As Mitt Romney is expected to accept the Republican Party's nomination as the U.S. presidential candidate at the Republican National Convention (RNC), a USA Today/Gallup poll released Thursday showed Romney's favorability among Americans has improved significantly from July.

The Aug. 20-22 survey found that 48 percent of Americans hold a favorable view of Romney and 46 percent an unfavorable view. His image, still slightly lower than the record 50 percent rating in May when he clinched the Republican nomination, is a big improvement from mid-July, when only 39 percent of Americans viewed him favorably, compared to 48 percent who viewed him unfavorably.

Romney's improved image could benefit him as he takes the stage at the RNC Thursday night to accept party nomination and tout his platform to challenge President Barack Obama in the November presidential election.

Still, Romney lags behind Obama by 48 percent to 53 percent in terms of favorability among American voters, the poll showed.

The gap in favorability could be an obstacle to a victory for Romney, former governor of Massachusetts and a successful businessman, the Gallup said in a report.

The latest poll also showed that Obama is still more likable than Romney among Americans, by a margin of 54 percent to 31 percent.

However, Romney, a former successful businessman, is regarded by Americans as being more capable than Obama to handle the economy and deal with federal budget deficit.

Fifty-two percent of Americans say Romney can handle the economy better, compared to 43 percent who believe Obama can do a better job. On dealing with budget deficit, Romney holds a lead over Obama by 54 percent to 39 percent.

Economy is the top issue in this year's tight race to the White House as the economic recovery is fragile and the unemployment rate has been hovering above 8 percent.

More than 40,000 delegates, activists and supporters are attending the RNC, held in Tampa, Florida. Romney and House Representative Paul Ryan were formally nominated Tuesday night as the presidential and vice presidential candidates, and Ryan already made his acceptance speech Wednesday night.

With the likability rating in mind, the Republican Party focuses on personalizing Romney to fill the gap with Obama, by highlighting his wife Ann Romney's speech at the RNC Tuesday night, in which she talked about Romney as a loving husband.