TWI688274B

TWI688274B - Image calibration method and image calibration system

Info

Publication number: TWI688274B
Application number: TW107118215A
Authority: TW
Inventors: 黃振誠
Original assignee: 明基電通股份有限公司
Priority date: 2018-05-29
Filing date: 2018-05-29
Publication date: 2020-03-11
Also published as: TW202005363A

Abstract

An image calibration method includes projecting an image to an image plane by a projector for displaying a projection image on the image plane, generating a first edge turning image of the projection image, generating a second edge turning image of the projection image, detecting a first included angle between a first edge and a second edge of the projection image according to the first edge turning image, detecting a second included angle between a third edge and a fourth edge of the projection image according to the second edge turning image, and generating a calibrated projection image according to a first included angle and a second included angle in order to calibrate distortion of the projection image.

Description

影像校正方法及影像校正系統 Image correction method and image correction system

本發明揭露一種影像校正方法及影像校正系統，尤指一種具有自動校正投射影像失真功能的影像校正方法及影像校正系統。 The invention discloses an image correction method and an image correction system, in particular an image correction method and an image correction system with an automatic correction function for projected image distortion.

隨著科技日新月異，各種顯示技術也越來越發達。高解析度的顯示器以及機動性高的投影設備也廣於應用在日常生活中。投影技術可擴展一般螢幕顯示器之外的顯示應用，像是空間藝術、擴增實境以及死角消減應用等等。如今，許多立體投影技術透過光學科技，並結合設計概念的創新呈現下，可創造出更令人驚艷的視覺傳達效果，以呈現出具超現實的場域空間影像。此外，在現今空間利用率緊繃的環境中，當我們需要大尺寸的顯示畫面時，短距離的投影設備就顯得相當實用。短距離的投影設備可以應用於各種空間，特別是小型的會議室。短距離的投影設備也稱為短焦投影機。這種短焦投影機的成像距離較短，因此投影機的光線照射距離不會太長，可以保護使用者的眼睛。並且，短焦投影機所投影的畫面亮度，也比較不會隨著投影面積的加大而快速遞減。因此，短焦投影機也具有節能環保、護眼以及降低後期維護成本的優勢。 With the rapid development of technology, various display technologies are becoming more and more developed. High-resolution displays and highly mobile projection devices are also widely used in daily life. Projection technology can expand display applications beyond the general screen display, such as space art, augmented reality and dead angle reduction applications. Today, many stereoscopic projection technologies, through optical technology and innovative design concepts, can create more stunning visual communication effects to present surreal field spatial images. In addition, in today's tight space utilization environment, when we need a large-size display screen, short-distance projection equipment becomes quite practical. Short-distance projection equipment can be applied to various spaces, especially small meeting rooms. Short-distance projection devices are also called short-throw projectors. The imaging distance of this short-throw projector is short, so the light irradiation distance of the projector will not be too long, which can protect the eyes of the user. In addition, the brightness of the screen projected by the short-throw projector is less likely to decrease rapidly as the projection area increases. Therefore, short-throw projectors also have the advantages of energy saving and environmental protection, eye protection and lower maintenance costs.

然而，投射畫面容易扭曲是短焦投影機容易出現的問題，原因是成像距離越短，經光學原理產生的影像變形也較明顯。特別是當短焦投影機發生水平旋轉或是垂直旋轉偏移時，投射畫面將會產生梯形失真。目前投射畫面的梯形失真可以使用手動的方式調整投影機的水平以及垂直軸來校正，或是利用投影機內建的自動梯形校正功能來校正投射畫面。然而，因短焦投影機的成像距離短，因此當投射畫面的寬度很大時，投射比(Throw Ratio)會變得很小。這將導致投影機無法自動偵測到投射畫面失真的部分，而導致校正品質較差。因此，目前短焦投影機的投射畫面校正的方法仍需要改良。 However, the easy distortion of the projected picture is a problem that occurs in short-throw projectors, because the shorter the imaging distance, the more obvious the image distortion caused by the optical principle. Especially when the short-throw projector is rotated horizontally or vertically, the projected image will have trapezoidal distortion. Currently projected Keystone distortion can be corrected by adjusting the horizontal and vertical axes of the projector manually, or by using the automatic keystone correction function built into the projector to correct the projected image. However, due to the short imaging distance of the short-throw projector, when the width of the projected picture is large, the throw ratio (Throw Ratio) becomes small. This will cause the projector to fail to automatically detect the distorted part of the projected image, resulting in poor calibration quality. Therefore, the method of correcting the projected image of the short-throw projector still needs improvement.

本發明一實施例提出一種影像校正方法，包含投影機投影影像至影像平面，以使影像平面顯示投射影像，產生投射影像之第一邊緣轉折影像，產生投射影像之第二邊緣轉折影像，依據第一邊緣轉折影像，偵測投射影像之第一邊及第二邊所夾的第一夾角，依據第二邊緣轉折影像，偵測投射影像之第三邊及第四邊所夾的第二夾角，及依據第一夾角及第二夾角校正投射影像，以產生校正後的投射影像。投射影像的形狀係為四邊形，校正後的投射影像之形狀係為矩形。第一夾角及第二夾角係為投射影像之對角線的兩夾角。 An embodiment of the present invention provides an image correction method, which includes a projector projecting an image onto an image plane so that the image plane displays the projected image, generates a first edge-turned image of the projected image, and generates a second edge-turned image of the projected image. An edge-turned image, detecting the first angle between the first and second sides of the projected image, and according to the second edge-turned image, detecting the second angle between the third and fourth sides of the projected image, And correct the projected image according to the first included angle and the second included angle to generate a corrected projected image. The shape of the projected image is a quadrangle, and the shape of the projected image after correction is a rectangle. The first angle and the second angle are the two angles of the diagonal of the projected image.

本發明另一實施例提出一種影像校正系統，包含投影機、螢幕、第一相機及第二相機。投影機用以將影像投影至影像平面。螢幕面對於投影機，用以提供影像平面以顯示投射影像。第一相機耦接於投影機，用以擷取投射影像之第一邊緣轉折區域的第一擷取影像。第二相機耦接於投影機，用以擷取投射影像之第二邊緣轉折區域的第二擷取影像。投影機將第一擷取影像及第二擷取影像，依據第一相機、第二相機與投影機的相對位置，產生第一邊緣轉折影像及第二邊緣轉折影像，依據第一邊緣轉折影像，偵測投射影像之第一邊及第二邊所夾的第一夾角，依據第二邊緣轉折影像，偵測投射影像之第三邊及第四邊所夾的第二夾角，依據第一夾角及第二夾角校正投射影像，以產生校正後的投射影像，並將校正後的投射影像投影至影像平面。 Another embodiment of the present invention provides an image correction system, including a projector, a screen, a first camera, and a second camera. The projector is used to project the image onto the image plane. The screen surface is used for the projector to provide an image plane to display the projected image. The first camera is coupled to the projector and used to capture the first captured image of the first edge transition area of the projected image. The second camera is coupled to the projector and used to capture the second captured image of the second edge transition area of the projected image. The projector generates the first edge-turned image and the second edge-turned image according to the relative positions of the first camera, the second camera, and the projector according to the relative positions of the first camera, the second captured image, and the first edge-turned image. Detects the first angle between the first and second sides of the projected image, turns the image according to the second edge, and detects the second angle between the third and fourth sides of the projected image, based on the first and The second included angle corrects the projection image to generate a corrected projection image, and projects the corrected projection image onto the image plane.

100:影像校正系統 100: Image correction system

10:投影機 10: Projector

11:螢幕 11: Screen

12:第一相機 12: The first camera

13:第二相機 13: Second camera

C1:第一影像擷取方向 C1: The first image capture direction

C2:第二影像擷取方向 C2: Second image capture direction

D1:投影方向 D1: Projection direction

PIMG:投射影像 PIMG: Projected image

R1:第一邊緣轉折區域 R1: first edge transition area

R2:第二邊緣轉折區域 R2: Second edge transition area

EIMG1:第一邊緣轉折影像 EIMG1: the first edge transition image

EIMG2:第二邊緣轉折影像 EIMG2: Second edge transition image

CAP1:第一擷取影像 CAP1: the first captured image

CAP2:第二擷取影像 CAP2: second captured image

L1:第一邊 L1: first side

L2:第二邊 L2: second side

L3:第三邊 L3: third side

L4:第四邊 L4: the fourth side

A1:第一夾角 A1: The first angle

A2:第二夾角 A2: Second angle

H:水平軸 H: horizontal axis

V:垂直軸 V: vertical axis

L1’:調整後的第一邊 L1’: Adjusted first side

L2’:調整後的第二邊 L2’: Adjusted second side

L3’:調整後的第三邊 L3’: Adjusted third side

L4’:調整後的第四邊 L4’: Adjusted fourth side

CIMG:校正後的投射影像 CIMG: Corrected projected image

S801至S806:步驟 S801 to S806: Steps

第1圖係為本發明之影像校正系統之實施例的示意圖。 Figure 1 is a schematic diagram of an embodiment of the image correction system of the present invention.

第2圖係為第1圖之影像校正系統中，第一相機所取得之第一擷取影像的示意圖。 Figure 2 is a schematic diagram of the first captured image obtained by the first camera in the image correction system of Figure 1.

第3圖係為第1圖之影像校正系統中，第二相機所取得之第二擷取影像的示意圖。 FIG. 3 is a schematic diagram of the second captured image obtained by the second camera in the image correction system of FIG. 1.

第4圖係為第1圖之影像校正系統中，投影機僅在水平軸發生轉動偏移而使投射影像失真的示意圖。 FIG. 4 is a schematic diagram of the image correction system of FIG. 1 in which the projector only rotates on the horizontal axis to distort the projected image.

第5圖係為第1圖之影像校正系統中，投影機僅在垂直軸發生轉動偏移而使投射影像失真的示意圖。 FIG. 5 is a schematic diagram of the image correction system of FIG. 1 in which the projector only rotates on the vertical axis to distort the projected image.

第6圖係為第1圖之影像校正系統中，投射影像同時發生水平方向失真以及垂直方向失真的示意圖。 FIG. 6 is a schematic diagram of horizontal distortion and vertical distortion of the projected image in the image correction system of FIG. 1.

第7圖係為第1圖之影像校正系統中，投影機將投射影像校正，以產生校正後的投射影像之示意圖。 Figure 7 is a schematic diagram of the image correction system of Figure 1 in which the projector corrects the projected image to produce a corrected projected image.

第8圖係為第1圖之影像校正系統中，影像校正方法的流程圖。 Figure 8 is a flowchart of the image correction method in the image correction system of Figure 1.

第1圖係為本發明之影像校正系統100之實施例的示意圖。影像校正系統100包含投影機10、螢幕11、第一相機12及第二相機13。投影機10用以將影像投影至影像平面。在影像校正系統100中，投影機10可為短焦投影機或是一般的投影機。影像平面可為任何光線吸收率低於100%的平面。例如，螢幕11可提供影像平面或是單色的牆壁也可提供影像平面。在本實施例中，螢幕11面對於投影機10，用以提供影像平面以顯示投射影像。例如，投影機10可以將畫素為1024×768的影像，依據投影方向D1投影到螢幕11，以產生投射影像PIMG。投射影像PIMG的形狀可為四邊形。然而，投射影像PIMG的形狀可能會因為投影機10位置的偏移或旋轉而失真。例如，投射影像PIMG的形狀可能失真為梯形或是任何非矩形的四邊形。第一相機12耦接於投影機10，用以取得第一擷取影像(如第2圖之第一擷取影像CAP1)。第一擷取影像包含投射影像PIMG之第一邊緣轉折區域R1。然而，第一擷取影像可利用第一相機12，沿著第一擷取方向C1而產生，故第一擷取方向C1與投影方向D1的差異性會造成第一擷取影像的歪斜。第二相機13耦接於投影機10，用以取得第二擷取影像(如第3圖之第二擷取影像CAP2)。第二擷取影像包含投射影像PIMG之第二邊緣轉折區域R2。然而，第二擷取影像可利用第二相機13，沿著第二擷取方向C2而產生，故第二擷取方向C2與投影方向D1的差異性會造成第二擷取影像的歪斜。在影像校正系統100中，投影機10可將第一擷取影像及第二擷取影像，依據第一相機12、第二相機13與投影機10的相對位置，產生第一邊緣轉折影像EIMG1及第二邊緣轉折影像EIMG2。意即，投影機10可依據第一相機12與投影機10的相對位置將第一擷取影像轉變，以產生第一邊緣轉折影像EIMG1。投影機10可依據第二相機13與投影機10的相對位置將第二擷取影像轉變，以產生第二邊緣轉折影像EIMG2。然而，本發明並未被此限制。例如，第一相機12以及第二相機13可以各自產生第一邊緣轉折影像EIMG1及第二邊緣轉折影像EIMG2，再將第一邊緣轉折影像EIMG1及第二邊緣轉折影像EIMG2的訊息傳送至投影機10。任何合理的技術變更都屬於本發明所揭露的範疇。投影機10可依據第一邊緣轉折影像EIMG1，偵測投射影像PIMG之第一邊及第二邊所夾的第一夾角，依據第二邊緣轉折影像EIMG2，偵測投射影像PIMG之第三邊及第四邊所夾的第二夾角。其中，第一邊、第二邊、第三邊以及第四邊圍成投射影像PIMG的區域。並且，投影機10可依據第一夾角及第二夾角校正投射影像PIMG，以產生校正後的投射影像，再將校正後的投射影像投影至影像平面(由螢幕11提供)。於其他實施例中，若第一擷取方向C1、投影方向 D1及第二擷取方向C2三者方向相同(即相互重合)，則第一擷取影像即為第一邊緣轉折影像EIMG1，以及第二擷取影像即為第二邊緣轉折影像EIMG2。於此，則無需依據第一相機12、第二相機13與投影機10的相對位置進行轉變。下文將詳述影像校正系統100校正影像的方法以及原理。 FIG. 1 is a schematic diagram of an embodiment of the image correction system 100 of the present invention. The image correction system 100 includes a projector 10, a screen 11, a first camera 12, and a second camera 13. The projector 10 is used to project the image onto the image plane. In the image correction system 100, the projector 10 may be a short-throw projector or a general projector. The image plane can be any plane whose light absorption rate is less than 100%. For example, the screen 11 may provide an image plane or a monochrome wall or an image plane. In this embodiment, the screen 11 faces the projector 10 to provide an image plane to display the projected image. For example, the projector 10 can project an image with pixels of 1024×768 on the screen 11 according to the projection direction D1 to generate a projected image PIMG. projection The shape of the image PIMG can be a quadrangle. However, the shape of the projected image PIMG may be distorted due to the displacement or rotation of the projector 10 position. For example, the shape of the projected image PIMG may be distorted into a trapezoid or any non-rectangular quadrilateral. The first camera 12 is coupled to the projector 10 for obtaining a first captured image (such as the first captured image CAP1 in FIG. 2). The first captured image includes the first edge transition region R1 of the projected image PIMG. However, the first captured image can be generated by the first camera 12 along the first captured direction C1. Therefore, the difference between the first captured direction C1 and the projection direction D1 may cause the first captured image to be skewed. The second camera 13 is coupled to the projector 10 for obtaining a second captured image (such as the second captured image CAP2 in FIG. 3). The second captured image includes the second edge transition region R2 of the projected image PIMG. However, the second captured image can be generated along the second capturing direction C2 using the second camera 13, so the difference between the second capturing direction C2 and the projection direction D1 can cause the second captured image to be skewed. In the image correction system 100, the projector 10 can generate the first edge-turned image EIMG1 and the first captured image and the second captured image based on the relative positions of the first camera 12, the second camera 13, and the projector 10. The second edge turns the image EIMG2. That is, the projector 10 can transform the first captured image according to the relative position of the first camera 12 and the projector 10 to generate the first edge-turned image EIMG1. The projector 10 can transform the second captured image according to the relative position of the second camera 13 and the projector 10 to generate a second edge-turned image EIMG2. However, the present invention is not limited by this. For example, the first camera 12 and the second camera 13 can each generate a first edge-turned image EIMG1 and a second edge-turned image EIMG2, and then send the first edge-turned image EIMG1 and the second edge-turned image EIMG2 to the projector 10 . Any reasonable technical changes belong to the scope disclosed by the present invention. The projector 10 can detect the first angle between the first and second sides of the projected image PIMG based on the first edge-turned image EIMG1, and detect the third and the third side of the projected image PIMG based on the second-edge turned image EIMG2 The second angle between the fourth side. Among them, the first side, the second side, the third side, and the fourth side form an area where the image PIMG is projected. Moreover, the projector 10 can correct the projected image PIMG according to the first included angle and the second included angle to generate a corrected projected image, and then project the corrected projected image onto the image plane (provided by the screen 11). In other embodiments, if the first capturing direction C1, the projection direction The directions of D1 and the second capturing direction C2 are the same (that is, coincide with each other), then the first captured image is the first edge-turned image EIMG1, and the second captured image is the second edge-turned image EIMG2. Here, there is no need to change according to the relative positions of the first camera 12, the second camera 13 and the projector 10. The method and principle of image correction by the image correction system 100 will be described in detail below.

第2圖係為影像校正系統100中，第一相機12所取得之第一擷取影像CAP1的示意圖。第3圖係為影像校正系統100中，第二相機13所取得之第二擷取影像CAP2的示意圖。第一相機12可與投影機10分離設置，並利用有線或無線的方式進行資料傳輸。因此，第一相機12與投影機10會產生第一相對位置。第一相對位置的定義可為以投影機10為原點時，第一相機12相對於原點的空間三軸方向以及距離。如前述提及，由於第一相機12依據第一影像擷取方向C1擷取包含投射影像PIMG之第一邊緣轉折區域R1的第一擷取影像CAP1，且第一相機12與投影機10之間具有第一相對位置，因此第一影像擷取方向C1與投影方向D1不同。這將導致第一相機12所擷取的第一擷取影像CAP1內之第一邊緣轉折區域R1之結構將發生歪斜，例如轉折區域的夾角影像出現失真的情況。因此，投影機10會依據投影機10與第一相機12的第一相對位置，產生第一調整參數。例如，投影機10可利用第一調整參數，將第一擷取影像CAP1的影像擷取方向校正為與投影方向D1一致，使第一擷取影像CAP1接近於螢幕11所呈現之投射影像PIMG的第一邊緣轉折影像EIMG1。類似地，第二相機13可與投影機10分離設置，並利用有線或無線的方式進行資料傳輸。因此第二相機13與投影機10會產生第二相對位置。第二相對位置的定義可為以投影機10為原點時，第二相機13相對於原點的空間三軸方向以及距離。如前述提及，由於第二相機13依據第二影像擷取方向C2擷取包含投射影像PIMG之第二邊緣轉折區域R2的第二擷取影像CAP2，且第二相機13與投影機10之間具有第二相對位置，因此第二影像擷取方向C2與投影方向D1不同。這將導致第二相機13所擷取的第二擷取影像CAP2內之第二邊緣轉折區域R2之結構發生歪斜，例如轉折區域的夾角影像出現失真的情況。因此，投影機10會依據投影機10與第二相機13的第二相對位置，產生第二調整參數。例如，投影機10可利用第二調整參數，將第二擷取影像CAP2的影像擷取方向校正為與投影方向D1一致，使第二擷取影像CAP2接近於螢幕11所呈現之投射影像PIMG的第二邊緣轉折影像EIMG2。 FIG. 2 is a schematic diagram of the first captured image CAP1 obtained by the first camera 12 in the image correction system 100. FIG. 3 is a schematic diagram of the second captured image CAP2 obtained by the second camera 13 in the image correction system 100. The first camera 12 can be installed separately from the projector 10, and data transmission can be performed by wired or wireless means. Therefore, the first camera 12 and the projector 10 generate a first relative position. The first relative position can be defined as the three-axis spatial direction and distance of the first camera 12 relative to the origin when the projector 10 is used as the origin. As mentioned above, since the first camera 12 captures the first captured image CAP1 including the first edge transition area R1 of the projected image PIMG according to the first image capturing direction C1, and between the first camera 12 and the projector 10 With the first relative position, the first image capturing direction C1 is different from the projection direction D1. This will cause the structure of the first edge transition region R1 in the first captured image CAP1 captured by the first camera 12 to be skewed, for example, the angle image of the transition region is distorted. Therefore, the projector 10 generates the first adjustment parameter according to the first relative position of the projector 10 and the first camera 12. For example, the projector 10 can use the first adjustment parameter to correct the image capturing direction of the first captured image CAP1 to be consistent with the projection direction D1, so that the first captured image CAP1 is close to the projected image PIMG presented on the screen 11 The first edge turns the image EIMG1. Similarly, the second camera 13 can be set separately from the projector 10, and the data transmission can be performed in a wired or wireless manner. Therefore, the second camera 13 and the projector 10 will generate a second relative position. The definition of the second relative position may be the spatial triaxial direction and distance of the second camera 13 relative to the origin when the projector 10 is used as the origin. As mentioned above, since the second camera 13 captures the second captured image CAP2 including the second edge transition region R2 of the projected image PIMG according to the second image capturing direction C2, and between the second camera 13 and the projector 10 With the second relative position, the second image capturing direction C2 is different from the projection direction D1. This will result in the second captured image CAP2 captured by the second camera 13 The structure of the second edge transition region R2 is distorted, for example, the angle image of the transition region is distorted. Therefore, the projector 10 generates the second adjustment parameter according to the second relative position of the projector 10 and the second camera 13. For example, the projector 10 can use the second adjustment parameter to correct the image capturing direction of the second captured image CAP2 to be consistent with the projection direction D1, so that the second captured image CAP2 is close to the projected image PIMG presented on the screen 11 The second edge turns the image EIMG2.

然而，本發明不限制由第一相機12以及第二相機13擷取投射影像PIMG的部分影像區域，再經過影像處理之後產生第一邊緣轉折影像EIMG1以及第二邊緣轉折影像EIMG2。例如，影像校正系統100也可以僅利用單一相機，以轉動的方式於兩個不同的時間內，擷取投射影像PIMG的兩個不同部分的影像區域，並依序產生第一邊緣轉折影像EIMG1以及第二邊緣轉折影像EIMG2。任何合理的技術變更都屬於本發明所揭露的範疇。並且，如前述提及，投影機10可為短焦投影機，第一相機12以及第二相機13可為兩非廣角鏡頭相機。由於第一相機12以及第二相機13可為非廣角鏡頭相機，因此擷取到的影像不會有廣角變形。並且，第一相機12以及第二相機13也具備製程容易且價格低廉的優點。 However, the present invention does not limit the capturing of part of the image area of the projected image PIMG by the first camera 12 and the second camera 13, and after image processing, the first edge-turned image EIMG1 and the second edge-turned image EIMG2 are generated. For example, the image correction system 100 can also use only a single camera to capture two different parts of the projected image PIMG in two different times in a rotating manner, and sequentially generate the first edge-turned image EIMG1 and The second edge turns the image EIMG2. Any reasonable technical changes belong to the scope disclosed by the present invention. Moreover, as mentioned above, the projector 10 may be a short-throw projector, and the first camera 12 and the second camera 13 may be two non-wide-angle lens cameras. Since the first camera 12 and the second camera 13 may be non-wide-angle lens cameras, the captured images will not have wide-angle distortion. In addition, the first camera 12 and the second camera 13 also have the advantages of easy manufacturing process and low cost.

第4圖係為影像校正系統100中，投影機10僅在水平軸H發生轉動偏移而使投射影像PIMG失真的示意圖。如前述，投射影像PIMG的形狀可能會因為投影機10的轉動而失真。例如，當投影機10僅在水平軸H發生轉動偏移時(例如往下或往上傾斜)，投影機10投影在螢幕11的投射影像PIMG會產生梯形失真。例如，投射影像PIMG中之第一邊L1及第四邊L4平行，第二邊L2及第三邊L3不平行，且第一夾角A1及第二夾角A2中至少一者不為直角。原理解釋如下。當投影機10在水平軸H發生轉動偏移時，投影機10所發出之影像上側的光束長度會與影像下側的光束長度不一致。例如，影像上側的光束比較短，投影到螢幕11之投射影像PIMG的第一邊L1就會比較短。影像下側的光束比較長，投影到螢幕11之投射影像PIMG的第四邊L4就會比較長。因此，投射影像PIMG會變為第一邊L1 較短而第四邊L4較長的梯形。由於投射影像PIMG失真為梯形，因此第一邊緣轉折影像EIMG1內之投射影像PIMG的第一夾角A1非為直角，且第一邊緣轉折影像EIMG2內之投射影像PIMG的第二夾角A2非為直角。當第一夾角A1或第二夾角A2非為直角時，投影機10將判斷投射影像PIMG為失真的情況，而進入影像校正的步驟。例如，投影機10可依據第一夾角A1及第二夾角A2，調整投射影像PIMG之第二邊L2及第三邊L3，以產生校正後的投射影像之調整後的第二邊及調整後的第三邊。調整後的第二邊及調整後的第三邊互相平行。並且，雖然投射影像PIMG的第一邊L1以及第四邊L4為平行，但因為第二邊L2及第三邊L3需要調整，因此第一邊L1或第四邊L4的長度也需要調整，以使投射影像PIMG為矩形，且符合在投射焦距下之預設影像輸出尺寸。例如，第四邊L4會被縮減到與第一邊L1相同的長度，以使投射影像PIMG的四個端點的角度為直角。因此，影像校正系統100具有垂直梯形影像校正(V-Keystone)的功能。 FIG. 4 is a schematic diagram of the image correction system 100 in which the projector 10 rotates only on the horizontal axis H to distort the projected image PIMG. As mentioned above, the shape of the projected image PIMG may be distorted by the rotation of the projector 10. For example, when the projector 10 only rotates and shifts on the horizontal axis H (for example, tilts downward or upward), the projected image PIMG of the projector 10 projected on the screen 11 will generate trapezoidal distortion. For example, the first side L1 and the fourth side L4 in the projected image PIMG are parallel, the second side L2 and the third side L3 are not parallel, and at least one of the first included angle A1 and the second included angle A2 is not a right angle. The principle is explained as follows. When the projector 10 rotates and shifts on the horizontal axis H, the length of the beam on the upper side of the image emitted by the projector 10 will not match the length of the beam on the lower side of the image. For example, if the light beam on the upper side of the image is relatively short, the first side L1 of the projected image PIMG projected on the screen 11 will be relatively short. The light beam on the lower side of the image is relatively long, and the fourth side L4 of the projected image PIMG projected on the screen 11 will be relatively long. Therefore, the projected image PIMG will become the first side L1 The trapezoid is shorter and the fourth side L4 is longer. Since the distortion of the projected image PIMG is trapezoidal, the first included angle A1 of the projected image PIMG in the first edge transition image EIMG1 is not a right angle, and the second included angle A2 of the projected image PIMG in the first edge transition image EIMG2 is not a right angle. When the first included angle A1 or the second included angle A2 is not a right angle, the projector 10 determines that the projected image PIMG is distorted, and enters the image correction step. For example, the projector 10 may adjust the second side L2 and the third side L3 of the projected image PIMG according to the first included angle A1 and the second included angle A2 to generate the adjusted second side and the adjusted side of the projected image after correction The third side. The adjusted second side and the adjusted third side are parallel to each other. Moreover, although the first side L1 and the fourth side L4 of the projected image PIMG are parallel, since the second side L2 and the third side L3 need to be adjusted, the length of the first side L1 or the fourth side L4 also needs to be adjusted to Make the projected image PIMG rectangular and conform to the preset image output size at the projected focal length. For example, the fourth side L4 will be reduced to the same length as the first side L1, so that the angles of the four end points of the projected image PIMG are right angles. Therefore, the image correction system 100 has the function of vertical keystone image correction (V-Keystone).

第5圖係為影像校正系統100中，投影機10僅在垂直軸V發生轉動偏移而使投射影像PIMG失真的示意圖。如前述，投射影像PIMG的形狀可能會因為投影機10的轉動而失真。例如，當投影機10僅在垂直軸V發生轉動偏移時(例如往左或往右傾斜)，投影機10投影在螢幕11的投射影像PIMG會產生梯形失真。例如，投射影像PIMG中之第二邊L2及第三邊L3平行，第一邊L1及第四邊L4不平行，且第一夾角A1及第二夾角A2中至少一者不為直角。原理解釋如下。當投影機10在垂直軸V發生轉動偏移時，投影機10所發出之影像左側的光束長度會與影像右側的光束長度不一致。例如，影像左側的光束比較短，投影到螢幕11之投射影像PIMG的第二邊L2就會比較短。影像右側的光束比較長，投影到螢幕11之投射影像PIMG的第三邊L3就會比較長。因此，投射影像PIMG會變為第二邊L2較短而第三邊L3較長的梯形。由於投射影像PIMG失真為梯形，因此第一邊緣轉折影像EIMG1內之投射影像PIMG的第一夾角A1非為直角，且第二邊緣轉折影像 EIMG2內之投射影像PIMG的第二夾角A2非為直角。當第一夾角A1或第二夾角A2非為直角時，投影機10將判斷投射影像PIMG為失真的情況，而進入影像校正的步驟。例如，投影機10可依據第一夾角A1及第二夾角A2，調整投射影像PIMG之第一邊L1及第四邊L4，以產生校正後的投射影像之調整後的第一邊及調整後的第四邊。調整後的第一邊及調整後的第四邊互相平行。並且，雖然投射影像PIMG的第二邊L2以及第三邊L3為平行，因為第一邊L1及第四邊L4需要調整，因此第二邊L2或第三邊L3的長度也需要調整，以使投射影像PIMG為矩形，且符合在投射焦距下之預設影像輸出尺寸。例如，第三邊L3會被縮減到與第二邊L2相同的長度，以使投射影像PIMG的四個端點的角度為直角。因此，影像校正系統100具有水平梯形影像校正(H-Keystone)的功能。 FIG. 5 is a schematic diagram of the image correction system 100 in which the projector 10 rotates only on the vertical axis V to distort the projected image PIMG. As mentioned above, the shape of the projected image PIMG may be distorted by the rotation of the projector 10. For example, when the projector 10 is only rotationally offset in the vertical axis V (for example, tilted to the left or right), the projected image PIMG of the projector 10 projected on the screen 11 may generate trapezoidal distortion. For example, the second side L2 and the third side L3 in the projected image PIMG are parallel, the first side L1 and the fourth side L4 are not parallel, and at least one of the first included angle A1 and the second included angle A2 is not a right angle. The principle is explained as follows. When the projector 10 is rotationally offset in the vertical axis V, the beam length on the left side of the image emitted by the projector 10 will be inconsistent with the beam length on the right side of the image. For example, if the light beam on the left side of the image is relatively short, the second side L2 of the projected image PIMG projected on the screen 11 will be relatively short. The light beam on the right side of the image is relatively long, and the third side L3 of the projected image PIMG projected on the screen 11 will be relatively long. Therefore, the projected image PIMG becomes a trapezoid in which the second side L2 is shorter and the third side L3 is longer. Since the projected image PIMG is distorted in a trapezoidal shape, the first angle A1 of the projected image PIMG in the first edge-turned image EIMG1 is not a right angle, and the second edge-turned image The second included angle A2 of the projected image PIMG in EIMG2 is not a right angle. When the first included angle A1 or the second included angle A2 is not a right angle, the projector 10 determines that the projected image PIMG is distorted, and enters the image correction step. For example, the projector 10 may adjust the first side L1 and the fourth side L4 of the projected image PIMG according to the first included angle A1 and the second included angle A2 to generate the adjusted first side and the adjusted side of the projected image after correction The fourth side. The adjusted first side and the adjusted fourth side are parallel to each other. Moreover, although the second side L2 and the third side L3 of the projected image PIMG are parallel, because the first side L1 and the fourth side L4 need to be adjusted, the length of the second side L2 or the third side L3 also needs to be adjusted so that The projected image PIMG is rectangular and conforms to the preset image output size at the projection focal length. For example, the third side L3 will be reduced to the same length as the second side L2, so that the angles of the four endpoints of the projected image PIMG are right angles. Therefore, the image correction system 100 has the function of horizontal keystone image correction (H-Keystone).

第6圖係為影像校正系統100中，投射影像PIMG同時發生水平方向失真以及垂直方向失真的示意圖。第7圖係為影像校正系統100中，投影機10將投射影像PIMG校正，以產生校正後的投射影像CIMG之示意圖。在影像校正系統100中，如前述提及，投射影像PIMG可以利用水平梯形影像校正或是垂直梯形影像校正的功能校正影像失真。並且，當投影機10在垂直軸V以及水平軸H同時發生轉動偏移而使投射影像PIMG失真時，影像校正系統100也可以將失真的投射影像PIMG校正為矩形，說明如下。當投影機10在垂直軸V以及水平軸H同時發生轉動偏移而使投射影像PIMG失真時，投射影像PIMG的四個邊都可能都會產生歪斜，導致投射影像PIMG的四個端點的夾角都不是直角。例如，在第6圖中，投影機10依據第一邊緣轉折影像EIMG1內之第一夾角A1以及依據第二邊緣轉折影像EIMG2內之第二夾角A2，偵測出第一邊L1及第四邊L4不平行，且第二邊L2及第三邊L3不平行。因此，投影機10可依此判斷投射影像PIMG同時發生了水平影像失真以及垂直影像失真。接著，投影機10可依據第一夾角A1，調整投射影像PIMG之第一邊L1及第二邊L2，以產生互相垂直的調整後的第一邊L1’及調整後的第二邊L2’。以及，投影機10可依據第二夾角A2，調整投射影像PIMG之第三邊L3及第四邊L4，以產生互相垂直的調整後的第三邊L3’及調整後的第四邊L4’。並且，如前述提及，由於投射影像PIMG為四個邊所圍成的影像，屬於一個封閉的影像範圍。因此，調整投射影像PIMG之第一邊L1、第二邊L2、第三邊L3以及第三邊L4的斜率時，也要同時調整第一邊L1、第二邊L2、第三邊L3以及第三邊L4的長度。如此，調整後的第一邊L1’、調整後的第二邊L2’、調整後的第三邊L3’以及調整後的第四邊L4’可圍成如第7圖所示的矩形區域，即產生校正後的投射影像CIMG。並且，調整後的第一邊L1’的長度等於調整後的第四邊L4’的長度，且調整後的第二邊L2’的長度等於調整後的第三邊L3’的長度。需要特別說明的是，上述當投射影像PIMG同時發生水平方向失真以及垂直方向失真的調整方法(即，同時調整第一邊L1、第二邊L2、第三邊L3以及第四邊L4的方法)，可以作為影像校正系統100的通用調整方法。換句話說，可在無需在判斷投射影像PIMG是否同時在水準軸H和垂直軸V發生轉動偏移的前提條件下執行，故可以達到快速執行的功效，如下步驟：先依據第一夾角，調整投射影像的第一邊及第二邊，以產生互相垂直的調整後的第一邊及調整後的第二邊。接著，依據第二夾角調整投射影像的第三邊及第四邊，以產生互相垂直的調整後的第三邊及調整後的第四邊，再依據調整後的第一邊、調整後的第二邊、調整後的第三邊及調整後的第四邊產生校正後的投射影像。並且，當遇到無需調整的第一邊及/或第二邊、及/或第三邊、及/或第四邊時，則可不用調整對應的邊之斜率，或者可直接將對應的邊微調其長度後，視為調整後的邊。 FIG. 6 is a schematic diagram of horizontal and vertical distortions of the projected image PIMG in the image correction system 100 at the same time. FIG. 7 is a schematic diagram of the image correction system 100 in which the projector 10 corrects the projected image PIMG to generate a corrected projected image CIMG. In the image correction system 100, as mentioned above, the projected image PIMG can use the functions of horizontal trapezoid image correction or vertical trapezoid image correction to correct image distortion. In addition, when the projector 10 simultaneously rotates on the vertical axis V and the horizontal axis H to distort the projected image PIMG, the image correction system 100 may also correct the distorted projected image PIMG into a rectangle, as described below. When the projector 10 rotates on the vertical axis V and the horizontal axis H at the same time to distort the projected image PIMG, all four sides of the projected image PIMG may be skewed, resulting in the included angle of the four endpoints of the projected image PIMG Not at right angles. For example, in FIG. 6, the projector 10 detects the first side L1 and the fourth side based on the first angle A1 in the first edge-turned image EIMG1 and the second angle A2 in the second edge-turned image EIMG2 L4 is not parallel, and the second side L2 and the third side L3 are not parallel. Therefore, the projector 10 can determine the horizontal image distortion and the vertical image distortion of the projected image PIMG accordingly. Then, the projector 10 can adjust the first side L1 and the second side L2 of the projected image PIMG according to the first included angle A1 to generate the adjusted first side L1' and the mutually perpendicular The adjusted second side L2’. And, the projector 10 can adjust the third side L3 and the fourth side L4 of the projected image PIMG according to the second included angle A2 to generate an adjusted third side L3' and an adjusted fourth side L4' that are perpendicular to each other. And, as mentioned above, since the projected image PIMG is an image surrounded by four sides, it belongs to a closed image range. Therefore, when adjusting the slopes of the first side L1, the second side L2, the third side L3, and the third side L4 of the projected image PIMG, the first side L1, the second side L2, the third side L3, and the The length of the three sides L4. In this way, the adjusted first side L1', the adjusted second side L2', the adjusted third side L3', and the adjusted fourth side L4' can enclose a rectangular area as shown in FIG. 7, That is, the corrected projected image CIMG is generated. And, the length of the adjusted first side L1' is equal to the length of the adjusted fourth side L4', and the length of the adjusted second side L2' is equal to the length of the adjusted third side L3'. It should be noted that the above method for adjusting the horizontal distortion and the vertical distortion of the projected image PIMG occurs at the same time (ie, the method of simultaneously adjusting the first side L1, the second side L2, the third side L3, and the fourth side L4) Can be used as a general adjustment method for the image correction system 100. In other words, it can be executed without the premise of judging whether the projected image PIMG is rotated on the horizontal axis H and the vertical axis V at the same time, so the effect of rapid execution can be achieved. The following steps: first adjust according to the first included angle Projecting the first side and the second side of the image to produce an adjusted first side and an adjusted second side that are perpendicular to each other. Then, adjust the third and fourth sides of the projected image according to the second included angle to produce the adjusted third and fourth sides that are perpendicular to each other, and then the adjusted first and adjusted second sides according to The second side, the adjusted third side, and the adjusted fourth side produce the corrected projected image. In addition, when the first side and/or the second side, and/or the third side, and/or the fourth side that do not need to be adjusted are encountered, the slope of the corresponding side may not be adjusted, or the corresponding side may be directly changed After fine-tuning its length, it is regarded as the adjusted edge.

在影像校正系統100中，投影機10可為短焦投影機，投射比(Throw Ratio)可為0.3~0.45。投射比以數學表示可為d/W，其中d為投影機10與影像平面(螢幕11)之間的距離，而W為校正後的投射影像CIMG之寬度。然而，本發明卻不被特定的投射比所侷限。例如，投影機10可支援更小的投射比，以更節省投影空間並能產生更寬敞的投射影像。 In the image correction system 100, the projector 10 may be a short-throw projector, and the throw ratio (Throw Ratio) may be 0.3 to 0.45. The projection ratio can be expressed mathematically as d/W, where d is the distance between the projector 10 and the image plane (screen 11), and W is the width of the corrected projected image CIMG. However, the present invention is not limited by a specific projection ratio. For example, the projector 10 can support a smaller projection ratio to save more investment Shadow space and can produce a wider projection image.

第8圖係為影像校正系統100中，影像校正方法的流程圖。影像校正方法的流程包含步驟S801至步驟S806。任何合理的步驟變更都屬於本發明所揭露的範疇，步驟S801至步驟S806說明如下。 FIG. 8 is a flowchart of the image correction method in the image correction system 100. The flow of the image correction method includes steps S801 to S806. Any reasonable step change belongs to the scope disclosed by the present invention, and steps S801 to S806 are described as follows.

步驟S801：投影機10投影影像至影像平面，以使影像平面顯示投射影像PIMG；步驟S802：產生投射影像PIMG之第一邊緣轉折影像EIMG1；步驟S803：產生投射影像PIMG之第二邊緣轉折影像EIMG2；步驟S804：依據第一邊緣轉折影像EIMG1，偵測投射影像PIMG之第一邊L1及第二邊L2所夾的第一夾角A1；步驟S805：依據第二邊緣轉折影像EIMG2，偵測投射影像PIMG之第三邊L3及第四邊L4所夾的第二夾角A2；步驟S806：依據第一夾角A1及第二夾角A2校正投射影像PIMG，以產生校正後的投射影像CIMG。 Step S801: The projector 10 projects the image onto the image plane so that the image plane displays the projected image PIMG; Step S802: Generate the first edge-turned image EIMG1 of the projected image PIMG; Step S803: Generate the second edge-turned image EIMG2 of the projected image PIMG Step S804: Detect the first included angle A1 between the first side L1 and the second side L2 of the projected image PIMG based on the first edge-turned image EIMG1; Step S805: Detect the projected image based on the second edge-turned image EIMG2 The second included angle A2 between the third side L3 and the fourth side L4 of PIMG; Step S806: Correct the projected image PIMG according to the first included angle A1 and the second included angle A2 to generate a corrected projected image CIMG.

步驟S801至步驟S806的詳細說明已於前文中詳述，故於此將不再贅述。在影像校正系統100中，第一夾角A1及第二夾角A2可為投射影像PIMG的相對的兩個夾角，且第一夾角A1的端點及第二夾角A2的端點之連線可為投射影像PIMG之對角線。例如，上述實施例中，第一邊緣轉折影像EIMG1內之第一夾角A1，即為投射影像PIMG左上端點對應的夾角。第二邊緣轉折影像EIMG2內之第二夾角A2，即為投射影像PIMG右下端點對應的夾角。然而，影像校正系統100也可以利用投射影像PIMG右上端點對應的夾角以及左下端點對應的夾角來校正投射影像PIMG。並且，影像校正系統100計算夾角的方式可依據夾角兩邊的斜率來計算。例如，於第6圖中，於第一邊緣轉折影像EIMG1被產生後，影像校正系統100可以取得通過第一邊L1的兩點座標，以使第一邊L1符合線性方程式 Y=AL1×X+BL1，其中AL1為第一邊L1的斜率，BL1為第一邊L1對原點的偏移量，Y和X為直角座標系中之垂直軸和水平軸的座標。類似地，影像校正系統100可以取得通過第二邊L2的兩點座標，以使第二邊L2符合線性方程式Y=AL2×X+BL2，其中AL2為第二邊L2的斜率，BL2為第二邊L2對原點的偏移量，Y和X為直角座標系中，垂直軸和水平軸的座標。影像校正系統100可利用第一邊L1以及第二邊L2的斜率，檢測第一邊L1以及第二邊L2之第一夾角A1是否垂直。然而，影像校正系統100可以用任何影像辨識或是數值計算的方式來偵測第一夾角A1以及第二夾角A2，本發明並不被上述的演算法所侷限。 The detailed description of steps S801 to S806 has been detailed in the foregoing, so it will not be repeated here. In the image correction system 100, the first included angle A1 and the second included angle A2 may be opposite two included angles of the projected image PIMG, and the connection between the endpoint of the first included angle A1 and the endpoint of the second included angle A2 may be the projection The diagonal of the image PIMG. For example, in the above embodiment, the first included angle A1 in the first edge-turned image EIMG1 is the included angle corresponding to the upper left end of the projected image PIMG. The second angle A2 in the second edge transition image EIMG2 is the angle corresponding to the lower right end of the projected image PIMG. However, the image correction system 100 can also use the included angle corresponding to the upper right end of the projected image PIMG and the included angle corresponding to the lower left end to correct the projected image PIMG. In addition, the method of calculating the included angle by the image correction system 100 can be calculated according to the slopes on both sides of the included angle. For example, in FIG. 6, after the first edge-turned image EIMG1 is generated, the image correction system 100 can obtain the two-point coordinates passing through the first side L1, so that the first side L1 conforms to the linear equation Y=AL1×X+BL1, where AL1 is the slope of the first side L1, BL1 is the offset of the first side L1 from the origin, and Y and X are the coordinates of the vertical and horizontal axes in the rectangular coordinate system. Similarly, the image correction system 100 can obtain the two-point coordinates passing through the second side L2 so that the second side L2 conforms to the linear equation Y=AL2×X+BL2, where AL2 is the slope of the second side L2 and BL2 is the second The offset of the edge L2 from the origin, Y and X are the coordinates of the vertical axis and the horizontal axis in the rectangular coordinate system. The image correction system 100 can use the slopes of the first side L1 and the second side L2 to detect whether the first angle A1 of the first side L1 and the second side L2 is perpendicular. However, the image correction system 100 can detect the first included angle A1 and the second included angle A2 by any image recognition or numerical calculation method, and the present invention is not limited by the above algorithm.

綜上所述，本發明描述了一種影像校正方法及影像校正系統，可應用於短焦投影機產生之投射影像的失真校正。影像校正系統可引入了一個以上的非廣角相機，來偵測投射影像之對角線的兩個夾角。影像校正系統可依據投射影像之對角線的兩個夾角，修正投射影像的四個邊，以產生矩形之修正後的投射影像。並且，由於影像校正系統引入的相機為非廣角相機，因此相機所擷取的影像不會受到有廣角變形或是廣角失真的影響。非廣角相機的製程也較為簡單，且成本低廉。並且，影像校正系統的相機只要擷取到投射影像之對角線的兩個夾角的影像即可，不需要擷取到全幅的投射影像，故影像校正系統的校正功能不會受到傳統廣角相機的視野限制。因此，本發明的影像校正系統，除了具有製程簡單且成本低廉的優點外，也具有很高的投射影像校正品質。 In summary, the present invention describes an image correction method and image correction system, which can be applied to the distortion correction of a projected image generated by a short-throw projector. The image correction system can introduce more than one non-wide-angle camera to detect the two included angles of the diagonal of the projected image. The image correction system can correct the four sides of the projected image according to the two included angles of the diagonal of the projected image to generate a rectangular projected image after correction. Furthermore, since the camera introduced by the image correction system is a non-wide-angle camera, the image captured by the camera will not be affected by wide-angle distortion or wide-angle distortion. The manufacturing process of non-wide-angle cameras is relatively simple, and the cost is low. In addition, the camera of the image correction system only needs to capture the two diagonal images of the projected image, and does not need to capture the full-scale projected image, so the correction function of the image correction system will not be affected by the traditional wide-angle camera. Limited vision. Therefore, in addition to the advantages of simple manufacturing process and low cost, the image correction system of the present invention also has high projection image correction quality.

以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 The above are only the preferred embodiments of the present invention, and all changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the present invention.

100:影像校正系統 100: Image correction system

10:投影機 10: Projector

11:螢幕 11: Screen

12:第一相機 12: The first camera

13:第二相機 13: Second camera

C1:第一影像擷取方向 C1: The first image capture direction

C2:第二影像擷取方向 C2: Second image capture direction

D1:投影方向 D1: Projection direction

PIMG:投射影像 PIMG: Projected image

R1:第一邊緣轉折區域 R1: first edge transition area

R2:第二邊緣轉折區域 R2: Second edge transition area

EIMG1:第一邊緣轉折影像 EIMG1: the first edge transition image

EIMG2:第二邊緣轉折影像 EIMG2: Second edge transition image

Claims

一種影像校正方法，包含：一投影機投影一影像至一影像平面，以使該影像平面顯示一投射影像；一第一相機擷取該投射影像之一第一邊緣轉折區域的一第一擷取影像；依據該投影機與該第一相機的一第一相對位置，產生一第一調整參數；依據該第一調整參數及該第一擷取影像，產生該投射影像之一第一邊緣轉折影像；一第二相機擷取該投射影像之一第二邊緣轉折區域的第二擷取影像；依據該投影機與該第二相機的一第二相對位置，產生一第二調整參數；依據該第二調整參數及該第二擷取影像，產生該投射影像之一第二邊緣轉折影像；依據該第一邊緣轉折影像，偵測該投射影像之一第一邊及一第二邊所夾的一第一夾角；依據該第二邊緣轉折影像，偵測該投射影像之一第三邊及一第四邊所夾的一第二夾角；及依據該第一夾角及該第二夾角校正該投射影像，以產生一校正後的投射影像；其中該投射影像的形狀係為一四邊形，該校正後的投射影像之形狀係為一矩形，且該第一夾角及該第二夾角係為該投射影像之相對的兩夾角。 An image correction method includes: a projector projecting an image onto an image plane so that the image plane displays a projected image; a first camera captures a first capture of a first edge transition area of the projected image An image; generating a first adjustment parameter based on a first relative position of the projector and the first camera; generating a first edge-turned image of the projected image based on the first adjustment parameter and the first captured image A second camera captures a second captured image of a second edge-turning area of the projected image; generates a second adjustment parameter based on a second relative position of the projector and the second camera; based on the first Two adjustment parameters and the second captured image to generate a second edge-turned image of the projected image; based on the first edge-turned image, detect the one sandwiched between a first side and a second side of the projected image A first included angle; detecting a second included angle between a third side and a fourth side of the projected image based on the second edge-turned image; and correcting the projected image based on the first included angle and the second included angle To generate a corrected projection image; wherein the shape of the projection image is a quadrilateral, the shape of the corrected projection image is a rectangle, and the first angle and the second angle are the projection image The opposite angle.

如請求項1所述之方法，其中該投影機之一投射比(Throw Ratio)為0.3~0.45，且該投射比係為該投影機至該影像平面之一距離，與該校正後的投射影像之一寬度的比值。 The method according to claim 1, wherein a projection ratio (Throw Ratio) of the projector is 0.3 to 0.45, and the projection ratio is a distance from the projector to the image plane and the corrected projection image The ratio of one width.

如請求項1所述之方法，其中該投影機係為一短焦投影機，該第一相機及該第二相機係為非廣角鏡頭相機。 The method of claim 1, wherein the projector is a short-throw projector, and the first phase The camera and the second camera are non-wide-angle lens cameras.

一種影像校正系統，包含：一投影機，用以將一影像投影至一影像平面；一螢幕，面對於投影機，用以提供該影像平面以顯示一投射影像；一第一相機，耦接於該投影機，用以擷取該投射影像之一第一邊緣轉折區域的一第一擷取影像；及一第二相機，耦接於該投影機，用以擷取該投射影像之一第二邊緣轉折區域的一第二擷取影像；其中該投影機依據該投影機與該第一相機的一第一相對位置，產生一第一調整參數，依據該投影機與該第二相機的一第二相對位置，產生一第二調整參數，該投影機依據該第一調整參數及該第一擷取影像，將該第一擷取影像轉變，以產生該第一邊緣轉折影像，該投影機依據該第二調整參數及該第二擷取影像，將該第二擷取影像轉變，以產生該第二邊緣轉折影像，依據該第一邊緣轉折影像，偵測該投射影像之一第一邊及一第二邊所夾的一第一夾角，以及依據該第二邊緣轉折影像，偵測該投射影像之一第三邊及一第四邊所夾的一第二夾角，依據該第一夾角及該第二夾角校正該投射影像，以產生一校正後的投射影像，並將該校正後的投射影像投影至該影像平面。 An image correction system includes: a projector for projecting an image onto an image plane; a screen facing the projector for providing the image plane to display a projected image; and a first camera coupled to The projector is used to capture a first captured image of a first edge transition area of the projected image; and a second camera, coupled to the projector, used to capture a second of the projected image A second captured image of the edge-turning area; wherein the projector generates a first adjustment parameter based on a first relative position of the projector and the first camera, and a first adjustment parameter based on the projector and the second camera Two relative positions, a second adjustment parameter is generated, the projector converts the first captured image according to the first adjustment parameter and the first captured image to generate the first edge-turned image, the projector The second adjustment parameter and the second captured image, transforming the second captured image to generate the second edge-turned image, based on the first edge-turned image, detecting a first edge of the projected image and A first included angle between a second side, and a second included angle detected between a third side and a fourth side of the projected image based on the second edge-turned image, based on the first included angle and The second included angle corrects the projected image to generate a corrected projected image, and projects the corrected projected image onto the image plane.

如請求項4所述之系統，其中該投影機依據該第一夾角，調整該投射影像之該第一邊及該第二邊，以產生互相垂直的一調整後的第一邊及一調整後的第二邊，以及該投影機依據該第二夾角，調整該投射影像之該第三邊及該第四邊，以產生互相垂直的一調整後的第三邊及一調整後的第四邊，且依據該調整後的第一邊、該調整後的第二邊、該調整後的第三邊及該調整後的第四邊，產生該校正後的投射影像。 The system according to claim 4, wherein the projector adjusts the first side and the second side of the projected image according to the first included angle to generate an adjusted first side and an adjusted side perpendicular to each other The second side and the projector adjusts the third side and the fourth side of the projected image according to the second angle to produce an adjusted third side and an adjusted fourth side that are perpendicular to each other And according to The corrected projected image is generated according to the adjusted first side, the adjusted second side, the adjusted third side, and the adjusted fourth side.

如請求項4所述之系統，其中投影機之一投射比(Throw Ratio)為0.3~0.45，且該投射比係為該投影機至該影像平面之一距離，與該校正後的投射影像之一寬度的比值。 The system according to claim 4, wherein a projection ratio (Throw Ratio) of the projector is 0.3~0.45, and the projection ratio is a distance between the projector and the image plane, and the corrected projection image The ratio of one width.

如請求項4所述之系統，其中若該投影機在一水平軸發生一轉動偏移且在一垂直軸未發生一轉動偏移，該影像平面上的該投射影像中之該第一邊及該第四邊平行，該第二邊及該第三邊不平行，且該第一夾角及該第二夾角中至少一者不為直角。 The system of claim 4, wherein if the projector has a rotational offset on a horizontal axis and no rotational offset on a vertical axis, the first side of the projected image on the image plane and The fourth side is parallel, the second side and the third side are not parallel, and at least one of the first included angle and the second included angle is not a right angle.

如請求項7所述之系統，其中該投影機依據該第一夾角及該第二夾角，調整該第二邊及該第三邊，以產生該校正後的投射影像之一調整後的第二邊及一調整後的第三邊，且該調整後的第二邊及該調整後的第三邊互相平行，並依據該調整後的第二邊及該調整後的第三邊校正該第一邊及該第四邊。 The system according to claim 7, wherein the projector adjusts the second side and the third side according to the first angle and the second angle to generate an adjusted second of one of the corrected projected images And an adjusted third side, and the adjusted second side and the adjusted third side are parallel to each other, and the first side is corrected according to the adjusted second side and the adjusted third side Side and the fourth side.

如請求項4所述之系統，其中若該投影機在一垂直軸發生一轉動偏移且在一水平軸未發生一轉動偏移，該影像平面上的該投射影像中之該第二邊及該第三邊平行，該第一邊及該第四邊不平行，且該第一夾角及該第二夾角中至少一者不為直角。 The system of claim 4, wherein if the projector has a rotational offset on a vertical axis and no rotational offset on a horizontal axis, the second side of the projected image on the image plane and The third side is parallel, the first side and the fourth side are not parallel, and at least one of the first included angle and the second included angle is not a right angle.

如請求項9所述之系統，其中該投影機依據該第一夾角及該第二夾角，調整該第一邊及該第四邊，以產生該校正後的投射影像之一調整後的第一邊及一調整後的第四邊，且該調整後的第一邊及該調整後的第四邊互相平行，並依據該調整後的第一邊及該調整後的第四邊校正該第二邊及該第三邊。 The system according to claim 9, wherein the projector adjusts the first side and the fourth side according to the first included angle and the second included angle to generate one of the corrected projected images after adjustment One side and an adjusted fourth side, and the adjusted first side and the adjusted fourth side are parallel to each other, and the second is corrected according to the adjusted first side and the adjusted fourth side Side and the third side.

如請求項4所述之系統，其中該投影機係為一短焦投影機，該第一相機及該第二相機係為非廣角鏡頭相機。 The system according to claim 4, wherein the projector is a short-throw projector, and the first camera and the second camera are non-wide-angle lens cameras.