Image forming apparatus for forming images in multiple resolution modes

An image forming apparatus comprising:

• an image processing unit configured to perform image processing to image data, the image processing including filer processing for converting a plurality of pixel values of the image data based on filter coefficients and thinning processing for thinning a plurality of pixels of the image data, wherein the filter coefficients are used to convert a target pixel based on the pixels adjacent to the target pixel in a predetermined direction;
• an image forming unit configured to form an image based on the image data to which the image processing is performed by the image processing unit;
• a measurement unit configured to measure a measurement image formed by the image forming unit;
• a controller configured to control the image processing unit to perform the thinning processing to measurement image data without performing the filter processing, to control the image forming unit to form the measurement image based on the measurement image data to which the thinning processing is performed by the image processing unit, to control the measurement unit to measure the measurement image, and to control an image forming condition based on a measurement result of the measurement image.