JP5489566B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device such as a projector or a monitor, and more particularly to an image display device having an aspect ratio conversion function and an image size enlargement / reduction function.

  There are various formats of image signals (video signals). For example, the video system includes SD (Standard Definition) video with an aspect ratio of 4: 3 and resolution of 640 × 480, and HD (High Definition) video with an aspect ratio of 16: 9 and resolution of 1920 × 1080. For monitors used in personal computers, XGA having an aspect ratio of 4: 3 and resolution of 1024 × 768, SXGA having an aspect ratio of 5: 4 and resolution of 1280 × 1024, and WUXGA having an aspect ratio of 16:10 and resolution of 1920 × 1200. Etc.

  On the other hand, in an image display device (display) to which image signals of these various formats are input, scaling processing such as aspect ratio conversion and enlargement / reduction is performed so that images can be displayed satisfactorily.

  Many displays have the following scaling modes: (1) A mode in which enlargement / reduction is performed so as to fit in the vertical or horizontal direction of the display while maintaining the aspect ratio (hereinafter referred to as mode 1). (2) Dot by Dot mode (hereinafter referred to as mode 2). (3) A mode (full display mode) in which aspect ratio conversion and enlargement / reduction are performed and the display is displayed at full resolution (hereinafter referred to as mode 3). And these modes are comprised so that a user can select arbitrarily.

  FIG. 9 shows a case where HD video is displayed on a WUXGA display with an aspect ratio of 16:10, and then the input video is switched to SD video. Strictly speaking, when the HD video is displayed, the aspect ratio of the HD video is different from that of the display, but since the aspect ratio is very close, it is assumed that mode 3 for displaying the entire display screen is selected (FIG. 9). (A)). When the input video is switched to the SD video in this state, a horizontally long video is displayed in mode 3 (FIG. 9B). Therefore, the user manually changes the setting from mode 3 to mode 1 or mode 2 (FIG. 9C).

  FIG. 10 shows a case where an XGA video is displayed on an SXGA + display with an aspect ratio of 4: 3, and then the input video is switched to the SXGA video. When an XGA image is displayed, it is assumed that mode 1 or mode 3 for displaying the image on the entire screen is selected (FIG. 10A). When the input video is switched to the SXGA video in this state, the processing in mode 1 or mode 3 is performed, so that the resolution at the edge of the video is lowered, and it may be impossible to decode with a small font. (FIG. 10 (b)). In such a case, the screen size is reduced, but it is preferable to display the video in mode 2 in which enlargement / reduction is not performed. For this reason, the user manually changes the setting from mode 1 or mode 3 to mode 2 (FIG. 10C).

  As described above, conventionally, each time the input video format is switched, the user needs to change the mode of the scaling process by his / her own operation, which causes the user to feel troublesome.

  As methods for solving such a problem, there are methods disclosed in Patent Document 1 and Patent Document 2. In Patent Document 1, for example, when a video (letterbox) in which a 16: 9 video is inserted by blanking the top and bottom of an SD video is input, the top and bottom blank portions are detected and only the effective video area is detected. A method for automatically switching the aspect conversion processing mode is disclosed. Patent Document 2 discloses a method for facilitating an aspect conversion processing mode change operation using a remote controller.

JP 2001-238149 A JP 2005-303860 A

  However, although the method disclosed in Patent Document 1 is effective for an image with a blank at the top and bottom, it is not effective for an image without such a blank. In addition, although the method disclosed in Patent Document 2 has improved operability, it does not automatically switch the aspect conversion processing mode, and eventually requires a change operation by the user.

  Therefore, the present invention provides an image display device that can automatically switch whether or not to perform scaling processing according to the format of an input image signal.

An image display device according to an aspect of the present invention is an image display device including a display unit capable of displaying an image, the conversion unit performing aspect ratio conversion of an input image signal input to the device, and the input Detecting means for detecting an aspect ratio of the image signal, and the converting means, when the difference between the aspect ratio of the display means and the aspect ratio of the input image signal exceeds a predetermined threshold greater than 0, It operates in a first mode that converts the aspect ratio of the input image signal, and operates in a second mode that does not convert the aspect ratio of the input image signal if the aspect ratio is below the predetermined threshold. .

An image display device according to another aspect of the present invention is an image display device including a display unit capable of displaying an image, and a processing unit that performs enlargement / reduction processing of an input image signal input to the device. The detection means for detecting the image size of the input image signal and the processing means when the difference between the image size that can be displayed by the display means and the image size of the input image signal exceeds a predetermined threshold value greater than zero. Is operated in a first mode in which the image size of the input image signal is enlarged / reduced based on the difference in image size, and the input image signal is input while the difference in image size is below the predetermined threshold. It is characterized by operating in the second mode in which the image size enlargement / reduction processing of the image signal is not performed .

  According to the present invention, the mode that automatically performs the aspect ratio conversion and enlargement / reduction processing and the mode that does not perform the processing are automatically switched according to the aspect ratio and the image size of the input image signal. A display device can be realized.

1 is a diagram illustrating a configuration of a projector that is Embodiment 1 of the present invention. FIG. FIG. 6 is a diagram illustrating an aspect conversion processing mode according to the first embodiment. 3 is a flowchart showing the flow of processing in the first embodiment. FIG. 3 is a diagram illustrating an outline of aspect ratio conversion in the first embodiment. FIG. 6 is a diagram illustrating a modification of the projector that is Embodiment 1. FIG. 6 is a diagram illustrating a configuration of a projector that is Embodiment 2 of the present invention. 9 is a flowchart showing a flow of processing in Embodiment 2. FIG. 10 is a diagram illustrating an outline of resolution conversion processing according to the second embodiment. The figure which shows the outline | summary of the conventional aspect-ratio conversion. The figure which shows the outline | summary of the conventional resolution conversion process.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a projector (image projection apparatus) as an image display apparatus according to the first embodiment of the present invention.

  In FIG. 1, 1 is a projector. The analog video signal (input image signal) Vi input to the projector 1 is decoded and A / D converted by the input signal processing unit 10 and converted into a digital signal.

  The digital video signal is subjected to scaling processing such as aspect ratio conversion by the digital video signal processing unit 11 and is displayed on the liquid crystal panel 13 as a display element (display unit) capable of displaying an image via the panel driving unit 12. The The liquid crystal panel 13 in the present embodiment is a WUXGA panel (resolution 1920 × 1200) having an aspect ratio of 16:10.

  The synchronization signal or enable signal SYNCi of the input video signal Vi decoded by the input signal processing unit 10 is input to the input format detection unit (detection means) 14 where the aspect ratio Asp_In of the input video signal Vi is detected. .

The aspect ratio Asp_In is
Asp_In = horizontal effective size of input video signal ÷ vertical effective size.

Further, the aspect ratio Asp_Out of the liquid crystal panel 13 is, in this embodiment,
Asp_Out = 1920 ÷ 1200 = 1.6
It is. The aspect ratio Asp_Out is stored in the panel aspect ratio memory 17.

  On the other hand, the aspect ratio threshold memory 15 stores a threshold value Asp_th that is a predetermined value in advance. The threshold value Asp_th is a guideline for determining how much the aspect ratio is different from the aspect ratio conversion. Here, Asp_th = 0.2 as an example.

  An aspect ratio Asp_In of the input video signal Vi, an aspect ratio Asp_Out of the liquid crystal panel 13, and a threshold value Asp_th from the aspect ratio threshold memory 15 are input to the aspect conversion processing determination unit (calculation unit and switching unit) 16. The aspect conversion process determination unit 16 determines a scaling process mode from these pieces of information by a predetermined determination process, and transmits the determination result to the digital video signal processing unit (conversion unit) 11. The predetermined determination process will be described later.

  The digital video signal processing unit 11 performs scaling processing according to the determined scaling processing mode (scaling mode: referred to as aspect conversion processing mode in the following description). In this embodiment, three modes shown in FIG. 2 are provided as aspect conversion processing modes. Here, as an example, a case where an SXGA input video signal is displayed on the WUXGA liquid crystal panel 13 will be described.

  (1) As shown in FIG. 2A, a mode in which enlargement / reduction is performed simultaneously in the vertical and horizontal directions while maintaining the aspect ratio (hereinafter referred to as mode 1).

  (2) As shown in FIG. 2B, a mode (Dot By Dot) in which neither enlargement nor reduction is performed (hereinafter referred to as mode 2).

  (3) As shown in FIG. 2 (c), a mode (full display mode) in which the image is displayed at full display resolution by performing enlargement / reduction for aspect ratio conversion and vertical / horizontal (hereinafter referred to as mode 3).

  These aspect conversion processing modes are switched (selected) by the aspect conversion processing determination unit 16. In the present embodiment, mode 3 corresponds to the first mode, and mode 1 corresponds to the second mode.

  Next, the flow of processing up to the aspect conversion processing mode determination performed by the input format detection unit 14 and the aspect conversion processing determination unit 16 will be described with reference to FIGS. FIG. 3 is a flowchart showing the processing flow, and FIG. 4 shows an input video signal and a display video on the liquid crystal panel 13.

  In STEP1, the input format detection unit 14 determines whether or not the format of the input video signal Vi has changed. If there is a change, the process proceeds to STEP2, and if there is no change, STEP1 is repeated.

  In STEP 2, the input format detection unit 14 calculates the horizontal size H_en and the vertical size V_en of the effective video area of the input video signal Vi based on the HSYNC (horizontal synchronization signal), VSYNC (vertical synchronization signal), and DataEnable of the input video signal Vi. To do.

Next, in STEP 3, the input format detection unit 14 calculates (detects) the aspect ratio Asp_In of the input video signal Vi by the following equation.
Asp_In = H_en ÷ V_en
Next, in STEP 4, the aspect conversion processing determination unit 16 is an absolute value of a difference between the aspect ratio Asp_In of the input video signal Vi and the aspect ratio Asp_Out of the liquid crystal panel 13.
| Asp_In-Asp_Out |
Is calculated. Then, the absolute value of the difference in aspect ratio is compared with the threshold value Asp_th.

  If | Asp_In-Asp_Out |> Asp_th, the aspect conversion processing determination unit 16 proceeds to STEP 5 and sets the aspect conversion processing mode to mode 1; otherwise, the aspect conversion processing mode is set to mode 3. Set.

In FIG. 4A, when the input video signal is XGA (1024 × 768), the aspect ratio of the input video signal is
Asp_In = 1024 ÷ 768 = 1.33
It is.

On the other hand, the aspect ratio of the liquid crystal panel 13 of WUXGA is
Asp_Out = 1920 ÷ 1200 = 1.6
It is.

For this reason,
| Asp_In-Asp_Out | = 0.27> Asp_th = 0.2
It is. Therefore, mode 1 is selected as the aspect conversion processing mode. That is, the enlargement process is performed with the aspect ratio preserved. Here, an example is shown in which the vertical direction is enlarged until the screen is full. However, the present invention is not limited to this, and a method of enlarging with a predetermined overscan amount as shown in FIG. 4B is used. May be.

In FIG. 4C, when the input video signal is HD video (1920 × 1080), the aspect ratio of the input video signal is
Asp_In = 1920 ÷ 1080 = 1.77
It is.

On the other hand, the aspect ratio of the WUXGA liquid crystal panel 13 is 1.6 as described above. For this reason,
| Asp_In-Asp_Out | = 0.17 <Asp_th = 0.2
It is. Therefore, mode 3 is selected as the aspect conversion processing mode. That is, the enlargement process is performed on the entire screen of the liquid crystal panel 13.

  Thus, in this embodiment, when the difference between the aspect ratio of the input video signal and the aspect ratio of the liquid crystal panel 13 is smaller than the threshold value Asp_th, that is, when the aspect ratio of the input video signal is close to the aspect ratio of the liquid crystal panel 13, An image is displayed on the entire screen of the liquid crystal panel 13. When the aspect ratio difference is larger than the threshold value Asp_th, that is, when the aspect ratio of the input video signal is significantly different from the aspect ratio of the liquid crystal panel 13, the aspect ratio is set to prevent the display video from becoming horizontally long or vertically long. Will not change. Since these processes (modes) are automatically switched, a good video display can be performed without requiring troublesome operations by the user.

  As illustrated in FIG. 5, an aspect threshold value changing unit 20 that can change the threshold value Asp_th according to a user operation (switch operation or command communication operation) may be added to the configuration illustrated in FIG. 1. Since the degree of necessity for preventing a portrait or landscape image from being converted by the aspect conversion varies depending on the user's preference, the aspect threshold change unit 20 can be provided to automatically switch the mode according to the user's preference.

  FIG. 6 shows the configuration of a projector that is Embodiment 2 of the present invention.

  In FIG. 6, 3 is a projector. The analog video signal (input image signal) Vi input to the projector 3 is decoded and A / D converted by the input signal processing unit 10 and converted into a digital signal. The digital video signal is subjected to scaling processing such as aspect ratio conversion by the digital video signal processing unit 11 and displayed on the liquid crystal panel 40 as a display element (display means) via the panel driving unit 12. The liquid crystal panel 40 in the present embodiment is an SXGA + panel (resolution 1400 × 1050) having an aspect ratio of 4: 3.

  The synchronization signal or enable signal SYNCi of the input video signal Vi decoded by the input signal processing unit 10 is input to the input format detection unit 30, where the resolution of the input video signal Vi (effective video area: image size). Is detected.

The resolution of the input video signal Vi includes a horizontal effective size (H_en_IN) and a vertical effective size (V_en_IN).
The resolution (image size) of the liquid crystal panel 40 is
H_en_OUT = 1400
V_en_OUT = 1050
It is. The resolution is stored in the panel resolution memory 33.

The resolution threshold memory 31 stores a threshold Res_th as a predetermined value in advance. Res_th is a guideline for determining how much the resolution of the input video signal and the resolution of the liquid crystal panel 40 are different from each other. In this embodiment, as an example,
Res_th = 10 [%]
And

  The scaling processing determination unit 34 receives the resolution (H_en_IN, V_en_IN) of the input video signal, the resolution (H_en_OUT, V_en_OUT) of the liquid crystal panel 40, and the threshold value Res_th from the resolution threshold value memory 31. The scaling processing determination unit 34 determines a scaling mode by a predetermined determination process from these pieces of information, and transmits the determination result to the digital video signal processing unit (processing unit) 11. The predetermined determination process will be described later.

  The digital video signal processing unit 11 performs an enlargement / reduction process according to the determined scaling process mode (scaling mode: referred to as an enlargement / reduction mode in the following description). In the present embodiment, three modes 1 to 3 similar to the first embodiment are provided as the enlargement / reduction mode. In this embodiment, mode 1 and mode 3 correspond to the first mode, and mode 2 corresponds to the second mode.

  Next, the flow of processing until the enlargement / reduction mode determination performed by the input format detection unit 30 and the scaling processing determination unit 34 will be described with reference to FIGS. 7 and 8. FIG. 7 is a flowchart showing the flow of the processing, and FIG. 8 shows an input video signal and a display video on the liquid crystal panel 40.

  In STEP 101, the input format detection unit 30 determines whether or not the format of the input video signal Vi has changed. If there is a change, the process proceeds to STEP 102, and if there is no change, STEP 101 is repeated.

  In STEP102, the input format detection unit 30 calculates the horizontal size H_en_IN and the vertical size V_en_IN of the effective video area of the input video signal Vi based on HSYNC, VSYNC, and DataEnable of the input video signal Vi.

Next, in STEP 4, the scaling processing determination unit 34 is an absolute value of a difference between the resolution of the input video signal and the resolution of the liquid crystal panel 40.
| 1- (H_en_IN / H_en_OUT) | × 100
| 1- (V_en_IN / V_en_OUT) | × 100
Is calculated. Then, these are compared with the threshold Res_th.

The scaling process determination unit 34
| 1- (H_en_IN / H_en_OUT) | × 100 <Res_th
Or
| 1- (V_en_IN / V_en_OUT) | × 100 <Res_th
If so, the enlargement / reduction mode is set to mode 2. Otherwise, the enlargement / reduction mode is set to mode 1 or mode 3.

In FIG. 8A, the input video signal is SXGA (1280 × 1024), and its resolution is
H_en_IN = 1280
V_en_IN = 1024
It is.

On the other hand, the resolution of the SXGA + liquid crystal panel 40 is
H_en_OUT = 1400
V_en_OUT = 1050
It is. For this reason,
| 1- (H_en_IN / H_en_OUT) | × 100 = 8.5 [%]
<Res_th = 10 [%]
| 1- (V_en_IN / V_en_OUT) | × 100 = 2.5 [%]
<Res_th = 10 [%]
It is. Therefore, mode 2 is selected as the enlargement / reduction mode. That is, enlargement / reduction processing is not performed.

In FIG. 8B, the input video signal is XGA (1024 × 768). The resolution of the input video signal is
H_en_IN = 1024
V_en_IN = 768
It is.

On the other hand, the resolution of the SXGA + liquid crystal panel 40 is as described above.
H_en_OUT = 1400
V_en_OUT = 1050
It is. For this reason,
| 1- (H_en_IN / H_en_OUT) | × 100 = 27 [%]
> Res_th = 10 [%]
| 1- (V_en_IN / V_en_OUT) | × 100 = 27 [%]
> Res_th = 10 [%]
It is. Therefore, mode 1 or mode 3 is selected as the enlargement / reduction mode. That is, the image is displayed on the entire liquid crystal panel 40 by performing the enlargement / reduction process.

  As described above, in this embodiment, when the difference between the resolution of the input video signal and the resolution of the liquid crystal panel 40 is smaller than the threshold Res_th, that is, when the resolution of the input video signal is close to the resolution of the liquid crystal panel 40, the image quality of the display video is displayed. The enlargement / reduction processing is not performed with emphasis on. When the resolution difference is larger than the threshold Res_th, that is, when the resolution of the input video signal is significantly different from the resolution of the liquid crystal panel 40, the enlargement / reduction processing is performed with emphasis on the size of the display video. Since these processes (modes) are automatically switched, a good video display can be performed without requiring troublesome operations by the user.

  In this embodiment, a resolution threshold value changing unit (not shown) that can change the threshold value Res_th according to a user operation (switch operation or operation by command communication) may be added to the configuration shown in FIG. . Since the degree of necessity for preventing the resolution from being degraded by the enlargement / reduction process varies depending on the user's preference, the mode can be automatically switched according to the user's preference by providing the resolution threshold value changing unit.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

  In each of the above embodiments, a projector using a liquid crystal panel as a display element has been described. However, the present invention can also be applied to a projector using a display element other than the liquid crystal panel (for example, a digital micromirror device). Furthermore, the present invention can be applied to various image display devices such as computer monitors and television monitors.

  It is possible to provide an image display device that automatically switches between a mode in which aspect ratio conversion or enlargement / reduction processing is performed and a mode in which it is not performed according to the aspect ratio and image size of the input image signal.

DESCRIPTION OF SYMBOLS 1,3 Projector 10 Input processing part 11 Digital video signal processing part 13,40 Liquid crystal panel 14,30 Input format detection part 16 Aspect conversion process determination part 34 Scaling process determination part

Claims (4)

An image display device comprising display means capable of displaying an image,
Conversion means for performing an aspect ratio conversion of an input image signal input to the apparatus;
Detecting means for detecting an aspect ratio of the input image signal ,
The conversion means is a first mode for converting the aspect ratio of the input image signal when the difference between the aspect ratio of the display means and the aspect ratio of the input image signal exceeds a predetermined threshold value greater than zero. An image display apparatus that operates and operates in a second mode that does not convert an aspect ratio of the input image signal when the threshold value is below the predetermined threshold . The image display apparatus according to claim 1, wherein the conversion unit does not convert the aspect ratio of the input image signal when the difference in the aspect ratio is greater than 0 and less than the threshold value . An image display device comprising display means capable of displaying an image,
Processing means for performing enlargement / reduction processing of an input image signal input to the apparatus;
Detecting means for detecting an image size of the input image signal;
When the difference between the image size that can be displayed by the display unit and the image size of the input image signal exceeds a predetermined threshold value greater than 0 , the processing unit is configured to input the input image signal based on the difference in the image size. In the first mode in which the image size enlargement / reduction processing is performed, the image size enlargement / reduction processing of the input image signal is not performed while the difference between the image sizes falls below the predetermined threshold. An image display device that operates in a mode . The image display device according to claim 3, wherein the processing unit does not perform an enlargement / reduction process of the image size of the input image signal when the difference in the image sizes is greater than 0 and less than the threshold value. .