WO2019010917A1 - Method and system for color calibration of projection image - Google Patents

Abstract

The invention discloses a color calibration method and system for projecting images, the color calibration method comprising: projecting a reference pattern onto a target projection surface; acquiring a projection of the reference pattern on the target projection surface; comparing the reference patterns The color attribute and the projected color attribute generate a color calibration table; the projected image is calibrated according to the color calibration table. The invention solves the problem of image distortion caused by uneven reflectance or uneven color of the projection surface; the cost is low and the use is convenient.

Description

Color calibration method and system for projected image Technical field

The present invention relates to the field of projection technology, and in particular, to a method and system for color calibration of a projected image.

Background technique

Projection technology is widely used in life and work, and is a device that can project images or video onto a screen. However, the limitation of space and conditions is often projected on a variety of planes. Due to the reflectivity, flatness, and unevenness of the projection plane, the projected image is distorted and the effect is not good.

The current projection technology mainly focuses on the problem of projection deformation. For example, the patent publication CN105100792A provides a geometric projection imaging automatic correction device and a correction method thereof, and the correction method of the geometric projection imaging automatic correction device includes: a projector When the image processor is projected, the image processor projects the original projection content onto the projection screen through the projector; the camera captures the current image on the projection screen and transmits it to the image processor; the image processor compares the original projection content with the image captured by the camera. , judging whether the picture captured by the camera has deviation from the original projection content, if it is continued, if not, the correction ends; the image processor calculates the specific deviation value of the picture captured by the camera and the original projection content, and passes the image distortion correction tool. , performing inverse deviation graphic processing; the calibration ends.

For another example, the publication No. CN106162124A discloses a calibration method for outputting an image of a projector, comprising the steps of: forming a plurality of mark patterns on a screen; acquiring a mark pattern by using an image forming device, and calculating a corresponding mark; a point, and a standard geometry formed by the marker point on the image plane of the imaging device; projecting a plurality of feature pattern patterns on the screen using a projector; recording a plurality of the feature pattern patterns projected on the projector image plane and imaging The position of the device image plane; comparing the positions of each of the recorded feature patterns in the two image planes, calculating the mapping rules of the two image planes; according to the feature pattern graphics, under the image plane of the imaging device The position and mapping rules are used to calculate the maximum effective projection area of the projector; the projection picture is distorted according to the mapping rule and the maximum effective projection area.

The above two patents mainly solve the problem of geometric deformation of the projected image; in the actual projection imaging, the projection plane such as the curtain or the wall is often contaminated, and the projection image may be color cast, and the contrast and brightness may not meet the requirements of use.

In the prior art, the color problem of the image has not been sufficiently paid attention to and solved, and these problems are often encountered when we use the projection device.

Summary of the invention

The invention mainly solves the problem that the projection device has different influences on the use of the material of the projection plane, including the reflection image, the background color, the projection image color cast, the contrast is not required, etc. during the projection, and the above-mentioned deficiencies of the prior art are A color calibration method and system for projected images are proposed.

The color calibration method of the projected image includes the steps of:

S1, projecting the reference pattern to the target projection surface;

S2: acquiring a projection of the reference pattern on the target projection surface;

S3, comparing a color attribute of the reference pattern with a color attribute of the projection, generating a color calibration table;

S4, calibrating the projected image according to the color calibration table.

Further, comparing the color attribute of the reference pattern with the color attribute of the projection, generating a color calibration table includes:

Dividing the projection into a plurality of regions according to a color attribute of the reference pattern and a color attribute of the projection;

A color calibration table containing calibration parameters for each region is generated.

Further, the method further includes the steps of:

Whether the position of the projection device changes is determined every predetermined time interval; if it is changed, the process goes to step S1.

Further, after calibrating the projected image according to the color calibration table, the method further includes:

Get the light intensity of the environment in which it is located;

The brightness of the projected image is adjusted according to the illumination intensity.

Further, the attributes of the color include: brightness, chromaticity, and saturation of the color.

In another aspect, the present invention also provides a color calibration system for a projected image; comprising:

a projection module for projecting a reference pattern to a target projection surface;

a projection acquisition module, configured to acquire a projection of the reference pattern on the target projection surface;

a calibration table generating module, configured to compare a color attribute of the reference pattern with a color attribute of the projection to generate a color calibration table;

A projected image calibration module for calibrating the projected image according to the color calibration table.

Further, the calibration table generating module includes:

a region dividing sub-module, configured to divide the projection into a plurality of regions according to a color attribute of the reference pattern and a color attribute of the projection;

A calibration table generation sub-module is used to generate a color calibration table containing calibration parameters for each region.

Further, it also includes:

The judging module is configured to determine whether the position of the projection device is changed every predetermined time interval; if the change occurs, the module projection module is called, and the projection image is recalibrated.

Further, it also includes:

a light intensity acquisition module for acquiring the light intensity of the environment in which it is located;

And a brightness adjustment module, configured to adjust brightness of the projected image according to the illumination intensity.

Further, the attributes of the color include: brightness, chromaticity, and saturation of the color.

The invention is based on the human visual perception characteristic, uses the complementary color principle to eliminate the difference of the projection plane, expands the use scene, and improves the user experience.

The method provided by the invention is low in cost and convenient and convenient.

DRAWINGS

1 is a flowchart of a method for color calibration of a projected image according to Embodiment 1 of the present invention;

2 is a flowchart of a method for color calibration of a projected image according to Embodiment 2 of the present invention;

3 is a structural block diagram of a color calibration system for a projected image according to Embodiment 3 of the present invention.

Detailed ways

The technical solutions of the present invention are further described below with reference to the accompanying drawings, but the present invention is not limited to the embodiments.

It should also be understood that the specific embodiments described herein are merely for understanding the invention and are not intended to The invention is defined.

Embodiment 1

This embodiment provides a color calibration method for a projected image, and FIG. 1 shows a flowchart thereof. The method is applied to a projection device, which comprises an imaging device that automatically collects environmental information for calibration so that the projected image meets user requirements. The color calibration method of the projected image is detailed as follows:

In step S101, the reference pattern is projected onto the target projection surface.

The reference pattern may be a solid color, such as three primary colors, red, green, and blue; respectively, performing color cast compensation on various primary colors.

When using a projection device, the target projection surface can be a wall, hanging paper or cloth, etc.; in life and work, the wall is often used as a target projection surface.

In life and work, there are no dedicated projection planes due to conditional restrictions. In many cases, other planes are replaced, but it is easy to achieve a good effect on the projected image due to defects in the projection plane.

Further, the reflectivity, the flatness, the background color, and the like of the projection plane may affect the display of the image, causing the color cast of the projected image and the contrast to be less than required, which affects the user experience.

Many projection planes have localized contamination, and there are large chromatic aberrations or defects in some areas, which are clearly observed on the projected image.

For example, when the wall is used as the target projection surface, it is likely that there are many contaminated areas on the wall, and chromatic aberration will inevitably occur. The general projection equipment is powerless at this time. The invention utilizes the complementary color principle to eliminate the difference between these projection plane regions and ensure the user experience.

In step S102, a projection of the reference pattern on the target projection surface is acquired.

Specifically, the present invention relates to a projection apparatus including an image acquisition device for collecting a projection of a reference pattern on a target projection surface.

In step S103, a color calibration table is generated by comparing a color attribute of the reference pattern with a color attribute of the projection.

The color attributes include: brightness, chrominance, saturation.

Brightness refers to the brightness of the picture, in units of candela per square meter (cd/m2) or nits, which is the candlelight per square meter.

Further, when the brightness of the projection is too low or too high, our eyes are often difficult to adapt, time It is easy to cause damage to the eyes after a long time.

Saturation refers to the degree of vividness of a color, and the degree of saturation depends on the proportion of the color component and the achromatic component in the color.

Optionally, when the target projection surface is a projection surface of uniform color, the calibration parameters in the color calibration table are the same in each part of the projection.

Optionally, when the target projection surface portion is contaminated, the color difference between the contaminated portion and the other portion is large, and the reflectance is different; the calibration parameter in the color calibration table is different from the region in the contaminated region, and the correction may be made. Their differences narrowed.

Specifically, if the reflectance of the target projection surface is low in the contaminated area, the light loss rate is large, resulting in a large loss of saturation in the portion, for example, the reflectance of the contaminated area to green and blue is 70%, and other parts are The reflectance is 90%; when the projected image is a green image with a saturation of 50%; after calculation, it is known that the saturation of blue and green is increased by 43% for the contaminated area, and the other areas need to be increased by 11%; After the calculated parameters are corrected, the projections are made consistent with the reference pattern.

The color correction table includes color correction parameters, and the color correction parameters may include correction parameters of a plurality of color attributes.

Optionally, when determining the correction parameter, more actual experience of the user may be considered, and the projected image is added to obtain a better experience.

In step S104, the projected image is calibrated according to the color calibration table.

The projected image is corrected according to the color calibration table acquired in step S103 so that the projected image conforms to the user's needs.

Further, the calibrated projected image is more suitable for the user's needs.

The attributes of the color include: brightness, chromaticity, and saturation of the color.

Embodiment 2

This embodiment provides a color calibration method for a projected image, and FIG. 2 shows a flowchart thereof. Details are as follows:

In step S201, the reference pattern is projected onto the target projection surface.

In step S202, a projection of the reference pattern on the target projection surface is acquired.

In this embodiment, step S201 and step S202 are the same as those in the first embodiment, and are not described herein again.

In step S203, the projection is divided into a plurality of regions according to the color attribute of the reference pattern and the color attribute of the projection.

Since the material characteristics of each part of the target projection surface are different, the calibration parameters of each part are different; further, before the correction parameters are determined, the projection needs to be divided according to the material characteristics; the color correction parameters of the same area are the same. The color correction parameters of different areas are different.

Specifically, for example, there is a color difference between a certain area of the target projection surface and other areas, and the area may be separately divided into one area to separately determine the color correction parameters of the area.

In step S204, a color calibration table including correction parameters of the respective regions is generated.

Specifically, the color calibration parameters of each region are respectively determined according to the regions divided in step S203.

Further, the color correction parameters of each region are grouped into a color calibration parameter table.

The table includes color correction parameters for each color attribute of each region, and the projection device corrects the projection image according to the parameter.

In step S205, the projected image is calibrated according to the color calibration table.

The steps corresponding to the first embodiment are the same, and will not be described here.

In step S206, the illumination intensity of the environment in which it is located is acquired.

In step S207, the brightness of the projected image is adjusted according to the illumination intensity.

Specifically, the projection device collects ambient light to acquire the brightness of the ambient light.

Alternatively, when the brightness of the ambient light is large, the eye may feel illegible when viewing the projected image. Over time, even damage to the eyes; at this time, the projection device appropriately adjusts the brightness of the projected image according to the intensity of the ambient light, so that the projected image is easily recognized and viewed.

Alternatively, when the brightness of the environment is small, there is also a problem; only when the brightness of the ambient light and the projected image are at an appropriate ratio, the eye can comfortably view the projected image.

Further, it is determined whether the position of the projection device is changed every predetermined time interval; if it is changed, the process proceeds to step S201.

Specifically, when the projection device is moved, the target projection surface also changes, and the color calibration parameter table determined in step S204 is also unavailable.

Further, when the projection device is moved, the color calibration parameter table is re-determined to adapt to the new one. Target projection surface.

Further, it can be determined in various ways whether the position of the projection device is moved, for example, a positioning device is mounted on the projection device.

Optionally, the projection device is equipped with a GPS positioning device for acquiring location information of the projection device.

The attributes of the color include: brightness, chromaticity, and saturation of the color.

The above-described steps are not strictly performed, and all changes that are foreseeable and do not affect the implementation of the function should be within the scope of the present invention.

Embodiment 3

This embodiment provides a color calibration system for a projected image, and FIG. 3 shows a structural block diagram thereof. The system includes an imaging device that can acquire a projected image. Details are as follows:

The projection module 310 is configured to project the reference pattern to the target projection surface.

The projection acquisition module 320 is configured to acquire a projection of the reference pattern on the target projection surface.

The calibration table generating module 330 is configured to compare a color attribute of the reference pattern with a color attribute of the projection to generate a color calibration table.

The projected image calibration module 340 is configured to calibrate the projected image according to the color calibration table.

The calibration table generation module 330 includes:

The area dividing sub-module 331 is configured to divide the projection into a plurality of regions according to the color attribute of the reference pattern and the color attribute of the projection.

A calibration table generation sub-module 332 is used to generate a color calibration table containing calibration parameters for the various regions.

Also includes:

The determining module 370 is configured to determine whether the position of the projection device changes every predetermined time interval; if the change occurs, call the module projection module and recalibrate the projected image.

Also includes:

The illumination intensity acquisition module 350 is configured to acquire the illumination intensity of the environment in which it is located.

The brightness adjustment module 360 is configured to adjust the brightness of the projected image according to the illumination intensity.

The attributes of the color include: brightness, chromaticity, and saturation of the color.

The projection module 310 projects the reference pattern to the target projection surface, and the projection acquisition module 320 acquires the Referring to the projection of the pattern on the target projection surface, the calibration table generation module 330 generates a color calibration table for calibrating the projection image by comparing the color attributes of the reference pattern with the color attributes of the projection. The projected image calibration module 340 then calibrates the projected image based on the color calibration table.

Optionally, the calibration table generation module 330 includes a region division sub-module 331 and a calibration table generation sub-module 332.

Further, the region dividing sub-module 331 divides the projection into a plurality of regions according to the color attribute of the reference pattern and the color attribute of the projection. It is convenient to determine different calibration parameters in different areas according to the projection plane. The calibration table generation sub-module 332 generates a color calibration table containing calibration parameters for the various regions.

The judging module 370 can also determine whether the position of the projection device is moving, and has decided whether to re-determine the color calibration table.

The illumination intensity acquisition module 350 and the brightness adjustment module 360 can adjust the brightness of the projected image according to the intensity of the ambient light to enable the user to obtain a good look and feel.

In the embodiments provided herein, it should be understood that the methods and systems described are illustrative and may vary by adjustment in actual implementation.

In addition, the specific names of the respective functional units or modules are only for the purpose of facilitating mutual differentiation and are not intended to be used in the scope of the present invention.

The specific embodiments described herein are merely illustrative of the spirit of the invention. A person skilled in the art can make various modifications or additions to the specific embodiments described or in a similar manner, without departing from the spirit of the invention or as defined by the appended claims. The scope.

Claims (10)

A color calibration method for a projected image, comprising the steps of: S1, projecting the reference pattern to the target projection surface; S2: acquiring a projection of the reference pattern on the target projection surface; S3, comparing a color attribute of the reference pattern with a color attribute of the projection, generating a color calibration table; S4, calibrating the projected image according to the color calibration table. The color calibration method of the projected image according to claim 1, wherein the comparing the color attribute of the reference pattern with the color attribute of the projection, generating a color calibration table comprises: Dividing the projection into a plurality of regions according to a color attribute of the reference pattern and a color attribute of the projection; A color calibration table containing calibration parameters for each region is generated. The color calibration method for a projected image according to claim 1, further comprising the steps of: Whether the position of the projection device changes is determined every predetermined time interval; if it is changed, the process goes to step S1. The color calibration method of the projected image according to claim 1, further comprising: after calibrating the projected image according to the color calibration table, further comprising: Get the light intensity of the environment in which it is located; The brightness of the projected image is adjusted according to the illumination intensity. The color calibration method of a projected image according to claim 1, 2, 3 or 4, wherein the attributes of the color comprise: brightness, chromaticity and saturation of the color. A color calibration system for projecting images, comprising: a projection module for projecting a reference pattern to a target projection surface; a projection acquisition module, configured to acquire a projection of the reference pattern on the target projection surface; a calibration table generating module, configured to compare a color attribute of the reference pattern with a color attribute of the projection to generate a color calibration table; A projected image calibration module for calibrating the projected image according to the color calibration table. A color calibration system for a projected image according to claim 6, wherein said school The quasi-table generation module includes: a region dividing sub-module, configured to divide the projection into a plurality of regions according to a color attribute of the reference pattern and a color attribute of the projection; A calibration table generation sub-module is used to generate a color calibration table containing calibration parameters for each region. The color calibration system for a projected image according to claim 6, further comprising: The judging module is configured to determine whether the position of the projection device is changed every predetermined time interval; if the change occurs, the module projection module is called, and the projection image is recalibrated. The color calibration system for a projected image according to claim 6, further comprising: a light intensity acquisition module for acquiring the light intensity of the environment in which it is located; And a brightness adjustment module, configured to adjust brightness of the projected image according to the illumination intensity. A color calibration system for a projected image according to claim 6, 7, 8 or 9, wherein the attributes of the color comprise: brightness, chromaticity and saturation of the color.

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