Method of displaying a three-dimensional image

A method of displaying a three-dimensional image is disclosed. The method includes the steps of receiving a left-eye gray level image array and a right-eye gray level image array; converting the left-eye gray level image array and the right-eye gray level image array into a left-eye luminance image array and a right-eye luminance image array respectively; receiving a left-eye compensation array; adjusting the right-eye luminance image array in accordance with the left-eye luminance array and the left-eye compensation array; converting the adjusted right-eye luminance image array into an adjusted right-eye gray level image array; displaying the adjusted right-eye gray level image array.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to a method of displaying a three-dimensional image, and more particularly, to a method of displaying a three-dimensional image which eliminates ghost images.

2. Description of the Prior Art

Please refer toFIG. 1.FIG. 1is a diagram illustrating a three-dimensional (3D) image display device composed by a conventional flat panel display device and a micro-optical element. As shown inFIG. 1, the three-dimensional image display device is generally composed by a conventional flat panel display device and a micro-optical element (e.g. a parallax barrier or lenticular lens, etc.). The flat panel display device displays images corresponding to each individual perspective on corresponding pixels, or displays images corresponding to each individual perspective at different time intervals. The purpose of the micro-optical element is to project images corresponding to each individual perspective to corresponding horizons in space.

Please refer toFIG. 2.FIG. 2is a diagram illustrating each eye of a user perceiving an extra dot due to leakage from images of the other eye. As shown inFIG. 2, during image processing of the conventional three-dimensional image display device, the left and right eye input images are obtained from a video input end. Images corresponding to a perspective of the left eye are displayed in even lines of the three-dimensional image display device, and images corresponding to a perspective of the right eye are displayed in odd lines of the three-dimensional image display device. The left and right eyes of the user, which are positioned at appropriate perspectives, observe images corresponding to perspectives of the left and right eye, and then the brain fuses the observed images together for the user to perceive three-dimensional images.

The efficiency of the micro-optical element splitting light beams may not be 100% due to design and technical limitations, as well as possible variations occurring during processing. Therefore, in reality, human eyes also observe images corresponding to other vision perspectives in certain perspectives. As shown inFIG. 2, each of the left and right eyes should only see one white dot, theoretically, but due to leakage from images of the other eye, an extra grey dot is perceived by both eyes of the user. Such phenomenon is known as a ghost image or crosstalk. The ghost image or crosstalk phenomenon degrades quality of the three-dimensional images, delivering an uncomfortable viewing experience to the user, or even resulting in sensations of dizziness or headache, etc.

SUMMARY OF THE INVENTION

The present invention discloses a method for displaying a three-dimensional image. The method comprises receiving a left-eye gray level image array and a right-eye gray level image array; converting the left-eye gray level image array and the right-eye gray level image array into a left-eye luminance image array and a right-eye luminance image array respectively; receiving a compensation array; adjusting the right-eye luminance image array according to the left-eye luminance image array and the compensation array; converting the adjusted right-eye luminance image array into an adjusted right-eye gray level image array; and displaying the adjusted right-eye gray level image array on a display platform.

The present invention further discloses a method for displaying a three-dimensional image. The method comprises receiving a left-eye gray level image array and a right-eye gray level image array; converting the left-eye gray level image array and the right-eye gray level image array into a left-eye luminance image array and a right-eye luminance image array respectively; receiving a compensation array; adjusting the right-eye luminance image array according to the left-eye luminance image array, the right-eye luminance image array and the compensation array; converting the adjusted right-eye luminance image array into an adjusted right-eye gray level image array; and displaying the adjusted right-eye gray level image array on a display platform.

DETAILED DESCRIPTION

Please refer toFIG. 3.FIG. 3is a flow chart illustrating a method of displaying a three-dimensional (3D) image according to an embodiment of the present invention. Steps of the method are detailed as below:

Step402: receiving a left-eye gray level image array and a right-eye gray level image array;

Step404: converting the left-eye gray level image array and the right-eye gray level image array into a left-eye luminance image array and a right-eye luminance image array respectively;

Step406: receiving a compensation array;

Step408: adjusting the right-eye luminance image array according to the left-eye luminance image array and the compensation array;

Step410: converting the adjusted right-eye luminance image array into an adjusted right-eye gray level image array; and

Step412: displaying the adjusted right-eye gray level image array on a flat panel display device.

In step404, the right-eye gray level image array is converted to the right-eye luminance image array according to formula (1a), and the left-eye gray level image array is converted to the left-eye luminance image array according to formula (1b). Formula (1a) is utilized to describe an element in an nth row and mth column of the right-eye gray level image array. Formula (1b) is utilized to describe an element in an nth row and mth column of the left-eye gray level image array.
IRnm=(BRnm/255)γ(1a)
ILnm=(BLnm/255)γ(1b)

wherein BRnmrepresents the element in the nth row and mth column of the right-eye gray level image array, IRnmrepresents the element in the nth row and mth column of the right-eye luminance image array, BLnmrepresents the element in the nth row and mth column of the left-eye gray level image array, ILnmrepresents the element in the nth row and mth column of the left-eye luminance image array, and value of γ is generally “2.3”. Formulae (1a) and (1b) are merely exemplary embodiments; the conversion method of step404of the present invention is not limited to formulae (1a) and (1b). Taking an 8-bit image as an example, the gray levels of BLnmand BRnmare in a range of gray levels 1-255.

In step408, the left-eye luminance image array and the compensation array are substituted into formula (2) for adjusting each right-eye element in the right-eye luminance image array, so as to eliminate ghost images in the right-eye luminance image array caused by the left-eye luminance image array. Referring back toFIG. 3, for the element in the nth row and mth column of the right-eye luminance image array, the ghost image caused by the left-eye luminance image array exists in the nth row and mth column of the right-eye luminance image array, so the element in the nth row and mth column of the right-eye luminance image array is subtracted by Cnm×ILnm.
IRnm′=IRnm−Cnm×ILnm(2)

where IRnm′ represents the element in the nth row and mth column of the adjusted right-eye luminance image array, ILnmrepresents the element in the nth row and mth column of the left-eye luminance image array, and Cnmrepresents the element in the nth row and mth column of the compensation array. Furthermore, elements of the compensation array can be all identical, or partially identical, or set to be different from each other according to characteristics of the flat panel display device.

After eliminating ghost images in the right-eye luminance image array, step410can then be performed. The adjusted right-eye luminance image array is converted into an adjusted right-eye gray level image array according to formula (3):
BRnm′=(IRnm′)(1/γ)×255  (3)

According to the method illustrated inFIG. 3, ghost images in the right-eye luminance image array can be eliminated by utilizing the compensation array. The method of utilizing the compensation array to eliminate ghost images in the left-eye luminance image array is similar to the method of utilizing the compensation array to eliminate ghost images in the right-eye luminance image array, so the detailed description thereof is omitted hereinafter.

Please refer toFIG. 4.FIG. 4is a flow chart illustrating a method of displaying a three-dimensional image according to another embodiment of the present invention. Steps of the method are detailed as below:

Step502: receiving a left-eye gray level image array and a right-eye gray level image array;

Step504: converting the left-eye gray level image array and the right-eye gray level image array into a left-eye luminance image array and a right-eye luminance image array respectively;

Step506: receiving a compensation array;

Step508: adjusting the right-eye luminance image array according to the left-eye luminance image array, the compensation array and the right-eye luminance image array;

Step510: converting the adjusted right-eye luminance image array into an adjusted right-eye gray level image array; and

Step512: displaying the adjusted right-eye gray level image array on a flat panel display device.

The difference between embodiments illustrated inFIG. 4andFIG. 5is step508. In step508, the left-eye luminance image array, the compensation array and the right-eye luminance image array are substituted into formula (4), for adjusting the right-eye luminance image array.
IRnm′=IRnm−Cnm×ILnm+Cnm×IRnm(4)

In other words, in step508, in addition to eliminating ghost images in the nth row and mth column, the reduced luminance due to eliminating ghost images in the nth row and mth column can also be compensated for preventing overall luminance of the right-eye luminance image array from decreasing due to executing formula (4).

Apart from formula (4), step508can also be realized with formula (5), meaning formula (4) can be replaced by formula (5) in this case. By utilizing formula (5), a crosstalk phenomenon caused by formula (2) can be further reduced.
IRnm′=IRnm−Cnm×ILnm+Cnm2IRnm(5)

Please refer toFIG. 5.FIG. 5is a flow chart illustrating a method of displaying a three-dimensional image according to another embodiment of the present invention. Steps of the method are detailed as below:

Step602: receiving a left-eye gray level image array and a right-eye gray level image array;

Step604: converting the left-eye gray level image array and the right-eye gray level image array into a left-eye luminance image array and a right-eye luminance image array, respectively;

Step606: receiving a compensation array;

Step608: adjusting the right-eye luminance image array according to the left-eye luminance image array and the compensation array, then dividing each element of the adjusted right-eye luminance image array by a difference between one and a square of the corresponding element of the compensation array;

Step610: converting the adjusted right-eye luminance image array from step608into an adjusted right-eye gray level image array; and

Step612: displaying the adjusted right-eye gray level image array on a flat panel display device.

The embodiment illustrated inFIG. 5is derived from the embodiment ofFIG. 4. In the embodiment ofFIG. 4, crosstalk is generated again by a compensated component for compensating the leakage from perspectives of left and right eyes, and continued recursing compensation results in an infinite geometric series. In step608, left-eye luminance image array, compensation array and right-eye luminance image array are substituted into formula (6) for adjusting the right-eye luminance image array.

Embodiments illustrated inFIG. 3,FIG. 4andFIG. 5mentioned above utilize the left-eye luminance image array and the compensation array to adjust the right-eye luminance image array. However,FIG. 3,FIG. 4andFIG. 5are not limited to this, such that the right-eye luminance image array and the compensation array can also be utilized to adjust the left-eye luminance image array in a similar manner. The detailed description is omitted hereinafter.

Please refer toFIG. 6.FIG. 6is a diagram illustrating a multi-view 3D image display device according to an embodiment of the present invention. Due to characteristics of the multi-view 3D image display device, all vision perspectives have to be considered during a compensation process. The compensation process is performed according to formula (7):

I1′=I1-C12×I2-C13×I3⁢⁢…I2′=I2-C21×I1-C23×I3⁢⁢…I3′=I3-C31×I1-C32×I2⁢⁢…⋮(7)
where C12represents the light intensity ratio of leakage leaked from perspective 1 to perspective 2, C13represents the light intensity ratio of leakage leaked from perspective 1 to perspective 3, and so on; I1′ represents the adjusted image luminance of perspective 1, I1represents the unadjusted image luminance of perspective 1, I2′ represents the adjusted image luminance of perspective 2, I2represents the unadjusted image luminance of perspective 2, and so on.

In conclusion, the prior art generates ghost images or crosstalk, delivering an uncomfortable viewing experience to the user. For the method of displaying three-dimensional images of the present invention, elements of the compensation array are not limited to being identical to each other. Furthermore, elements of the compensation array of the present invention can be set by the manufacturer when the display panel is manufactured, or adjusted by the user according to practical demands. This way, the present invention can eliminate ghost images effectively, improving quality of the three-dimensional images.