초록 ▼

In a method and a circuit for determining a contour-defining angle formed by a contour in an image within a relatively small region thereof with a predetermined direction, the steps include selecting the region so that said contour passes as closely as possible through a center thereof, and subdivid

In a method and a circuit for determining a contour-defining angle formed by a contour in an image within a relatively small region thereof with a predetermined direction, the steps include selecting the region so that said contour passes as closely as possible through a center thereof, and subdividing the region into a number of sectors of substantially equal areas distributed substantially symmetrically about its center, and separated from one another by respective separation lines, the number being an even number and at least four, and one of the separation lines coinciding with the predetermined direction, obtaining brightness signals from each of the sectors in dependence of the proportion of the dark-to-light areas extending over each respective sector, generating difference signals from respective oppositely disposed sectors, processing the difference signals so as to identify the sector in which the transition from the light area to the dark area occurs, and determining by further processing the contour-defining angle.

대표청구항 ▼

In a method of determining a contour-defining angle formed by a contour in an image within a relatively small region thereof with a predetermined direction, the contour being defined by the transition from a light area to a dark area within said region, the steps comprising, selecting said region so

In a method of determining a contour-defining angle formed by a contour in an image within a relatively small region thereof with a predetermined direction, the contour being defined by the transition from a light area to a dark area within said region, the steps comprising, selecting said region so that said contour passes as closely as possible through a center thereof, subdividing said region into a number of sectors of substantially equal areas distributed substantially symmetrically about said center, and separated from one another by respective separation lines, aid number being an even number and at least four, one of said separation lines coinciding with said predetermined direction, obtaining brightness signals from each of said sectors in dependence of the proportion of the dark-to-light areas extending over each respective sector, generating difference signals from respective oppositely disposed sectors, one of said difference signals being associated with said transition from said light area to said dark area having a value below a maximum value obtained from each of the remaining difference signals, save the difference signal associated with the transition from said dark area to said light area, thereby identifying the sector in which the transition from said light area to said dark area occurs, and determining a first angle-defining quotient of the difference signal obtained, on one hand, from the so identified sector and the sector adjacent thereto as viewed along a prearranged angular direction, and, on the other hand, from one of said difference signals having said maximum value, whereby the contour-defining angle is obtained as the sum of said first angle and a second angle which is subtended between said predetermined direction and said one separation line, as viewed along said prearranged angular direction.