JP2007121625A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for improving visibility of a display image on an image display device which is put on the head or face and through which the outside can be seen. <P>SOLUTION: A control unit detects luminance and color temperature and sets coefficients (a), (b), (c) based upon an image signal obtained through imaging operation of a camera unit 7 (#3) and determines the large/small relation between the measured luminance and a specified threshold α (#4). When the measured luminance is larger than the threshold α (YES at #4), the quantity of light of an LED (the quantity of display light of the LED) is adjusted according to the measured luminance (#5). Then the control unit determines whether the color temperature of the image deviates from a specified range (#6) and adjusts display colors according to a value (k) calculated by using large/small relation between (a) and ad, large/small relation between (c) and cd, the coefficients (a), (b), (c), and an expression (1), when the color temperature deviates from the specified range (YES at #6). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image display device that is attached to a head or a face and allows a user to see through the outside world.

  Conventionally, there is known an image display device that is attached to a user's head or face and provides an image to the user's eyeball in the vicinity thereof. Patent Documents 1 to 3 listed below include this type of image display device. The technology concerning is proposed.

  In the following Patent Document 1, in a head-mounted display unit having a display unit configured to be attachable to a user's face, a drawing image and a menu for drawing related to the drawing image are simultaneously displayed on the display unit In addition, in consideration of the visibility of the drawing image and the menu, the line-of-sight detecting means for detecting the line of sight of the user, and the technology for changing the display form in a predetermined display area in the display unit according to the detected line of sight of the user Is disclosed.

  The following Patent Document 2 relates to an image display device that provides different images having parallax for both the left and right eyes, and visually senses the depth of an object using a stereoscopic function based on a difference in convergence angle between both eyes. There is a description.

In the following Patent Document 3, in a display device in which display information is spatially overlapped with video information of a subject in a front vision of an observer and guided to an eyeball within the same field of view, character information of the display information is transmitted to the outside world. A configuration for spatially displaying stereoscopic information with respect to video information (see-through image) has been proposed.
JP-A-9-191438 JP 2002-92656 A JP-A-9-127455

  In the image display device capable of see-through the outside world as in Patent Document 3, when the transmittance of the display unit is relatively high, it becomes difficult to distinguish between the image of the outside world and the display image. The performance will be reduced. In addition, when a high-frequency component is included in an external image, it becomes difficult to distinguish a display image, and in particular, the visibility of characters is reduced. Furthermore, when the image of the outside world is biased to a specific color, the color of the display image may be significantly different from the actual color. Note that Patent Documents 1 and 2 do not describe an image display device that can see through the outside world.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique for improving the visibility of a display image in an image display device that is attached to a head or a face and allows a user to see through the outside. To do.

  The invention described in claim 1 is an image display device attached to the head or the face and capable of see-through from the outside, and performs a photoelectric conversion operation by receiving a display means for displaying an image and a light image of a subject. And a display mode changing unit that changes a display mode of the image according to an image obtained by an imaging operation of the imaging unit.

  According to the present invention, since the display mode of the image is changed according to the image obtained by the imaging operation of the imaging means, it is possible to improve the visibility of the display image in the image display device.

  According to a second aspect of the present invention, in the image display device according to the first aspect, the display mode changing means includes a color temperature detecting means for detecting a color temperature of an image obtained by an imaging operation of the imaging means, Display color adjusting means for adjusting the display color of the image according to the color temperature detected by the color temperature detecting means, and display control means for causing the display means to display an image whose display color has been adjusted by the display color adjusting means. Are provided.

  According to this invention, the color temperature of the image is detected, the display color of the image on the display unit is adjusted according to the detected color temperature, and the image on which the color temperature has been adjusted is displayed on the display unit. It is possible to suppress the occurrence of a state in which the image displayed on the display means is significantly different from the actual subject.

  According to a third aspect of the present invention, in the image display device according to the second aspect, a luminance detection unit that detects the luminance of the image, and an image of the display unit according to the luminance detected by the luminance detection unit. A display light amount adjusting means for adjusting the display light amount is further provided.

  According to the present invention, the brightness of the image is detected, and the display light amount of the image on the display means is adjusted according to the detected brightness. For example, when the brightness of the external subject is very high, the display means It can suppress that the visibility of the image to display falls.

  According to a fourth aspect of the present invention, in the image display device according to the first aspect, the display mode changing means includes a spatial frequency detecting means for detecting a spatial frequency of an image obtained by the imaging operation of the imaging means, Display light amount adjusting means for adjusting the display light amount of the image on the display means according to the spatial frequency detected by the spatial frequency detecting means, and displaying the image whose display light amount is adjusted by the display light amount adjusting means on the display means And a display control means.

  According to this invention, the spatial frequency of the image is detected, the display light amount of the image on the display means is adjusted according to the detected spatial frequency, and the image is displayed on the display means with the display light amount. It is possible to suppress a decrease in the visibility of images displayed on the screen, particularly characters.

  According to a fifth aspect of the present invention, in the image display device according to the fourth aspect of the present invention, the image display device further includes a luminance detection unit that detects the luminance of the image, and the display light amount adjustment unit is detected by the spatial frequency detection unit. The display light quantity of the image is adjusted in accordance with the spatial frequency and the brightness detected by the brightness detecting means.

  According to the present invention, not only the spatial frequency of the image but also the luminance of the image is detected, and the display light amount of the image on the display means is adjusted according to the detected spatial frequency and luminance. It is possible to suppress a reduction in the visibility of the image displayed on the display means when the brightness of the screen is very high.

  According to the present invention, the display color or the display light amount of the image on the display means is adjusted according to at least one element among the color temperature, luminance, and spatial frequency of the image. Visibility can be improved.

  An embodiment of an image display device according to the present invention will be described. 1 is a front view showing a configuration of an embodiment of an image display apparatus according to the present invention, FIG. 2 is a plan view with respect to FIG. 1, and FIG. 3 is a right side view with respect to FIG. It is assumed that a three-dimensional coordinate system is set in which the left-right direction of FIG.

  As shown in FIGS. 1 to 3, the image display device 1 is a head-mounted display device (head mounted display (HMD)) that is used by being placed in the vicinity of the eyeball of the user of the image display device 1. The first and second transparent substrates 2 and 3, the bridge 4, the frames 5 and 6, the camera unit 7, and the display housings 8 and 9.

  The first and second transparent substrates 2 and 3 are U-shaped and substantially flat transparent bodies respectively provided corresponding to the left and right eyeballs. As will be described later, the display housings 8 and 9 are fitted in a space formed by being surrounded by the first and second transparent substrates 2 and 3.

  The bridge 4 is a short rod-like member that spans a predetermined position facing each other of the first and second transparent substrates 2 and 3 that are arranged parallel to the XY plane and arranged in the X-axis direction. 2 and the second transparent substrate 3 are held in a relative positional relationship with a predetermined gap therebetween.

  The frames 5 and 6 are long members made of a flexible elastic material or the like. The frames 5 and 6 are hooked on the user's ears or the temporal region, and are held on the head of the image display device 1. This is for adjusting the mounting position. The frames 5 and 6 are configured to be rotatable in the directions of arrows P and Q in the rotating portions 5a and 6a. When the image display device 1 is not used, the frames 5 and 6 are indicated by the arrows P and It can be made compact by rotating in the Q direction along the first and second transparent substrates 2 and 3.

  The camera unit 7 captures a subject in front of the user's eyes, and is attached to, for example, one frame 5. FIG. 4 is a cross-sectional view showing the internal configuration of the camera unit 7. As shown in FIG. 4, the camera unit 7 takes a lens unit 11 in which a zoom lens optical system is arranged in a cylindrical housing 10 and an optical image of a subject guided by the lens unit 11 (photoelectric sensor). Image sensor 12 to be converted), an image sensor substrate 13 that supports the image sensor 12, and a cable 14 for transmitting a pixel signal obtained by the imaging operation of the image sensor 12 to a control unit (not shown). Has been. The variable power lens group and the focus lens group of the lens unit 11 are configured to be driven in the optical axis direction by a motor (not shown), and the display magnification is changed when the variable power lens group is driven in the optical axis direction. When the focus lens group is driven in the optical axis direction, focus adjustment is performed.

  The image pickup device 12 performs photoelectric conversion into image signals of R, G, and B components according to the amount of light of the subject light image formed by the lens unit 11. The image sensor 12 has R (red), G (green), and B (blue) color filters in a checkered pattern on the surface of each CCD of an area sensor in which CCDs (Charge Coupled Devices) are two-dimensionally arranged. It is composed of a single-plate type color area sensor that is affixed to a so-called Bayer system. As the image pickup element 12, a CCD image sensor, a CMOS image sensor, a VMIS image sensor, or the like can be employed.

  The display housings 8 and 9 have the same configuration, and display an image (video) taken by the camera unit 7 and provide it to the eyeball. FIG. 5 is a cross-sectional view taken along line AA in FIG. 2 and mainly shows the internal configuration of the display housings 8 and 9.

  As shown in FIG. 5, the display housings 8 and 9 include a housing portion 15, an LED (Light Emitting Diode) 16, a collimator lens 17, an LCD (Liquid Crystal Display) 18, a prism 19, and a HOE (HOE). Holographic Optical Element) 20, and the LED 16, the collimator lens 17, and the LCD 18 are built in the casing 15. It is attached in a manner that protrudes upward.

  The LED 16 is a point light source composed of a white light emitting diode (LED) including a predetermined wavelength color. The collimator lens 17 makes the light from the LED 16 substantially parallel and projects it onto the LCD 18. The LCD 18 generates video based on the image signal of the camera unit 7 and is, for example, a transmissive liquid crystal display panel.

  The prism 19 is a substantially plate-like transparent member made of glass, transparent resin, or the like, and reflects light from the LCD 18 a plurality of times inside. The upper end portion of the prism 19 is formed with a thick portion 19a whose front side is formed in a wedge shape so as to be thicker upward so that most of the light from the LCD 18 can be collected inside. .

  A tapered surface 19b is formed at the lower end of the prism 19, and the prism 19 is joined to the tapered surfaces 2a and 3a formed on the first and second transparent substrates 2 and 3 via the HOE 20 ( For example, it is bonded. The front and back surfaces of the prism 19 are flush with the front and back surfaces of the first and second transparent substrates 2 and 3. Thus, the prism 19 is integrated with the first and second transparent substrates 2 and 3 in a single plate shape.

  The HOE 20 is a volume phase type hologram optical element having a positive power, which is configured by a so-called free-form surface that is optically axisymmetric, and is supported at a lower end portion of the prism 19 with a predetermined inclination angle. The HOE 20 irradiates the light guided by the prism 19 to provide a hologram image to the eyeball using the light interference phenomenon.

  In the display housings 8 and 9 having the above configuration, the light emitted from the LED 16 illuminates the LCD 18 through the collimator lens 17, and a plurality of subject lights generated by the LCD 18 by this illumination are within the prism 19. After the total reflection is performed once, it is diffracted by the HOE 20 and guided to the user's eyeball as a virtual image.

  Furthermore, the prism 19 guides light incident from the front to the user's eyeball. As a result, the user can see through the outside world (front subject) and can visually recognize the image (video) taken by the camera unit 7 superimposed on the outside world (front subject).

  The tapered surfaces 2a and 3a formed on the first and second transparent substrates 2 and 3 cancel (cancel) light refraction at the tapered surface 19b of the prism 19, that is, due to the prism effect on the tapered surface 19b. In order to prevent the light from the arrow W side from bending upward, the user can observe the external light through the prism 19, the first and second transparent substrates 2, 3 and the HOE 20 without distortion.

  FIG. 6 is a block diagram showing an electrical configuration of the image display apparatus 1.

  As shown in FIG. 6, the image display device 1 includes a camera unit 7, an LCD 18, a signal processing unit 21, an A / D conversion unit 22, a timing control circuit 23, an image memory 24, a VRAM 25, and a control. Part 26.

  The camera unit 7 corresponds to the camera unit 7 shown in FIGS. 1, 2, and 4, and photographs a subject in front of the user wearing the image display device 1. The LCD 18 corresponds to the LCD 18 shown in FIG. 5 and displays an image based on the image data obtained by the camera unit 7.

  The signal processing unit 21 performs predetermined analog signal processing on the analog image signal output from the image sensor 12. The signal processing unit 21 includes a CDS (correlated double sampling) circuit and an AGC (auto gain control) circuit. The CDS circuit reduces noise of the image signal, and the AGC circuit adjusts the level of the image signal.

  The A / D conversion unit 22 converts the analog R, G, and B pixel signals output from the signal processing unit 21 into digital pixel signals composed of a plurality of bits (for example, 10 bits). The signal after the A / D conversion process of the A / D conversion unit 22 is referred to as image data.

  The timing control circuit 23 generates clocks CLK1 and CLK2 based on the reference clock CLK0 output from the control unit 26. The clock CLK1 is supplied to the image sensor 12 (see FIG. 4) in the camera unit 7, and the clock CLK2 is also supplied. The operations of the image sensor 12 and the A / D converter 22 are controlled by outputting them to the A / D converter 22 respectively.

  The image memory 24 is a memory used as a work area for performing various processing on image data by the control unit 26. The VRAM 25 has an image signal recording capacity corresponding to the number of pixels of the LCD 18, and is a pixel signal buffer memory constituting an image reproduced and displayed on the LCD 18.

  The control unit 26 reads a ROM (Read Only Memory) that stores each control program, a RAM (Random Access Memory) that temporarily stores data such as arithmetic processing and control processing, and the control program from the ROM. It comprises a CPU (central processing unit) to be executed, etc., and receives a signal from a shooting start switch (not shown) to control the imaging operation of the camera unit 7 and the display operation of the LCD 18. The control unit 26 is mounted on the control unit, and exchanges images with the camera unit 7 and the LCD 18 via the cable 14.

  As described above, the image display device 1 of the present embodiment is configured so that the outside (front subject) can see through when the user wears the image display device 1, so that the brightness of the outside subject is high. When it is relatively high or when the subject is biased to a specific color, it is conceivable that the visibility of the image displayed by the image display device 1 is lowered or significantly different from the actual color of the subject.

  Therefore, in this embodiment, in order to solve this problem, the control unit 26 functionally includes a luminance detection unit 27, a color temperature detection unit 28, a display light amount adjustment unit 29, and a display color adjustment unit 30. is doing.

  The luminance detection unit 27 detects the average luminance of the entire image related to the image data after the A / D conversion processing by the A / D conversion unit 22. That is, the luminance detection unit 27 calculates an average value of each pixel value after A / D conversion processing obtained from each pixel of the image sensor 12, and detects the luminance based on this average value. The luminance detection unit 27 corresponds to the luminance detection unit.

  The color temperature detection unit 28 detects the color temperature of the image related to the image data after the A / D conversion processing by the A / D conversion unit 22. As for the color temperature, the pixel value of the R (red) pixel is represented by “R”, the pixel value of the G (green) pixel is represented by “G”, and the pixel value of the B (blue) pixel is represented by “B”. , The ratio G / R of the pixel value of the G (green) pixel and the pixel value of the R (red) pixel, and the ratio of the pixel value of the G (green) pixel and the pixel value of the B (blue) pixel Since there is a predetermined relationship with G / B, the relationship between the ratio G / R and the ratio G / B and the color temperature is stored in a table format, for example, in the ROM of the control unit 26, and the color When the image data is output from the A / D converter 22, the temperature detector 28 calculates the ratio G / R and the ratio G / B from the image data, and the calculated ratio G / R and ratio G / B. The color temperature corresponding to B is derived with reference to the ROM. The color temperature detection unit 28 corresponds to the color temperature detection means.

  The display light amount adjustment unit 29 adjusts the display light amount of the LCD 18 according to the luminance detected by the luminance detection unit 27. In the present embodiment, the display light amount adjustment unit 29 increases the light emission amount of the LED 16 in accordance with the increase in luminance when the luminance detected by the luminance detection unit 27 is equal to or greater than the predetermined threshold value α. The display light amount adjustment unit 29 corresponds to the display light amount adjustment means.

  The display color adjustment unit 30 adjusts the display color of the LCD 18 according to the color temperature detected by the color temperature detection unit 28. In the present embodiment, when the color temperature detected by the color temperature detection unit 28 deviates from a predetermined range, the display color adjustment unit 30 adjusts the display color of the LCD 18 in the direction opposite to the direction of the deviation.

  Specifically, as in the present embodiment, the image sensor 12 is a so-called Bayer image sensor in which R (red), G (green), and B (blue) color filters are attached in a checkered pattern. In this case, the display color adjusting unit 30 multiplies the pixel value R of the R (red) pixel, the pixel value G of the G (green) pixel, and the pixel value B of the B (blue) pixel by a predetermined coefficient. The predetermined coefficient is set so that the sum of the colors becomes white. That is, the display color adjusting unit 30 sets the coefficients a, b, and c so that aR + bG + cB = L (white) when the predetermined coefficients are represented as a, b, and c.

The display color adjusting unit 30 then adjusts the color temperature when a <ad, c <cd when the coefficients set by the above-described method are ad, bd, cd under illumination by sunlight (d-line). If a> ad, c> cd, the color temperature is determined to be low, and the color temperature of the image is shifted to the opposite side. Since the color temperature is higher in the order of blue, white, and red, for example, when the image is reddish, the color temperature is shifted to the blue side. The shift amount is
k = (a-ad) / (c-cd) (1)
It is determined according to the value of k calculated in The display color adjustment unit 30 corresponds to the display color adjustment unit. The display light amount adjustment unit 29 and the display color adjustment unit 30 constitute display control means.

  Next, display processing by the control unit 26 will be described. FIG. 7 is a flowchart showing this display processing.

  As shown in FIG. 7, when the power is turned on by an unillustrated power button (YES in step # 1), the control unit 26 causes the camera unit 7 (image sensor 12) to perform an imaging operation (step # 2). ). The control unit 26 detects the luminance and color temperature and sets the coefficients a, b, and c based on the image signal obtained by this imaging operation (step # 3).

  Then, the control unit 26 determines the magnitude relationship between the measured luminance (hereinafter referred to as measured luminance) and a predetermined threshold value α (step # 4). As a result of the determination, if the measured luminance is equal to or greater than the threshold value α (YES in step # 4), the light amount of the LED 16 (display light amount of the LCD 18) is adjusted according to the measured luminance (step # 5). On the other hand, if it is less than the threshold value α (NO in step # 4), the process proceeds to step # 6 without executing step # 5.

  After the processing of step # 4 or # 5, the control unit 26 determines whether or not the color temperature of the image detected in step # 3 is deviated from the predetermined range (step # 6). As a result of the determination, if the color temperature is not deviated from the predetermined range (NO in step # 6), the process returns to step # 2, while if the color temperature deviates from the predetermined range (step #). 6), the display color depends on the magnitude relationship between a and ad, the magnitude relationship between c and cd, and the value of k calculated using the coefficients a, b and c and the equation (1). (Step # 7).

  Until the power is turned off by the power button (NO in step # 8), control unit 26 executes the processes of steps # 3 to # 8 for each imaging operation by the camera unit, and the power is turned off. Then (YES in step # 8), a series of processing is terminated. Since the human eye has higher sensitivity than luminance, the luminance processing (Steps # 4 and # 5) is replaced with the processing regarding color temperature (Steps # 6 and # 7) in the display processing. Go ahead.

  As described above, the display color is adjusted according to the color temperature of the captured image, and the display light amount is adjusted according to the luminance of the image. Conventionally, the color of the outside world and the color of the display image are different from each other. Even when they are mixed, good visibility of the display image of the image display device 1 can be ensured.

  This case includes modifications described in the following [1] to [3] in addition to the above embodiment or instead of the above embodiment.

  [1] In the first embodiment, the display light amount is adjusted according to the luminance of the image. However, the present invention is not limited to this, and the display light amount is adjusted according to the luminance and spatial frequency of the image. Also good. FIG. 8 is a block diagram showing an electrical configuration of the second embodiment of the image display apparatus according to the present invention.

  As shown in FIG. 8, the image display device 1 ′ of the present embodiment is substantially the same in other configurations except that the function of the control unit 26 ′ is different from the function of the control unit 26 in the first embodiment. Therefore, only the differences will be described. The same members as those in the first embodiment are denoted by the same numbers as those in the first embodiment.

  The control unit 26 ′ in the present embodiment functionally includes a luminance detection unit 27, a spatial frequency analysis unit 31, and a display light amount adjustment unit 32. Note that the luminance detection unit 27 has substantially the same function as the luminance detection unit 27 in the first embodiment.

  The spatial frequency analysis unit 31 captures a captured image (after A / D conversion processing by the A / D conversion unit 22) when the luminance detected by the luminance detection unit 27 (hereinafter referred to as detection luminance) is equal to or higher than the threshold value α. The spatial frequency of the image) is analyzed. The spatial frequency analysis by the spatial frequency analysis unit 31 is performed as follows, for example.

As shown in FIG. 9, a predetermined region on the imaging surface of the image sensor 12 and a G ( Focusing on the green (G) pixels G _{1 to} G ₅ , the average value of the outputs of the pixels G _{1 to} G ₅ is calculated, and this average value is set as the threshold value Gth. Here, the reason why attention is paid to the pixel in which the G (green) filter is installed is that there are the most types of transmitted light source light compared to the R (red) and B (blue) filters. .

Also, creating a graph with the pixel G ₁ horizontal axis the sequence of ~G _5, the vertical axis the relative value of the pixel values of the pixels G ₁ ~G ₅ relative to the threshold. FIGS. 10A to 10C show graphs. In the graph created in this way, the spatial frequency is determined by the number of times that the curve formed by connecting the relative values of adjacent pixels intersects the threshold Gth.

  For example, for the graph shown in FIG. 10A, the spatial frequency analysis unit 31 analyzes that the number of times the curve intersects the threshold Gth is relatively small and the spatial frequency is low. In this case, there is no need to change the display light quantity. Further, for the graph shown in FIG. 10B, it is analyzed that the number of times the curve intersects the threshold Gth is relatively large and the spatial frequency is high. In this case, since it is considered that the visibility is lowered by mixing the display image and the background, it is necessary to change (increase) the display light amount. In the graph shown in FIG. 10C, the number of times the curve intersects the threshold value Gth is relatively large, but the relative value changes within a predetermined range Gw centered on the threshold value Gth, so that the density of the image is Analyzes when there are few. In this case, there is no need to change the display light quantity. The spatial frequency analysis unit 31 corresponds to a spatial frequency detection unit.

  The display light amount adjustment unit 32 adjusts the display light amount of the LCD 18 according to the detection luminance by the luminance detection unit 27 and the spatial frequency analysis result by the spatial frequency analysis unit 31. That is, when the detected luminance is equal to or higher than the threshold value α, the display light amount adjustment unit 32 has a spatial frequency analyzed with respect to the reference value β calculated from the number of times the curve intersects the threshold value Gth and the predetermined range Gw. If it is small (for example, in the case of the graphs shown in FIGS. 10A and 10C), it is determined that adjustment of the display light quantity of the LCD 18 is not necessary, while the analyzed spatial frequency is equal to or higher than the reference value β ( For example, in the case of the graph shown in FIG. 10B, the amount of light displayed on the LCD 18 is adjusted according to the detected luminance and spatial frequency. The display light amount adjustment unit 32 corresponds to the display light amount adjustment unit. The spatial frequency analyzing unit 31 and the display light amount adjusting unit 32 constitute display control means.

  FIG. 11 is a flowchart of the display process in the present embodiment.

  As shown in FIG. 11, when the power is turned on by an unillustrated power button (YES in step # 11), the control unit 26 causes the camera unit 7 (image sensor 12) to perform an imaging operation (step # 12). ). The control unit 26 measures the luminance based on the image signal obtained by this imaging operation (step # 13).

  Then, the control unit 26 determines the magnitude relationship between the luminance detected in step # 13 (hereinafter referred to as detected luminance) and the predetermined threshold value α (step # 14). As a result of the determination, if the detected luminance is less than the threshold α (NO in step # 14), the process returns to step # 12, whereas if the detected luminance is equal to or higher than the threshold α (step In step # 15, the spatial frequency of the captured image is analyzed (step # 15).

  Then, the control unit 26 determines the magnitude relationship between the analyzed spatial frequency and the reference value β (reference value calculated from the number of times the curve intersects the threshold Gth and the predetermined range Gw) for the spatial frequency ( Step # 16). As a result of the determination, if the analyzed spatial frequency is less than the reference value β (NO in step # 16), the process returns to step # 12, while the analyzed spatial frequency and the reference value β for the spatial frequency are greater than or equal to the reference value β. (YES in step # 16), the amount of light displayed on the LCD 18 is adjusted according to the luminance detected in step # 13 and the spatial frequency analyzed in step # 15 (step # 17).

  Until the power is turned off by the power button (NO in step # 18), control unit 26 executes the processing of steps # 12 to # 18 for each imaging operation by the camera unit, and the power is turned off. Then (YES in step # 18), a series of processing is terminated.

  As described above, it is also possible to ensure good visibility of the display image of the image display device 1 by adjusting the display light amount according to both the spatial frequency and the luminance of the captured image. Although the display light amount is adjusted according to both the spatial frequency and the brightness of the captured image, the present invention is not limited to this, and the display light amount may be adjusted only according to the spatial frequency.

  [2] In the first embodiment, the display color is adjusted according to the color temperature of the captured image, and the display light amount is adjusted according to the luminance of the image. It is also possible to assume a form in which only the adjustment of the display color according to the color temperature of the image is performed without adjusting the light amount.

  [3] The image display device of each embodiment provides images to both eyes, but only one of the display housings 8 and 9 is installed to provide an image to one eyeball. You may do.

1 is a front view showing a configuration of a first embodiment of an image display device according to the present invention. It is a top view with respect to FIG. It is a right view with respect to FIG. It is sectional drawing which shows the internal structure of a camera unit. It is arrow sectional drawing seen from the arrow AA line of FIG. It is a block diagram which shows the electrical structure of an image display apparatus. It is a flowchart which shows a display process. It is a block diagram which shows the electric constitution of 2nd Embodiment of the image display apparatus which concerns on this invention. It is a figure for demonstrating the analysis method of a spatial frequency. The horizontal axis an array of pixels G ₁ ~G _5, a graph of the vertical axis the relative value of the pixel values of the pixels G ₁ ~G ₅ relative to the threshold. It is a flowchart of the display process in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 7 Camera unit 8, 9 Display housing | casing 10 Housing | casing 11 Lens unit 12 Image pick-up element 13 Image pick-up element board | substrate 14 Cable 15 Case part 16 LED
17 Collimator lens 18 LCD
19 Prism 19a Thick part 19b Tapered surface 20 HOE
26 Control Unit 27 Luminance Detection Unit 28 Color Temperature Detection Units 29 and 32 Display Light Amount Adjustment Unit 30 Display Color Adjustment Unit 31 Spatial Frequency Analysis Unit

Claims (5)

An image display device that is attached to the head or face and allows the user to see through the outside world,
Display means for displaying an image;
An image display apparatus comprising: a display mode changing unit that changes a display mode of the image according to an image obtained by an imaging operation of an imaging unit that receives a light image of a subject and performs a photoelectric conversion operation. The display mode changing means includes
Color temperature detection means for detecting the color temperature of an image obtained by the imaging operation of the imaging means;
Display color adjusting means for adjusting the display color of the image according to the color temperature detected by the color temperature detecting means;
The image display apparatus according to claim 1, further comprising: a display control unit that causes the display unit to display an image whose display color has been adjusted by the display color adjustment unit. Luminance detection means for detecting the luminance of the image;
The image display apparatus according to claim 2, further comprising: a display light amount adjusting unit that adjusts a display light amount of the image on the display unit according to the luminance detected by the luminance detection unit. The display mode changing means includes
Spatial frequency detection means for detecting a spatial frequency of an image obtained by the imaging operation of the imaging means;
Display light amount adjusting means for adjusting the display light amount of the image on the display means according to the spatial frequency detected by the spatial frequency detecting means;
The image display apparatus according to claim 1, further comprising a display control unit that causes the display unit to display an image whose display light amount has been adjusted by the display light amount adjustment unit. A luminance detecting means for detecting the luminance of the image;
5. The display light amount adjusting unit adjusts the display light amount of an image according to a spatial frequency detected by the spatial frequency detecting unit and a luminance detected by the luminance detecting unit. Image display device.

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