Image quality issues have plagued the launch of the already delayed Sigma DP1, leading the firm to change the digital compact camera?s ?entire image-processing pipeline?.

?We tried to optimise the image quality, but we found it was difficult to achieve image quality as good as in our other SD [DSLR] cameras,? admits Sigma?s chief operating officer Kazuto Yamaki.

?The images looked okay, but they clearly did not have the special image qualities that we see in our SD cameras: delicate, refined and three-dimensional images rendered in fine detail.’

The news comes nine months after Sigma revealed a redesigned prototype of the camera which added a hotshoe and had been due for UK release in May (pictured).

Sigma Japan has confirmed it is still carrying out tests on the DP1, a model first showcased in autumn 2006 when Sigma hailed it as the world?s first digital compact to feature a near APS-C-size imaging sensor.

The firm is yet to announce final specifications or confirm a launch date for the camera, which it bills as a ?high-end? model.

Sigma?s UK office today confirmed that the DP1 will still carry a 14-million-pixel Foveon X3 sensor.

In a statement on the Sigma Japan website, Yamaki adds: ‘After a careful evaluation, we found that the image processing pipeline we had developed? was not ideal for achieving the best image quality, as it was intended for the faster image processing speed, and we needed to make major revisions to it.?

Yamaki explained that the company decided to change the camera?s entire image processing pipeline ?after long and sometimes intense discussions?.

Commenting on the Japanese statement, a UK spokesman told AP: ?Photographers who wish to use a camera of this type will want to achieve the optimum in quality. For this reason, our parent company in Japan has decided to release the DP1 to market only when it fully matches the highest expectations of the exacting photographer.?

Interest in the DP1 has been ?dramatic? despite continued delays to its launch, claims the firm?s UK office.

Sigma unveiled the DP1 at last year?s Photokina photography trade show in Cologne, Germany.