Image processing method for improving display resolution by diagonal jitter

Abstract

The invention relates to an image processing method for improving display resolution by diagonal jitter, which comprises the following steps of: S1, converting a high-resolution input image into two low-resolution images through an FPGA (Field Programmable Gate Array) or a special ASIC (Application Specific Integrated Circuit); s2, the two low-resolution images are output to a low-resolution display chip, and an LED drive circuit generates corresponding optical signals according to the input PWM signals and transmits the optical signals to the display chip; the low-resolution display chip converts the image data into visible light, modulates the light signal and the visible light, and outputs the modulated light signal and visible light to the galvanometer; s3, the galvanometer receives the parallel light output by the low-resolution display chip, a digital-to-analog conversion circuit converts a digital waveform into a specific current waveform and outputs the specific current waveform to the galvanometer, so that the galvanometer moves at a certain frequency, amplitude and time sequence, and the parallel light cooperates with vibration of the galvanometer to generate and output a high-resolution image; the galvanometer is a one-position galvanometer and jitters twice along the diagonal line. Through the above steps, the resolution of the image is improved through the jitter of the diagonal line of the galvanometer, the structure is simple, the cost is low, and the practical value is high.

Description

Technical Field

[0001] The present invention relates to the technical field of image resolution, and in particular to an image processing method for improving display resolution by diagonal dithering. Background Art

[0002] LCOS (Liquid Crystal on Silicon) display technology is an innovative display solution that combines reflective liquid crystal display with complementary metal oxide semiconductor (CMOS) technology. LCOS chips can be used in AR / VR head-mounted devices, LCOS projection, LCOS display and other occasions, which usually require images with higher resolutions. In the existing technology, some technologies improve the display resolution by shaking the galvanometer, and achieve 4 times the resolution display by shaking 2 galvanometers in 4 directions. Although the resolution can be improved and the image processing algorithm is simple, the cost is high, and there are high requirements for the refresh rate and bandwidth of the display chip, so the practical value is not high.

[0003] Therefore, there is an urgent need to provide an image processing method for improving display resolution by diagonal dithering to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and to provide an image processing method for improving display resolution by diagonal dithering. The image resolution is improved by diagonal dithering of a galvanometer and the method has a simple structure, low cost and high practical value.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] An image processing method for improving display resolution by diagonal dithering, characterized by comprising the following steps:

[0007] Step S1: Convert the high-resolution input image into two low-resolution images through FPGA or dedicated ASIC;

[0008] Step S2: output the two low-resolution images to the low-resolution display chip, the LED driving circuit generates a corresponding light signal according to the input PWM signal and transmits it to the display chip; the low-resolution display chip converts the image data into visible light, and modulates the light signal and the visible light and outputs them to the galvanometer;

[0009] Step S3: The galvanometer receives the parallel light output by the low-resolution display chip, and the digital-to-analog conversion circuit converts the digital waveform into a specific current waveform and outputs it to the galvanometer, so that the galvanometer moves with a certain frequency, amplitude and timing, and the parallel light cooperates with the vibration of the galvanometer to generate and output a high-resolution image; the galvanometer is a one-bit galvanometer and shakes twice along the diagonal.

[0010] Optionally, the galvanometer mirror is diagonally shaken, and the shaking amplitude of the galvanometer mirror is 0.5 pixels.

[0011] Optionally, step S3 includes:

[0012] Step S31: displaying a first low-resolution image at a first position;

[0013] Step S32: by shaking the galvanometer along the diagonal line, the image is moved by 0.5 pixels on the X-axis, and the image is also moved by 0.5 pixels on the Y-axis to reach a second position, and a second low-resolution image is displayed at the second position;

[0014] Step S33: Overlap the first low-resolution image and the second low-resolution image to obtain a high-resolution output image.

[0015] Optionally, the pixel in the high-resolution image formed in step S33 is an equivalent pixel formed by four adjacent pixels in the image formed by the overlap of the first low-resolution image and the second low-resolution image, the pixel position is the geometric center of the four adjacent pixels, and the brightness of the pixel is the average value of the brightness of the four pixels g=(g1+g2+g3+g4) / 4.

[0016] Optionally, the resolution of the high-resolution output image formed in step S33 is twice that of the high-resolution input image, and the pixels are arranged at an angle of 45°.

[0017] Optionally, the first low-resolution image uses the original image coordinates (0, 0) as the first pixel point, and is resampled by traversing the original image in units of 1.5 pixel spacing in the horizontal and vertical directions; the second low-resolution image uses the original image coordinates (0.75, 0.75) as the first pixel point, and is resampled by traversing the original image in units of 1.5 pixel spacing in the horizontal and vertical directions.

[0018] Optionally, the step of calculating any pixel in the generated image includes:

[0019] Step S331: set g(m,n) to the pixel in row m and column n in the generated image;

[0020] Step S332: The mapping coordinates of g(m,n) in the original image are (0.75+1.5m, 0.75+1.5n). The mapping coordinates are converted into (r+i,c+j), where r and c are the integer parts, and i and j are the decimal parts. The grayscale values ​​of the four adjacent groups of pixels at the mapping point are g1(r,c), g2(r,c+1), g3(r+1,c), g4(r+1,c+1). The brightness mapping value of the pixel is g(m,n)=g1(r,c)(1-i)(1-j)+g2(r,c+1)(1-i)j+g3(r+1,c)(1-j)i+g4(r+1,c+1)i×j.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] In the present invention, in the image processing method for improving display resolution by diagonal jitter, FPGA or ASIC is used to transform the high-resolution input image into two low-resolution images, and the two low-resolution images are output to the low-resolution display chip, so as to control the galvanometer to move with a certain amplitude and timing; the low-resolution display chip receives the optical signal and image data, and converts it into visible light and modulates it to output it to the galvanometer; the galvanometer receives the parallel light output by the low-resolution display chip, and the galvanometer is used to receive different current waveforms to generate different vibration displacements, and the digital-to-analog conversion circuit converts the digital waveform into a specific current waveform and outputs it to the galvanometer, so that the galvanometer moves according to a certain frequency, amplitude and timing, and the parallel light cooperates with the vibration of the galvanometer to generate and output a high-resolution image, and the direction of movement of the galvanometer is along the pixel diagonal direction, the galvanometer is a one-bit galvanometer, and it jitters twice along the diagonal, and the one-bit galvanometer and the diagonal jitter generate an image with twice the high-resolution image. Through the above steps, the resolution of the image is improved by the diagonal jitter of the galvanometer, and the structure is simple, the cost is low, and it has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 It is the first low-resolution image in the present invention.

[0025] Figure 3 It is the second low-resolution image in the present invention.

[0026] Figure 4 For the present invention Figure 2 and Figure 3 Overlay chart.

[0027] Figure 5 It is a new equivalent pixel map that retains the original pixels in the present invention.

[0028] Figure 6 It is a new pixel image after removing the original pixel image in the present invention.

[0029] Figure 7 It is the algorithm block diagram of the FGPA in the present invention.

[0030] Figure 8 For the display in the present invention Figure 2 The generation algorithm diagram. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0032] The technical solution of the present invention proposes an image processing method for improving display resolution by diagonal dithering.

[0033] Reference Figures 1 to 8 In this embodiment, the following steps are included:

[0034] Step S1: Convert the high-resolution input image into two low-resolution images through FPGA or dedicated ASIC;

[0035] Step S2: output the two low-resolution images to the low-resolution display chip, the LED driving circuit generates a corresponding light signal according to the input PWM signal and transmits it to the display chip; the low-resolution display chip converts the image data into visible light, and modulates the light signal and the visible light and outputs them to the galvanometer;

[0036] Step S3: The galvanometer receives the parallel light output by the low-resolution display chip. The digital-to-analog conversion circuit converts the digital waveform into a specific current waveform and outputs it to the galvanometer, so that the galvanometer moves with a certain frequency, amplitude and timing. The parallel light cooperates with the vibration of the galvanometer to generate and output a high-resolution image. The galvanometer is a one-bit galvanometer and shakes twice along the diagonal.

[0037] Optionally, in this embodiment, in the image processing method for improving display resolution by diagonal jitter, FPGA or ASIC is used as an algorithm processing module, which carries important image processing algorithms, mainly transforms a high-resolution input image into two low-resolution images that are related to each other, and outputs the two low-resolution images to a low-resolution display chip. At the same time, the FPGA also cooperates with the timing of the display chip to output the image, thereby controlling the galvanometer to move with a certain amplitude and timing; the LED driving circuit generates a corresponding light signal according to the input PWM signal and transmits it to the display chip. The low-resolution display chip receives the light signal and image data and converts them into visible The light is modulated and output to the galvanometer; the galvanometer receives the parallel light output by the low-resolution display chip, and the galvanometer is used to receive different current waveforms to generate different vibration displacements. The digital-to-analog conversion circuit converts the digital waveform into a specific current waveform and outputs it to the galvanometer, so that the galvanometer moves according to a certain frequency, amplitude and timing. The parallel light cooperates with the vibration of the galvanometer to generate and output a high-resolution image. The direction of movement of the galvanometer is along the diagonal direction of the pixel. The galvanometer is a one-bit galvanometer and shakes twice along the diagonal. The one-bit galvanometer and the diagonal shaking generate an image with twice the high-resolution image, which realizes the output of high-resolution images, while requiring low cost and refresh rate of the display chip. Through the above steps, the resolution of the image is improved by the diagonal shaking of the galvanometer, and the structure is simple, the cost is low, and it has high practical value.

[0038] In this embodiment, the galvanometer mirror is diagonally shaken, and the shaking amplitude of the galvanometer mirror is 0.5 pixels. The image resolution produced by diagonal shaking twice is increased by two times.

[0039] In this embodiment, step S3 includes:

[0040] Step S31: Displaying a first low-resolution image at a first position; referring to Figure 2 , through a certain algorithm, the original image is transformed into two low-resolution images. Figure 2 a first low-resolution image displayed for a first position;

[0041] Step S32: by shaking the galvanometer along the diagonal line, the image moves 0.5 pixels on the X axis, and the image also moves 0.5 pixels on the Y axis to reach the second position, and a second low-resolution image is displayed at the second position. Figure 3 .

[0042] Step S33: Overlap the first low-resolution image and the second low-resolution image to obtain a high-resolution output image. Figure 4 ,Will Figure 2 and Figure 3 After superposition, we get Figure 4 , Figure 4A high-resolution image synthesized with negligible pixel size.

[0043] Optionally, in this embodiment, the pixel in the high-resolution image formed in step S33 is an equivalent pixel formed by four adjacent pixels in the image formed by the first low-resolution image and the second low-resolution image overlapping. That is, since the pixel has a certain size and cannot be ignored, the pixel actually formed is Figure 4 An equivalent pixel formed by four adjacent pixels in the image is located at the geometric center of the four adjacent pixels. Figure 5 , the brightness of the pixel is the average brightness of the four pixels, that is, g = (g1 + g2 + g3 + g4) / 4, Figure 5 The four-pointed star in is the new equivalent pixel formed, and Figure 5 The original old pixels of the image are retained to make it easier to see how the new pixels form in relation to the old pixels.

[0044] Optionally, the resolution of the high-resolution output image formed in step S33 is twice that of the high-resolution input image, and the pixels are arranged at an angle of 45°. Figure 6 For the image of new pixels left after removing the original pixels, refer to Figure 6 It can be found that the resolution is twice as high as that of the input image, and the pixels are arranged at 45° instead of vertically and horizontally.

[0045] Optionally, refer to Figure 7 In this embodiment, the first resolution image uses the original image coordinate (0, 0) as the first pixel point, and is resampled by traversing the original image in units of 1.5 pixel spacing in the horizontal and vertical directions; the second low resolution image uses the original image coordinate (0.75, 0.75) as the first pixel point, and is resampled by traversing the original image in units of 1.5 pixel spacing in the horizontal and vertical directions.

[0046] Optionally, in this embodiment, the step of calculating any pixel in the generated image includes:

[0047] Step S331: set g(m,n) to the pixel in row m and column n in the generated image;

[0048] Step S332: The mapping coordinates of g(m,n) in the original image are (0.75+1.5m, 0.75+1.5n). The mapping coordinates are transformed into (r+i,c+j), where r and c are integer parts, and i and j are decimal parts. The grayscale values ​​of the four groups of pixels adjacent to the mapping point are obtained as g1(r,c), g2(r,c+1), g3(r+1,c), and g4(r+1,c+1). The brightness mapping value of the pixel is g(m,n)=g1(r,c)(1-i)(1-j)+g2(r,c+1)(1-i)j+g3(r+1,c)(1-j)i+g4(r+1,c+1)i×j. The algorithm principle is as follows: Figure 8 ; Further, in this embodiment, display Figure 1 The calculation step of generating is to transform the pixel (m, n) coordinates to (0+1.5m, 0+1.5n). The remaining steps are the same as those of display Figure 2 The steps are the same.

[0049] The above-mentioned embodiments only express the implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. An image processing method for improving display resolution by diagonal dithering, characterized in that: The following steps are involved: Step S1: Convert the high-resolution input image into two low-resolution images through FPGA or dedicated ASIC; Step S2: output the two low-resolution images to the low-resolution display chip, the LED driving circuit generates a corresponding light signal according to the input PWM signal and transmits it to the display chip; the low-resolution display chip converts the image data into visible light, and modulates the light signal and the visible light and outputs them to the galvanometer; Step S3: The galvanometer receives the parallel light output by the low-resolution display chip, and the digital-to-analog conversion circuit converts the digital waveform into a specific current waveform and outputs it to the galvanometer, so that the galvanometer moves with a certain frequency, amplitude and timing, and the parallel light cooperates with the vibration of the galvanometer to generate and output a high-resolution image; the galvanometer is a one-bit galvanometer and shakes twice along the diagonal.

2. The image processing method for improving display resolution by diagonal dithering according to claim 1, characterized in that: The galvanometer mirror is diagonally shaken, and the shaking amplitude of the galvanometer mirror is 0.5 pixels.

3. The image processing method for improving display resolution by diagonal dithering according to claim 2, characterized in that: The step S3 comprises: Step S31: displaying a first low-resolution image at a first position; Step S32: by shaking the galvanometer along the diagonal line, the image is moved by 0.5 pixels on the X-axis, and the image is also moved by 0.5 pixels on the Y-axis to reach a second position, and a second low-resolution image is displayed at the second position; Step S33: Overlap the first low-resolution image and the second low-resolution image to obtain a high-resolution output image.

4. The image processing method for improving display resolution by diagonal dithering according to claim 3, characterized in that: The pixel in the high-resolution image formed in step S33 is an equivalent pixel formed by four adjacent pixels in the image formed by the overlap of the first low-resolution image and the second low-resolution image. The pixel position is the geometric center of the four adjacent pixels, and the brightness of the pixel is the average value of the brightness of the four pixels g=(g1+g2+g3+g4) / 4.

5. The image processing method for improving display resolution by diagonal dithering according to claim 1, characterized in that: The resolution of the high-resolution output image formed in step S33 is twice that of the high-resolution input image, and the pixels are arranged at an angle of 45°.

6. The image processing method for improving display resolution by diagonal dithering according to claim 3, characterized in that: The first low-resolution image uses the original image coordinates (0, 0) as the first pixel point, and is resampled and traversed in units of 1.5 pixel spacing in the horizontal and vertical directions; the second low-resolution image uses the original image coordinates (0.75, 0.75) as the first pixel point, and is resampled and traversed in units of 1.5 pixel spacing in the horizontal and vertical directions.

7. The image processing method for improving display resolution by diagonal dithering according to claim 6, characterized in that: The calculation step of generating any pixel in the image comprises: Step S331: set g(m,n) to the pixel in row m and column n in the generated image; Step S332: The mapping coordinates of g(m,n) in the original image are (0.75+1.5m, 0.75+1.5n). The mapping coordinates are converted into (r+i,c+j), where r and c are the integer parts, and i and j are the decimal parts. The grayscale values ​​of the four adjacent groups of pixels at the mapping point are g1(r,c), g2(r,c+1), g3(r+1,c), g4(r+1,c+1). The brightness mapping value of the pixel is g(m,n)=g1(r,c)(1-i)(1-j)+g2(r,c+1)(1-i)j+g3(r+1,c)(1-j)i+g4(r+1,c+1)i×j.

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