponds to the state in which the inversion phenomenon occurs.

  Therefore, in the converted data created by the rearrangement process in step S109, the gradation value “63” is treated as the gradation value “64” and the gradation value “64” is treated as the gradation value “63”. As a result, it is possible to provide a characteristic that the brightness naturally changes in accordance with the gradation value given as shown in FIG.

  Perform rearrangement processing as described above, and create conversion data that partially converts the output relative to the input so that the brightness gradually increases as the given gradation value increases Then, the created conversion data is updated and stored so as to be stored in the gradation storage unit 15a (step S110), and the processing of FIG.

  Thereafter, until the process of FIG. 2 is executed again, the content of the gradation storage unit 15a is not rewritten, and the brightness naturally increases sequentially with the increase of the input gradation value. Thus, the gradation value is read, and the micromirror element 16 is driven to display according to the gradation value.

  As described above in detail, according to the present embodiment, it is possible to form and project a light image having natural brightness according to the gradation value of the input image.

(Another operation example 1 of one embodiment)
In the operation of the present embodiment, it is assumed that conversion data that rearranges the gradation values in accordance with the order of the measured brightness for the content stored in the gradation storage unit 15a in step S109 of FIG. 2 is created. As explained above, as another operation example, not only rearranging the gradation values so that the brightness increases, but also approximating the brightness of the gradation values to be the original ideal brightness. explain.

  FIG. 4A illustrates a case where the actually measured brightness R2 characteristic is different from the ideal brightness I2 characteristic according to the gradation value.

  FIG. 4B is a digital diagram in which the brightness R2 and the ideal brightness I2 as measured values for the gradation values shown in FIG. 4A are changed in steps according to the actual control contents. This is indicated by the value characteristics.

  Therefore, in another operation example of the present embodiment, instead of the processing content in step S109, the gradation value in which each gradation approximates the desired brightness based on the content stored in the gradation storage unit 15a. It is assumed that conversion data such as

As the conversion data to be created, for example, if the gradation value before conversion → the gradation value after conversion,
0 gradation → 0 gradation
1 gradation → 0 gradation or 1 gradation
2 gradations → 1 gradation
3 gradations → 1 gradation or 2 gradations
4 gradations → 2 gradations
:
:
With such a content, it is possible to have a characteristic that provides almost the desired brightness corresponding to a given gradation value.

  As described above, not only the portion where the tone value is inverted but also the entire tone value of 1 to 255 so that the desired brightness can be obtained corresponding to the given tone value. When the conversion data for converting the output gradation value with respect to the input gradation value is created, the created conversion data is updated and stored in the gradation storage unit 15a in the subsequent step S110.

  Thereafter, the contents of the gradation storage unit 15a are not rewritten until the process of FIG. 2 is executed again, and the gradation value is such that the desired brightness is obtained corresponding to the input gradation value. And the micromirror element 16 is driven to display according to the gradation value.

  As described above in detail, according to the present embodiment, it is possible to form and project a light image having a natural brightness that almost faithfully reproduces the brightness of the gradation value of the input image.

(Other operation example 2 of one embodiment)
Further, as another operation example, not only the gradation values are rearranged so that the brightness of each gradation approximates the ideal brightness, but also conversion data is created, and a plurality of pieces of image data for one frame are generated at the time of projection. Divided into sub-frames, each color image of R, G, B is projected in a time-sharing manner in each sub-frame, and one color image is divided into a plurality of frames and projected, so that each color image is originally projected A case will be described in which the brightness at each gradation value suitable for is further approximated so as to be the ideal brightness.

  FIG. 5A shows a case where the actually measured brightness R3 characteristic is different from the ideal brightness I3 characteristic according to the gradation value as a digital value characteristic that changes stepwise. Is.

  Therefore, in another operation example 2 of the present embodiment, instead of the processing content in step S109 described above, different gradations are necessary in the subframes divided into a plurality based on the content stored in the gradation storage unit 15a. By selecting this, conversion data is created so that each gradation has a gradation value very close to the desired brightness in one frame.

  FIG. 5B illustrates a part of the content of the converted data when one frame is divided into two subframes.

  For example, when the gradation value “3” is projected, the gradation value “1” is selected in the first subframe, and the gradation value “2” is selected in the second subframe. Projection is executed with a brightness that is an intermediate tone value between the tone value “1” and the tone value “2”. As a result, the ideal brightness at the given tone value “3” is obtained. It is possible to provide characteristics that are very close to the desired brightness.

  As described above, the conversion data for converting the input gradation value into each output gradation value divided into a plurality of subframes so as to obtain a characteristic that has almost the desired brightness corresponding to the given gradation value. In step S110, the created conversion data is updated and set to be stored in the gradation storage unit 15a.

  Thereafter, the contents of the gradation storage unit 15a are not rewritten until the process of FIG. 2 is executed again, and the gradation value is such that the desired brightness is obtained corresponding to the input gradation value. And the micromirror element 16 is driven to display according to the gradation value.

  As described above in detail, according to the present embodiment, a light image having a natural brightness that is reproduced almost faithfully by approximating the tone value of the input image by the ideal brightness of the tone value. And can be projected.

  In FIG. 5 (B), one frame is divided into two subframes. However, the present invention is not limited to this, and one frame is divided into three or more subframes. It is also possible to create conversion data that obtains the tone value at 1. It is easier to create a tone value that approximates the desired tone value as the number of divisions increases.

  Moreover, although the said embodiment demonstrated the case where the light source which carries out light emission drive of the three colors LED of R, G, B by time division was used, this invention does not limit the kind of light source, for example, A method of appropriately coloring light source light from a white LED using a color wheel, a method of obtaining R, G, B emission as excitation light by selectively irradiating a plurality of phosphors with laser light The present invention can be similarly applied to various types of light sources.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the functions executed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiment includes various stages, and various inventions can be extracted by an appropriate combination of a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, if the effect is obtained, a configuration from which the constituent requirements are deleted can be extracted as an invention.

1 is a block diagram showing a schematic functional configuration of a data projector apparatus according to an embodiment of the present invention. 6 is a flowchart showing the processing content of a gradation correction operation according to the embodiment. The figure which illustrates the measurement result and correction content in the gradation correction operation according to the embodiment. The figure which illustrates the measurement result in other operation examples 1 concerning the embodiment. The figure which illustrates the measurement result and the content of correction | amendment in the other operation example 2 which concerns on the embodiment. The figure explaining the case where an image is projected with the DLP projector apparatus which uses LED as a light source. The figure which shows the relationship between the gradation value of the image etc. with the LED light source of FIG. 6, and the light quantity of modulated light.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Data projector apparatus, 11 ... Input / output connector part, 12 ... Input / output interface (I / F), 13 ... Image conversion part (scaler), 14 ... Video RAM, 15 ... Projection image processing part, 15a ... Gradation memory , 16 ... micromirror element (SOM), 17 ... LED array, 18 ... housing, 19 ... integrator, 20 ... mirror, 21 ... projection lens unit, 22 ... R driver, 23 ... G driver, 24 ... B driver, 25 ... Projection light processing unit, 26 ... Illuminance sensor, 27 ... CPU, 28 ... Main memory, 29 ... Program memory, 30 ... Operation unit, 31 ... Audio processing unit, 32 ... Wireless LAN interface (I / F), 33 ... Speaker 34, wireless LAN antenna, SB, system bus.

Claims (7)

A light source with a non-constant amount of light for a period of one frame of the image;
Light modulating means for modulating and emitting light from the light source to a predetermined number of gradations using pulse width modulation;
Storage means for storing the relationship between each gradation value in the predetermined number of gradations and the amount of light emitted from the light source and modulated by the light modulation means for each gradation value in a period of one frame of the image When,
Projecting means for projecting light modulated by the light modulation means as image light based on the relationship stored in the storage means,
Further comprising measuring means for measuring the light amount of the light source for each gradation expressed by the light modulation means,
The storage means rearranges the gradation values of 1 and 2, which are the pair of gradation values in which the light amount is decreased as the gradation value increases, A projection apparatus, wherein the relationship is updated and stored in association with the light quantity so as to increase with an increase.   The storage means stores a gradation value for the light modulation means to modulate the light from the light source to a light amount approximate to an ideal light amount corresponding to each gradation value. The projection apparatus according to 1. The light modulation means divides one image frame into a plurality of subframes to modulate light from the light source,
The storage means stores, for each of the plurality of subframes, a gradation value for the light modulation means to modulate the light from the light source to a light amount that approximates an ideal light amount corresponding to each gradation value. The projection apparatus according to claim 2.   4. The projection apparatus according to claim 2, wherein the ideal value is a light amount value for each gradation value emitted from the light source when the light amount of the light source in a predetermined period is constant. The light source consists of a red light source, a green light source, and a blue light source,
The storage means has a relationship between each gradation value in the predetermined number of gradations and a light amount of each gradation value emitted from the light source and modulated by the light modulation means for each gradation value in a predetermined period. The projection apparatus according to claim 1, wherein each of the colors is stored. A light source having a non-constant amount of light for a period of one image frame, a light modulator that modulates and emits light from the light source to a predetermined number of gradations using pulse width modulation, and light modulated by the light modulator A projection method in an apparatus including a projection unit that projects the image light as image light,
Relationship between each gradation value in the predetermined number of gradations and the light amount of each gradation value emitted from the light source and modulated by the light modulation unit for each gradation value in the period of one frame of the image A storing step for storing
A projection control step of projecting light modulated by the light modulation unit as image light based on the relationship stored in the storage step as image light, and the light source for each gradation value expressed by the light modulation unit Measuring step of measuring the amount of light,
The storing step rearranges the gradation value 1 and the gradation value 2 which are the pair of gradation values whose light amount is reduced as the gradation value increases, A projection method, wherein the relationship is updated and stored in association with the light quantity so as to increase with an increase. A light source having a non-constant amount of light for a period of one image frame, a light modulator that modulates and emits light from the light source to a predetermined number of gradations using pulse width modulation, and light modulated by the light modulator A program that is executed by a computer built in an apparatus including a projection unit that projects image light as image light,
Relationship between each gradation value in the predetermined number of gradations and the light amount of each gradation value emitted from the light source and modulated by the light modulation unit for each gradation value in the period of one frame of the image A memory step for storing
A projection control step for projecting light modulated by the light modulation unit based on the relationship stored in the storage step as image light by the projection unit; and the light source for each gradation value expressed by the light modulation unit. A computer to execute a measurement step of measuring the amount of light of
The storing step rearranges the gradation value 1 and the gradation value 2 as a pair of gradation values in which the light amount decreases as the gradation value increases, A program for causing a computer to execute the association so as to update and store the relationship in association with the increase so that the amount of light increases.

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