Projection device and projection device wall color distortion and brightness correction method

Abstract

This invention relates to a projection device and a method for correcting color distortion and brightness on a projection surface. The method includes: setting the brightness ratios of the R, G, and B channels of the projection device to 100%; projecting a feature image containing only black and white colors; selecting a region from the feature image as a correction region; obtaining the average grayscale values ​​of the R, G, and B channels corresponding to black and white based on the correction region; calculating the final adjustment ratio for each channel and performing optical-mechanical colorimetric adjustment; and calculating the brightness adjustment value and performing optical-mechanical brightness adjustment based on parameters output by the camera module in the projection device. This invention achieves the correction of color distortion and brightness in projection devices.

Description

Technical Field

[0001] This invention relates to the field of projection technology, and in particular to a projection device and a method for correcting color distortion and brightness on a projection device wall. Background Technology

[0002] With the development of projection technology, projection has gradually become a widely used multimedia display method. However, in actual use, due to different wall decoration effects and wall colors, when the projector image is projected onto a wall of different colors, the superposition of the image colors and wall colors can lead to color distortion.

[0003] Existing color distortion correction schemes often require an additional color feature image for correction, while brightness correction is often performed by sensing the ambient brightness through an ALS (ambient light sensor). Since the ALS is often installed above or in front of the projector, its brightness value differs from that of the projected image, resulting in low accuracy. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a projection device and a method for correcting color distortion and brightness on the projection device wall.

[0005] The specific plan is as follows:

[0006] A method for correcting wall color distortion and brightness using a projection device includes the following steps:

[0007] S1: After setting the brightness ratio of the R, G, and B channels of the projection device to 100% respectively, project a feature image containing only black and white colors through the projection device.

[0008] S2: Select a region from the feature image as the correction region;

[0009] S3: Obtain the average gray values ​​of the R, G, and B channels corresponding to all white pixels within the correction area, aveR, aveG, and aveB, and use the average gray value of the G channel as the average brightness of white, brightness_w.

[0010] S4: Obtain the average grayscale value of the G channel corresponding to all black pixels in the correction area, and use it as the average brightness_b corresponding to black;

[0011] S5: Calculate the brightness difference between white and black: brightness = brightness_w - brightness_b;

[0012] S6: Calculate the current gain value curGain_R of channel R and the current gain value curGain_B of channel B;

[0013] curGain_R = 1024 * aveG / aveR

[0014] curGain_B = 1024 * aveG / aveB

[0015] Where aveR represents the average gray value of the R channel; aveG represents the average gray value of the G channel; and aveB represents the average gray value of the B channel.

[0016] S7: Calculate the initial adjustment ratios for the R, G, and B channels:

[0017] ratio_R = curGain_R / targetR

[0018] ratio_G = 1

[0019] ratio_B = curGain_B / targetB

[0020] Where ratio_R represents the initial adjustment ratio of the R channel, ratio_G represents the initial adjustment ratio of the G channel, ratio_B represents the initial adjustment ratio of the B channel, targetR represents the standard gain value of the R channel, and targetB represents the standard gain value of the B channel.

[0021] S8: Normalize the initial adjustment ratios of the R, G, and B channels to obtain the final adjustment ratios of the R, G, and B channels;

[0022] new_ratio_R=1-(1-ratio_R / max_ratio)*coff0

[0023] new_ratio_G=1-(1-1 / max_ratio)*coff0

[0024] new_ratio_B=1-(1-ratio_B / max_ratio)*coff0

[0025] Where max_ratio represents the maximum value among ratio_R, ratio_G, and ratio_B; coff0 represents the chroma adjustment coefficient, which ensures that the minimum value among the calculated new_ratio_R, new_ratio_G, and new_ratio_B is greater than the set lower limit of the adjustment ratio; new_ratio_R represents the final adjustment ratio of the R channel; new_ratio_G represents the final adjustment ratio of the G channel; and new_ratio_B represents the final adjustment ratio of the B channel.

[0026] S9: Calculate the brightness adjustment value white_nits based on the brightness difference value brightness and the values ​​of AE_Target, Cur_exposure, and total_gain output by the camera module in the current projection device.

[0027] white_nits=Coff*brightness / AE_Target / Cur_exposure / total_gain / 8

[0028] Where Coff represents the brightness adjustment coefficient, used to reduce the brightness difference between optical engines produced in different batches; AE_Target represents the current exposure; Cur_exposure represents the target value for automatic exposure; and total_gain represents the total gain.

[0029] S10: Adjust the optical engine brightness according to the brightness adjustment value, and adjust the optical engine chromaticity according to the final adjustment ratio of the R, G, and B channels.

[0030] Furthermore, the feature image is an image used for gradient correction and / or confocal projection of the projection device.

[0031] Furthermore, the correction region is the area in the feature image that is close to the center of the image.

[0032] Furthermore, the standard gain value of the R channel is the current gain value of the R channel under standard conditions; the standard gain value of the B channel is the current gain value of the B channel under standard conditions; the standard environment is a direct projection at a distance of 2 meters onto a white wall in a dark room.

[0033] Furthermore, the method for adjusting the optical-mechanical brightness based on the brightness adjustment value is as follows: a mapping table corresponding to the brightness adjustment value and the brightness sequence number is pre-constructed; when the brightness adjustment value is calculated, the corresponding brightness sequence number is obtained by looking up the table, and the corresponding optical-mechanical brightness is set by the brightness sequence number.

[0034] A projection device includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the method described above in the embodiments of the present invention.

[0035] The present invention adopts the above technical solution, which integrates color distortion correction and brightness correction into a single correction image. The correction image uses the same feature image used in the original gradient correction or focus, which improves the correction speed, increases the correction accuracy, and enhances the user experience. Attached Figure Description

[0036] Figure 1 The diagram shown is a flowchart of a method according to an embodiment of the present invention. Detailed Implementation

[0037] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention.

[0038] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0039] Example 1:

[0040] This invention provides a method for correcting wall color distortion in projection equipment, such as... Figure 1 As shown, the method includes the following steps:

[0041] S1: After setting the brightness ratio of the three channels R (red), G (green), and B (blue) of the projection device (projector) to 100%, project a feature image containing only black and white colors through the projection device.

[0042] To reduce the frequent switching of feature images during user operation, this embodiment will use the feature images used by the projection device itself for gradient correction and / or focusing as feature images used for color distortion and brightness correction.

[0043] S2: Select a region from the feature image as the correction region.

[0044] To avoid interference from the external environment, in this embodiment, it is preferable to select the area near the center of the image as the correction area. The shape and size can be set by the user and are not limited here.

[0045] S3: Obtain the average gray values ​​of the R, G, and B channels corresponding to all white pixels within the correction area, aveR, aveG, and aveB, and use the average gray value of the G channel as the average brightness of white, brightness_w.

[0046] S4: Obtain the average grayscale value of the G channel corresponding to all black pixels within the correction area, and use it as the average brightness_b corresponding to black.

[0047] S5: Calculate the brightness difference between white and black: brightness = brightness_w - brightness_b.

[0048] S6: Calculate the current gain value curGain_R of channel R and the current gain value curGain_B of channel B;

[0049] curGain_R = 1024 * aveG / aveR

[0050] curGain_B = 1024 * aveG / aveB

[0051] Where aveR represents the average gray value of the R channel; aveG represents the average gray value of the G channel; and aveB represents the average gray value of the B channel.

[0052] S7: Calculate the initial adjustment ratios for the R, G, and B channels:

[0053] ratio_R = curGain_R / targetR

[0054] ratio_G = 1

[0055] ratio_B = curGain_B / targetB

[0056] Wherein, ratio_R represents the initial adjustment ratio of the R channel, ratio_G represents the initial adjustment ratio of the G channel, ratio_B represents the initial adjustment ratio of the B channel, targetR represents the standard gain value of the R channel, and targetB represents the standard gain value of the B channel. The standard gain value of each projection device needs to be calibrated before use. In this embodiment, the standard gain value is obtained by simulating a standard environment used by a user. The standard environment is set as a front projection at a distance of 2 meters onto a white wall in a dark room. The standard gain value of the R channel is the current gain value of the R channel under the standard environment; the standard gain value of the B channel is the current gain value of the B channel under the standard environment.

[0057] S8: Normalize the initial adjustment ratios of the R, G, and B channels to obtain the final adjustment ratios of the R, G, and B channels:

[0058] new_ratio_R=1-(1-ratio_R / max_ratio)*coff0

[0059] new_ratio_G=1-(1-1 / max_ratio)*coff0

[0060] new_ratio_B=1-(1-ratio_B / max_ratio)*coff0

[0061] Wherein, max_ratio represents the maximum value among ratio_R, ratio_G, and ratio_B; coff0 represents the chroma adjustment coefficient, which ensures that the minimum value among the calculated new_ratio_R, new_ratio_G, and new_ratio_B is greater than the set lower limit of the adjustment ratio; the value of the lower limit of the adjustment ratio can be set by those skilled in the art according to the usage, initially set to 0.5, and then appropriately increased, such as set to 0.8. The chroma adjustment coefficient coff0 can be adjusted according to the required lower limit of the adjustment ratio; new_ratio_R represents the final adjustment ratio of the R channel; new_ratio_G represents the final adjustment ratio of the G channel; and new_ratio_B represents the final adjustment ratio of the B channel.

[0062] S9: Calculate the brightness adjustment value white_nits based on the brightness difference value brightness and the values ​​of AE_Target, Cur_exposure, and total_gain output by the camera module in the current projection device.

[0063] white_nits=Coff*brightness / AE_Target / Cur_exposure / total_gain / 8

[0064] Wherein, Coff represents the brightness adjustment coefficient, which is used to reduce the brightness difference between different batches of optical engines. When the light emitted by the optical engine is brighter, the brightness adjustment coefficient is increased, and when the light emitted by the optical engine is dimmer, the brightness adjustment coefficient is decreased. In this embodiment, after batch experiments, the value is set to 170; AE_Target represents the current exposure; Cur_exposure represents the automatic exposure target value; and total_gain represents the total gain.

[0065] S10: Adjust the optical engine brightness according to the brightness adjustment value, and adjust the optical engine chromaticity according to the final adjustment ratio of the R, G, and B channels.

[0066] In this embodiment, the method for adjusting the optical-mechanical brightness based on the brightness adjustment value is as follows: a mapping table corresponding to the brightness adjustment value and the brightness sequence number is pre-constructed; when the brightness adjustment value is calculated, the corresponding brightness sequence number is obtained by looking up the table, and the corresponding optical-mechanical brightness is set by the brightness sequence number (each brightness sequence number corresponds to a brightness value).

[0067] The method proposed in this embodiment can be configured to be activated via a remote control in a projection device.

[0068] Example 2:

[0069] The present invention also provides a projection device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps in the method embodiment described above in Embodiment 1 of the present invention.

[0070] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A method for correcting wall color distortion and brightness in a projection device, characterized in that, Includes the following steps: S1: After setting the brightness ratio of the R, G, and B channels of the projection device to 100% respectively, project a feature image containing only black and white colors through the projection device. S2: Select a region from the feature image as the correction region; S3: Obtain the average gray values ​​of the R, G, and B channels corresponding to all white pixels within the correction area, aveR, aveG, and aveB, and use the average gray value of the G channel as the average brightness of white, brightness_w. S4: Obtain the average grayscale value of the G channel corresponding to all black pixels in the correction area, and use it as the average brightness_b corresponding to black; S5: Calculate the brightness difference between white and black: brightness = brightness_w - brightness_b; S6: Calculate the current gain value curGain_R of channel R and the current gain value curGain_B of channel B; curGain_R = 1024 * aveG / aveR curGain_B = 1024 * aveG / aveB Where aveR represents the average gray value of the R channel; aveG represents the average gray value of the G channel; and aveB represents the average gray value of the B channel. S7: Calculate the initial adjustment ratios for the R, G, and B channels: ratio_R = curGain_R / targetR ratio_G = 1 ratio_B = curGain_B / targetB Where ratio_R represents the initial adjustment ratio of the R channel, ratio_G represents the initial adjustment ratio of the G channel, ratio_B represents the initial adjustment ratio of the B channel, targetR represents the standard gain value of the R channel, and targetB represents the standard gain value of the B channel. S8: Normalize the initial adjustment ratios of the R, G, and B channels to obtain the final adjustment ratios of the R, G, and B channels; new_ratio_R=1-(1-ratio_R / max_ratio)*coff0 new_ratio_G=1-(1-1 / max_ratio)*coff0 new_ratio_B=1-(1-ratio_B / max_ratio)*coff0 Where max_ratio represents the maximum value among ratio_R, ratio_G, and ratio_B; coff0 represents the chroma adjustment coefficient, which ensures that the minimum value among the calculated new_ratio_R, new_ratio_G, and new_ratio_B is greater than the set lower limit of the adjustment ratio; new_ratio_R represents the final adjustment ratio of the R channel; new_ratio_G represents the final adjustment ratio of the G channel; and new_ratio_B represents the final adjustment ratio of the B channel. S9: Calculate the brightness adjustment value white_nits based on the brightness difference value brightness and the values ​​of AE_Target, Cur_exposure, and total_gain output by the camera module in the current projection device. white_nits=Coff*brightness / AE_Target / Cur_exposure / total_gain / 8 Where Coff represents the brightness adjustment coefficient, used to reduce the brightness difference between optical engines produced in different batches; AE_Target represents the current exposure; Cur_exposure represents the target value for automatic exposure; and total_gain represents the total gain. S10: Adjust the optical engine brightness according to the brightness adjustment value, and adjust the optical engine chromaticity according to the final adjustment ratio of the R, G, and B channels.

2. The method for correcting wall color distortion and brightness in a projection device according to claim 1, characterized in that: The feature image is an image used for gradient correction and / or confocal projection on a projection device.

3. The method for correcting wall color distortion and brightness in a projection device according to claim 1, characterized in that: The correction region is the area in the feature image that is close to the center of the image.

4. The method for correcting wall color distortion and brightness in a projection device according to claim 1, characterized in that: The standard gain value of the R channel is the current gain value of the R channel under standard conditions; the standard gain value of the B channel is the current gain value of the B channel under standard conditions; the standard environment is a direct projection at a distance of 2 meters onto a white wall in a dark room.

5. The method for correcting wall color distortion and brightness in a projection device according to claim 1, characterized in that: The method for adjusting the optical-mechanical brightness based on the brightness adjustment value is as follows: a mapping table corresponding to the brightness adjustment value and the brightness sequence number is pre-constructed; when the brightness adjustment value is calculated, the corresponding brightness sequence number is obtained by looking up the table, and the corresponding optical-mechanical brightness is set by the brightness sequence number.

6. A projection device, characterized in that: It includes a processor, a memory, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the method as described in any one of claims 1 to 5.

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