Method and apparatus for image stitching in a camera monitor system

Abstract

To provide a vehicle operator with an enhanced field of view.SOLUTION: Obtaining a first image from a first camera, the first image depicting a first area extending along a first side of the commercial vehicle, obtaining a second image from a second camera, the second image depicting a second area extending along a second side of the commercial vehicle opposite the first side, obtaining a third image from a third camera, the third image depicting a rear area behind the commercial vehicle, and performing a perspective transformation on the first image, the second image, and the third image to obtain an updated image set, wherein: The method includes the steps of: updating each of the first, second, and third images in the updated image set; and stitching the images of the updated image set together to form a combined image in which the third image is disposed between the first image and the second image, and in which the first region, the second region, and the rear region are respectively delineated.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to camera monitor systems (CMS), and more particularly to methods and apparatus for providing image stitching in a CMS. [Background technology]

[0002] Vehicle camera systems for mirror replacement or mirror view supplementation are utilized in commercial vehicles to enhance the vehicle operator's ability to view the commercial vehicle's surroundings. Camera monitoring systems (CMS) utilize one or more cameras to provide the vehicle operator with an enhanced field of view. In some instances, mirror replacement systems cover a wider field of view than traditional mirrors or include views not fully captured through traditional mirrors. When multiple cameras provide images to vehicle occupants, it can be difficult for the driver to effectively analyze the images. Summary of the Invention

[0003] A method for a camera monitor system (CMS) according to one embodiment of the present disclosure includes steps of acquiring a first image from a first camera depicting a first area extending along a first side of a commercial vehicle; acquiring a second image from a second camera depicting a second area extending along a second side of the commercial vehicle opposite the first side; acquiring a third image from a third camera depicting a rear area behind the commercial vehicle; performing a perspective transformation on the first image, the second image, and the third image to obtain an updated image set, whereby each of the first image, the second image, and the third image is updated in the updated image set; and stitching images of the updated image set together to form a combined image in which the third image is disposed between the first image and the second image and in which the first area, the second area, and the rear area are respectively depicted.

[0004] In a further embodiment of the above embodiment, the field of view of the third camera overlaps the field of view of the first camera and the field of view of the second camera.

[0005] In a further embodiment of any of the above embodiments, the third image includes a left portion extending along a left edge of the third image and a right portion extending along a right edge of the third image, and the stitching is performed such that, in the combined image, the left portion of the third image is stitched to a central portion of the first image and the right portion of the third image is stitched to a central portion of the second image.

[0006] In a further embodiment of any of the above embodiments, the first camera, the second camera, and the third camera have respective optical axes that intersect the ground plane at respective optical angles, the optical angle of the third camera being less than 90° and greater than the respective optical angles of the first camera and the second camera.

[0007] In a further embodiment of any of the above embodiments, the first camera is mounted to the cab of the commercial vehicle on the first side, the second camera is mounted to the cab on the second side of the commercial vehicle, and the third camera is mounted to a trailer of the commercial vehicle.

[0008] In a further embodiment of any of the above embodiments, the first camera, the second camera, and the third camera have respective focal lengths, and the focal length of the third camera is shorter than the respective focal lengths of the first camera and the second camera.

[0009] In a further embodiment of any of the above embodiments, the method includes, before performing the perspective transformation, performing at least one of distortion correction on the first image from the first camera to mitigate image distortion caused by a lens or sensor of the first camera, distortion correction on the second image from the second camera to mitigate image distortion caused by a lens or sensor of the second camera, and distortion correction on the third image from the third camera to mitigate image distortion caused by a lens or sensor of the third camera.

[0010] In a further embodiment of any of the above embodiments, the method includes cropping at least one of the first image, the second image, and the third image before stitching.

[0011] In a further embodiment of any of the above embodiments, the step of stitching the images of the updated image set together to form a combined image includes performing a first mapping of a first plurality of points of the third image in the updated image set to the first image in the updated image set, performing a second mapping of a second plurality of points of the third image in the updated image set to the second image in the updated image set, aligning the first image, the second image, and the third image in the updated image set based on the first mapping and the second mapping, and blending the first image in the updated image set, the second image in the updated image set, and the third image in the updated image set to obtain the combined image.

[0012] In a further embodiment of any of the above embodiments, the method includes displaying the first image on a first electronic display within the commercial vehicle; displaying the second image on a second electronic display within the commercial vehicle; and displaying the combined image on a third electronic display within the commercial vehicle positioned between the first electronic display and the second electronic display.

[0013] A camera monitor system (CMS) according to an exemplary embodiment of the present disclosure includes a first camera, a second camera, and a third camera mounted at different locations on a commercial vehicle. The camera monitor system also includes a processing circuit operably connected to the memory, the processing circuit being configured to: acquire a first image from the first camera depicting a first area extending along a first side of the commercial vehicle; acquire a second image from a second camera depicting a second area extending along a second side of the commercial vehicle opposite the first side; acquire a third image from a third camera depicting a rear area behind the commercial vehicle; perform a perspective transformation on the first image, the second image, and the third image to obtain an updated image set, whereby each of the first image, the second image, and the third image is updated in the updated image set; and stitch together images of the updated image set to form a combined image in which the third image is disposed between the first image and the second image and in which the first area, the second area, and the rear area are respectively depicted.

[0014] In a further embodiment of the above embodiment, the field of view of the third camera overlaps the field of view of the first camera and the field of view of the second camera.

[0015] In a further embodiment of any of the above embodiments, the third image includes a left portion extending along a left edge of the third image and a right portion extending along a right edge of the third image, wherein the left portion of the third image is stitched to a central portion of the first image and the right portion of the third image is stitched to a central portion of the second image in the combined image.

[0016] In a further embodiment of any of the above embodiments, the first camera, the second camera, and the third camera have respective optical axes that intersect the ground plane at respective optical angles, the optical angle of the third camera being less than 90° and greater than the respective optical angles of the first camera and the second camera.

[0017] In a further embodiment of any of the above embodiments, the first camera and the second camera are mounted in a cab of the commercial vehicle, and the third camera is mounted in a trailer of the commercial vehicle.

[0018] In a further embodiment of any of the above embodiments, the first camera, the second camera, and the third camera have respective focal lengths, and the focal length of the third camera is shorter than the respective focal lengths of the first camera and the second camera.

[0019] In a further embodiment of any of the above embodiments, the processing circuitry is configured to, before performing the perspective transformation, perform at least one of distortion correction on the first image from the first camera to mitigate image distortion caused by a lens or sensor of the first camera, distortion correction on the second image from the second camera to mitigate image distortion caused by a lens or sensor of the second camera, and distortion correction on the third image from the third camera to mitigate image distortion caused by a lens or sensor of the third camera.

[0020] In a further embodiment of any of the above embodiments, the processing circuitry is configured to crop at least one of the first image, the second image, and the third image before stitching.

[0021] In a further embodiment of any of the above embodiments, to stitch images of the updated image set, the processing circuitry is configured to: perform a first mapping of a first plurality of points of the third image in the updated image set to the first image in the updated image set; perform a second mapping of a second plurality of points of the third image in the updated image set to the second image in the updated image set; align the first image, the second image, and the third image in the updated image set based on the first mapping and the second mapping; and blend the first image, the second image, and the third image in the updated image set to obtain the combined image.

[0022] In a further embodiment of any of the above embodiments, the processing circuitry is configured to display the first image on a first electronic display within the commercial vehicle, display the second image on a second electronic display within the commercial vehicle, and display the combined image on a third electronic display within the commercial vehicle positioned between the first electronic display and the second electronic display.

[0023] The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or their respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, except where such features are incompatible. [Brief explanation of the drawings]

[0024] The present disclosure may be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. [Figure 1] 1 is a schematic front view of a commercial vehicle equipped with a camera monitor system (CMS) used to provide at least Class II and Class IV views. [Figure 2] 2 is a schematic bird's-eye view of the commercial vehicle of FIG. 1 with a CMS providing Class II, Class IV, Class V, Class VI, and Class VIII views. [Figure 3] 1 is a schematic top view of an exemplary vehicle cab interior; [Figure 4] FIG. 4 is a perspective view of the inside of the vehicle cab of FIG. 3. [Figure 5] 2 is a schematic diagram of the commercial vehicle of FIG. 1 and two relevant optical angles of the CMS camera. [Figure 6A] An example of an image from the first CMS camera. [Figure 6B] An example of an image from a second CMS camera. [Figure 6C] An example image from the third CMS camera. [Figure 7A] 6B is an example of the image of FIG. 6A after perspective transformation. [Figure 7B] 6C is an example of the image of FIG. 6B after perspective transformation. [Figure 7C] 6D is an example of the image of FIG. 6C after perspective transformation. [Figure 8] This is a merge of the images of Figures 7A-7C. [Figure 9] 1 is a flowchart of an exemplary method for a CMS. DETAILED DESCRIPTION OF THE INVENTION

[0025] 1-4 show schematic diagrams of a commercial vehicle 10. The commercial vehicle 10 includes a vehicle cab or "tractor" 12 for towing a trailer 14, which pivots relative to the tractor 12 during turns. In this disclosure, the commercial vehicle 10 is shown as a commercial truck having a single trailer, although it is understood that other commercial vehicle configurations (e.g., different types or quantities of trailers) may be used.

[0026] A pair of camera arms 16A-16B includes respective bases fixed to, for example, the tractor 12. A pivoting arm is supported by the base and may be articulated relative thereto. At least one rear-facing camera 20A-20B is disposed on or within each of the camera arms 16A-16B. The cameras 20A-20B are "rear-facing" in that they face toward the rear of the commercial vehicle 10. Each of the exterior cameras 20A-20B has an exterior field of view (FOV) that includes at least one of a Class II view and a Class IV view (FIG. 2), each of which represents a view legally mandated in the commercial trucking industry. EX1 , FOV EX2 The cameras 20A-20B are part of a camera monitor system (CMS) 15 (see FIG. 3).

[0027] 2, camera 20A extends along a first side 27A of commercial vehicle 10 and provides a view of a first region 28A that is included in the Class II and Class IV views of camera 20A, and camera 20B extends along a second side 27B of commercial vehicle 10 and provides a view of a second region 28B that is included in the Class II and Class IV views of camera 20B.

[0028] A Class II view of a given side of the commercial vehicle 10 is a subset of a Class IV view of the same side of the commercial vehicle 10. If desired, multiple cameras can be used in each camera arm 16A-16B to provide these views. For example, Class II (narrow angle) and Class IV (wide angle) views are defined in the European R46 legislation, and the United States and other countries may have similar driving visibility requirements for commercial trucks. References to "class" views are not intended to be limiting, but rather as an example of the types of views provided to the display from particular cameras.

[0029] Each camera arm 16A-16B may also provide a housing that encloses electronics, e.g., a controller, configured to provide various features of CMS 15. Camera arms 16A-16B may be attached, for example, to a roof mount location above the cab door (as shown) or to a door mount bracket or station.

[0030] If Class V and / or Class VI views are also desired, a camera housing 16C and camera 20C may be positioned at or near the front of the commercial vehicle 10 to provide these views (FIG. 2).

[0031] The backup camera 20D provides a field of view (FOV) of the rear area behind the commercial vehicle 10. EX3 This provides the field of view FOV EX1 , FOV EX2 Backup camera 20D may be mounted, for example, at the top / centerline of the trailer, at the trailer bumper / bed level, or at a top corner of the rear of the trailer. Thus, in the example of FIGS. 1-2 , camera 20A is mounted to the cab 12 of commercial vehicle 10 on a first side, camera 20B is mounted to the cab 12 of commercial vehicle 10 on a second side, and camera 20D is mounted to the rear of trailer 14 of the commercial vehicle.

[0032] Alternatively, or in addition to the rear trailer camera, a camera mounted on the rear of the tractor 12 and providing a field of view FOV even when the trailer 14 is uncoupled from the cab 12. EX1 , FOV EX2 Overlapping FOV EX4 A "fifth wheel camera" may be provided that provides a fifth wheel camera 20E. The fifth wheel camera 20E may be mounted anywhere between the lateral plane of the fifth wheel fixture and the top / roof edge of the tractor, for example.

[0033] FIG. 3 is a schematic top view of an exemplary vehicle cab 24, and FIG. 4 is a perspective view of the vehicle cab 24. Referring now to FIGS. 3-4, electronic displays 18A-18E (which may be, for example, video displays such as LCD displays) and cameras 20A-20E are shown. The various electronic displays 18A-18E and cameras 20A-20E are part of the CMS 15 and thus function as CMS displays and CMS cameras. As used herein, a "CMS camera" 20 is a camera configured to record images of the environment surrounding the commercial vehicle 10, and a "CMS display" 18 is an electronic display (e.g., an LCD) configured to capture the feed from these cameras.

[0034] CMS 15 includes a CMS electronic control unit (ECU) 22 that includes processing circuitry that functions as a controller and supports the operation of CMS 15. CMS ECU 22 is operatively connected to memory (which may include any one or combination of volatile memory elements (e.g., random access memory (RAM) such as DRAM, SRAM, SDRAM, VRAM, etc.)) and / or non-volatile memory elements (e.g., ROM, hard drive, tape, CD-ROM, etc.). The processing circuitry may include one or more microprocessors, microcontrollers, application specific integrated circuits (ASICs), etc.

[0035] CMS displays 18A-18B are positioned on the driver's side and passenger's side, respectively, within the vehicle cab 12 on or near the A-pillars 19A-19B and display Class II and Class IV views on each side of the commercial vehicle 10, which provide rearward-facing side views along the commercial vehicle 10 captured by exterior cameras 20A-20B.

[0036] As mentioned above, if Class V and Class VI views are also required, camera housing 16C and camera 20C may be located at or near the front of commercial vehicle 10 to provide these views ( FIG. 2 ). In the example of FIG. 3 , additional displays 18C-18E are provided. Display 18C, located in vehicle cab 24 near the top center of the windshield, may be used to display Class V and Class VI views toward the front of commercial vehicle 10 or a backup camera view (from camera 20D or 20E) to the driver. Display 18D is located in the center console area of ​​vehicle cab 24 and may be used as a backup display or for other purposes such as navigation, infotainment, etc. Display 18E may be part of the instrument cluster, for example, and may be used as a backup display.

[0037] If desired, camera arms 16A-16B may also include conventional mirrors integrated therewith, although CMS 15 may be used to replace the mirrors entirely. In additional examples, multiple camera arms may be included on each side, with each arm housing one or more cameras and / or mirrors.

[0038] As described in more detail below, CMS ECU 22 is configured to perform image stitching to combine the views of CMS camera 20A ("first camera"), CMS camera 20B ("second camera"), and CMS camera 20D or 20E ("third camera"). While the use of camera 20E is an option for a third camera, the embodiments described below focus on camera 20D.

[0039] In the example described below, cameras 20A, 20B, and 20D each have a focal length, and the focal length of camera 20D is shorter than the focal lengths of each of CMS cameras 20A-20B, thereby giving camera 20D a wider field of view than cameras 20A, 20B. In one or more embodiments, CMS cameras 20A-20B have the same focal length.

[0040] 5 is a schematic diagram of a commercial vehicle 10 and two associated optical angles 52A, 52B, each less than 90°. As shown, CMS camera 20A has a first optical axis 50A, and CMS camera 20D has a second optical axis 50B. Optical angle 52A is formed between optical axis 50A of camera 20A and ground plane G at their intersection. Optical angle 52B is formed between optical axis 50B of CMS camera 20D and ground plane G at their intersection. As shown in FIG. 5, optical angle 52A is less than optical angle 52B.

[0041] As described in more detail below, CMS ECU 22 performs image stitching of images from cameras 20A, 20B, and 20D (or 20E) to generate a combined image that allows vehicle occupants to have a panoramic view of areas 28A-28C and effectively see through to trailer 14.

[0042] FIG. 6A is an exemplary first image 60A from camera 20A showing region 28A extending along side 27A of commercial vehicle 10 before correction or perspective transformation.

[0043] FIG. 6B is an exemplary second image 62A from camera 20B showing area 28B extending along side 27B opposite side 27A of commercial vehicle 10, showing the area behind the commercial vehicle.

[0044] Figure 6C is an exemplary third image 64A from camera 20D showing region 28C before correction or perspective transformation. While camera 20D is shown in Figure 5 as being at the top rear of trailer 14, the image in Figure 6C was taken with camera 20D at a lower position at the rear of trailer 14 (e.g., at or near the bottom of the rear of trailer 14).

[0045] Figure 7A is an example of the first image 60A of Figure 6A after a perspective transformation as image 60B. As shown, the perspective transformation stretches the left side of image 60A and shortens the right side of image 60A.

[0046] Figure 7B is an example of the second image 62A of Figure 6B after a perspective transformation as image 62B. As shown, the perspective transformation stretches the right side of image 60A and shortens the left side of image 60A.

[0047] FIG. 7C is an example of the third image of FIG. 6C after perspective transformation as image 64B.

[0048] FIG. 8 shows an example of a combined image 68 that is a stitched combination of the images of FIGS. 7A-7C, in which a third image 64A is positioned between the first image 60A and the second image 62A, and the first region 28A, the second region 28B, and the rear region 28C are depicted to provide a panoramic view of regions 28A-28C, respectively.

[0049] 6C and 7C, the third image 64 includes a left portion 66A along the left side of the third image 64 and a right portion 66B along the right side of the third image 64. After perspective transformation, these are fitted to the lower left edge 70A and the lower right edge 70B of the image 64B, respectively. In the example of FIG. 8, image stitching is performed such that in the combined image 68, the left portion 66A of the third image 64A is stitched to the central region 65A of the first image 60A, and the right portion 66B of the third image 64A is stitched to the central region 65B of the second image 62A. As used herein, "central region" means image data that is at least 25% away from each edge of the original images 60A, 62A. Using image 60A as an example, if image 60A has a width W1 and a length L1, the "central region" is at least 0.25 away from the left and right sides of image 60A and at least 0.25 away from the top and bottom sides of image 60A. Using image 62A as an example, if image 62A has a width W2 and a length L2, the "central region" is at least 0.25 away from the left and right sides of image 62A and at least 0.25 away from the top and bottom sides of image 62A.

[0050] In one or more embodiments, before performing the perspective transformation of step 108, at least one of distortion correction is performed on the first image 60A from the first camera 20A to mitigate image distortion caused by the lens or sensor of the first camera 20A, distortion correction on the second image 62A from the second camera 20B to mitigate image distortion caused by the lens or sensor of the second camera 20B, and distortion correction on the third image 64A from the third camera 20D to mitigate image distortion caused by the lens or sensor of the third camera 20D. In one or more embodiments, each of these distortion corrections is performed. However, it is understood that these are non-limiting examples and that distortion correction of one or more of the images 60A, 62A, 64A can be omitted.

[0051] In one or more embodiments, prior to image stitching in step 110, at least one of the first image 60A, the second image 62A, and the third image 64A is cropped.

[0052] 9 is a flowchart of an example method 100 for CMS. A first image 60A is acquired from a first camera depicting a first region 28A extending along a first side 27A of the commercial vehicle 10 (step 102).

[0053] A second image 62A is acquired from a second camera depicting a second region 28B extending along a second side 27B opposite the first side 27A of the commercial vehicle 10 (step 104).

[0054] A third image 64A is acquired from a third camera depicting a rear area 28C behind the commercial vehicle 10 (step 106), where the third camera's field of view FOV EX3 is the field of view of the first camera FOV EX1 and the field of view FOV of the second camera EX2 It overlaps with.

[0055] A perspective transformation is performed on the first image 60A, the second image 62A, and the third image 64A to obtain an updated image set (step 108), whereby each of the first image 60A, the second image 62A, and the third image 64A is updated within the updated image set.

[0056] The updated images 60A, 62A, and 64A of the updated image set are stitched together to form a combined image 68 in which the third image 64A is positioned between the first image 60A and the second image 62A, and in which the first region 28A, the second region 28B, and the rear region 28C are depicted, respectively (step 110).

[0057] In one or more embodiments, the stitching of step 110 includes mapping a first plurality of points of the third image 64 in the updated image set to the first image 60 in the updated image set (e.g., along the bottom left edge 70A of the updated third image 64B) and mapping a second plurality of points of the third image in the updated image set to the second image in the updated image set (e.g., along the bottom right edge 70B of the updated third image 64B). The stitching includes aligning and blending the first image 60, the second image 62, and the third image 64 in the updated image set to obtain a combined image based on the first mapping and the second mapping.

[0058] As described above, the first camera 20A, the second camera 20B, and the third camera 20D have respective optical axes that intersect the ground plane G at respective optical angles, and in one or more embodiments, the optical angle of the third camera 20D is less than 90° and greater than the respective optical angles of the first camera 20A and the second camera 20B.

[0059] Combined image 68 is displayed on an electronic display within commercial vehicle 10, such as display 18C, 18D, or 18E (each between displays 18A and 18B). At the same time, the image from camera 20A may continue to be displayed on display 18A, and the image from camera 20B may continue to be displayed on display 18B.

[0060] While exemplary embodiments have been disclosed, those of ordinary skill in this art would recognize that certain modifications would come within the scope of the following claims, and for that reason the following claims should be studied to determine their true scope and content.

Claims

1. 1. A method for a camera monitor system (CMS), comprising: acquiring a first image from a first camera depicting a first area extending along a first side of the commercial vehicle; acquiring a second image from a second camera depicting a second area extending along a second side of the commercial vehicle opposite the first side; acquiring a third image from a third camera depicting a rear area behind the commercial vehicle; performing a perspective transformation on the first image, the second image, and the third image to obtain an updated image set, whereby each of the first image, the second image, and the third image is updated within the updated image set; stitching the images of the updated image set together to form a combined image in which the third image is disposed between the first image and the second image and in which the first region, the second region, and the posterior region are depicted, respectively; A method comprising:

2. The method of claim 1 , wherein the field of view of the third camera overlaps the field of view of the first camera and the field of view of the second camera.

3. the third image includes a left portion extending along a left edge of the third image and a right portion extending along a right edge of the third image; 2. The method of claim 1, wherein the stitching is performed such that, in the combined image, the left portion of the third image is stitched to the center portion of the first image and the right portion of the third image is stitched to the center portion of the second image.

4. the first camera, the second camera, and the third camera have respective optical axes that intersect a ground plane at respective optical angles; The method of claim 1 , wherein the optical angle of the third camera is less than 90° and greater than the optical angles of each of the first camera and the second camera.

5. the first camera is mounted in a cab at the first side of the commercial vehicle; the second camera is mounted in the cab at the second side of the commercial vehicle; The method of claim 4 , wherein the third camera is mounted on a trailer of the commercial vehicle.

6. the first camera, the second camera, and the third camera have respective focal lengths; The method of claim 1 , wherein the focal length of the third camera is shorter than the focal length of each of the first camera and the second camera.

7. before the step of performing the perspective transformation, distortion correction for the first image from the first camera to mitigate image distortion caused by the lens or sensor of the first camera; distortion correction for the second image from the second camera to mitigate image distortion caused by the lens or sensor of the second camera; and distortion correction for the third image from the third camera to mitigate image distortion caused by the lens or sensor of the third camera. The method of claim 1 , comprising performing at least one of the following steps:

8. Before stitching, The method of claim 1 , comprising cropping at least one of the first image, the second image, and the third image.

9. Stitching the images of the updated image set together to form a combined image comprises: performing a first mapping of a first plurality of points of the third image in the updated set of images to the first image in the updated set of images; performing a second mapping of a second plurality of points of the third image in the updated set of images to the second image in the updated set of images; and Based on the first mapping and the second mapping, registering the first image, the second image, and the third image in the updated image set; and blending the first image in the updated image set, the second image in the updated image set, and the third image in the updated image set to obtain the combined image. The method of claim 1 , comprising:

10. displaying the first image on a first electronic display within the commercial vehicle; displaying the second image on a second electronic display within the commercial vehicle; displaying the combined image on a third electronic display within the commercial vehicle positioned between the first electronic display and the second electronic display; The method of claim 1 , comprising:

11. a first camera, a second camera, and a third camera mounted at different positions on the commercial vehicle; processing circuitry operatively connected to the memory; The processing circuitry comprises: acquiring a first image from the first camera depicting a first area extending along a first side of the commercial vehicle; acquiring a second image from the second camera depicting a second area extending along a second side of the commercial vehicle opposite the first side; acquiring a third image from the third camera depicting a rear area behind the commercial vehicle; performing a perspective transformation on the first image, the second image, and the third image to obtain an updated image set, whereby each of the first image, the second image, and the third image is updated within the updated image set; and stitching the images of the updated image set together to form a combined image in which the third image is disposed between the first image and the second image and in which the first region, the second region, and the posterior region are respectively depicted. A camera monitor system (CMS) configured to:

12. 12. The camera monitor system of claim 11, wherein the field of view of the third camera overlaps the field of view of the first camera and the field of view of the second camera.

13. the third image includes a left portion extending along a left edge of the third image and a right portion extending along a right edge of the third image; 12. The camera monitor system of claim 11, wherein in the combined image, the left portion of the third image is stitched to the center portion of the first image and the right portion of the third image is stitched to the center portion of the second image.

14. the first camera, the second camera, and the third camera have respective optical axes that intersect a ground plane at respective optical angles; 12. The camera monitor system of claim 11, wherein the optical angle of the third camera is less than 90 degrees and greater than the optical angles of each of the first and second cameras.

15. the first camera and the second camera are mounted in a cab of the commercial vehicle; 15. The camera monitor system of claim 14, wherein the third camera is mounted on a trailer of the commercial vehicle.

16. the first camera, the second camera, and the third camera have respective focal lengths; 12. The camera monitor system of claim 11, wherein the focal length of the third camera is shorter than the focal length of each of the first camera and the second camera.

17. The processing circuitry, before performing the perspective transformation, distortion correction for the first image from the first camera to mitigate image distortion caused by the lens or sensor of the first camera; distortion correction for the second image from the second camera to mitigate image distortion caused by the lens or sensor of the second camera; and distortion correction for the third image from the third camera to mitigate image distortion caused by the lens or sensor of the third camera.

12. The camera monitor system of claim 11, configured to perform at least one of the following:

18. The processing circuitry, before performing stitching, The camera monitor system of claim 11 configured to crop at least one of the first image, the second image, and the third image.

19. To stitch images of the updated image set, the processing circuitry: performing a first mapping of a first plurality of points of the third image in the updated set of images to the first image in the updated set of images; performing a second mapping of a second plurality of points of the third image in the updated set of images to the second image in the updated set of images; and Based on the first mapping and the second mapping, registering the first image, the second image, and the third image in the updated image set; and blending the first image, the second image, and the third image in the updated image set to obtain the combined image.

12. The camera monitor system of claim 11 configured to:

20. The processing circuitry displaying the first image on a first electronic display within the commercial vehicle; displaying the second image on a second electronic display within the commercial vehicle; and displaying the combined image on a third electronic display within the commercial vehicle positioned between the first electronic display and the second electronic display.

12. The camera monitor system of claim 11 configured to:

Images