Downtown Atlanta, which convention planners have pegged as dirty in surveys, is in the middle of a $10 million-plus makeover.

Central Atlanta Progress is installing decorative gates around tree boxes, replacing uneven sidewalks, restoring public art and repairing the fountain at Margaret Mitchell Square.

To improve traffic flow, the group has upgraded pedestrian signage and added or updated street signals and re-striped car lanes to make driving easier.

Money for the work comes from the downtown booster group, as well as the city, state and Atlanta Downtown Improvement District.

"Ideally most of the projects will do a couple of things," Jennifer Ball, vice president of planning and economic development for CAP. "It will increase public safety by also addressing the perception that downtown is dirty."

A top priority has been to install the decorative planters along Peachtree Street to discourage pedestrians from crossing between intersections and improve safety, Ball said. Police barriers had been used to force pedestrians to cross at lights, but the result was ugly.

Downtown's image is important to metro Atlanta's $11 billion convention and tourism business. As cities across the United States add new buildings to the glut of meetings facilities nationwide  -- despite a shrinking customers base -- it becomes more important that Atlanta reduce liabilities, experts say.

In addition to cleanliness, downtown has an overabundance of parking lots and derelict or empty buildings, with storefronts or facades papered over by dozens of signs advertising upcoming concerts.

"Perceptions really do matter if people think there is an issue," said Tim Calkins, a branding expert at Northwestern University's Kellogg School of Management. "Brands are shaped by all sorts of little cues, things like signage, cleanliness and how people feel and react to the environment."

Calkins said conventioneers won't name appearance as a reason a city loses its business -- they are more likely to say it's simply because their membership wants to go somewhere else. So if lack of cleanliness shows up in surveys, it's clear that's a problem.

Some businesses have taken a lead in improving the area's look. Cousins Properties renovated a building next to its 191 Peachtree Tower and leased it to men's retailer JoS. A. Bank. The conversion of the old Macy's building into 200 Peachtree, a multi-purpose office site, brought cleaner, more polished facades with the addition of Sweet Georgia's Juke Joint and Meehan's Public House.

In February, Atlanta-based Hooters of America almost doubled the size of its location at the corner of Peachtree and International Boulevard with a makeover that included new indoor and outdoor finishes. The company also added a patio to create an energy that Terry Marks, the restaurateur's president and chief executive officer, doesn't think was there before.

"There tends to be a momentum effect" when companies begin investing in their properties, he said. "Investment begets investment."

Calkins sounded a note of caution. Other attributes such as the ease of traveling to  Atlanta, the cost of doing business here and the health of the Georgia World Congress Center play a much bigger role in snagging tourism and convention traffic than a downtown facelift, he said.

Still, cities with perception issues like Atlanta need to show they are making improvements.

"That's one of the reasons that this is an opportunity," he said. "Cities are always either deteriorating or improving. They rarely stand still."