No, this student in complete school uniform is not asking for pardon. The reason for this full bow while on bended knees is to give the highest tribute to his teacher during the Teacher's Day celebration called "Wai Kru" ceremony.
In Thailand, this is how they pay tribute to their teachers on this occasion. While in some other countries including the Philippines, students show their love to their mentors by offering them bouquet of flowers , thank you letters, cakes and chocolates, here in Thailand they do it in a unique way.
"Wai Kru" is held on a Thursday, a day which according to Thai beliefs is a special day for teachers, at the beginning of the academic year. On this day, Thai students also offer flowers to thier teachers - usually dok khem (called santan in the Philippines) and white jasmine garlands.
While the students are doing the "wai", their teachers will also pat their heads and utter wishes and prayers that the students will be succesful in their studies.
If you wish to read more about Wai Kru, click here: Teacher Appreciation Day