MANKATO, Minn. -- A Minnesota football coach sidelined by accusations of child pornography involving his own children reacted with relief Friday after a judge dismissed the case, saying he was "thankful to be waking up from this nightmare."

Todd Hoffner, the head coach at Minnesota State-Mankato, was effectively cleared when a judge agreed with his assertion that innocent family videos had been misinterpreted. He had been escorted off a football practice field and arrested in August after a university employee came across cellphone videos of his children dancing and playing naked.

"My wife and I have anticipated this day for a very long time," Hoffner said in a news conference at his attorneys' offices. "It has finally taken a person with courage and authority to realize what these videos were."

Hoffner said he wanted to return to work as soon as possible. The university said he will remain on administrative leave until its own investigation is complete. Hoffner has been on leave since the videos were discovered on his university-issued cellphone in August and turned over to police.

Hoffner testified earlier that his three young children asked him to videotape a skit they had concocted after taking a bubble bath. His wife, Melodee, has defended him, as have supporters who held candlelight vigils on his behalf.

A search of his home computer found no evidence of child porn, and social workers found no evidence that the couple's children had been abused.

In her ruling released Friday, Blue Earth County District Judge Krista Jass said she didn't find any evidence that the videos amounted to pornography.

"The videos under consideration here contain nude images of Defendant's minor children dancing and acting playful after a bath. That is all they contain," Jass wrote in her 24-page ruling dismissing the charges.

Hoffner's attorney, Jim Fleming, singled out assistant county prosecutor Mike Hanson for bringing charges in the first place, saying, "Hanson essentially argued that this was child pornography because he knows it when he sees it."

Hanson said in a statement that his office didn't agree with the dismissal but accepted it.

"Our office was trying to enforce a statute enacted to protect children," he said. "No matter what the prosecutor does in a controversial case with a high-profile suspect, they will be criticized. We do not go looking for cases like this, they are brought to us."

University spokesman Dan Benson said he had no timetable for when the school's investigation would be completed.

Hoffner, 46, of Eagle Lake, had been charged with one count of using minors in a sexual performance or pornographic work and one count of possessing child pornography. Both are felonies.

He has been sidelined for what has turned into an outstanding season for the Mavericks. They are 12-0 and host Missouri Western on Saturday in the national Division II quarterfinals.

The circumstances of the case, close on the heels of the Penn State scandal involving sexually abused children and authority figures who didn't intervene, invited questions about whether the university had overreacted to the videos.

Fleming, the coach's attorney, said Friday that it was for "others to decide" whether the Penn State case played a part in how Hoffner's case was handled.

"In light of all that's happened, it would be hard for me to say it wasn't at least a factor," Fleming said.

At an earlier hearing on his motion for dismissal, Hoffner testified that he had told his children to go take a bubble bath last June so he could get some work done. Hoffner said the children later came down in towels and asked him to videotape them. He said he never directed the kids, and never watched the video afterward or showed it to anyone.

The videos came to light after Hoffner took his problematic cellphone to work to be checked out.

The coach was escorted off the football practice field on Aug. 17 by university officials after the school turned the videos over to police, and he was arrested four days later.

Hanson, the assistant prosecutor, had argued earlier that the decision on whether or not the videos were pornography should be left to a jury, and disputed the claim that the images were innocent family fun.

Hoffner was entering his fifth year as head football coach at the school, where he had a 34-13 record. He led the Mavericks to the playoffs in 2008 and 2009, and a share of the Northern Sun Intercollegiate Conference title in 2011. He was named NSIC coach of the year in 2009.

Word of the case's dismissal was just starting to spread Friday night on campus at the university, which with its roughly 15,000 students is among the state's largest. Sam Moyer, a senior from the Rochester area, said the charges were not a frequent topic of discussion among students.

"I know quite a few people who thought this was just him making family memories -- not a sexual act," Moyer said. "It's such a big conclusion to jump to, that he was some sexual predator. That ruins someone's life."