Image pickup apparatus, image pickup method, and recording medium

#The aspect of the embodiments relates to an image pickup apparatus that picks up a plurality of images with different in-focus positions.

#In a case where an image of a plurality of subjects that are positioned at significantly different distances from an image pickup apparatus such as a digital camera is to be picked up or a case where an image of a subject that is long in a depth direction is to be picked up, only some of the subjects may be in focus due to an insufficient depth of field. Alternatively, in a case where it is to acquire an image with a very high perceived resolution, the image should be picked up with a shallow depth of field, and thus the entire subject may not be in the depth of field. As a solution to this situation, Japanese Patent Application Laid-Open No. H10-290389 discusses a so-called depth composition technology in which a plurality of images with different in-focus positions is picked up, only in-focus areas are extracted from each of the images to combine the images into one image, and thereby a composite image in which all imaging areas are in focus is generated.

#However, in the depth composition technology discussed in Japanese Patent Application Laid-Open No. H10-290389, since the depth of field is expanded in the composite processing, it is not possible to verify before picking up images whether the depth of field is expanded. It is therefore hard to obtain an expected composite image unless a user predicts a result of depth composition when the user picks up the images and sets the number of images to be picked-up and a variation of in-focus positions to appropriate values. Once an unexpected composite image is generated, there is no choice but to pick up images again from the beginning and the image that has been already combined becomes useless.

#FIG. 1 is a block diagram illustrating a hardware configuration of a digital camera according to an exemplary embodiment of the disclosure.

#FIG. 2 is a flowchart for describing generation of a composite image according to the exemplary embodiment of the disclosure.

#FIG. 3 is a diagram for describing an example of presentation of additional image pick-up according to the exemplary embodiment of the disclosure.

#An exemplary embodiment of the disclosure will be described in detail with reference to the accompanying drawings.

#FIG. 1 is a block diagram illustrating a hardware configuration of a digital camera according to the present exemplary embodiment. The digital camera 100 can pick up still images, record information about in-focus positions, and calculate contrast values and combine images as well. The digital camera 100 can enlarge or reduce picked-up and stored images, or images input from the outside.

#A control unit 101 is a signal processor, such as a central processing unit (CPU) or a micro-processing unit (MPU), and controls each part of the digital camera 100 while reading out in advance a program stored in a read-only memory (ROM) 105, which will be described below. For example, as will be described below, the control unit 101 issues instructions on a start and an end of image pick-up to an image pick-up unit 104, which will be described below. Alternatively, the control unit 101 issues an instruction on image processing to an image processing unit 107, which will be described below, on the basis of a program stored in the ROM 105. An instruction from a user is input to the digital camera 100 by an operation unit 110, which will be described below, and reaches each part of the digital camera 100 via the control unit 101.