An image processing device and method, a program, and a recording medium whereby the detection precision of a motion vector by the gradient method is further improved. A counter value computing unit acquires the number of valid pixels, the number of pixels having no gradient in the horizontal direction, and the number of pixels having no gradient in the vertical direction from a valid pixel number counter, a no-horizontal-gradient counter, and a no-vertical-gradient counter, computes the ratio between valid pixels within a computation block and one-sided gradient pixels among the valid pixels, and controls the value of a flag which a flag setting unit sets in accordance with the computation results. The flag setting unit sets the value of a gradient flag, and outputs the gradient flag to the subsequent stage. At the subsequent stage, gradient method computation and vector evaluation processing are executed based on the gradient flag. The above can be applied to a signal processing device for performing frame frequency conversion processing from a 24P signal to a 60P signal.