Two "sensitive, tough and even humorous" images taken by the American artist Pat Martin have won the Taylor Wessing portrait prize.
The £15,000 prize was awarded to Martin at London's National Portrait Gallery on Tuesday evening.
The photographs are of his now dead mother with whom he had a difficult, often painful relationship.
"For most of my life, I misunderstood my mother and witnessed how the world misunderstood her," he said.
Martin's mother struggled with addiction throughout her life, which resulted in the artist finding it hard to build a close mother and child bond with her.
"Photographing her became a way of looking into a mirror and finding details never noticed. There were always new ones to discover, and something new to hide.
"I began this project at the 11th hour, and needing to reconnect, I chose to focus where I was fearful to look.
"When I recognised I was without a document of her existence, the camera became a magnet, pulling in her direction over and over and taking one memory at a time."
The judges all agreed Martin's portraits were "in turn sensitive, tough and even humorous", a statement said.
"The photographer has captured something of the struggle and pride of his mother which they felt speaks to the fragility of human experience and the power of the photographic portrait to express loss and evoke memory," the statement added.
Three further portraits from Martin's series will be included in the gallery's exhibition of competition entries opening on 7 November.
Tuesday's ceremony also saw two runners-up awarded prizes.
Second Prize: Neil by Enda Bowe
The portrait entitled Neil from the series Love's Fire Song by Enda Bowe came in second place, winning the artist £3,000.
Bowe, who also came second in 2018's competition, is an Irish photographer based in London.
His work aims to tell a story while celebrating the beauty of the seemingly mundane.
Bowe's picture Neil is of a young man photographed as part of the photographer's series focusing on the Belfast Conway estate.
"l concentrated on the ordinary, the everyday," said the artist.
"I used a saturated colour palette with only subtle symbolisms, and without reference to the specific locations they were taken.
"Free from political and geographical context, the photographs speak of longing, yearning, aspirations and vulnerabilities of young people in Belfast today."
The judges' statement said they "responded to the simplicity and beauty" of the portrait. They also found the image "conveyed something of the confusion, uncertainty and rebellion of youth".
Third Prize: The Hubbocks by Garrod Kirkwood
The Hubbucks, a photograph from the series England by Garrod Kirkwood, won the third place prize of £2,000.
British artist Kirkwood's picture shows a family setting off on a holiday adventure - a moment full of promise and possibility.
Kirkwood is based on the North East coast of England and is inspired by the area and those who live there.
He described The Hubbucks, which was taken in Whitley Bay, as "a cinematic scene from real life".
"This is a magical moment and portrait of a family and group of individuals that we all can relate to," he added.
The judges said they enjoyed the "vibrancy and sense of spontaneity" in the image.
They added: "The photograph which shows a family - carefree and ready for adventure - was one that revelled in a collectively treasured holiday memory."
All submissions to the Taylor Wessing competition are judged anonymously. The winners were chosen from 3,700 entries from 1,611 photographers across 70 countries.
Fifty-five portraits by 31 artists will be on show at the exhibition opening this week.
Shane Gleghorn from Taylor Wessing said he believed visitors would find the final selection "challenging, evocative and uplifting".
The exhibition will run from Thursday until 16 February 2020 at London's National Portrait Gallery.