Of the students with high salaries, how many took the computer vision course?
high salaries refers to salary = 'High';
SELECT COUNT(T1.student_id) FROM RA AS T1 INNER JOIN registration AS T2 ON T2.student_id = T1.student_id INNER JOIN course AS T3 ON T2.course_id = T3.course_id WHERE T1.salary = 'high' AND T3.name = 'Computer Vision'