CN110177262A - A kind of projection accelerated method, system and device based on bit depth segmentation - Google Patents

Abstract

The invention provides a projection acceleration method, system and device based on bit depth segmentation, which belongs to the field of computer graphics. The method divides the brightness value of a single channel of a ²ⁿ -order n-bit depth image into high n-i bits and low i bits. The sum of the two parts of the bit, irradiating the micromirror with 2 ^(n‑i) units of light source brightness generates high n‑i bits, and irradiating the micromirror with 1 unit of light source brightness generates low i bits, thus without reducing the image quality , to reduce the number of inversion cycles required for the high n-i bits of a single channel, thereby reducing the projection cycle of the entire image and increasing the projection speed. The projection acceleration method, system, and device of the present invention can realize projection acceleration without reducing the bit depth of the image, that is, realize accelerated projection without reducing image quality, and are applicable to various bit depth image sequences with different numbers of channels, and have broad application prospects.

Description

Projection acceleration method, system and device based on bit depth segmentation

technical field

The invention belongs to the field of computer graphics, and more specifically relates to a projection acceleration method, system and device based on bit depth segmentation.

Background technique

With the increasingly widespread application of computer images and the further improvement of automation, computers play an irreplaceable role in the field of industrial measurement. The 3D depth information is crucial to the task completion and performance of the system, but the optical image processed by the traditional computer reflects the brightness and color information of the light source of the scene, and loses the 3D depth information in reality. With the development of three-dimensional measurement sensors, multi-frequency phase shift methods have been widely used, mainly three-frequency four-step phase shift methods, and the measurement speed depends on the projection speed of the projection device and the synchronous acquisition speed of the camera. Currently, the mainstream industrial cameras The bottleneck basically lies in the projection speed.

Today's more advanced projection device DLP (Digital Light Processing) has the following characteristics compared with traditional projection devices:

(1) Reflective imaging is adopted. The formation of the image is realized by the flipping of DMD (Digital Micromirror Device) micromirror array (referred to as micromirror array). It has the characteristics of high native contrast and miniaturization of the machine. The projection speed and resolution are both higher;

(2) A grayscale image is generated by means of integration. Different grayscales correspond to different flipping duty cycles, and the highest frame rate of projection depends on the frequency of micromirror flipping;

(3) Up to 4 light source channels (R-G-B-IR, that is, red-green-blue-infrared) can be modulated; in some DLP devices, the IR channel will be replaced by the W channel (white, white light) for adjustment The display brightness of the RGB image (for example, when the ambient light is strong, the image needs to be brightened to see clearly), because increasing the display brightness will reduce the saturation of the RGB image, resulting in a decrease in image quality, some types of DLP will disable or remove the IR channel or W channel; according to different DLP types, each light source channel can project independently or sequentially.

The task of grayscale modulation is completed by the light source and the micromirror. A feasible way to increase the projection speed is to reduce the flip cycle of the micromirror. However, if the bit depth of the projected image can be reduced, the flipping cycle of the micromirror can be reduced to achieve a faster projection speed, and even the required image can be compressed to within the storage capacity limit of the preloaded space to achieve the maximum projection speed. However, the 1st order width of 2 ^m bit depth map is equivalent to 2 ^nm times of 1st order width of 2 ⁿ bit depth map, n>m, 1 unit brightness of 2 ^m bit depth map is also equivalent to 1 of 2 ⁿ bit depth map 2 ^nm times the unit luminance, therefore, reducing the image bit depth will result in a drastic drop in the image's color scale, resulting in a drastic drop in image quality. For example, an 8-bit depth single-channel grayscale image has 256 levels of grayscale, while a 7-bit depth single-channel grayscale image has only 128 levels of grayscale. The 8-bit grayscale image has more serious jaggedness, which affects the accuracy of measurement.

Therefore, there is an urgent need for a method that can increase the projection speed without reducing the image quality.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention provides a projection acceleration method, system and device based on bit- ^depth segmentation. The sum of the ni bit and the low i bit, irradiate the micromirror with 2 ⁽ⁿⁱ⁾ units of light source brightness to generate the high ni bit, and irradiate the micromirror with 1 unit of light source brightness to generate the low i bit, thus without reducing the image quality Next, the number of flip cycles required for the high ni bit of a single channel is reduced, thereby reducing the projection cycle of the entire image and increasing the projection speed.

In order to achieve the above object, according to one aspect of the present invention, a projection acceleration method based on bit depth segmentation is provided, which is used for accelerated projection of a DLP projection device. At the pixel position, the state of the micromirror is 1, otherwise the state of the micromirror is 0, then the state of the micromirror in a single flip cycle is 1 or 0, for an image to be projected with n-bit depth, the projection acceleration method includes the following steps:

S101. Divide the ²ⁿ -order luminance N _total of a single channel into the sum of the luminance of the high ni bit and the low i bit, where n>i≥2, recorded as:

N _total = N _high + N _low

In the formula, N is _always any integer between 0 and 2 ⁿ -1, N _high indicates high ni-bit brightness, N _low indicates low i-bit brightness; high ni-bit brightness is obtained according to step S102, and low i-bit brightness is obtained according to step S103 is processed and obtained;

S102. Under the corresponding channel, irradiate with the brightness of the light source of 2 ⁽ⁿⁱ⁾ units, and need 1 flip cycle with the state of 1 to produce a luminous flux of 2 ⁽ⁿⁱ⁾ cycles of a unit of light source. At this time, each state is 1 The amount of brightness change in the flip cycle is 2 ⁽ⁿⁱ⁾ steps, so that the brightness is accumulated by flipping the micromirror, and the brightness of the high ni bit is N _high ;

S103. Under the corresponding channel, irradiating with 1 unit of light source brightness requires 2 ⁱ flipping cycles with a state of 1 to produce luminous flux of 1 unit light source with 2 ⁱ cycles. At this time, the brightness of each flipping cycle with a state of 1 changes The amount is 1 order, so that the luminance is accumulated by flipping the micromirror, and the luminance N _low of low i bits is generated.

Further, in step S101,

N _total = X × 2 ⁽ⁿⁱ⁾ unit light source brightness + Y × 1 unit light source brightness

N _height = X × 2 ⁽ⁿⁱ⁾ unit light source brightness

N _low = Y × 1 unit light source brightness

In the formula, X is the number of flipping cycles required for the micromirror state to be 1 when the light source brightness of 2 ⁽ⁿⁱ⁾ units is irradiated under the corresponding channel,

Y is the number of flip cycles required for the micromirror state to be 1 when irradiating with a light source brightness of 1 unit under the corresponding channel;

When N _total = 0 of the corresponding channel, it is required that the state of the micromirror is 0 in all flip cycles under the corresponding channel, and at this time X=0, Y=0.

Further, the projection acceleration method includes the following steps:

Step 1: For a frame of n-bit depth image, according to steps S101-S103, decompose the brightness of all pixels under all channels in the image, and calculate the corresponding X, Y values;

Step 2: For a single channel, first irradiate all micromirrors 2 ⁽ⁿⁱ⁾ -1 flipping cycles with a light source brightness of 2 ⁽ⁿⁱ⁾ units, and then illuminate all micromirrors 2 ⁱ -1 flipping cycles with a light source brightness of 1 unit, in:

The state of the micromirror corresponding to the pixel of N _total = 0 is 0 in all flip cycles;

For the micromirror corresponding to the pixel with X=0 and Y>1, the state of the micromirror is all 0 in the first 2 ⁽ⁿⁱ⁾ -1 flipping cycles; there are Y flipping cycle micromirrors in the next 2 ⁱ -1 flipping cycles The state is 1, and the state of the micromirror is 0 for 2 ⁱ -1-Y flip cycles;

For the micromirror corresponding to the pixel with X>1 and Y=0, there are X flipping cycles in the first 2 ⁽ⁿⁱ⁾ -1 flipping cycles. The state of the micromirror is 1, and the state of the micromirror is 2 ⁽ⁿⁱ⁾ -1-X flipping cycles The state is 0; the state of the micromirror is 0 in the last 2 ⁱ -1 flip cycles;

For the micromirror corresponding to the pixel with X>1 and Y>1, there are X flipping cycles in the first 2 ^{(ni) -1} flipping cycles. The state is 0; in the last 2 ⁱ -1 flip cycles, the state of the micromirror is 1 for Y flip cycles, and the state of the micromirror is 0 for 2 ⁱ -1-Y flip cycles.

Further, the projection acceleration method includes the following steps:

Step 1: For a frame of n-bit depth image, according to steps S101-S103, decompose the brightness of all pixels under all channels in the image, and calculate the corresponding X, Y values;

Step 2: For a single channel, first irradiate all micromirrors 2 ⁱ -1 flipping cycles with a light source brightness of 1 unit, and then illuminate all micromirrors 2 ⁽ⁿⁱ⁾ -1 flipping cycles with a light source brightness of 2 ⁽ⁿⁱ⁾ units, in:

The state of the micromirror corresponding to the pixel of N _total = 0 is 0 in all flip cycles;

For the micromirror corresponding to the pixel with X=0 and Y>1, the state of the micromirror is 1 for Y flipping cycles in the first 2 ⁱ -1 flipping cycles, and the state of the micromirror is 0 for 2 ⁱ -1-Y flipping cycles; The state of the micromirror is all 0 in the last 2 ⁽ⁿⁱ⁾ -1 flipping cycles;

For the micromirror corresponding to the pixel with X>1 and Y=0, the state of the micromirror is 0 in the first 2 ⁱ -1 flipping cycles; there are X flipping cycles in the next 2 ^{(n -i)} -1 flipping cycles The state of the micromirror is 1, and the state of the micromirror is 0 for 2 ⁽ⁿⁱ⁾ -1-X flip cycles;

For the micromirror corresponding to the pixel with X>1 and Y>1, the state of the micromirror is 1 for Y flipping cycles in the first 2 ⁱ -1 flipping cycles, and the state of the micromirror is 0 for 2 ⁱ -1-Y flipping cycles; In the last 2 ⁽ⁿⁱ⁾ -1 flipping cycles, the state of the micromirror is 1 for X flipping cycles, and the state of the micromirror is 0 for 2 ⁽ⁿⁱ⁾ -1-X flipping cycles.

Further, when n is an even number, i=n/2, i≥2; when n is an odd number, i=(n±1)/2, i≥2.

To achieve the above object, according to another aspect of the present invention, a projection acceleration system based on bit depth segmentation is provided, including a processor and a projection acceleration program module; when the projection acceleration program module is called by the processor, Perform the projection acceleration method as described previously.

In order to achieve the above object, according to another aspect of the present invention, a DLP projection device based on bit depth segmentation is provided, including a micromirror array, a light source, a projection lens and a processor. The mirror composition is used to reflect the light emitted by the light source to the designated position of the projection lens. The processor is used to control the brightness of the light source and the flip angle of each micromirror. In a single flip cycle, the light emitted by the light source is reflected to the designated position of the projection lens. position, the state of the micromirror is recorded as 1, otherwise the state of the micromirror is 0, and also includes a projection acceleration program module; when the projection acceleration program module is called by the processor, it executes the projection acceleration method as described above.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

(1) The present invention decomposes the 2n-order luminance of a single channel of an ⁿ -bit depth image into the sum of high ni-bit luminance and low i-bit luminance, and utilizes 2 ⁽ⁿⁱ⁾ units of light source luminance to generate high-ni-bit 2 ⁽ⁿⁱ⁾ -level grayscale pattern, using 1 unit of light source brightness to generate 2 ⁱ -level grayscale patterns of low i bits, thereby reducing the flip period occupied by each level of grayscale change of high ni bits to 1, thereby reducing the number of single channels The total number of flip cycles required for projection without reducing bit depth, enabling projection acceleration without loss of image quality.

(2) The ²ⁿ -level luminance of a single channel of a traditional n-bit depth image needs to occupy ²ⁿ -1 flip cycles to represent ²ⁿ -level luminance changes from 0 to ²ⁿ -1. However, in the method of the present invention, the low i bits of a single channel need to occupy 2 ⁱ -1 flip cycles, while the high ni bits only need to occupy 2 ⁽ⁿⁱ⁾ -1 flip cycles, so a single channel needs a total of 2 ⁽ⁿⁱ⁾ +2 ⁱ - Two inversion cycles can represent 2 ⁿ -order brightness changes from 0 to 2 ⁿ -1, which greatly reduces the total number of inversion cycles required for single-channel projection of a frame of image, but the total bit depth of the stored image does not change.

(3) In the present invention, the value of i determines the efficiency of projection. When n is an even number, i=n/2 can maximize the projection efficiency; when n is an odd number, i=(n±1)/2 Both can maximize the projection efficiency.

(4) The present invention can be implemented only by changing the control program of light source and micromirror flipping, without changing the structure of the existing DLP, so it is easy to popularize and does not increase additional equipment modification costs.

(5) The present invention is not only applicable to the projection of RGB images, but also applicable to the projection of grayscale images. According to the different types of DLP equipment channels, the scheme of the present invention can be used for grayscale image projection under the white light channel, or through The RGB channel overlay realizes the projection of the grayscale image.

(6) The present invention can realize projection acceleration without reducing the bit depth of the image, that is, realizes accelerated projection without generating jagged teeth, and is especially suitable for occasions that require precise measurement using grayscale images.

(7) The method of the present invention is applicable to various bit-depth image sequences with different channel numbers, and has broad application prospects.

Description of drawings

Fig. 1 is a flow chart of the main steps of a method for improving projection speed based on bit depth segmentation in the present invention;

Fig. 2 is the flowchart of embodiment 1 of the present invention;

Fig. 3 is the flowchart of embodiment 2 of the present invention;

Fig. 4 is a flow chart of Embodiment 3 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

In order to facilitate the understanding of the present invention, it is necessary to introduce some basic principles and working process of the existing DLP projection device:

DLP is the abbreviation of "Digital Light Processing", literally translated as digital light processing, that is, the original image to be projected is processed into a digital signal, and then the light is projected into an image according to the digital signal. The core device of DLP is DMD (Digital Micromirror Device, digital micromirror chip, referred to as micromirror array), which is a mirror array composed of a large number of micromirrors that can be flipped to a fixed angle. Each micromirror in the micromirror array corresponds to a pixels. Its basic projection principle is to reflect the required light to the projection lens through the micromirror, and reflect the unnecessary light to the light absorber for absorption, so as to realize the projection of the image, and the reflection direction is determined by controlling the angle of the micromirror. Achieved. Therefore, the light source adjustment and pattern formation of the DLP projection device operate separately.

Generally, the micromirror angle of DMD has three gears of +12°, 0°, and -12°. 0° is the initial position. At +12°, the reflected light is directed toward the projection lens, which is recorded as "on" or "1", and at -12° Reflected light is directed towards the light absorber, noted as "off" or "0". In one flip cycle, the state of the micromirror can only be 1 or 0, that is, the angle of the micromirror is either +12° or -12°.

The pattern formation of DLP is based on the RGB color mode. The RGB value is the brightness of the respective colors of the three channels of RGB. In DLP, it is realized by integrating the brightness of the light source. For a 16 million-color DLP (that is, a DLP for outputting an 8-bit depth map), the three RGB channels each have 256 levels from 0 to 255. The existing DLP projection method is to irradiate the corresponding micromirror under the corresponding RGB channel with a light source brightness of constant 1 unit intensity according to the RGB value of the pixel to be projected. Every time the light source is reflected by the micromirror to the projection lens, the corresponding The pixel position accumulates 1 unit of light source brightness, and the RGB value is equal to the number of flip cycles when the micromirror state is 1 under the corresponding RGB channel. For example, pixels with RGB values of 255, 120, and 50 indicate that the corresponding micromirror occupies 255 flipping cycles with a state of 1 under the R channel, 120 flipping cycles with a state of 1 under the G channel, and 50 flipping cycles under the B channel. A toggling cycle with a state of 1.

In the field of computer graphics, a single-channel image specifically refers to a grayscale image (note: a single channel is different from a single channel, and "single-channel image" is a fixed term), and the channel brightness of a grayscale image is called grayscale. Using DLP to project a grayscale image, you only need to set the RGB value of the projected pixel to be equal to the grayscale of the corresponding pixel in the original single-channel image. For example, pixels with a grayscale of 76 in the original 8-bit depth single-channel image have corresponding RGB values of 76, 76, and 76 when projected by DLP.

Since the maximum brightness of the three RGB channels of the 8-bit depth map is 255, each of the three RGB channels requires 1 unit of light source brightness to accumulate 255 times. Therefore, each channel needs at least 255 flip cycles to represent the corresponding 0-255 A total of 256 levels of brightness. Depending on the type of DLP available, the three channels can be illuminated simultaneously or alternately. If the three RGB channels are irradiated at the same time, it takes at least 255 flip cycles to display an 8-bit depth RGB image or grayscale image.

For each channel of DLP, in the 255 flip cycles, the number of flip cycles with the micromirror state being 1 determines the brightness of the channel. The existing DLP is irradiated with a constant light source brightness of 1 unit, for example, under the R channel There are 76 inversion periods in which the state of the micromirror is 1, and the state of the micromirror is 0 in the rest of the inversion periods, then the brightness of the R channel of the pixel corresponding to the micromirror is 76; the state of the micromirror is all 0 in 255 inversion periods, then the The brightness of the R channel corresponding to the micromirror is 0. Assuming that the flipping frequency of the micromirror is 1020Hz and all channels are projected at the same time, the frame rate for projecting an 8-bit depth image is 1020Hz÷255=4Hz.

The method of projecting acceleration by compressing the bit depth is as follows. When the bit depth is compressed from 8 bits to 7 bits, the brightness of a single channel is compressed from 256 steps to 128 steps, thereby reducing the number of flip cycles from 255 to 127. At this time, the frame rate of projection is increased to 1020Hz÷127=8.03Hz, and the projection speed is doubled. However, since the brightness can only be changed in units of 2 after compression, the quality of the obtained image will drop significantly, and jaggies can be clearly seen. The higher the compression ratio, the greater the decline in image quality.

Based on the basic principles of the above-mentioned DLP and DMD, in order to keep the bit depth constant while improving the projection speed, that is, to keep the image quality from declining, as shown in Figure 1, the present invention proposes the following scheme:

For an image to be projected with an n-bit depth, the projection acceleration method includes the following steps:

S101. Divide the ²ⁿ -order luminance N _total of a single channel into the sum of the luminance of the high ni bit and the low i bit, where n>i≥2, recorded as:

N _total = N _high + N _low

In the formula, N is _always any integer between 0 and 2 ⁿ -1, N _high indicates high ni-bit brightness, N _low indicates low i-bit brightness; high ni-bit brightness is obtained according to step S102, and low i-bit brightness is obtained according to step S103 is processed and obtained;

If the brightness of a single channel is directly expressed by the brightness of the light source, then:

N _total = X × 2 ⁽ⁿⁱ⁾ unit light source brightness + Y × 1 unit light source brightness

N _height = X × 2 ⁽ⁿⁱ⁾ unit light source brightness

N _low = Y × 1 unit light source brightness

In the formula, X is the number of flip cycles required for the micromirror state to be 1 when the light source brightness of 2 ⁽ⁿⁱ⁾ units is irradiated under the corresponding channel, and the value of X is 0 to 2 ⁽ⁿⁱ⁾ -1, a total of 2 ⁽ⁿⁱ⁾ order;

Y is the number of inversion cycles required for the micromirror state to be 1 when irradiating with a light source brightness of 1 unit under the corresponding channel, and the value of Y has a total of 2 ⁱ steps from 0 to 2 ⁱ -1;

When N _total = 0 of the corresponding channel, it is required that the state of the micromirror is 0 in all flip cycles under the corresponding channel, and at this time X=0, Y=0.

S102. Under the corresponding channel, irradiate with the brightness of the light source of 2 ⁽ⁿⁱ⁾ units, and need 1 flip cycle with the state of 1 to produce a luminous flux of 2 ⁽ⁿⁱ⁾ cycles of a unit of light source. At this time, each state is 1 The amount of change in the brightness of the flip cycle is 2 ⁽ⁿⁱ⁾ steps, thereby generating a brightness N _high of high ni bits;

S103. Under the corresponding channel, irradiating with 1 unit of light source brightness requires 2 ⁱ flipping cycles with a state of 1 to produce luminous flux of 1 unit light source with 2 ⁱ cycles. At this time, the brightness of each flipping cycle with a state of 1 changes The amount is 1 order, thereby generating the brightness N _low of the low i bits.

According to the above method of the present invention, the high ni bits only need to occupy 2 ⁽ⁿⁱ⁾ -1 flip cycles, and the low i bits need to occupy 2 ⁱ -1 flip cycles, so the total projection cycle of a single channel can be reduced to 2 ^{( ni)} +2 ⁱ -2 pcs. Wherein, the sequence of steps S102 and S103 can be exchanged.

In particular, when n is an even number, i=n/2 can maximize the projection efficiency; when n is an odd number, i=(n±1)/2 can maximize the projection efficiency.

The method of the present invention is further described below in conjunction with several specific examples:

[Example 1] n is an even number, i=n/2.

As shown in Figure 2, a method for improving projection speed based on bit depth segmentation in this embodiment includes the following steps:

S101. Divide the single channel 2 ⁿ -level brightness N _total of the n-bit depth image into the sum of two parts of high n/2 bits and low n/2 bits of brightness N _high and N _low :

N _total = X × 2 ^(n/2) unit light source brightness + Y × 1 unit light source brightness

N _height = X × 2 ^(n/2) unit light source brightness

N _low = Y × 1 unit light source brightness

In the formula, X is the number of flipping cycles in which the required micromirror state is 1 when the light source brightness of 2 ^(n/2) units is irradiated under the corresponding channel,

Y is the number of flip cycles required for the micromirror state to be 1 when irradiating with a light source brightness of 1 unit under the corresponding channel;

When N _total = 0 of the corresponding channel, it is required that the state of the micromirror is 0 in all flip cycles under the corresponding channel, and at this time X=0, Y=0.

S102, for high n/2 bits, irradiate with 2 ^(n/2) units of light source brightness, and 1 flip cycle can produce luminous flux of 2 ^(n/2) flip cycles under 1 unit light source irradiation, so high n The brightness change of /2 bits has 2 ^(n/2) levels, a total of [2 ^(n/2) -1]×2 ^(n/2) steps, and a total of 2 ^(n/2) -1 flip cycles are required, each The state of the micromirror is 1 or 0 in each flipping cycle, and the brightness change amount of each flipping cycle is 2 ^(n/2) , so that the brightness can be accumulated by flipping the micromirror, and the brightness of n/2 bits higher can be generated.

S103. For low n/2 bits, irradiating with 1 unit of light source brightness, 1 flip cycle can generate luminous flux of 1 unit of light source brightness, so the brightness change of low n/2 bits has 2 ^(n/2) steps, A total of 2 ^(n/2) -1 flipping cycles are required, the state of the micromirror is 1 or 0 in each flipping cycle, and the amount of brightness change in each flipping cycle is 1 order, so that the brightness can be accumulated by flipping the micromirror. Generates the lower n/2 bits of luminance.

In this embodiment, for a single channel, when 2 ^(n/2) units of light source brightness are used for light irradiation, in one flip cycle, it is 2 ^(n/2) times of the channel light irradiation of 1 unit light source brightness, so in Under the condition of a certain total amount of illumination, the total number of flip cycles required for a single channel projection will be greatly reduced. In the multi-channel projection mode, the total number of flip cycles required for all channels will also be greatly reduced. Therefore, under the bit-depth segmentation strategy of the present invention, no matter it is single-channel image projection or multi-channel image projection, the projection speed can be improved.

[Example 2] 8-bit grayscale image, n=8, i=4.

As shown in Figure 3 and Table 1, for an 8-bit grayscale image, the upper 4 bits represent a total of 16 grayscale changes from 0 to 15, which requires 15 flip cycles to achieve, and each state is 1 flip The amount of change in the periodic grayscale is 16 levels; and the lower 4 bits also represent a total of 16 grayscale changes from 0 to 15, which need to occupy 15 flipping cycles to achieve, and the amount of grayscale change in each flipping cycle with a state of 1 is 1 step .

Table 1 Schematic diagram of 256-level brightness segmentation of 8-bit grayscale image

Since the light source and pattern formation of the DLP projection device operate separately, we can divide the generation of the 256-level grayscale image into two parts, use 16 units of light source brightness to generate a 15-level grayscale pattern with 4 bits higher, and use 1 unit The brightness of the light source generates a 16-level grayscale pattern with the lower 4 bits. When irradiating with 16 units of light source, only 1 micromirror period is needed to generate 16 periods of luminous flux of 1 unit of light source. Taking 1 pixel as an example, if its grayscale value is 76, and its 8-bit binary representation is 01001100, its upper four bits are 0100=4, that is, X=4, and its lower four bits are 1100=12, that is, Y=12.

In order to produce this gray scale, according to the traditional DLP projection method, whether it is the white channel (gray=76) or the RGB channel (R=76, G=76, B=76), a single channel requires 255 flip cycles, of which 76 The state of the micromirror is 1 in one flip cycle, and the state of the micromirror is 0 in the remaining 179 flip cycles. Under the bit-depth segmentation strategy of the present invention, a single channel only needs 30 flipping cycles, and the first 15 cycles are irradiated with a light source brightness of 16 units, wherein the state of the micromirror is 1 in X=4 flipping cycles, and the last 15 The cycle is irradiated with the brightness of the light source of 1 unit, where Y=12 flipping cycles, the state of the micromirror is 1, then calculated according to the luminous flux, the brightness value generated by a single channel in these 30 cycles is:

76＝4×1(period)×16(light source brightness)+12×1(period)×1(light source brightness)

In this embodiment, the projection cycle of a single channel of an 8-bit grayscale image is reduced from 255 flip cycles to 30, and the projection speed is increased by 8.5 times. The illumination order of this embodiment can be exchanged, that is, the first 15 cycles can also be irradiated with the brightness of the light source of 1 unit, wherein the state of the micromirror is 1 in the 12 flip cycles, and the gray pattern of the lower 4 bits is first generated; the last 15 The cycle is irradiated with the light source brightness of 16 units, and the state of the micromirror is 1 in the 4 flip cycles to generate the upper 4-bit pattern.

For 8-bit RGB images (commonly known as 16 million colors or 16.78 million colors images), the brightness (i.e. RGB value) of each channel can be divided according to the brightness segmentation method of a single channel according to Table 1 of this embodiment, the illumination method, The flipping method of the micromirror is the same and will not be repeated here.

[Example 3] 4-bit depth image, n=4, i=2.

As shown in Figure 4 and Table 2, the 16-level brightness of a single channel of a 4-bit depth image is divided into two parts, the upper 2 bits and the lower 2 bits, and the upper 2 bits represent a total of 4 levels of brightness changes from 0 to 3. Occupy 3 flipping cycles to achieve, the amount of brightness change in each flipping cycle when the state is 1 is 4 levels; and the lower 2 bits also represent a total of 4 levels of grayscale changes from 0 to 3, which need to occupy 3 flipping cycles to achieve, each The luminance change amount of a flip cycle with the state being 1 is 1 step.

Table 2 Schematic diagram of 16-level brightness division of 4-bit depth image

The 4-level grayscale change of the upper 2 bits, if irradiated with 4 units of light source brightness, requires 1 flip cycle to generate luminous flux of 1 unit of light source for 4 cycles, and the state of the micromirror is 1 or 0 in each flip cycle. The brightness change of each inversion cycle is 4 levels, and it needs to occupy 3 inversion cycles to generate a 4-level grayscale pattern with the upper 2 bits; similarly, the 4-level grayscale change in the lower 2 bits needs to occupy 3 inversion cycles, each The brightness change of the flipping cycle is 1 level. With 1 unit of light source brightness for irradiation, it takes 3 flipping cycles to produce a 4-level grayscale change of the lower 2 bits. The state of the micromirror in each flipping cycle is 1 or 0. In this embodiment, the flip cycle of the micromirror is reduced from 15 to 6, and the projection speed is increased by 2.5 times.

It should be noted that the luminance of a light source per unit in a 4-bit depth map is equivalent to 2 ^8-4 = 16 times the luminance of a light source in 1 unit of an 8-bit depth map. Therefore, the brightness of each level of a 4-bit depth map varies greatly, and the jaggedness is very large. Obviously, the present invention can avoid further degradation of the quality of the 4-bit depth map while increasing the projection speed of the 4-bit depth map.

It can be understood from the above embodiments that the present invention is applicable to fast projection processing of various bit depth images, such as 7-bit depth, 10-bit depth, 16-bit depth, etc. The projection acceleration operation methods and principles of different bit depths are the same, and the difference Only in the values of n and i, the values of n and i can be directly substituted into the method of the present invention. Under the premise that n>i≥2, n being an even or odd number does not affect the realization of the present invention. In addition, it can be seen from the above embodiments that the greater the bit depth of the original image, the more obvious the projection speed-up effect of the present invention.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (7)

1. a kind of projection accelerated method based on bit depth segmentation, the acceleration for DLP projection arrangement is projected, note DLP projection dress When the light that light source emits is reflected into corresponding location of pixels by the micro mirror set, the state of micro mirror is 1, and otherwise the state of micro mirror is 0, Then individually the state of micro mirror is 1 or 0 in the overturning period, which is characterized in that for the image to be projected of n bit depth, which adds Fast method the following steps are included:

S101, by the 2 of single channelⁿRank brightness N_AlwaysIt is divided into the sum of high n-i and low i two parts brightness, i >=2 n > are denoted as:

N_Always=N_{It is high}+N_{It is low}

In formula, N_AlwaysIt is 0~2ⁿArbitrary integer between -1, N_{It is high}Indicate high n-i brightness, N_{It is low}Indicate low i brightness；High n-i bright Degree handles to obtain according to step S102, and low i brightness handles to obtain according to step S103；

S102, under corresponding channel, with 2^(n-i)The light-source brightness of unit is irradiated, and needs the overturning period that 1 state is 1 just It can produce 1 flat light source 2^(n-i)The luminous flux in a period, the overturning periodic brightness variable quantity that each state is 1 at this time is 2^{(n -i)}Rank generates high n-i of brightness N to carry out brightness accumulation by overturning micro mirror_{It is high}；

S103, under corresponding channel, be irradiated with the light-source brightness of 1 unit, need 2ⁱThe overturning period that a state is 1 can be with Generate 1 flat light source 2ⁱThe luminous flux in a period, the overturning periodic brightness variable quantity that each state is 1 at this time is 1 rank, thus logical It crosses overturning micro mirror and carries out brightness accumulation, generate low i of brightness N_{It is low}。

2. a kind of projection accelerated method based on bit depth segmentation as described in claim 1, which is characterized in that step S101 In,

N_Always=X × 2^(n-i)The flat light source brightness flat light source brightness of+Y × 1

N_{It is high}=X × 2^(n-i)Flat light source brightness

N_{It is low}The flat light source brightness of=Y × 1

In formula, X is under corresponding channel, with 2^(n-i)When the light-source brightness of unit is irradiated, required micro mirror state is 1 to turn over Turn-week issue,

Y be under corresponding channel, when being irradiated with the light-source brightness of 1 unit, required micro mirror state be 1 the overturning period Number；

The N of corresponding channel_AlwaysWhen=0, needing state of the micro mirror under corresponding channel in all rollovers period is 0, at this time X=0, Y=0.

3. a kind of projection accelerated method based on bit depth segmentation as claimed in claim 2, which is characterized in that including walking as follows It is rapid:

Step 1: for the image of a frame n bit depth, owning according to step S101~S103 under all channels in the image The brightness of pixel is decomposed, and calculates the value of corresponding X, Y；

Step 2: for single channel, first with 2^(n-i)The light-source brightness of unit irradiates all micro mirrors 2^(n-i)- 1 overturning period, then All micro mirrors 2 are irradiated with the light-source brightness of 1 unitⁱ- 1 overturning period, in which:

N_AlwaysState of the corresponding micro mirror of=0 pixel within all rollovers period is 0；

The corresponding micro mirror of the pixel of X=0 and Y > 1, preceding 2^(n-i)Micro mirror state is 0 in -1 overturning period；Rear 2ⁱ- 1 Having Y overturning period micro mirror state in the overturning period is 1,2ⁱ- 1-Y overturning period micro mirror states are 0；

The corresponding micro mirror of the pixel of X > 1 and Y=0, preceding 2^(n-i)There is X overturning period micro mirror state to be in -1 overturning period 1,2^(n-i)- 1-X overturning period micro mirror states are 0；Rear 2ⁱMicro mirror state is 0 in -1 overturning period；

The corresponding micro mirror of the pixel of X > 1 and Y > 1, preceding 2^(n-i)There is X overturning period micro mirror state to be in -1 overturning period 1,2^(n-i)- 1-X overturning period micro mirror states are 0；Rear 2ⁱHaving Y overturning period micro mirror state in -1 overturning period is 1, 2ⁱ- 1-Y overturning period micro mirror states are 0.

4. a kind of projection accelerated method based on bit depth segmentation as claimed in claim 2, which is characterized in that including walking as follows It is rapid:

Step 1: for the image of a frame n bit depth, owning according to step S101~S103 under all channels in the image The brightness of pixel is decomposed, and calculates the value of corresponding X, Y；

Step 2: for single channel, all micro mirrors 2 first being irradiated with the light-source brightness of 1 unitⁱ- 1 overturning period, then with 2^(n-i) The light-source brightness of unit irradiates all micro mirrors 2^(n-i)- 1 overturning period, in which:

N_AlwaysState of the corresponding micro mirror of=0 pixel within all rollovers period is 0；

The corresponding micro mirror of the pixel of X=0 and Y > 1, preceding 2ⁱHaving Y overturning period micro mirror state in -1 overturning period is 1, 2ⁱ- 1-Y overturning period micro mirror states are 0；Rear 2^(n-i)Micro mirror state is 0 in -1 overturning period；

The corresponding micro mirror of the pixel of X > 1 and Y=0, preceding 2ⁱMicro mirror state is 0 in -1 overturning period；Rear 2^(n-i)- 1 Having X overturning period micro mirror state in the overturning period is 1,2^(n-i)- 1-X overturning period micro mirror states are 0；

The corresponding micro mirror of the pixel of X > 1 and Y > 1, preceding 2ⁱHaving Y overturning period micro mirror state in -1 overturning period is 1, 2ⁱ- 1-Y overturning period micro mirror states are 0；Rear 2^(n-i)Having X overturning period micro mirror state in -1 overturning period is 1,2^(n-i)- 1-X overturning period micro mirror states are 0.

5. a kind of projection accelerated method based on bit depth segmentation as described in Claims 1 to 4 any one, feature exist In, when n is even number, i=n/2, i >=2；When n is odd number, i=(n ± 1)/2, i >=2.

6. a kind of projection acceleration system based on bit depth segmentation, which is characterized in that accelerate program including processor and projection Module；The projection accelerates program module when being called by the processor, executes as described in Claims 1 to 5 any one Projection accelerated method.

7. a kind of DLP projection arrangement based on bit depth segmentation, including micro mirror array, light source, projection lens and processor, micro- Lens array is made of multiple micro mirrors that can independently overturn, and the light for emitting light source reflexes to the designated position of projection lens, Processor is used to control light-source brightness and the flip angle of each micro mirror of control emits light source within the individually overturning period Light when reflexing to the designated position of projection lens the state of micro mirror be denoted as 1, otherwise the state of micro mirror is 0, which is characterized in that also Accelerate program module including projection；The projection accelerates program module when being called by the processor, executes such as claim 1 Projection accelerated method described in~5 any one.