Focus adjustment method

A focus adjustment method, adapted for a projection system, wherein the projection system comprises a projection target and a projection device having a range-finding array element and a processor, the range-finding array element is electrically connected to the processor, the range-finding array element comprises a plurality of range-finding elements and the range-finding elements respectively define a plurality of measurement mesh points on the projection target, and the focus adjustment method comprises:

• defining a plurality of ranging regions from the measurement mesh points, wherein each of the ranging regions comprises more than one measurement mesh point;
• enabling all the corresponding range-finding elements in the ranging regions to perform a ranging measurement on the projection target to generate a plurality of original ranging values;
• performing an averaging calculation on the original ranging values corresponding to each of the ranging regions to generate a plurality of average region ranging values;
• and
• determining whether the average region ranging values are within a preset range to generate an optimal ranging value, and adjusting a lens focus of the projection device according to the optimal ranging value,
• wherein enabling all the corresponding range-finding elements in the ranging regions to perform the ranging measurement on the projection target to generate the original ranging values comprises:
• selecting a part of the ranging regions among the ranging regions as a region to be measured;
• enabling a plurality of transmitters corresponding to all the range-finding elements in the region to be measured to transmit a plurality of ranging signals to the projection target, wherein the transmitters transmit the ranging signals to the measurement mesh points corresponding to the range-finding elements on the projection target;
• measuring a plurality of reflected ranging signals reflected by the projection target through a plurality of receivers corresponding to all the range-finding elements in the region to be measured;
• and
• inputting the reflected ranging signals into a lookup table to output the original ranging values corresponding to the reflected ranging signals,
• wherein there are respective preset angles between the connecting line of all the range-finding elements and a centerline of the range-finding array element, wherein the centerline is a connecting line between a central range-finding element of the range-finding array element and the corresponding measurement mesh point on the projection target.

A focus adjustment method, adapted for a projection system, wherein the projection system comprises a projection target and a projection device having a range-finding array element and a processor, the range-finding array element is electrically connected to the processor, the range-finding array element comprises a plurality of range-finding elements and the range-finding elements respectively define a plurality of measurement mesh points on the projection target, and the focus adjustment method comprises:

• defining a plurality of ranging regions from the measurement mesh points, wherein each of the ranging regions comprises more than one measurement mesh point;
• enabling all the corresponding range-finding elements in the ranging regions to perform a ranging measurement on the projection target to generate a plurality of original ranging values;
• performing an averaging calculation on the original ranging values corresponding to each of the ranging regions to generate a plurality of average region ranging values;
• and
• determining whether the average region ranging values are within a preset range to generate an optimal ranging value, and adjusting a lens focus of the projection device according to the optimal ranging value,
• wherein determining whether the average region ranging values are within the preset range to generate the optimal ranging value comprises:
• determining whether the average region ranging values are all within the preset range, wherein
• when the average region ranging values are all within the preset range, the average region ranging value of a central ranging region is taken as the optimal ranging value, wherein the central ranging region is at a center of the ranging regions, and
• when the average region ranging values are not all within the preset range, whether one or two average region ranging values among the average region ranging values are out of the preset range is determined,
• wherein the focus adjustment method further comprising:
• when the one or two average region ranging values among the average region ranging values are out of the preset range, the ranging measurement and the averaging calculation are repeated on the ranging regions, and whether at least three average region ranging values among the ranging regions are within the preset range is determined,
• wherein the focus adjustment method further comprising:
• when at least three average region ranging values of the ranging regions are all within the preset range, an average of the at least three average region ranging values of the ranging regions is taken as the optimal ranging value, and
• when the at least three average region ranging values of the ranging regions are not all within the preset range, the ranging measurement and the averaging calculation are repeated on a plurality of supplementary ranging regions that are not the ranging regions, and whether at least three average region ranging values of the central ranging region and the supplementary ranging regions are all within the preset range is determined.

A focus adjustment method, adapted for a projection system, wherein the projection system comprises a projection target and a projection device having a range-finding array element and a processor, the range-finding array element is electrically connected to the processor, the range-finding array element comprises a plurality of range-finding elements and the range-finding elements respectively define a plurality of measurement mesh points on the projection target, and the focus adjustment method comprises:

• defining a plurality of ranging regions from the measurement mesh points, wherein each of the ranging regions comprises more than one measurement mesh point;
• enabling all the corresponding range-finding elements in the ranging regions to perform a ranging measurement on the projection target to generate a plurality of original ranging values;
• performing an averaging calculation on the original ranging values corresponding to each of the ranging regions to generate a plurality of average region ranging values;
• and
• determining whether the average region ranging values are within a preset range to generate an optimal ranging value, and adjusting a lens focus of the projection device according to the optimal ranging value,
• wherein enabling all the corresponding range-finding elements in the ranging regions to perform the ranging measurement on the projection target to generate the original ranging values comprises:
• selecting a part of the ranging regions among the ranging regions as a region to be measured;
• enabling a plurality of transmitters corresponding to all the range-finding elements in the region to be measured to transmit a plurality of ranging signals to the projection target, wherein the transmitters transmit the ranging signals to the measurement mesh points corresponding to the range-finding elements on the projection target;
• measuring a plurality of reflected ranging signals reflected by the projection target through a plurality of receivers corresponding to all the range-finding elements in the region to be measured;
• and
• inputting the reflected ranging signals into a lookup table to output the original ranging values corresponding to the reflected ranging signals,
• wherein performing the averaging calculation on the original ranging values corresponding to each of the ranging regions to generate the average region ranging values comprises:
• taking a connecting line between a central range-finding element among the range-finding elements corresponding to each of the regions to be measured and a corresponding central measurement mesh point on the projection target as a region centerline;
• determining that the region to be measured is a planar surface when a difference between a average region ranging value corresponding to each of the regions to be measured and the region centerline is less than a preset standard.