A three-dimensional (3D) measuring system that includes an external projector and an imager device. The imager device having a projector, a first camera and a second camera. The system further having one or more processors operably coupled to the display, the projector, the first camera and the second camera. The processors are responsive to executable computer instructions when executed on the one or more processors for projecting one or more random patterns on an object, recording one or more stereo images of the object, estimating a position and orientation of an imager device and registering scan data generated from the estimated position and orientation of the imager device into a coordinate system.

An image forming apparatus includes an image forming unit, a registration roller pair, an upstream roller pair, a detection unit, a driving device, a control unit. During execution of the accuracy priority mode, when a time from start of a rotation of the registration roller pair to detection of a leading edge of a sheet by the detection unit is a first time, a time from the detection of the leading edge to reach of a conveyance speed to the second speed is a second time, and, when a time from the start of the rotation to the detection of the leading edge is a third time, the time from the detection of the leading edge to the reach of the conveyance speed to the second speed is a fourth time, the third time is longer than the first time and the fourth time is shorter than the second time.