Mr Roughead suggested there were already signs the bounce which is expected from 2014, on the back of events such as Homecoming, the Ryder Cup and Commonwealth Games, may lead on to strong bookings for 2015 and beyond.
He said: "All the indicators we have had, anecdotally and empirically from some of our operators overseas and the airlines, have been very positive and forward bookings are very strong.
"Once we start to get the numbers in we will be in a better position to make some forecasts. At this stage we are pretty confident."
Mr Roughead was speaking from VisitScotland's annual two-day expo.
The event has attracted 700 buyers from around the world who will meet with 250 Scottish tourism businesses and organisations at the Scottish Exhibition and Conference Centre in Glasgow.
Mr Roughead said the improving global economic conditions are also helping to bring more visitors into the country.
He said: "In the United States the economy has begun to recover and that is being reflected in the corporate market, which is very encouraging.
"In terms of the so-called emerging markets there is still phenomenal growth coming out of China, with outbound travel there up 28%. Most of that is intra-region at the moment so what that means for us is we have a lot of work to do in developing that market for the future.
"Northern Europe in particular has had a strong recovery, while southern Europe has taken a little bit longer but there are some roots of recovery forming."
Mr Roughead is hopeful Scotland will continue to benefit from the staycation trend, where people choose to holiday in the UK rather than abroad, even if they start to have more disposable income.
He said: "When we hit the depth of the recession a lot of people were used to taking multiple holidays and they started to give those things up.
"We positioned Scotland very much as a short break destination in the UK and we believe that will remain resilient.
"What you may see is if people have more disposable income they may decide to go somewhere else as well."
Around £21 million of business is predicted to be generated by the agency's expo, which is the UK's longest established travel trade fair with a history stretching back 35 years.
Among the new exhibitors this year was the V&A Museum in Dundee, which was trying to give insight into how the attraction will look when it opens in 2017.
As yet there does not appear to be any drop-off in bookings on either side of the independence referendum vote.
Mr Roughead said tourism businesses needed to continue to invest in infrastructure and people to ensure they provide good customer service.
He remains hopeful that 2014 can provide a platform for growth in the coming years and said: "What you can hear from the exhibitors here is that they are very upbeat and buoyant and that is an indicator that through the year we are looking at a positive performance.
"We have a full and great programme for 2014 but we have to build for 2015 to 2025 now."
That view was echoed by VisitScotland's chairman Mike Cantlay, who added: "The conversations, discussions and business generated during the Expo will help ensure Scotland welcomes the world for many years to come."