An elbow fitting for use in a pneumatic product conveying system expands from the inlet pipe along the outer side of the elbow fitting and contracts along the outer side of the fitting toward the outlet pipe for guiding product particles into the outlet pipe. To achieve reliable opening, a forced opening mechanism is provide which is actuated by the movement of the ratchet or of the drive which moves the ratchet, and the ratchet or the drive causes the forced opening mechanism to positively engages the latch or an element which is dynamically connected to the latch so as to forcibly move the latch toward the release position. In one of the embodiments, the anchor and the pile sections are rotated separately by independent motors, thus expediting the installation of the pile in the pre-determined location. Each filtered image is analyzed to determine the object type of objects in the filtered image according to the key, and then data extracted from the analysis of the filtered images is combined into a vector graphic diagram. Although the non-light emitting display periods are continuous over nearly one frame period in the odd number lines of pixels when there is a gray scale change, non-light emission and light emission are repeated alternately at the same time for the even number lines of pixels.