It’s rare when a misconduct complaint filed against a Chicago police officer ends in discipline: Complaints records show officers were punished as a result of just 2 percent of the more than 28,000 misconduct accusations from 2011 to 2015.

One problem blamed for the low discipline rate is the immediate dismissal of more than a quarter of complaints in which an officer can’t be identified, says a transparency and digital rights advocacy group that has designed an online crowdsourcing tool to help determine the identities of involved officers.

Lucy Parsons Lab this week launched OpenOversight, a website the public can use to search for officers’ names, badge numbers and — when available — photographs. The first of its kind in the United States, the project enables users to search for officers by entering information about their rank, estimated age, race and gender.

The goal is to make it easier for witnesses and victims of police misconduct to file reports and to correctly identify the officers involved, said Freddy Martinez, director of Lucy Parsons Labs.

“We hear anecdotally, ‘I don’t know who it was but if I saw their face I would recognize them,” Mr. Martinez said of people who have been unable to file complaints. “That was one of the things we were trying to address.”

The project is being launched two years after the fatal police shooting of Laquan McDonald, a case that drew national attention. A video that showed Officer Jason Van Dyke fire 16 shots at the 17-year-old boy triggered public outcry when it was released last year. Since then, Officer Van Dyke was charged with murder, the city’s police chief was fired and the Justice Department opened a federal civil rights investigation into the police department’s practices.

But even as officials pledged greater transparency while working to reform the police department, journalists and advocates have stepped up their own open records requests in a bid to give the public more information about how the department operates.

The journalist nonprofit group Invisible Institute went to court over access to police complaint records. It succeeded in getting them released last year and created a searchable online database. The information it obtained shows that only a fraction of complaints resulted in discipline and highlighted instances in which officers convicted of crimes had racked up dozens of complaints that investigators deemed unfounded.

Citing recently obtained complaint data ranging back to 1967, the Chicago Tribune reported last week that seven officers had amassed more than 100 complaints apiece, while 62 officers racked up at least 70 complaints.

“Right now, people make complaints and then they never hear back from someone,” said Chaclyn Hunt, a civil rights attorney with Invisible Institute.

She said the crowdsourcing element of the OpenOversight photo database is a good way to address a problem that the Independent Police Review Authority, which handles police complaints, hasn’t devised a policy to handle.

Through anecdotes, Ms. Hunt said, she has heard that when a person doesn’t have the name or badge number of an officer, investigators might call the police department to check records for who was dispatched to a call or was on duty in a specific area. Other times, investigators show photo arrays to the people making complaints.

“But often they are photos that are taken when the officer graduated from the police academy and could be years old,” she said.

“I think it’s solving the problem from the best way they can from a citizen angle,” she said.

Neither a representative for the Chicago Police Department nor the Independent Police Review Authority responded to requests for comment on the OpenOversight project or the complaint process.

There is concern among the Chicago police union that the project may put officers at risk or potentially blow the cover of those operating in specialized undercover units.

“It seems to me a little extreme,” said Dean Angelo, president of the Chicago Fraternal Order of Police. “There are mechanisms in place to have everyone easily identified through the administrative procedures in place.”

Patrol cars are numbered, officers’ uniforms include last names and badge numbers, and police are now wearing body cameras, Mr. Angelo said.

Publishing images in a searchable database could put officers and their families at risk of being targeted in high-profile cases such as shootings, he said.

The OpenOversight project gathered Chicago Police Department rosters and other information on officers from prior public data requests. Mr. Martinez said images that have been uploaded to the system have come from the police department’s social media accounts as well as images taken at demonstrations or protests and posted by Twitter and Flickr users.

To make sure the photos are linked to the right officers, advocates are reviewing the images to see if badge numbers or names are visible on their uniforms and then reviewing historical data on the badge numbers as well as demographic data on the officers, Mr. Martinez said.

Out of the departments’ more than 12,000 officers, the advocate group has obtained and verified photos of about 1 percent of personnel.

Jennifer Helsby, the lead developer of the project, hopes the OpenOversight database can grow with the public’s help.

“We’re hoping the public launch of OpenOversight will mean more images and more volunteers,” Ms. Helsby said. “We are looking for pictures of officers in uniform, in public spaces, and who have their name and/or badge number clearly displayed.”