Vehicular vision system with camera calibration using calibration target

A vehicular vision calibration system, the system comprising:

• a camera disposed at a vehicle and having a field of view exterior of the vehicle, the camera capturing image data;
• an electronic control unit (ECU) comprising electronic circuitry and associated software;
• wherein the electronic circuitry of the ECU comprises an image processor for processing image data captured by the camera to detect presence of objects in the field of view of the camera;
• wherein the ECU, responsive to processing by the image processor of image data captured by the camera, captures image data representative of a target within the field of view of the camera, wherein a first portion of the target comprises a first geometric pattern and a second portion of the target comprises a second geometric pattern, and wherein, with the captured image data is representative of both the first portion and the second portion of the target;
• wherein the ECU detects, via processing at the image processor of the captured image data, first and second edges of the first portion of the target and third and fourth edges of the second portion of the target;
• wherein the ECU determines, via processing at the image processor of the captured image data, first edge pixels representative of the first detected edge of the first portion of the target, second edge pixels representative of the second detected edge of the first portion of the target, third edge pixels representative of the third detected edge of the second portion of the target, and fourth edge pixels representative of the fourth detected edge of the second portion of the target;
• wherein the ECU determines a first vanishing point based on the determined first edge pixels of the first portion of the target and the determined second edge pixels of the first portion of the target, and wherein the ECU determines a second vanishing point based on the determined third edge pixels of the second portion of the target and the determined fourth edge pixels of the second portion of the target;
• wherein the ECU determines camera orientation of the camera based on location of the determined first vanishing point relative to location of the determined second vanishing point;
• and
• wherein the ECU calibrates the camera based on the determined camera orientation.

A method for calibrating a vehicular vision system, the method comprising:

• equipping a vehicle with the vehicular vision system, the vehicular vision system comprising at least one vehicular camera disposed at the vehicle;
• placing a target within a field of view of the vehicular camera, wherein a first portion of the target comprises a first geometric pattern and a second portion of the target comprises a second geometric pattern, and wherein, with the target placed within the field of view of the vehicular camera, the first portion and the second portion are within the field of view of the vehicular camera;
• capturing image data with the camera, the captured image data representative of the field of view of the vehicular camera;
• providing the captured image data to an image processor;
• detecting, via processing at the image processor of the captured image data, first and second edges of the first portion of the target and third and fourth edges of the second portion of the target;
• determining, via processing at the image processor of the captured image data, first edge pixels representative of the first detected edge of the first portion of the target, second edge pixels representative of the second detected edge of the first portion of the target, third edge pixels representative of the third detected edge of the second portion of the target, and fourth edge pixels representative of the fourth detected edge of the second portion of the target;
• determining a first vanishing point based on the determined first edge pixels of the first portion of the target and the determined second edge pixels of the first portion of the target, and determining a second vanishing point based on the determined third edge pixels of the second portion of the target and the determined fourth edge pixels of the second portion of the target;
• determining, via processing by the image processor of the captured image data, at least two orthogonal vanishing point candidates based on the determined first vanishing point of the first portion of the target and based on the determined second vanishing point of the second portion of the target;
• determining an orientation matrix based on the determined orthogonal vanishing point candidates;
• determining camera orientation based on location of the determined orientation matrix;
• and
• calibrating the vehicular vision system for the vehicular camera based on the determined camera orientation.