# US 2015/0146033 A1 · Distance measurement apparatus and distance measurement method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0146033 A1 - Document ID: US20150146033A1 - Status: Published application - Kind: A1 - Application number: 14/407,569 - Filed: 2014-02-26 - Published: 2015-05-28 - Earliest claimed: 2013-04-15 - Assignees: Panasonic Intellectual Property Management Co., Ltd. - Applicants: Panasonic Intellectual Property Management Co., Ltd. - Inventors: Shunsuke Yasugi; Kozo Ezawa; Takashi Kawamura - Web page: https://patentgrep.com/patent/US20150146033A1 ## CPC - H04N 23/959: by adjusting depth of field during image capture, e.g. maximising or setting range based on scene characteristics - G01C 3/32: by focusing the object, e.g. on a ground glass screen - G02B 7/28: Systems for automatic generation of focusing signals - G02B 7/36: using image sharpness techniques {, e.g. image processing techniques for generating autofocus signals (image data processing per se G06T; in cameras having a solid state image sensor H04N23/67)} - G06T 7/571: from focus - G03B 13/36: Autofocus systems - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) ## Abstract A distance measurement apparatus includes: an imaging element that images an object by performing exposure and readout of electric charges sequentially for each row or column; an optical system that has a controllable in-focus position; an imaging control unit that moves the in-focus position at constant speed, and causes the imaging element to image the object sequentially while the in-focus position is being moved, to obtain blurred images; a distance measurement unit that measures a distance from a reference position in the optical system to the object using the blurred images and a point spread function dependent on object distance; and a correction unit that performs a correction process on the distance for each row or column according to a movement range of the in-focus position in which the in-focus position is moved during the exposure for each row or column when the blurred images are obtained. ## Claims ### Claim 1 A distance measurement apparatus comprising: an imaging element that includes photoelectric conversion elements arranged in rows and columns, and images an object by performing exposure and readout of electric charges sequentially for each of the rows or each of the columns; an optical system that is for forming an image of the object on the imaging element and has an in-focus position that is controllable; control circuitry; and a storage device, the control circuitry being operative to: (i) control the optical system to cause the in-focus position to move at constant speed and (ii) cause the imaging element to image the object sequentially while the in-focus position is being moved at the constant speed, to obtain a plurality of blurred images; measure a distance from a reference position in the optical system to the object using the plurality of blurred images and a point spread function dependent on object distance; and perform, before or after the measurement of the distance, a correction process on the distance for each of the rows or each of the columns according to a movement range of the in-focus position in which the in-focus position is moved during the exposure for the each of the rows or the each of the columns when the plurality of blurred images are obtained. ### Claim 2 (depends on 1) The distance measurement apparatus according to claim 1, wherein the control circuitry is operative to: obtain, as the plurality of blurred images, at least (n+1) blurred images where n is an integer greater than or equal to 1; when a point in time for starting exposure of the imaging element to obtain a first image which is one of the at least (n+1) blurred images that is obtained first is denoted by TS(1), a point in time for ending the exposure of the imaging element to obtain the first image is denoted by TE(1), a point in time for starting exposure of the imaging element to obtain a second image which is one of the at least (n+1) blurred images that is obtained last is denoted by TS(1+n), and a point in time for ending the exposure of the imaging element to obtain the second image is denoted by TE(1+n), (i) cause the in-focus position to be at a first position at TS(1); (ii) cause the in-focus position to be at a second position at TE(1+n), the second position being different from the first position; (iii) cause the in-focus position to move at the constant speed in a period from TS(1) to TE(1) and in a period from TS(1+n) to TE(1+n); measure the distance from the reference position to the object for each pixel in at least one of the first image or the second image using the point spread function, the first image, and the second image; and perform the correction process according to a movement range of the in-focus position in which the in-focus position is moved during the exposure for the each of the rows or the each of the columns when the first image and the second image are obtained. ### Claim 3 (depends on 2) The distance measurement apparatus according to claim 2, wherein the control circuitry is operative to cause the in-focus position to move, in the period from TS(1+n) to TE(1+n), at a speed equal to a speed at which the in-focus position moves in the period from TS(1) to TE(1). ### Claim 4 (depends on 3) The distance measurement apparatus according to claim 3, wherein the control circuitry is operative to, before the obtainment of the plurality of blurred images, determine whether or not a condition that the point in time for starting the exposure of the imaging element to obtain the second image is earlier than the point in time for ending the exposure of the imaging element to obtain the first image is satisfied, and upon determining that the condition is satisfied perform a process to obtain the plurality of blurred images, (ii) perform a process to measure the distance, and (iii) perform the correction process. ### Claim 5 (depends on 4) The distance measurement apparatus according to claim 4, wherein the control circuitry is operative to obtain, as the plurality of blurred images, at least (n+1) blurred images where n is an integer greater than or equal to 1, and when a point in time for starting exposure of the imaging element to obtain a (1+x)-th image which is one of the plurality of blurred images is denoted by TS(1+x), a point in time for ending the exposure of the imaging element to obtain the (1+x)-th image is denoted by TE(1+x), a point in time for starting exposure of the imaging element to obtain a (1+x+1)-th image which is one of the plurality of blurred images is denoted by TS(1+x+1), and a point in time for ending the exposure of the imaging element to obtain the (1+x+1)-th image is denoted by TE(1+x+1) where (n−1)≧x≧0, the control circuitry is operative to determine a sequence of points in time TE(1+x) and TS(1+x+1), and cause the in-focus position to move at the constant speed from a third position to a fourth position in a period from TS(1+x) to TE(1+x+1) upon determining that TE(1+x)>TS(1+x+1) holds, the fourth position being different from the third position. ### Claim 6 (depends on 5) The distance measurement apparatus according to claim 5, wherein upon determining that TE(1+x)